JAEA Abstracts

-Research results below have been sorted by order of journals name.

-Sorry, some research results below have no English abstract.

February 2008

36000149
AsS: Bulk inorganic molecular-based chalcogenide glass
Brazhkin, V. V.*; Gavrilyuk, A. G.*; Lyapin, A. G.*; Timofeev, Yu. A.*; Katayama, Yoshinori; Kohara, Shinji*
Applied Physics Letters 91(3), p.031912_1-031912_3(2007) ; (JAEA-J 03477)

A high pressure method to produce bulk chalcogenide glasses of a unique AsS composition has been developed. The structure, optical properties, and stability of the obtained glasses have been studied. Glasses have an intrinsic deep-red color, opticalpseudogap Eg≈1.75 eV, a broad Urbach absorption tail W_U≈120 meV, and high temperature stability up to 130°C. AsS glasses show photoinduced transformations, including photocrystallization. The glass structure is largely based on the quasimolecular As₄S₄ units with partial polymerization providing an example of an inorganic molecular-based glass.

36000150
Dynamic process of dendrite fragmentation in solidification from undercooled Si melt using time-resolved X-ray diffraction
Nagashio, Kosuke*; Nozaki, Kiyoshi*; Kuribayashi, Kazuhiko*; Katayama, Yoshinori
Applied Physics Letters 91(6), p.061916_1-061916_3(2007) ; (JAEA-J 03478)

The spontaneous dendrite fragmentation in solidification from undercooled Si melt was studeid by time-resolved 2D X-ray diffractometry using sinchrotron radiation. For the sample solidified at Δ T=261 K, several diffraction spots appeared at 1 ms after recalescence and the subsequent transition from spots to rings occurred within ˜25 ms, which suggests that the fragmentation occurred after recalescence but just at the initial stage of the plateau period. Although the present experiment supported that the driving force for the fragmentation is a capillarity effect at the plateau period, the time scale for the fragmentation differed from the current quantitative prediction.

36000151
Hydrothermal method grown large-sized zinc oxide single crystal as fast scintillator for future extreme ultraviolet lithography
Tanaka, Momoko; Nishikino, Masaharu; Yamatani, Hiroshi; Nagashima, Keisuke; Kimura, Toyoaki; Furukawa, Yusuke*; Murakami, Hidetoshi*; Saito, Shigeki*; Sarukura, Nobuhiko*; Nishimura, Hiroaki*; Mima, Kunioki*; Kagamitani, Yuji*; Ehrentraut, D.*; Fukuda, Tsuguo*
Applied Physics Letters 91(23), p.231117_1-231117_3(2007) ; (JAEA-J 03479)

The scintillation properties of a hydrothermal method grown zinc oxide (ZnO) crystal are evaluated for extreme ultraviolet (EUV) laser excitation at 13.9 nm wavelength. The exciton emission lifetime at around 380 nm is determined to be 1.1 ns, almost identical to ultraviolet laser excitation cases. This fast response time is sufficiently short for characterizing EUV lithography light sources having a few nanoseconds duration. The availability of large size ZnO crystal up to 3-inch is quite attractive for future lithography and imaging applications.

36000152
Plasma-assisted laser ablation of tungsten; Reduction in ablation power threshold due to bursting of holes/bubbles
Kajita, Shin; Ono, Noriyasu*; Takamura, Shuichi*; Sakaguchi, Wataru*; Nishijima, Dai*
Applied Physics Letters 91(26), p.261501_1-261501_3(2007) ; (JAEA-J 03480)

Nanosecond laser ablation of tungsten (W) that was exposed to helium plasmas was investigated using optical emission spectroscopy. Sub-micrometor holes/bubbles are formed on the surface of W specimen when it was exposed to the helium plasma at sufficient higher temperature (≥ 1500-1600 K). The onset pulse energy to detect W I becomes ˜ 0.2 J/cm^-2 after the W specimen was exposed to high-density helium plasmas, though the emission from a pure virgin W (before helium plasma irradiation) cannot be detected when the pulse energy was lower than 1 J/cm^-2. Laser-induced bursting of the holes/bubbles is suggested to be the physical mechanism leading to the significant reduction in the ablation power threshold.

36000153
Bias temperature instability characterization of advanced gate stacks
Fujieda, Shinji*; Terai, Masayuki*; Saito, Motofumi*; Toda, Akio*; Miura, Yoshinao*; Liu, Z.*; Teraoka, Yuden; Yoshigoe, Akitaka; Wilde, M.*; Fukutani, Katsuyuki*
ECS Transactions 6(3), p.185-202(2007) ; (JAEA-J 03482)

In order to find how bias temperature instability occurs in advanced gate stacks, we will review experimental results of our investigation on SiO₂, plasma-nitrided SiON, HfSiON and HfSiON with Ni-silicide electrodes. It thus seems that we need to clarify and control the chemical and physical influences on the insulator bulk and the insulator/Si interface caused by newly incorporated materials and process technologies, in order to ensure the reliability of bias temperature instability for advanced gate stacks.

36000154
Synthesis of pinguisane-type sesquiterpenoids acutifolone A, pinguisenol, and bisacutifolones by a Diels-Alder dimerization reaction
Shiina, Junichi*; Oikawa, Masataka; Nakamura, Kensuke; Obata, Rika*; Nishiyama, Shigeru*
European Journal of Organic Chemistry 2007(31), p.5190-5197(2007) ; (JAEA-J 03483)

It is important to synthesize bio-active compounds which will affect DNA repair system. The total synthesis of pinguisane-type sesquiterpenoids, acutifolone A and pinguisenol, has been achieved by using the Mukaiyama aldol reaction as the key step. The intermolecular Diels-Alder reaction of these monomeric natural products successfully led to stereoselective dimerization, leading to bisacutifolones A and B. Theoretical calculations revealed that the dimerization reaction proceeded through the most stable transition state.

36000155
Prospective performances in JT-60SA towards the ITER and DEMO relevant plasmas
Tamai, Hiroshi; Fujita, Takaaki; Kikuchi, Mitsuru; Kizu, Kaname; Kurita, Genichi; Masaki, Kei; Matsukawa, Makoto; Miura, Yukitoshi; Sakurai, Shinji; Sukegawa, Atsuhiko; Suzuki, Yutaka; Takase, Yuichi*; Tsuchiya, Katsuhiko; Campbell, D.*; Romanelli, F.*
Fusion Engineering and Design 82(5-14), p.541-547(2007) ; (JAEA-J 03484)

JT-60SA is positioned as the ITER satellite tokamak to conduct research elements to support and supplement ITER towards DEMO under the joint collaboration of Japan and EU. After the discussions in JA-EU Satellite Tokamak Working Group in 2005, the heating power is increased up to 41MW, 100s to ensure the ITER support research. With such increased heating power, the prospective plasma performances are analysed by the equilibrium and transport analysis codes. Operation window of a fully non-inductive current drive is extended to high density region. Simultaneous achievement of high equivalent Q_DT and high normalised beta is also expected in wide operational margin. Those prospects strongly indicate that JT-60SA is suitable machine to conduct the advanced research orienting to ITER and DEMO.

36000156
Burn control simulation experiments in JT-60U
Shimomura, Koji*; Takenaga, Hidenobu; Tsutsui, Hiroaki*; Mimata, Hideyuki*; Iio, Shunji*; Miura, Yukitoshi; Tani, Keiji; Kubo, Hirotaka; Sakamoto, Yoshiteru; Hiratsuka, Hajime; Ichige, Hisashi; Sueoka, Michiharu; Kawamata, Yoichi; Sakamoto, Ryuichi*; Kobayashi, Shinji*; Shimada, Ryuichi*
Fusion Engineering and Design 82(5-14), p.953-960(2007) ; (JAEA-J 03485)

36000157
Improvement of data processing system for advanced diagnostics in JT-60U
Oshima, Takayuki; Kiyono, Kimihiro; Sakata, Shinya; Sato, Minoru; Totsuka, Toshiyuki; Iba, Katsuyuki*; Ozeki, Takahisa; Hirayama, Toshio
Fusion Engineering and Design 82(5-14), p.1210-1215(2007) ; (JAEA-J 03486)

In JT-60U the data processing system, providing the data acquisition, producing the diagnostic data base, and communicating with the JT-60U control system. The MSP-ISP was replaced by a new Inter-Shot Processor based on the UNIX-OS of a workstation (UNIX-ISP) in 2005. The performance of UNIX-ISP is 2 times as high as that of the MSP-ISP in a stand-alone test using the data conversion program of the CXRS data. Thus we can expect the reduction of the processing time by the optimization of the total sequence. For the remote experiment, we have developed a system called RMSVR with which we can set discharge parameters from the remote site, and thereby the consistency of input parameters is checked. The high security of the remote experiment system is established by the certification and the encrypted communication based on ITBL. A verification test between a university and JAEA Naka indicates that the system using the HTTPS protocol is suitable for the remote experiment.

36000158
Evaluation of bending strain dependence of critical current of Nb₃Al conductor for coils with react-and-wind method
Kizu, Kaname; Tsuchiya, Katsuhiko; Shimada, Katsuhiro; Ando, Toshinari*; Hishinuma, Yoshimitsu*; Koizumi, Norikiyo; Matsukawa, Makoto; Miura, Yushi*; Nishimura, Arata*; Okuno, Kiyoshi; Seo, Kazutaka*; Takahata, Kazuya*; Tamai, Hiroshi; Yamada, Shuichi*
Fusion Engineering and Design 82(5-14), p.1493-1499(2007) ; (JAEA-J 03487)

36000159
A Control method of matrix converter for plasma control coil power supply
Shimada, Katsuhiro; Ito, Junichi*; Matsukawa, Makoto; Kurihara, Kenichi
Fusion Engineering and Design 82(5-14), p.1513-1518(2007) ; (JAEA-J 03488)

36000160
Neutronics experiment on a helium cooled pebble bed (HCPB) breeder blanket mock-up
Batistoni, P.*; Angelone, M.*; Bettinali, L.*; Carconi, P.*; Fischer, U.*; Kodeli, I.*; Leichtle, D.*; Ochiai, Kentaro; Perel, R.*; Pillon, M.*; Schäfer, I.*; Seidel, K.*; Verzilov, Y.*; Villari, R.*; Zappa, G.*
Fusion Engineering and Design 82(15-24), p.2095-2104(2007) ; (JAEA-J 03489)

A neutronics experiment has been performed in the frame of European Fusion Technology Program on a mock-up of the EU Test Blanket Module (TBM), Helium Cooled Pebble Bed (HCPB) concept, with the objective to validate the capability of nuclear data to predict nuclear responses, such as the tritium production rate (TPR), with qualified uncertainties. In the experiment, the TPR has been measured using Li₂CO₃ pellets at various depths at two symmetrical positions at each depth, one in the upper and one in the lower breeder cassette. Three independent measurements were performed by ENEA, TUD/VKTA and JAEA. The neutron flux in the beryllium layer was measured as well using activation foils.

36000161
In-pile tritium permeation through F82H steel with and without a ceramic coating of Cr₂O₃-SiO₂ Including CrPO₄
Nakamichi, Masaru; Kulsartov, T. V.*; Hayashi, Kimio; Afanasyev, S. E.*; Shestakov, V. P.*; Chikhray, Y. V.*; Kenzhin, E. A.*; Kolbaenkov, A. N.*
Fusion Engineering and Design 82(15-24), p.2246-2251(2007) ; (JAEA-J 03490)

36000162
Non-stoichiometory and vaporization characteristic of Li_2.1TiO_3.05 in hydrogen atmosphere
Hoshino, Tsuyoshi; Yasumoto, Masaru*; Tsuchiya, Kunihiko; Hayashi, Kimio; Nishimura, Hidetoshi*; Suzuki, Akihiro*; Terai, Takayuki*
Fusion Engineering and Design 82(15-24), p.2269-2273(2007) ; (JAEA-J 03491)

36000163
Pressurizing behavior on ingress of coolant into pebble bed of blanket of fusion DEMO reactor
Tsuru, Daigo; Enoeda, Mikio; Akiba, Masato
Fusion Engineering and Design 82(15-24), p.2274-2281(2007) ; (JAEA-J 03492)

In the safety design and technology of blankets for the Fusion DEMO reactor developed in Japan, coolant ingress in the blanket box structure is one of the most important events. Especially the thermal hydraulics in the pebble bed in the case of the high pressure coolant ingress is very important to evaluate the pressure propagation and coolant flow behavior. This paper presents the preliminary results of the pressure loss characteristics by the coolant ingress in the pebble bed. Experiments have been performed to simulate the helium coolant ingress into breeder and multiplier pebble beds and to evaluate the pressure loss in the pebble beds. The measured pressure losses are compared with the predicted values by Ergun's equation, which is the correlation equation on pressure loss of the flow through porous medium. The experimental results are discussed to identify the effect of constraint of pebble bed on the pressure relief performance of the pebble bed type solid breeder blanket.

36000164
Verification of nuclear data for DT neutron induced charged-particle emission reaction of light nuclei
Kondo, Keitaro; Murata, Isao*; Ochiai, Kentaro; Kubota, Naoyoshi; Miyamaru, Hiroyuki*; Takagi, Satoshi*; Shido, Shoichi*; Konno, Chikara; Nishitani, Takeo
Fusion Engineering and Design 82(15-24), p.2786-2793(2007) ; (JAEA-J 03493)

36000165
Thin slit streaming experiment for ITER by using D-T neutron source
Ochiai, Kentaro; Sato, Satoshi; Wada, Masayuki*; Kubota, Naoyoshi; Kondo, Keitaro; Yamauchi, Michinori; Abe, Yuichi; Nishitani, Takeo; Konno, Chikara
Fusion Engineering and Design 82(15-24), p.2794-2798(2007) ; (JAEA-J 03494)

Neutron streaming experiments have been conducted by using the FNS D-T neutron source at Japan Atomic Energy Agency under the ITER/ITA Task 73-10 in order to evaluate effects of the slit on nuclear properties and validate prediction accuracies on numerical simulations. The experimental assembly with a slit of 2 cm in width and 55 cm in depth was prepared with two iron blocks of 30 cm in height, 100 cm in width and 55cm in thickness as first campaign. The slit was located in the 12-cm upper part from the D-T neutron source point. In order to evaluate distributions of the neutron fluxes along the slit as a function of the depth from the assembly surface, fission reaction rates were measured by U-238 and U-235 micro-fission chambers. The experimental accuracies of these fission reaction rates are within 5%. Monte-Carlo calculation code, MCNP-4c, was used to calculate the U-238 and U-235 reaction rates and neutron energy spectra due to each measured position. From our first experiment, the following facts were found: (1) At d = 20 and 40 cm, reaction rates on U-238, which represent fast neutron flux, decreased by about three orders of magnitude along slits with 50 cm in depth. Monte Carlo calculation results agree well with measured values within 6 %. (2) Reaction rates on U-235, which represent thermal neutron flux, decrease by about one order of magnitude along slits with 50 cm in depth. Values of C/E of U-238 and U-235 reaction rates were 1.10-1.22 and 1.10-1.23 respectively and the calculated values overestimated slightly.

36000166
Safety design of radiation shielding for JT-60SA
Sukegawa, Atsuhiko; Sakurai, Shinji; Masaki, Kei; Kizu, Kaname; Tsuchiya, Katsuhiko; Shibama, Yusuke; Hayashi, Takao; Tamai, Hiroshi; Matsukawa, Makoto
Fusion Engineering and Design 82(15-24), p.2799-2804(2007) ; (JAEA-J 03495)

The JT-60SA is planned to be utilized in the existing JT-60 experimental building. The annual neutron fluence from the JT-60SA plasma would be increased up to about 130 times as high as the present JT-60U plasma. The radiation shielding structure of vacuum vessel and cryostat is designed so that no effective change is required to the site boundary condition of JT-60 for radiation safety. Neutron and photon transport calculations have been performed using ANISN, DOT3.5. Nuclear heating of the coil and neutron flux through the vacuum vessel was considered to determine the basic structure of the vacuum vessel. The thickness of the structural and shielding materials for the vacuum vessel to be optimized for the nuclear heating of the NbTi superconducting coil has been changed. So, the vacuum vessel is designed to be a double-walled structure made of SS316L. The inner space in the double wall is filled with a 140mm thickness of borated water for cooling and neutron shielding.

36000167
Tokamak and spherical tokamak research in Japan
Takase, Yuichi*; Kikuchi, Mitsuru; Maekawa, Takashi*; Matsukawa, Makoto; Nagata, Masayoshi*; Nishio, Satoshi; Ono, Yasushi*; Sato, Konosuke*; Tobita, Kenji
Fusion Science and Technology 51(2T), p.46-51(2007) ; (JAEA-J 03496)

Japanese tokamak and spherical tokamak (ST) research programs are described. Tokamak research will focus on steady state high(β_N = 3.5-5.5) research on JT-60SA (formerly NCT) in support of ITER and DEMO. JT-60SA will also serve as the Satellite Tokamak under the JA-EU Broader Approach framework. ST research has been reorganized as the All-Japan ST Research Program, aiming for creative and innovative research focused on ultra-high and ultra-long pulse regimes. Results of plasma start-up, RF heating, and plasma merging reconnection experiments are summarized. Prospects of contribution of low aspect ratio tokamaks to fusion energy development, are presented.

36000168
Wave excitation in magnetically confined plasmas with an anisotropic velocity distribution
Ichimura, Makoto*; Higaki, Hiroyuki*; Kakimoto, Shingo*; Yamaguchi, Yushi*; Nemoto, Takeki*; Katano, Makoto*; Kozawa, Isao*; Muro, Taishi*; Ishikawa, Masao; Moriyama, Shinichi; Suzuki, Takahiro; Watanabe, Tsuguhiro*; Cho, Teruji*
Fusion Science and Technology 51(2T), p.150-153(2007) ; (JAEA-J 03497)

In magnetically confined plasmas, fluctuations in the ion cyclotron range of frequency (ICRF) will be driven by the presence of non-thermal ion energy distribution. In strong ICRF heating experiments on the GAMMA 10 tandem mirror, plasmas with a strong temperature anisotropy have been formed. Alfven-ion-cyclotron (AIC) modes are spontaneously excited due to strong temperature anisotropy. High-energy ions are trapped in the local mirror and will form the velocity distribution with the strong anisotropy. To study the relation among the AIC modes, ICEs and beam-driven electrostatic instabilities with non-thermal energy distribution is the main purpose of this work. When the NBs are injected, the magnetic fluctuations due to injected beams and FP ions are detected by ICRF antennas used as pickup loops on JT-60U. The wave excitation near ion cyclotron and its higer harmonic frequencies are studied experimentally and theoretically in plasmas with non-thermal ion energy distribution.

36000169
Progress of high-power-gyrotron development for fusion research
Sakamoto, Keishi
Fusion Science and Technology 52(2), p.145-153(2007) ; (JAEA-J 03498)

Recent progress on the worldwide gyrotron development for fusion application is presented. After breakthroughs of gyrotron technologies in 1990s, significant progress has been obtained in 2000s, in particular, at long pulse gyrotron for a wide range of frequency from 84 GHz to 170 GHz. And, activities for advanced gyrotrons, e.g., a high power gyrotron using a coaxial-resonator, a multi-frequency gyrotron, etc are proceeded. For these progresses, improvements of gyrotron components such as a high efficiency mode converter, a wide-band window, etc, have contributed. The gyrotrons have been applied to major fusion devices for heating and MHD controls. At present, the development of the 1 MW class CW gyrotron is in the scope, which is applicable for the self-ignition experiment of fusion plasma and its sustain at ITER (International Thermonuclear Experimental Reactor).

36000170
Spectral effects of activation for liquid blanket relevant materials induced by D-T neutron irradiation
Li, Z.*; Tanaka, Teruya*; Muroga, Takeo*; Sato, Satoshi; Nishitani, Takeo
Fusion Science and Technology 52(4), p.817-820(2007) ; (JAEA-J 03499)

36000171
Effects of tube drawing on structural material for ITER test blanket module
Hirose, Takanori; Tanigawa, Hiroyasu; Enoeda, Mikio; Akiba, Masato
Fusion Science and Technology 52(4), p.839-843(2007) ; (JAEA-J 03500)

This paper presents the effects of tube milling process on microstructural properties of F82H, which is one of the most important issues for fabrication of the module. The 3500 mm long square tubes have been developed by cold rolling method. This tube is long enough to fabricate the first wall without any joint in the cooling path. Its surface roughness (Rz) and outer curvature are less than 1 microns and 1.4 mm, respectively. It is fine enough to reduce the assembly gap for Hot Isostatic Pressing (HIP) joint. Although the process introduced stretched microstructure containing dense precipitates, this anisotropic microstructure was successfully recovered by heat treatments corresponding to HIP process. This shows the milling process verified in this work could be applicable to blanket fabrication process.

36000172
Recombination centers in as-grown and electron-irradiated ZnO substrates
Son, N. T.*; Ivanov, G.*; Kuznetsov, A.*; Svensson, B. G.*; Zhao, Q. X.*; Willander, M.*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; Isoya, Junichi*; Janzén, E.*; Yakimova, R.*
Journal of Applied Physics 102(9), p.093504_1-093504_5(2007) ; (JAEA-J 03502)

Optical detection of magnetic resonance (ODMR) was performed to investigate defects in ZnO irradiated with 3 MeV electrons at room temperature. As a result, the Zn vacancy and some other centers were detected by ODMR. The Zn vacancy and two other centers whish are labeled as LU3 and LU4, were also commonly observed in different types of as-grown ZnO. Therefore, it can be concluded that the both LU3 and LU4 might be related to intrinsic defects, and they act as dominating recombination centers in irradiated and as-grown ZnO.

36000173
Helium isotopes as geochemical indicators of a serpentinized fore-arc mantle wedge
Umeda, Koji; McCrank, G. E.*; Ninomiya, Atsushi
Journal of Geophysical Research 112(B10), p.B10206_1-B10206_10(2007) ; (JAEA-J 03503)

New helium isotope data from hot springs on the eastern Kyushu Island were obtained from a large number of sampling points in order to elucidate the geographical distribution of ³He/⁴He ratios in the fore-arc regions of Southwest Japan. Systematic, regional variations in ³He/⁴He ratios can be identified clearly on between Kyushu Island (0.093-0.79 R_A), Shikoku Island (0.21-2.5 R_A) and the Kii Peninsula (0.39-7.4 R_A). The overall distribution of relative mantle helium reveals a close association with the occurrence of non-volcanic deep low-frequency tremors (LFT), which would be related to the presence of upward aqueous fluids produced by slab dehydration, in Southwest Japan. A flux of ³He carried by aqueous fluids via the mantle wedge is very low in Kyushu Island where the LFT are not found, resulting in a ³He/⁴He ratio lower than the atmospheric ratio.

36000174
Synthesis of endohedral ¹³³Xe-fullerenol by using higher fullerene
Watanabe, Satoshi; Katabuchi, Tatsuya*; Ishioka, Noriko; Matsuhashi, Shimpei
Journal of Nuclear and Radiochemical Sciences 8(2), p.105-107(2007) ; (JAEA-J 03504)

Hydrophilic endohedral ¹³³Xe-fullerenols [¹³³Xe@C₇₆(OH)_x and ¹³³Xe@C₈₄(OH)_x] were synthesized from hydrophobic endohedral ¹³³Xe-fullerenes. The yields were found to depend on the solubility of endohedral ¹³³Xe-fullerenols in o-dichlorobenzene and water phases, reflecting the number of OH groups of the product. The endohedral ¹³³Xe-fullerenols stored in 0.9 % NaCl solution were stable enough for the use in nuclear medicine.

36000175
Surface studies of tungsten erosion and deposition in JT-60U
Ueda, Yoshio*; Fukumoto, Masakatsu*; Nishikawa, Masahiro*; Tanabe, Tetsuo*; Miya, Naoyuki; Arai, Takashi; Masaki, Kei; Ishimoto, Yuki*; Tsuzuki, Kazuhiro*; Asakura, Nobuyuki
Journal of Nuclear Materials 363-365, p.66-71(2007) ; (JAEA-J 03505)

36000176
A New fast velocity-diffusion modelling for impurity transport in integrated edge plasma simulation
Shimizu, Katsuhiro; Takizuka, Tomonori; Kawashima, Hisato
Journal of Nuclear Materials 363-365, p.426-431(2007) ; (JAEA-J 03506)

For compatibility of high confinement core plasma with strong radiative divertor, it is necessary to establish the control method for impurity retention in the divertor region. We have been studying the impurity behavior in divertor plasmas with a simulation code, IMPMC. A conventional Monte-Carlo algorithm for scattering process in velocity space has a disadvantage that the impurity ions must be traced with a time step shorter than the slowing down time. The IMPMC code demands huge computational time in case of detached plasma. We have developed a new diffusion model using the analytical solution of Langevin equations. By the new diffusion model, we got a prospect of the self-consistent modeling of divertor plasmas and impurity transport, i.e. combining the SOLDOR/NEUT2D and the IMPMC Code. The unified code named SONIC clarifies the impurity transport in the MARFE plasma in consideration of kinetic effects. We carried out the simulation analysis for the JT-60U plasma at first with the IMPMC code. It was found that the radiation near the X-point during MARFE is caused dominantly by deeply penetrating carbons, which are dissociated from the methane (CH4) chemically sputtered from the private region.

36000177
Ion beam analysis of H and D retention in the near surface layers of JT-60U plasma facing wall tiles
Sugiyama, Kazuyoshi*; Hayashi, Takao; Krieger, K.*; Mayer, M.*; Masaki, Kei; Miya, Naoyuki; Tanabe, Tetsuo*
Journal of Nuclear Materials 363-365, p.949-954(2007) ; (JAEA-J 03507)

36000178
Comparison of boronized wall in LHD and JT-60U
Ashikawa, Naoko*; Kizu, Kaname; Yagyu, Junichi; Nakahata, Toshihiko*; Nobuta, Yuji; Nishimura, Kiyohiko*; Yoshikawa, Akira*; Ishimoto, Yuki*; Oya, Yasuhisa*; Okuno, Kenji*; Miya, Naoyuki; Hino, Tomoaki*; Masuzaki, Suguru*; Sagara, Akio*; Oyabu, Nobuyoshi*; LHD Experimental Group*
Journal of Nuclear Materials 363-365, p.1352-1357(2007) ; (JAEA-J 03508)

36000179
Search for luminescent materials under 14 MeV neutron irradiation
To, Kentaro*; Shikama, Tatsuo*; Nagata, Shinji*; Tsuchiya, Bun*; Yamauchi, Michinori; Nishitani, Takeo
Journal of Nuclear Materials 367-370(2), p.1128-1132(2007) ; (JAEA-J 03509)

36000180
Neutron elastic recoil detection for hydrogen isotope analysis in fusion materials
Kubota, Naoyoshi; Kondo, Keitaro; Ochiai, Kentaro; Nishitani, Takeo
Journal of Nuclear Materials 367-370(2), p.1596-1600(2007) ; (JAEA-J 03510)

The Neutron Elastic Recoil Detection Analysis (NERDA) using a neutron beam was proposed to extend the analyzing depth of hydrogen isotopes up to several hundreds micrometers. The 14.1 MeV neutrons beam produced by the Fusion Neutronics Source facility in Japan Atomic Energy Agency entered a sample from the normal direction. Emitted particles from the sample were measured using a ΔE-E counter telescope detector. Incident neutron fluence was monitored with a ²³⁸U fission chamber located behind the target chamber. The proof-of-principle experiment was performed using a standard sample of deuterated polyethylene film containing a known concentration of deuterium with the thickness of 100 μm. The depth resolution was evaluated to be 99 μm corresponding to 12% of the maximum probing depth of 801 μm for the sample. For a carbon-based Plasma Facing Component (PFC) sample the depth resolution was expected to be 61 μm, which was enough to reveal hydrogen isotope distributions of co-deposited layers. Also, we applied NERDA to analyses of hydrogen isotope distributions in PFCs of JT-60U.

36000181
Research and development of minor actinide-containing fuel and target in a future integrated closed cycle system
Osaka, Masahiko; Serizawa, Hiroyuki; Kato, Masato; Nakajima, Kunihisa; Tachi, Yoshiaki; Kitamura, Ryoichi; Miwa, Shuhei; Iwai, Takashi; Tanaka, Kenya; Inoue, Masaki; Arai, Yasuo
Journal of Nuclear Science and Technology 44(3), p.309-316(2007) ; (JAEA-J 03511)

36000182
Numerical study on tritium behavior by using isotope exchange reactions in thermochemical water-splitting iodine-sulfur process
Ohashi, Hirofumi; Sakaba, Nariaki; Nishihara, Tetsuo; Inagaki, Yoshiyuki; Kunitomi, Kazuhiko
Journal of Nuclear Science and Technology 44(11), p.1407-1420(2007) ; (JAEA-J 03512)

One of serious problems in the hydrogen production system assisted by the High Temperature Gas-cooled Reactor (HTGR) is a tritium mixture from the primary coolant to the product hydrogen by the permeation through the heat transfer tubes. A numerical analysis model for the tritium behavior in a thermochemical water-splitting Iodine-Sulfur (IS) process was developed by considering the isotope exchange reactions between the tritium and the hydrogen-containing process chemicals, i.e., H₂O, H₂SO₄ and HI. The tritium activity concentration in the IS process coupled with the High Temperature Engineering Test Reactor (HTTR), HTTR-IS system, was preliminarily evaluated. It was confirmed that the tritium activity concentration in the product hydrogen, CaH₂, increases by considering the isotope exchange reactions. And, CaH₂ was estimated as 1.51×10^-3Bq/cm³ (STP) (=16.8 Bq/g-H2). This paper describes the numerical analysis model and the results of parametric calculation.

36000183
Releases of cesium and poorly volatile elements from UO₂ and MOX fuels under severe accident conditions
Kudo, Tamotsu; Kida, Mitsuko; Nakamura, Takehiko; Nagase, Fumihisa; Fuketa, Toyoshi
Journal of Nuclear Science and Technology 44(11), p.1421-1427(2007) ; (JAEA-J 03513)

36000184
Effects of fuel oxidation and dissolution on volatile fission product release under severe accident conditions
Kudo, Tamotsu; Kida, Mitsuko; Nakamura, Takehiko; Nagase, Fumihisa; Fuketa, Toyoshi
Journal of Nuclear Science and Technology 44(11), p.1428-1435(2007) ; (JAEA-J 03514)

Release of volatile fission product from high burnup UO₂ fuel was examined in a steam atmosphere under severe accident conditions as a part of VEGA program. Effects of fuel oxidation and dissolution were totally evaluated, by comparing the results with those from previous inert, hydrogen and steam atmosphere tests. It was shown that oxidation of UO₂ to UO_2+x by steam generally enhances Cs and Kr release. However, the enhancement becomes smaller above the melting temperature of Zircaloy, about 2030 K, likely due to reduction of UO_2+x by molten Zircaloy. Quick dissolution of the fuel by molten Zircaloy and consequent burst release of Cs occur above about 2300 K in a hydrogen atmosphere, while the release rate does not increase so significantly for the examined temperature range (<2800 K) in the steam atmosphere. This corresponds to decrease in fuel dissolution rate by a factor of about 1/1000.

36000185
Environmental tritium in the vicinity of Tokai Reprocessing Plant
Fujita, Hiroki; Kokubun, Yuji; Koarashi, Jun
Journal of Nuclear Science and Technology 44(11), p.1474-1480(2007) ; (JAEA-J 03515)

36000186
Simple estimation of fission yields with selective channel scission model
Ota, Masayuki; Nakamura, Shoji
Journal of Nuclear Science and Technology 44(12), p.1491-1499(2007) ; (JAEA-J 03516)

The mass distributions of fission yields for neutron-induced fissions of ²³²Th, ²³³U, ²³⁵U, ²³⁶U, ²³⁸U, ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, ²⁴²Pu and for spontaneous fissions of ²⁴¹Am, ²⁴³Am and for fissions of ¹⁰⁶Pd and ¹⁹⁷Au were calculated by the selective channel scission (SCS) model with simple assumptions. The channel-dependent fission barriers were deduced by using shapes of fission fragments in the ground states. The present method makes it possible to estimate fission yields for a wide range of fissionable nuclei without adjustable parameters, although there exist discrepancies between the fission yields calculated by SCS model and the data of JENDL-3.3 in the mass regions of A = 80-95 and A = 135-150.

36000187
Thermal-neutron capture cross section and resonance integral of Americium-241
Nakamura, Shoji; Ota, Masayuki; Harada, Hideo; Fujii, Toshiyuki*; Yamana, Hajimu*
Journal of Nuclear Science and Technology 44(12), p.1500-1508(2007) ; (JAEA-J 03517)

The thermal-neutron capture cross-section(σ_0,g) and the resonance integral(I_0,g) leading to the ground state of ²⁴²Am by an activation method. On the basis of Westcott's convention, the σ_0,g was determined as 628± 22 b, and the I_0,g as 3.5± 0.3 kb.

36000188
Effects of fast reactor irradiation conditions on tensile and transient burst properties of ferritic/martensitic steel claddings
Yano, Yasuhide; Yoshitake, Tsunemitsu; Yamashita, Shinichiro; Akasaka, Naoaki; Onose, Shoji; Watanabe, Seiichi*; Takahashi, Heishichiro
Journal of Nuclear Science and Technology 44(12), p.1535-1542(2007) ; (JAEA-J 03518)

The effects of fast neutron irradiation have been investigated on the mechanical properties of 11Cr-0.5Mo-2W, Nb, V ferritic/martensitic (F/M) stainless steel (PNC-FMS) and 10.5Cr-1.5Mo, Nb, V F/M stainless steel (HT9M) claddings, especially tensile and transient burst properties. These two F/M claddings were irradiated in the experimental fast reactor JOYO using the PFB090 fuel test assembly. Post irradiation tensile and temperature-transient-to-burst tests were carried out for defueled cladding specimens. The results of mechanical tests for PNC-FMS cladding showed that there was no significant degradation in tensile and transient burst strengths even after fast neutron irradiation. However, these strengths for HT9M cladding tended to shift to lower values than those of as-received specimens. This different behavior of tensile and transient burst strengths was attributed to martensite structural stability which was related to the stable solid solution elements.

36000189
Molecular dynamics study on defect structure of gadolinia-doped thoria
Osaka, Masahiko; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*
Journal of Nuclear Science and Technology 44(12), p.1543-1549(2007) ; (JAEA-J 03519)

36000190
μSR study of the effects of Ce dilution on the development of the heavy-fermion state in (Ce,La)₂IrIn₈
Oishi, Kazuki; Heffner, R. H.; Ito, Takashi; Higemoto, Wataru; Morris, G. D.*; Hur, N.*; Bauer, E. D.*; Sarrao, J. L.*; Thompson, J. D.*; MacLaughlin, D. E.*; Shu, L.*
Journal of Physics and Chemistry of Solids 68(11), p.2068-2071(2007) ; (JAEA-J 03520)

36000191
Local neutron transmutation doping using isotopically enriched silicon film
Yamada, Yoichi; Yamamoto, Hiroyuki; Oba, Hironori; Sasase, Masato*; Esaka, Fumitaka; Yamaguchi, Kenji; Udono, Haruhiko*; Shamoto, Shinichi; Yokoyama, Atsushi; Hojo, Kiichi
Journal of Physics and Chemistry of Solids 68(11), p.2204-2208(2007) ; (JAEA-J 03521)

³⁰Si in natural Si has been widely used for a doping source, since ³⁰Si can be transmuted into ³¹P by thermal neutron (Neutron Transmutation Doping, NTD). NTD of nanostructure fabricated from ³⁰Si-enriched materials can serve as a controlled local doping method with tunable dopant concentration, which cannot be realized by conventional doping methods such as ion implantation. In the present study, ³⁰Si-enriched thin film has been fabricated in order to demonstrate the local NTD. The ³⁰Si-enriched film with thickness of 100 nm was deposited on the Si(100) substrate by plasma enhanced chemical vapor deposition using ³⁰Si-enriched SiF₄ as the source gases. The film contains 7.1 % of ³⁰Si, which is twice higher than that of natural Si. Possible contaminant, fluorine, is lower than 0.6 at.% determined from X-ray photoelectron spectra. Nanostructure of films and changes of electronic properties by the neutron irradiation will also be discussed.

36000192
Molecular-network-ionic structure transitions in liquid AlCl₃ and ZnCl₂ halogenides under pressure
Brazhkin, V. V.*; Lyapin, A. G.*; Popova, S. V.*; Katayama, Yoshinori; Saito, Hiroyuki; Utsumi, Wataru
Journal of Physics; Condensed Matter 19(24), p.246104_1-246104_10(2007) ; (JAEA-J 03522)

Liquid AlCl₃ and ZnCl₂ halogenides are studied by in-situ high-pressure high-temperature X-ray diffraction measurements. These halogenides have a quasi-molecular network structure in liquid state at normal pressure. They are intermediate between pure covalent and ionic melts. The present study is indicative of a rapid and strong breakdown of an intermediate range order in a tetrahedral network of melts for the initial pressure range and points to rather sharp transitions in liquids with the formation of a short-range order structure similar to ionic melt structures. Such a two-stage structural transformation under pressure is the general feature for a wide class of simple melts, including most of the pseudo-covalent halogenides.

36000193
Rapid determination of ⁸⁹Sr and ⁹⁰Sr in radioactive waste using Sr extraction disk and beta-ray spectrometer
Kameo, Yutaka; Katayama, Atsushi; Fujiwara, Asako; Haraga, Tomoko; Nakashima, Mikio
Journal of Radioanalytical and Nuclear Chemistry 274(1), p.71-78(2007) ; (JAEA-J 03523)

36000194
TEM/STEM observation of ZrC-coating layer for advanced high-temperature gas-cooled reactor fuel
Aihara, Jun; Ueta, Shohei; Yasuda, Atsushi; Ishibashi, Hideharu; Takayama, Tomoo; Sawa, Kazuhiro; Motohashi, Yoshinobu*
Journal of the American Ceramic Society 90(12), p.3968-3972(2007) ; (JAEA-J 03524)

Japan Atomic Energy Agency (JAEA) has started to study and develop ZrC coated fuel particles for advanced high temperature gas cooled reactors. This paper mainly focuses on the microstructures of the ZrC and isotropic dense pyrolytic carbon (PyC) coating layer produced in the early stage of the project. The structure of free carbon region in the ZrC coating layer appears to be such that c-plane was along with the ZrC grain boundary. It appears that the existence of the free carbon phase, especially with such structure, deteriorates the fission product (FP) retention performance in addition to the mechanical strength of ZrC. The PyC coating layer appears to be a medium-range ordered amorphous structure.

36000195
Protonation states of buried histidine residues in human deoxyhemoglobin revealed by neutron crystallography
Chatake, Toshiyuki*; Shibayama, Naoya*; Park, S.-Y.*; Kurihara, Kazuo; Tamada, Taro; Tanaka, Ichiro*; Niimura, Nobuo*; Kuroki, Ryota; Morimoto, Yukio*
Journal of the American Chemical Society 129(48), p.14840-14841(2007) ; (JAEA-J 03525)

A large crystal of human deoxy hemoglobin (Hb) was grown from D₂O solution (pD 6.3). The preliminary neutron diffraction experiment was carried out at the KUR reactor in RRI of Kyoto University, and the diffraction data set to 2.1 Å resolution was collected at JRR-3 reactor in JAEA using the BIX-3. The neutron crystal structure of Hb reveals that both the α- and β-distal histidines (Hisα58 and Hisβ63) adopt fully (doubly) protonated form. This finding sharply contrasts with existing results on R (relaxed) state liganded Hbs where such full protonation can never occur. This results suggest an interesting possibility that the both histidines could contribute to the T (tense) state Bohr effect of Hb. Indeed, the protonation/deprotonation of each distal histidine may have a direct impact on the oxygen affinity of the nearby heme group through sterical hindrance and/or polarity change in the heme pocket without affecting the allosteric equilibrium of Hb.

36000196
Strong-coupling superconductivity of CeIrSi₃ with He non-centrosymmetric crystal structure
Tateiwa, Naoyuki; Haga, Yoshinori; Matsuda, Tatsuma; Ikeda, Shugo; Yamamoto, Etsuji; Okuda, Yusuke*; Miyauchi, Yuichiro*; Settai, Rikio*; Onuki, Yoshichika
Journal of the Physical Society of Japan 76(8), p.083706_1-083706_4(2007) ; (JAEA-J 03526)

We studied the pressure-induced superconductor CeIrSi₃ with the non-centrosymmetric tetragonal structure under high pressure. The electrical resistivity and ac heat capacity were measured in the same run for the same sample. The critical pressure was determined to be P_c = 2.25 GPa, where the antiferromagnetic state disappears. The superconducting region is extended to high pressures of up to about 3.5 GPa, with the maximum transition temperature T_sc = 1.6 K around 2.5-2.7 GPa. At 2.58 GPa, a large heat capacity anomaly was observed at T_sc = 1.59 K. The jump of the heat capacity in the form of ΔC_ac/C_ac(T_sc) is 5.7 ± 0.1. This is the largest observed value among previously reported superconductors, indicating the strong-coupling superconductivity.

36000197
Gelation-induced phase separation of poly(vinyl alcohol) in mixed solvents of dimethyl sulfoxide and water
Takahashi, Nobuaki; Kanaya, Toshiharu; Nishida, Koji*; Kaji, Keisuke*
Macromolecules 40(24), p.8750-8755(2007) ; (JAEA-J 03527)

Time-resolved light scattering measurements have been performed on poly(vinyl alcohol) (PVA) in mixed solvents of dimethyl sulfoxide (DMSO) and water with various mixing ratios after quenching from 100°C to 25°C to examine physical gelation process. A broad scattering peak characteristic to phase separation appeared in the light scattering profiles after a certain incubation time (t_m) and the peak position Q_m moved to higher Q with annealing time. The results contradict the theoretical predictions and experimental observations for usual phase separation systems, suggesting effects of gelation (or network formation) on the phase separation. The growth kinetics significantly depend on the mixing ratio of DMSO and water, showing that the solvent quality is also a factor to affect the phase separation kinetics during the physical gelation process. The unusual phase separation kinetics is discussed in terms of gelation-induced phase separation.

36000198
Structure of nano-size oxides in ODS steels and its stability under electron irradiation
Oka, Keiichiro*; Onuki, Somei*; Yamashita, Shinichiro; Akasaka, Naoaki; Otsuka, Satoshi; Tanigawa, Hiroyasu
Materials Transactions 48(10), p.2563-2566(2007) ; (JAEA-J 03528)

For understanding the microstructural details of nano-size oxide particles, three types of ODS ferritic and austenitic steels were examined by high voltage electron microscopy, EDS and AP-FIM. The oxide included Y, Ti and O and showed a shell-like structure with different composition. The shell-like structure depends on crystal structure of the matrix during fabrication process. To evaluate the irradiation stability of the oxide particles, the electron irradiation was carried out to 47 dpa in the temperature range between room temperature and 923 K. During the irradiation, the oxide particles did not show obvious change in size. The irradiation behavior is discussed comparing with the results recently reported.

36000199
Density limit in discharges with high internal inductance on JT-60U
Yamada, Hiroshi*; Takenaga, Hidenobu; Suzuki, Takahiro; Fujita, Takaaki; Takizuka, Tomonori; Kamada, Yutaka; Asakura, Nobuyuki; Tsuda, Takashi; Takechi, Manabu; Matsunaga, Go; Sakamoto, Ryuichi*; Miura, Yukitoshi
Nuclear Fusion 47(11), p.1418-1424(2007) ; (JAEA-J 03529)

High densities exceeding the Greenwald limit by a factor of 1.7 have been obtained in discharges with high internal inductances of l_i as high as 2.8 in JT-60U L-mode plasmas. The internal inductance, which is an index of the edge magnetic shear, is controlled by ramping down the plasma current. In addition to the extension of the operational regime, confinement performance remains as good as an H89PL factor of 1.5 even above the Greenwald limit. While the earlier work of a high l_i study has indicated that core confinement improvement, the additional improvement of the tolerance against the high density is turned out to be correlated with high edge temperature. The normalized density when the detachment characterized by the decrease in a D_α signal at the divertor occurs is even higher in the case with no disruption than the case with a disruption. These comparisons have indicated that the improvement in thermal and particle transport does exist in the periphery and the edge in the high l_i plasmas, and mitigation of the density limit is observed coincidently. Although the high l_i discharge studied here lies outside of the usual parameter space for a steady-state operation of tokamak, demonstration of a stable discharge with good confinement beyond the Greenwald limit suggest the magnetic shear at the edge is one key parameter to uncover physical element of the operational density limit.

36000200
Volume recombination of C⁴⁺ in detached divertor plasmas of JT-60U
Nakano, Tomohide; Kubo, Hirotaka; Asakura, Nobuyuki; Shimizu, Katsuhiro; Konoshima, Shigeru; Fujimoto, Kayoko; Kawashima, Hisato; Higashijima, Satoru
Nuclear Fusion 47(11), p.1458-1467(2007) ; (JAEA-J 03530)

36000201
Controllability of large bootstrap current fraction plasmas in JT-60U
Sakamoto, Yoshiteru; Takenaga, Hidenobu; Fujita, Takaaki; Ide, Shunsuke; Suzuki, Takahiro; Takechi, Manabu; Kamada, Yutaka; Oyama, Naoyuki; Isayama, Akihiko; Koide, Yoshihiko; JT-60 Team
Nuclear Fusion 47(11), p.1506-1511(2007) ; (JAEA-J 03531)

Controllability of plasmas with a large bootstrap current fraction (f_BS) has been investigated in JT-60U. Dynamic change in current profile, especially q_min, which was induced by change in pressure profile at the internal transport barrier (ITB) through rotation control, was observed, indicating the strong linkage among the profiles. Response of pressure and current profiles to off-axis neutral beam injection is investigated and found that the alignment of peaks of total current profile and beam driven current profile affects to q_min location, and the change in toroidal rotation induces the movement of ITB location. The current profile in strong reversed shear plasma without current hole is largely varied in the core region by electron cyclotron current drive, while the ITB structure is not affected.

36000202
Studies on the behavior of tritium in components and structure materials of tritium confinement and detritiation systems of ITER
Kobayashi, Kazuhiro; Isobe, Kanetsugu; Iwai, Yasunori; Hayashi, Takumi; Shu, Wataru; Nakamura, Hirofumi; Kawamura, Yoshinori; Yamada, Masayuki; Suzuki, Takumi; Miura, Hidenori*; Uzawa, Masayuki*; Nishikawa, Masabumi*; Yamanishi, Toshihiko
Nuclear Fusion 47(12), p.1645-1651(2007) ; (JAEA-J 03532)

The confinement and removal of tritium are the key subjects for safety of ITER. The ITER buildings are confinement barriers of tritium. In a hot cell building, tritium is often released, as vapor and is in contact with the inner walls. Also those of an ITER tritium plant building will be exposed to tritium in an accident. However, the data are scarce, especially on the penetration of tritium into the concrete of the wall materials. The tritium released in the buildings is removed by the Atmosphere Detritiation Systems (ADS), where the tritium is oxidized by catalysts and is removed as water. Special gas of SF₆ is used in ITER, and is expected to be released in an accident such as fire. Although the SF₆ gas has the potential as a catalyst poison, the performance of ADS with the existence of SF₆ has not been confirmed yet. Tritiated water is produced in the regeneration process of ADS, and is subsequently processed by the ITER Water Detritiation System (WDS). One of the key components of WDS is an electrolysis cell. The electrolysis cell is made of organic compounds, and there is no data on the durability of the cell exposed to tritium. To overcome these issues in a global tritium confinement, a series of experimental studies have been carried out as an ITER R&D task: (1) tritium behavior in concrete; (2) effect of SF₆ on performance of ADS; and (3) tritium durability of electrolysis cell of ITER-WDS.

36000203
Radiation-induced grafting of dimethylaminoethylmethacrylate onto PE/PP nonwoven fabric
Kavakli, P. A.*; Kavakli, C.*; Seko, Noriaki; Tamada, Masao; Güven, O.*
Nuclear Instruments and Methods in Physics Research B 265(1), p.204-207(2007) ; (JAEA-J 03533)

A novel nonwoven fabric was prepared by radiation-induced graft polymerization of dimethylaminoethylmethacrylate (DMAEMA) onto polypropylene coated polyethylene nonwoven fabric. The trunk polymer was irradiated by electron beam at a voltage of 2 MeV and a current of 3 mA in a nitrogen atmosphere at dry-ice temperature at different doses. The degree of grafting was determined as a function of the total dose, monomer concentration, temperature, and reaction time. It was found that the degree of grafting of grafted polymer was greatly affected by reaction conditions. Grafting conditions were optimized, and about 150 % degree of grafting samples was used for further experiments. DMAEMA grafted polymer was later protonated by using acid solution to prepare adsorbent for the removal of anions. Adsorption experiments were performed in column mode for removal of hosphate. Approximately 2000 bed volumes of phosphate-free water can be produced from 10 ppb phosphate solution at high space velocity.

36000204
High-energy, high-contrast, multiterawatt laser pulses by optical parametric chirped-pulse amplification
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Yamamoto, Yoichi*; Tanoue, Manabu*; Akutsu, Atsushi; Shimomura, Takuya*; Kondo, Shuji; Kanazawa, Shuhei; Daido, Hiroyuki; Kimura, Toyoaki; Miyanaga, Noriaki*
Optics Letters 32(16), p.2315-2317(2007) ; (JAEA-J 03534)

We describe a compact, reliable, high-power, and high-contrast noncollinear optical parametric chirped-pulse amplifier system. With a broadband Ti:sapphire oscillator and grating-based stretching and compression, the chirped pulses are amplified from 0.1 nJ to 122 mJ in type-I β-barium borate optical parametric chirped pulse amplifiers with a total gain of over 10⁹ at 10 Hz repetition rate. Pulse compression down to 19-fs duration achieved after amplification indicates a peak power of 3.2 TW at an average power of 0.62 W. The pre-pulse contrast is measured to be less than 10^-8 on picosecond timescales.

36000205
Condition for the existence of complex modes in a trapped Bose-Einstein condensate with a highly quantized vortex
Fukuyama, Eriko*; Mine, Makoto*; Okumura, Masahiko; Sunaga, Tomoka*; Yamanaka, Yoshiya*
Physical Review A 76(4), p.043608_1-043608_11(2007) ; (JAEA-J 03535)

We consider a trapped Bose-Einstein condensate (BEC) with a highly quantized vortex. For the BEC with a doubly, triply or quadruply quantized vortex, the numerical calculations have shown that the Bogoliubov-de Gennes equations, which describe the fluctuation of the condensate, have complex eigenvalues. In this paper, we obtain the analytic expression of the condition for the existence of complex modes, using the method developed by Rossignoli and Kowalski for the small coupling constant. To derive it, we make the two-mode approximation. With the derived analytic formula, we can identify the quantum numbers of the complex modes for each winding number of the vortex. Our result is consistent with those obtained by the numerical calculation in the case that the winding number is two, three or four. We prove that the complex modes always exist when the condensate has a highly quantized vortex.

36000206
Single-domain Si(110)-16×2 surface fabricated by electromigration
Yamada, Yoichi; Girard, A.*; Asaoka, Hidehito; Yamamoto, Hiroyuki; Shamoto, Shinichi
Physical Review B 76(15), p.153309_1-153309_4(2007) ; (JAEA-J 03536)

Micrometer-wide, single-domain of Si(110)-16×2 reconstruction has been fabricated by means of controlled electromigration of surface atoms. The electromigration effect in DC heating process is found to line-up the reconstruction rows when the current direction matches to the orientation of the rows. This finding provides not only a well-controlled surface preparation method for Si(110), but also a new template for low-dimensional nanostructures.

36000207
Neutron capture cross sections of ¹⁸⁶Os, ¹⁸⁷Os, and ¹⁸⁹Os for the Re-Os chronology
Segawa, Mariko; Masaki, Tomohiro*; Nagai, Yasuki*; Temma, Yasuyuki*; Shima, Tatsushi*; Mishima, Kenji*; Igashira, Masayuki*; Goriely, S.*; Koning, A.*; Hilaire, S.*
Physical Review C 76(2), p.022802_1-022802_5(2007) ; (JAEA-J 03537)

Discrete as well as continuum γ-ray energy spectra from the neutron capture by ¹⁸⁶Os, ¹⁸⁷Os, and ¹⁸⁹Os have been taken for the first time at 5 ≤ En ≤ 90 keV by an anti-Compton NaI(Tl) spectrometer. The detection of a weak discrete γ-ray, about 0.5% of total γ-ray strength, demonstrates the high sensitivity of the present measurement. The energy spectra enabled us to accurately determine the reaction cross sections with a small systematic uncertainty. Based on the new cross sections, we re-estimate on the basis of a careful reaction cross section calculation the correction factor F_σ for the neutron capture on the 9.75-keV first excited state in ¹⁸⁷Os as a function of stellar temperature, as required to derive the age of the Galaxy within the Re-Os chronology.

36000208
Charge radii in macroscopic-microscopic mass models of axial asymmetry
Iimura, Hideki; Buchinger, F.*
Physical Review C 76(5), p.057302_1-057302_4(2007) ; (JAEA-J 03538)

We show that the charge radii of axially asymmetric nuclei calculated in the frame of finite-range droplet model are in better agreement with measured charge radii when axial asymmetry is taken into account. This improvement is mainly the result of a new set of ground-state quadrupole deformations β₂, generated when masses are calculated including axial asymmetry, and to a much lesser degree due to the inclusion of the axial asymmetry in the calculation of the charge radii itself.

36000209
Nonviscous metallic liquid Se
Brazhkin, V. V.*; Funakoshi, Kenichi*; Kanzaki, Masami*; Katayama, Yoshinori
Physical Review Letters 99(24), p.245901_1-245901_4(2007) ; (JAEA-J 03539)

Viscosity is one of the fundamental physical properties of liquids; for different melts it varies in an extremely wide range. Selenium is among the first elementary substances to have manifested, at compression, a phase transformation in the liquid state accompanied by melt metallization. Direct measurements by means of a real-time radiography show that the viscosity of liquid Se under pressure drops by 500 times to a very low level of 8 mPa s. This is the first case of viscosity measurements being performed both for a relatively viscous semiconducting state and a low-viscous metallic state of the same liquid substance. The viscosity of the Se melt strongly decreases with pressure along the melting curve in a semiconducting state and experiences a further significant drop at melt metallization. A similar phenomenon is expected to be observed in many chalcohenide, halogenide and oxide melts.

36000210
Research and development of imaging bolometers
Peterson, B. J.*; Konoshima, Shigeru; Kostryukov, A. Y.*; Seo, D. C.*; Liu, Y.*; Miroshnikov, I. V.*; Ashikawa, Naoko*; Parchamy, H.*; Kawashima, Hisato; Iwama, Naofumi*; Kaneko, Masashi*; LHD Team*; JT-60U Team
Plasma and Fusion Research (Internet) 2, p.S1018_1-S1018_4(2007) ; (JAEA-J 03541)

An overview of the research and development of imaging bolometers giving a perspective on the applicability of this diagnostic to a fusion reactor is presented. Traditionally the total power lost from a high temperature has been measured using one dimensional arrays of resistive bolometers. The large number of signal wires associated with these resistive bolometers poses hazards not only at the vacuum interface, but also in the loss of electrical contacts that has been observed in the presence of fusion reactor levels of neutron flux. Infrared imaging video bolometers (IRVB), on the other hand, use the infrared radiation from the absorbing metal foil to transfer the signal through the vacuum interface and out from behind a neutron shield. The IRVB can provide hundreds of channels of bolometric signal in an image of the plasma radiation. Recently a prototype IRVB has been deployed on the JT-60U tokamak which demonstrates the ability of this diagnostic to operate in a reactor environment.

36000211
Spatial variation of the foil parameters from in situ calibration of the JT-60U imaging bolometer foil
Araghy, H. P.*; Peterson, B. J.*; Hayashi, Hiromi*; Konoshima, Shigeru; Ashikawa, Naoko*; Seo, D. C.*; JT-60U Team
Plasma and Fusion Research (Internet) 2, p.S1116_1-S1116_4(2007) ; (JAEA-J 03542)

We obtain the local foil properties of the JT-60U imaging bolometer foil (a single graphite-coated gold foil with an effective area of 9 × 7 cm² and a nominal thickness of 2.5 microns) such as the thermal diffusivity and the product of the thermal conductivity and the thickness of the foil by the foil calibration. Calibration of the foil was made in situ using a He-Ne laser (˜27 mW) as a known radiation source to heat the foil. The thermal images of the foil are provided by an IR camera (micro-bolometer type). The parameters are determined by finite element modeling of the foil temperature and comparing the solution to the experimental results. In this work we apply this calibration technique to investigate the spatial variation of the foil parameters. Significant variation in the local temperature rise of the foil due to local heating by the laser beam indicates a spatial variation of the foil parameters. This variation is possibly due to nonuniformity in the carbon coating and/or the thickness of the foil. In a separate work, the spatial calibration data will be used to produce the bolometer intensity data to be utilized in the tomographic analyses.

36000212
Application of tomographic imaging to multi-pixel bolometric measurements
Liu, Y.*; Tamura, Naoki*; Peterson, B. J.*; Iwama, Naofumi*; Konoshima, Shigeru; LHD Experimental Group*; JT-60 Team
Plasma and Fusion Research (Internet) 2, p.S1124_1-S1124_4(2007) ; (JAEA-J 03543)

Two improved tomographic algorithms, including a linear (Tikhonov-Phillips) and a nonlinear (maximum entropy) regularisation method, have been employed for multi-pixel bolometric measurements in order to get as much information as possible while keeping the assumptions to a minimum. The most important features of these improved methods are the capability of reconstructing radiation distributions without any symmetry assumptions, built-in smoothing, and useful reconstructions with relatively few detectors. Furthermore, the effects of finite detector size have been taken into account with a full three dimensional treatment of the detector geometry. The application of tomographic imaging was implemented to a two-array X-ray camera on the Large Helical Device (LHD) and a two-dimensional infrared imaging bolometric pinhole camera on JT-60U. Pertinent examples of the results are presented both to illustrate the analysis techniques and to demonstrate the wealth of physics which can be studied.

36000213
Quantum beam studies on polymer crystallization under flow
Kanaya, Toshiharu; Matsuba, Go*; Ogino, Yoshiko*; Takahashi, Nobuaki; Nishida, Koji*
Polymer Journal 39(11), p.1085-1097(2007) ; (JAEA-J 03544)

One of the longstanding issues in polymer science is crystallization of polymers under flow, especially formation of the so-called shish-kebab. Recent progress in quantum beam technology shed light on the substantial nature in the shish-kebab formation. In this paper we review our recent experiments on polymer crystallization under flow using time-resolved depolarized light scattering, small-angle and wide-angle X-ray scattering and small-angle neutron scattering in a wide spatial scale from 0.1 nm to several tens m. These studies revealed that the shish-kebab formation is governed by a competition between the crystallization rate and the chain relaxation rate.

36000214
"Crystal lattice engineering", an approach to engineer protein crystal contacts by creating intermolecular symmetry; Crystallization and structure determination of a mutant human RNase 1 with a hydrophobic interface of leucines
Yamada, Hidenori*; Tamada, Taro; Kosaka, Megumi*; Miyata, Kohei*; Fujiki, Shinya*; Tano, Masaru*; Moriya, Masayuki*; Yamanishi, Mamoru*; Honjo, Eijiro; Tada, Horiko*; Ino, Takefumi*; Yamaguchi, Hiroshi*; Futami, Junichiro*; Seno, Masaharu*; Nomoto, Takashi*; Hirata, Tomoko*; Yoshimura, Motonobu*; Kuroki, Ryota
Protein Science 16(7), p.1389-1397(2007) ; (JAEA-J 03545)

In an attempt to control protein incorporation in a crystal lattice, a leucine zipper-like hydrophobic interface (comprising four leucine residues) was introduced into a helical region (helix 2) of the human pancreatic ribonuclease 1 (RNase 1) that was predicted to form a suitable crystallization interface. Although crystallization of wild type RNase 1 has not yet been reported, the RNase 1 mutant having four leucines (4L-RNase 1) was successfully crystallized under several different conditions. The crystal structures were subsequently determined by X-ray crystallography by molecular replacement using the structure of bovine RNase A. The overall structure of 4L-RNase 1 is quite similar to that of the bovine RNase A, and the introduced leucine residues formed the designed crystal interface. To further characterize the role of the introduced leucine residues in crystallization of RNase 1, the number of leucines was reduced to three or two (3L- and 2L-RNase 1, respectively). Both mutants crystallized and a similar hydrophobic interface as in 4L-RNase 1 was observed. A related approach to engineer crystal contacts at helix 3 of RNase 1 (N4L-RNase 1) was also evaluated. N4L-RNase 1 also successfully crystallized, and formed the expected hydrophobic packing interface. These results suggest that appropriate introduction of a leucine zipper-like hydrophobic interface can promote intra molecular symmetry for more efficient protein crystallization in crystal lattice engineering efforts.

36000215
Radiation processing of polymer (in Japanese)
Tamada, Masao
Genshiryoku eye 53(1), p.9-12(2007) ; (JAEA-J 03547)

The applications of graft polymerization, crosslinking, and decomposition in the radiation processing of polymer were described. The graft polymerization is propagated by the radical created with high energy radiation to the polymer. The crosslinking reaction is caused by the recombination of the radicals. The graft adsorbent was effective in the cadmium removal from the waste of the marine products processing. Moreover, it is effective also for the recovery of the uranium in seawater and the scandium in the hot spring water. The gel made by the crosslinking reaction was practically used as a wound dressing. It is utilized as bedsore prevention mat and treatment of livestock's excrement. The polylactic acid has thermal resistance by the crosslinking. Decomposed alginate showed the effect of plant growth promoter.

36000216
Visualization of uptake and transportation of cadmium by plant using positron imaging technique (in Japanese)
Matsuhashi, Shimpei
Isotope News (634), p.7-9(2007) ; (JAEA-J 03548)

36000217
Wettability effect on bubble formation at orifice type nozzle
Bucheeri, A.; Kogawa, Hiroyuki; Naoe, Takashi; Futakawa, Masatoshi; Maekawa, Katsuhiro*
Jikken Rikigaku 7(4), p.331-336(2007) ; (JAEA-J 03549)

A mercury target system will be installed in Japan Proton Accelerator Complex (J-PARC). High intense proton beams injected into the target will induce cavitation by pressure waves. Injection of microbubbles with 50 to 200 μm in diameter into mercury may be effective to reduce cavitation damage. Bubble generation in mercury is difficult because of its poor wettability. Therefore, we artificially change wetting condition in water to simulate bubble formation in poor wetting conditions. Experimentally, visualization of bubble growth at an orifice type nozzle of 100 μm in diameter was done by a high-speed CCD camera. Wetting condition on the orifice surface was worsen by coating it with a water-repellent. Computational Fluid Dynamics simulation was carried out under stagnant water to understand the effect of wettability on bubble formation from the orifice nozzle. It was found that the bubble diameter depends on contact angle and it increases as wetting become worse.

36000218
Super-parallel simulation systems for sophisticated radiation therapy (in Japanese)
Saito, Kimiaki; Saito, Hidetoshi*; Kunieda, Etsuo*; Narita, Yuichiro*; Myojoyama, Atsushi*; Fujisaki, Tatsuya*; Kawase, Takatsugu*; Kaneko, Katsutaro*; Ozaki, Masahiro*; Deloar, H. M.*; Hirai, Masaaki*; Oku, Yohei*; Tajima, Toshiki; Yamagiwa, Mitsuru; Koga, J. K.; Esirkepov, T. Z.; Bulanov, S. V.; Miyajima, Satoshi*; Okazaki, Yoshiko*; Date, Hiroyuki*; Sutherland, K.*; Hishikawa, Yoshio*; Murakami, Masao*
Joho Shori 48(10), p.1081-1088(2007) ; (JAEA-J 03550)

36000219
High-dose dosimetry and its application (in Japanese)
Kojima, Takuji; Seito, Hajime
Keisoku Hyojun To Keiryo Kanri 57(3), p.23-28(2007) ; (JAEA-J 03551)

36000220
Innovative Water Reactor for Flexible Fuel Cycle (FLWR) for TRU recycling (in Japanese)
Okubo, Tsutomu; Onuki, Akira
Konsoryu 21(4), p.366-372(2007) ; (JAEA-J 03552)

The innovative Water Reactor for FLexible fuel cycle (FLWR) has been investigated to realize multiple recycling of transuranium elements (TRUs) based on the well-experienced light water reactor (LWR) technologies for sustainable energy supply. Among the related key issues, thermal-hydraulic study for the tight-lattice core to clarify the core coolability is important one. To recycle TRUs accumulated in the spent fuel is also important from a view point of significantly reducing the emvironmental burden given by them. In addition to this, to attain the capability of multiple recycling of Pu gives the sustainability in the energy supply as far as the parent material of U-238 is available. Based on research outcomes of establishing FLWR concept and confirming key performances such as core coolability, FLWR is considered to be one of the useful options in the next generation LWR technologies.

36000221
Separation of americium from plutonium-solvent extraction raffinate and conversion to americium oxide (in Japanese)
Sugikawa, Susumu; Nakazaki, Masato; Kimura, Akihiro; kida, Takashi*; Kihara, Takehiro*; Akabori, Mitsuo; Minato, Kazuo; Suda, Kazuhiro*; Chikazawa, Takahiro*
Nippon Genshiryoku Gakkai Wabun Rombunshi 6(4), p.476-483(2007) ; (JAEA-J 03553)

A one-step simple extraction chromatography method using TODGA (N,N,N,N'-tetraoctyl-diglycolamide) adsorbent column has been developed to separate the americium from plutonium-solvent extraction raffinate. The raffinate contained Am(˜620 mg/l), Np(˜107 mg/l), Ag(˜2000 mg/l), Fe(˜290 mg/l), Cr(˜38 mg/l), Ni(˜52 mg/l) and trace of TBP. Small-scale and scale-up tests for separation of americium and conversion to americium oxide were carried out in NUCEF. Efforts were made to increase yield and purity of americium. The americium was separated with 83-92% yields and 97-98% purities by small-scale tests and 85-95% yields and 98-99% purities by scale-up tests. The yields for conversion of americium nitrate solution to americium oxide were 89-100% by small-scale tests and 85-96 % by scale-up tests. Approximately 1.8 gram americium oxide was recovered from 6 litres of the raffinate and supplied for the research on the high-temperature chemistry of TRU.

36000222
Expeimental investigation of thermal margin in tight-lattice rod bundle; Large-scale thermal-hydraulic experiments under high pressure conditions (in Japanese)
Tamai, Hidesada
Nippon Genshiryoku Gakkai-Shi 49(11-12), p.745-749(2007) ; (JAEA-J 03554)

An Innovative Water Reactor for Flexible Fuel Cycle (FLWR) core has a tight-lattice bundle structure and it is operated under low mass velocity and high void fraction conditions, for aiming at the achievement of a high conversion ratio of plutonium mixed oxide (MOX) fuel. These conditions make core cooling difficult, and the FLWR thermal-hydraulic characteristics under such conditions are not known well. The confirmation of thermal-hydraulic characteristics is, therefore, one of the most important R&D requirements for the FLWR design. We investigated the thermal-hydraulic performance of the FLWR core using a test section with 37-rod bundles under high pressure conditions simulating the FLWR operating conditions. The result obtains that the FLWR has sufficient thermal margins for cooling of the core.

36000223
Histry of fast breeder reactor development in Japan, 1 (in Japanese)
Ito, Kazumoto; Suzuki, Soju
Nippon Genshiryoku Gakkai-Shi 50(1), p.44-49(2008) ; (JAEA-J 03556)

36000224
Theoretical investigation of the displacement burst observed in nanoindentation by collective dislocation loops nucleation model (in Japanese)
Tsuru, Tomohito; Shibutani, Yoji*
Nippon Kikai Gakkai Rombunshu, A 73(732), p.877-882(2007) ; (JAEA-J 03557)

Abrupt growth of displacement observed in the relationship between indent load and indent depth in nanoindentation of crystalline materials, so-called displacement burst, has been recognized as one of the representative examples for the nanoplastic behavior. This behavior corresponds to the early stage of the plastic deformation and has greatly been influenced by the collective dislocation emission. In the present paper, we construct the simplified model of the first displacement burst by using the elastic theory based on both the Hertzian contact theory and the classical theory of dislocations to evaluate displacement burst under nanoindentation. As the result, there is strong correlation between burst width and critical indent depth where dislocation emission occur. Finally, it is shown that more than one hundred high-density dislocations are emitted simultaneously and surface step corresponding to each dislocation causes significant displacement burst.

36000225
New vista of laser acceleration; GeV over cm (in Japanese)
Tajima, Toshiki
Pariti 23(1), p.9-10(2008) ; (JAEA-J 03558)

36000226
Application of clear polymethylmethacrylate dosimeter, Radix RN-15 to several kGy range (in Japanese)
Seito, Hajime; Ichikawa, Tatsuya*; Watanabe, Hiroshi*; Kojima, Takuji
Radioisotopes 56(12), p.777-785(2007) ; (JAEA-J 03561)

Basic characteristics of Radix RN-15; a commercially available undyed polymethylmethacrylate dosimeter, was studied also in the dose range 1˜10 kGy, for its wide application to radiation processing especially for the evaluation to decide sterilization dose and the quality assurance of food irradiation. The measurable dose range of 1˜10 kGy is obtained at the read-out wavelength of 280 nm that is shorter than conventional read-out wavelength of 320 nm. The post-irradiation stability of dose response for 6 kGy is less than 4˜5% for longer than 24 h after irradiation. The dose response slope at 6kGy while held at irradiation temperatures in the range -40˜40 degree, increases with temperature up to 20 degree as the maximum, and decreases at higher temperatures. Radix RN-15 has linear temperature dependence with a coefficient of +0.25%/degree, relative to the dose response at under 20 degree, at irradiation temperature in the range -40˜20 degree.

36000227
Analysis of ¹²⁹I in radioactive wastes by accelerator mass spectrometry (in Japanese)
Katayama, Atsushi; Kameo, Yutaka; Nakashima, Mikio
Radioisotopes 56(12), p.787-793(2007) ; (JAEA-J 03562)

Determination of the concentration of ¹²⁹I in radioactive wastes is important according to waste management and environmental concern. In the present work, accelerator mass spectrometry (AMS) was applied to measurement of ¹²⁹I/¹²⁷I ratio to determine ¹²⁹I concentration in radioactive waste. Solid-phase extraction disks (Anion-SR) for chemical separation of iodine from radioactive waste samples were used to prepare AMS targets. This method made it possible to swiftly separate iodide ions from sample solutions, compared with a conventional liquid-liquid extraction method. Considering contamination of a sample with ¹²⁹I from a work site environment, we derived the suitable amount of the ¹²⁷I carrier to keep the background value of the ¹²⁹I/¹²⁷I ratio as low as possible. The present method was successfully applied to laboratory standards and liquid waste samples arising from nuclear facilities in Japan Atomic Energy Agency.

36000228
Realization of a nuclear fusion experiment from a remote place by the advanced security (in Japanese)
Ozeki, Takahisa
RIST News (44), p.3-8(2007) ; (JAEA-J 03563)

36000229
Research & Development of grid computing technology in center for computational science and e-systems of Japan Atomic Energy Agency (in Japanese)
Suzuki, Yoshio
RIST News (44), p.9-16(2007) ; (JAEA-J 03564)

36000230
Effect of γ-ray irradiation on enzymatic hydrolysis of spent corncob substrates from edible mushroom, enokitake(Flammulina velutipes) cultivation
Shimokawa, Tomoko*; Nakamura, Masaya*; Nagasawa, Naotsugu; Tamada, Masao; Ishihara, Mitsuro*
Shinrin Sogo Kenkyujo Kenkyu Hokoku 6(1), p.27-34(2007) ; (JAEA-J 03565)

The effect of γ-ray irradiation on enzymatic hydrolysis of spent enokitake mushroom substrate containing corncob meal and rice bran as major components was studied. Almost all the lignin component remained in the bottle though 34% of the original substrate was consumed. Polysaccharides consisting of glucose and xylose residues were the major components of the spent substrate. The saccharification rate of the spent substrate doubled with irradiation at a dose of 500 kGy, and the irradiated sample formed finer particles than the untreated sample after the same period of grinding. The holocellulose was apparently depolymerized by irradiation, resulted in the fragility of the substrate. An appreciable amount of xylan-derived sugars were extracted with water from the irradiated sample. The enzymatic saccharification rate of the irradiated spent enokitake substrate increased to over 80% with Cellulosin TP 25 from Trichoderma viride, which possesses endo-β-D-xylanase and β-D-xylosidase activities as well as cellulase activities.

36000231
Observation of high energy radiation in winter thunderstorms (in Japanese)
Torii, Tatsuo; Sugita, Takeshi*; Muraki, Yasushi*
Taiki Denki Gakkai-Shi 1(2), p.73-74(2007) ; (JAEA-J 03566)

The dose rate of the γ-rays increases in association with the activities of the winter thunderstorm. To investigate the time profile of the radiations during the winter thunderstorms, four sets of the radiation detectors were prepared which consist of the long proportional counters. Those results were compared with the results measured at the same time by the environmental radiation monitors set up around a nuclear power facility. Electric field was also measured by using a field mill. As a result, the following two types of the radiation enhancements have been found during the winter thunderstorm activities; the gradual variation of photon intensity with energy of a few MeV, and the burst type of the radiation that is attributed to the injection of high energy photons with the energy over 10MeV.

36000232
Long term hydrogen absorption behavior and hydrogen embrittlement of titanium overpack under anaerobic condition (in Japanese)
Taniguchi, Naoki; Suzuki, Hiroyuki*; Nakanishi, Tomoaki*; Nakayama, Takenori*; Masugata, Tsuyoshi*; Tateishi, Tsuyoshi*
Zairyo To Kankyo 56(12), p.576-584(2007) ; (JAEA-J 03567)

The long term hydrogen absorption behavior and the possibility of hydrogen embrittlement were studied for titanium overpack for high level radioactive waste disposal. The results of galvanostatic cathodic polarization tests showed that as the cathodic current density is lowered, the amount of absorbed hydrogen for a constant cathodic charge was increased as well as hydrogen permeated into inside of titanium. The hydrogen absorption ratio for a cathodic current density equivalent to the corrosion rate under anaerobic condition was estimated to nearly 100 percent, and the amount of absorbed hydrogen for 1000 years was evaluated to be 400 ppm. The mechanical property of titanium containing hydrogen depended on not only hydrogen concentration but also hydrogen distribution type. The more hydrogen distribution is uniform, the degree of embrittlement was larger. It was expected that the rupture of titanium overpack with 6 mm thickness would be initiated if the crack size in titanium is over about 2-3 mm under the stress corresponds to yield strength.

36000233
Numerical analysis of the hydrogen atom density in a negative ion source
Takato, Naoyuki; Hanatani, Junji*; Mizuno, Takatoshi*; Hatayama, Akiyoshi*; Tobari, Hiroyuki; Hanada, Masaya; Inoue, Takashi; Taniguchi, Masaki; Dairaku, Masayuki; Kashiwagi, Mieko; Watanabe, Kazuhiro; Sakamoto, Keishi
AIP Conference Proceedings 925 , p.38-45(2007) ; (JAEA-J 03568)

The production and transport processes of the H⁰ atom are numerically simulated to obtain the H⁰ atom density. The three dimensional transport code using the Monte Carlo method has been applied to H⁰ atoms in the large "JAEA 10 ampere negative ion source" under the Cs-seeded condition. In this study, the production rate of H⁰ atoms through the dissociation process of H₂ molecules is estimated from single probe characteristics of the Langmuir probe measurement. In addition, the energy relaxation process of H⁰ atoms is also considered. The results show that the existence of high-energy electrons and the energy relaxation process of H⁰ atoms affect the H⁰ atom density.

36000234
Comparison of SCC growth rate between in-core and EX-core tests in BWR simulated high temperature water
Kaji, Yoshiyuki; Ugachi, Hirokazu; Tsukada, Takashi; Matsui, Yoshinori; Omi, Masao; Nagata, Nobuaki*; Dozaki, Koji*; Takiguchi, Hideki*
Proceedings of 13th International Conference on Environmental Degradation of Materials in Nuclear Power Systems (CD-ROM) , 12p.(2007) ; (JAEA-J 03569)

Irradiation assisted stress corrosion cracking (IASCC) is one of the critical concerns when stainless steel components have been in service in light water reactors for a long period. In-core IASCC growth tests have been carried out using the compact tension type specimens of type 304 stainless steel that had been pre-irradiated up to a neutron fluence level around 1×10²⁵n/m² in pure water simulated boiling water reactor (BWR) coolant condition at the Japan Materials Testing Reactor (JMTR). In order to investigate the effect of synergy of neutron/γ radiation and stress/water environment on SCC growth rate, we performed post irradiation examinations (PIEs) in the several dissolved oxygen contents or hydrogen peroxide added environments under the same electrochemical potential condition. In this paper, results of the in-core SCC growth tests will be discussed comparing with the result obtained by PIEs from a viewpoint of the synergistic effects on IASCC.

36000235
Degradation modeling of InGaP/GaAs/Ge triple junction solar cells irradiated with various energy protons
Sato, Shinichiro; Miyamoto, Haruki; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Morioka, Chiharu*; Kawano, Katsuyasu*; Oshima, Takeshi
Proceedings of 17th International Photovoltaic Science and Engineering Conference (PVSEC-17) (CD-ROM) , p.502-503(2007) ; (JAEA-J 03570)

Degradation modeling of InGaP/GaAs/Ge triple junction (3J) solar cells with the use of a one dimensional optical device simulator, PC1D, is performed for cell lifetime prediction. By fitting the quantum efficiencies of 3J solar cells degraded by 30 keV, 150 keV, 3 MeV, or 10 MeV proton irradiation, the short circuit currents (Isc) and open circuit voltages (Voc) are simulated. The damage coefficient of minority carrier diffusion length (K_L) and carrier removal rate (R_C) of base carrier concentration of each sub cell are also estimated. The values of Isc and Voc obtained using the calculations show good agreement with experimental values. These results confirm that the degradation modeling method is effective for lifetime prediction of 3J solar cells.

36000236
Structural study on (Al)InGaP single-junction solar cell for performance improvement of triple-junction solar cells
Morioka, Chiharu*; Imaizumi, Mitsuru*; Sugimoto, Hiroki*; Sato, Shinichiro; Oshima, Takeshi; Tajima, Michio*
Proceedings of 17th International Photovoltaic Science and Engineering Conference (PVSEC-17) (CD-ROM) , p.504-505(2007) ; (JAEA-J 03571)

Radiation resistance of (Al)InGaP solar cells was examined in this study. The epitaxial structure, such as aluminum contents or carrier concentration (CC) in the base layer, is varied, whereas the base layer thickness is maintained at 1 μ m. The cells are irradiated with 3 MeV protons up to the fluence of 1 × 10¹⁴ cm^-2. Remaining factors of short-circuit current and open-circuit voltage show no significant difference between Al_0.2In_0.5Ga_0.3P and In_0.5Ga_0.5P cells. The graded CC structure in the base layer is ineffective to improve radiation resistance in the case of (Al)InGaP cells with a thick base layer, which implies that radiation degradation is not primarily attributable to the decrease in minority-carrier diffusion length.

36000237
Effects of irradiation temperature on degradation of electrical characteristics of InGaP solar cells
Miyamoto, Haruki; Sato, Shinichiro; Oshima, Takeshi; Morioka, Chiharu*; Imaizumi, Mitsuru*; Kawano, Katsuyasu*
Proceedings of 17th International Photovoltaic Science and Engineering Conference (PVSEC-17) (CD-ROM) , p.961-962(2007) ; (JAEA-J 03572)

InGaP and Si solar cells are irradiated with 10 MeV protons at fluences up to 1 × 10¹³ cm^-2 at room temperature (RT) and low temperature (LT). Results show that the remaining factor Voc irradiated at LT is higher than that at RT, and vice versa for Isc. The temperature coefficient of Voc after irradiation is greater than that before irradiation, although the coefficients of Isc are the same before and after irradiation. This degradation of the output performance of these solar cells can be interpreted in terms of a decrease in minority-carrier diffusion length.

36000238
Nuclear data needs for fast reactors
Chiba, Go
Proceedings of 2006 Symposium on Nuclear Data (CD-ROM) , 6p.(2007) ; (JAEA-J 03573)

In the present paper, we show that the neutronics parameter uncertainties expected in current design studies of fast reactors are reasonable when both differential and integral data are taken into consideration. This conclusion is based on an assumption that cross section covariance is properly evaluated. We attempt to verify the cross section covariance of JENDL-3.3 with the integral data, which were obtained at critical assemblies at Los Alamos National Laboratory. As a result, we suggest that uncertainty of P1 coefficient of elastic scattering cross sections of U-238 seems to be underestimated.

36000239
Cosmic-ray transport simulation in the atmosphere
Sato, Tatsuhiko; Niita, Koji*
Proceedings of 2006 Symposium on Nuclear Data (CD-ROM) , 6p.(2007) ; (JAEA-J 03574)

Estimation of cosmic-ray neutron spectra in the atmosphere has been an essential issue in the evaluation of the aircrew doses and the soft-error rates of semiconductor devices. We therefore performed Monte Carlo simulations for estimating neutron spectra, using the PHITS code coupled with the nuclear data library JENDL-High-Energy (JENDL/HE) file or the intra-nuclear cascade (INC) model for simulating high-energy neutron and proton induced nuclear reactions. The calculated spectra based on JENDL/HE agree with measured data very much for a wide altitude range even at ground level. On the other hand, the calculation adopting INC generally overestimates the measured data, especially at lower altitudes.

36000240
Atomistic investigation of structural changes and reaction energy induced by dislocation-grain boundary interaction process in fcc aluminum and bcc iron
Tsuru, Tomohito; Shibutani, Yoji*; Kaji, Yoshiyuki
Proceedings of 3rd Asian-Pacific Congress on Computational Mechanics (APCOM '07) & 11th International Conference on Enhancement and Promotion of Computational Method in Engineering and Science (EPMESC-11) (CD-ROM) , 8p.(2007) ; (JAEA-J 03575)

Interaction process of grain boundary and dislocation is one of the most important factors in the materials. Dislocations are successively piled up beside the grain boundary planes and they produce stress concentration which becomes a dominant stress factor of stress corrosion cracking (SCC). However, detailed mechanisms of the interaction between these processes and their influence on plastic behavior have yet to be definitively determined. In the present study, fundamental properties of the CSL grain boundaries and grain boundary-dislocations process are investigated by atomistic simulations. Then nudged elastic band (NEB) are performed to evaluate activation energy and minimum energy path in the interaction process of dislocation and Σ 3(111)<110> CSL. As a result, it is found that there is a strong correlation between grain boundary energy and excess free volume, and that the stable grain boundary can be high energy barrier to grain boundary-dislocation interaction.

36000241
Recent activities on aqueous partitioning at JAEA
Kimura, Takaumi; Komaki, Jun; Morita, Yasuji
Proceedings of 9th OECD/NEA Information Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation , p.151-158(2007) ; (JAEA-J 03576)

The Japan Atomic Energy Agency (JAEA) has been conducting research and development (R&D) on partitioning and transmutation (P&T) technologies using commercialized fast reactors (FR) or accelerator driven system (ADS) in the transmutation cycle. Various partitioning technologies have been investigated in the R&D activities for aqueouspartitioning of radioactive nuclides, especially actinides. This paper overviews some of the activities on the partitioning at JAEA.

36000242
Development of low-loss millimeter-wave antennas on fluorine substrate using electro-fine-forming fabrication
Ito, Naoki*; Mase, Atsushi*; Seko, Noriaki; Tamada, Masao; Sakata, Eiji*; Kogi, Yuichiro*
Proceedings of Asia-Pacific Microwave Conference 2006 (APMC 2006), Vol.1 (CD-ROM) , p.2031-2033(2006) ; (JAEA-J 03577)

Polytetrafluoroethylene (PTFE) has many desirable properties for substrates of millimeter-wave planar antennas such as low dielectric constant and loss tangent. However, it has weak adhesion to various metals. Surface treatment of PTFE via radiation-induced graft polymerization was carried out to improve the adhesion. The peel adhesion strength of the PTFE/Cu was attained to be 10.3 N/cm by the treatment. The dielectric function of grafted-PTFE remained almost unchanged after the graft polymerization. The design and fabrication of millimeter-wave antennas on the treated PTFE substrates have been performed using electro-fine-forming (EF2) technology.

36000243
A Comparative analysis of CABRI CIP0-1 and NSRR VA-2 reactivity initiated accident tests
Petit, M.*; Georgenthum, V.*; Sugiyama, Tomoyuki; Quecedo, M.*; Desquines, J.*
Proceedings of EUROSAFE Forum 2007 (Internet) , 9p.(2007) ; (JAEA-J 03578)

Zirlo is an improved fuel cladding material that was developed to accommodate constraints associated with increasing burnups in a more severe duty operation. The behavior of Zirlo irradiated above 75 GWd/t under RIA conditions was studied in CABRI CIP0-1 and NSRR VA-2 tests. The samples were initially similar but VA-2 failed at relatively low enthalpy whereas CIP0-1 did not fail. Because test conditions were different in terms of initial temperature, coolant nature and power pulse width, it is necessary to use a transient fuel code to compare the two results. Using SCANAIR and CLARIS it was shown that the concentration of hydrogen precipitates at the temperature of the test is of primary importance to assess both experiments in a consistent manner. The analysis demonstrated that room temperature is a testing condition much more severe than that expected at typical PWR conditions.

36000244
Stress corrosion cracking of zirconium used in the reprocessing plant
Kato, Chiaki; Motooka, Takafumi; Yamamoto, Masahiro
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM) , p.245-250(2007) ; (JAEA-J 03579)

We investigated stress corrosion cracking (SCC) of zirconium by constant load test and the small-scale mock-up test simulated the fuel dissolve. These tests operated in the simulated solution, which substituted non-radioactive elements, i.e. V with radioactive elements such as Pu and Np. From the results of constant load test, the cracks weren't observed on 150 MPa after 908 hours in approximately 3 % strain. However a lot of cracks caused by SCC were observed over 20 strain under high tensile stress in the simulated solution and the heat-transfer condition having more corrosive circumstance and noble potential accelerated the susceptibility of SCC. The cracking behavior would be caused by the creep phenomena. The small-scale mock-up test had been operated for about 50000 hours during 7 year. From the results, zirconium showed excellent corrosion resistance and no SCC was observed during these long-term operations.

36000245
Calculation of the pressure vessel failure fraction of fuel particle of gas turbine high temperature reactor 300C
Aihara, Jun; Ueta, Shohei; Mozumi, Yasuhiro; Sato, Hiroyuki; Motohashi, Yoshinobu*; Sawa, Kazuhiro
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM) , p.416-422(2007) ; (JAEA-J 03580)

In high temperature gas-cooled reactors (HTGRs), coated particles are used as fuels. For upgrading HTGR technologies, present SiC coating layer which is used as the 3rd layer could be replaced with ZrC coating layer which have much higher temperature stability in addition to higher resistance to chemical attack by fission product palladium than the SiC coating layer. The ZrC layer could deform plastically at high temperatures. Therefore, the Japan Atomic Energy Agency modified an existing pressure vessel failure fraction calculation code to treat the plastic deformation of the 3rd layer in order to predict failure fraction of ZrC coated particle under irradiation. Finite element method is employed to calculate the stress in each coating layer. The pressure vessel failure fraction of the coated fuel particles under normal operating condition of GTHTR300C is calculated by the modified code. The failure fraction is evaluated as low as 3.5×10^-6.

36000246
Fundamental study on electrolyte recycle process by phosphate conversion technique
Amamoto, Ippei; Kofuji, Hirohide; Myochin, Munetaka; Terai, Takayuki*
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM) , p.748-757(2007) ; (JAEA-J 03581)

FP such as alkali metals, alkaline earth metals and rare-earth elements are apt to remain in the eutectic medium used in pyroreprocessing even after treatment at the pyrocontactor step. It is desirable to have the spent electrolyte purified for recycling which in turn, could lead to the reduction of HLW. This study is carried out to evaluate the feasibility of the electrolyte recycling process by the phosphate conversion technique. First of all, a reference block flow diagram, which consists of three steps, was designed based on known developmental results from literature. Subsequently, evaluation was undertaken by comparison with conventional relevant experimental and theoretical analysis results after gathering the essential basic data for thermodynamic calculation. The obtained computational value was then reflected to establish the preliminary conceptual flow diagram which would facilitate the next discussion and experiment for the realization of this process.

36000247
Intergranular corrosion mechanism of ultra-low carbon type 304 stainless steel in a nuclear reprocessing plant
Ueno, Fumiyoshi; Kato, Chiaki; Motooka, Takafumi; Ichikawa, Shiro*; Yamamoto, Masahiro
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM) , p.1389-1393(2007) ; (JAEA-J 03582)

Authors were aimed for development of life evaluation method of components and clarification of corrosion mechanism of the components in nuclear reprocessing plant. Corrosion behavior of heat exchanger tubes in the reduced pressure evaporator made by ultra-low carbon type 304ULC stainless steel was studied. A simplified mock-up test apparatus was used for corrosion test with long-term test duration. Following results were obtained. The corrosion rates were increased from beginning of the test to more than 25,000 hours and then corrosion rate was reached to constant. From the measurement results of intergranular penetration depths, it was thought that intergranular corrosion was progressed on entire grain boundary around a grain and then the grain dropped out to the solution.

36000248
Basic knowledge on treating various wastes generated from practical operation of metal pyro-reprocessing
Nakayoshi, Akira; Kitawaki, Shinichi; Fukushima, Mineo; Kurata, Masaki*; Yahagi, Noboru*
Proceedings of International Symposium on EcoTopia Science 2007 (ISETS '07) (CD-ROM) , p.1062-1066(2007) ; (JAEA-J 03583)

Pyro-reprocessing is one of the promising reprocessing methods for recycling spent nuclear fuels generated from fast reactors. Comparing to the conventional aqueous-processes, following benefits are expected when introducing the pyro-reprocessing, such as reduction of environmental burden, enhancement of proliferation-resistant, enhancement of economical potential, efficient utilization of nuclear resources. The pyro-reprocessing will therefore become more attractive not only in developed countries regarding nuclear energy, but also in developing countries. As for reducing environmental burden, the most important subject is establishment of the nuclear fuel cycle, in which actinide elements are closed. Various kinds of intermediate waste which contains actinide elements are formed in the practical operation not only from the main steps of the pyro-reprocessing but also from related sub-streams.

36000249
LES on concentration fluctuation of a dispersing plume in the convective boundary layer capped by a temperature inversion (in Japanese)
Abe, Satoshi*; Nakayama, Hiromasa; Tamura, Tetsuro*
Dai-21-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Yoshishu (CD-ROM) , 7p.(2007) ; (JAEA-J 03585)

Large-eddy simulation is applied to the problem of plume dispersion in convective boundary layer (CBL) flow, which is time-sequentially generated by unsteady numerical simulation of spatially-developing boundary layer capped by a temperature inversion in the driver unit. Our objective is to investigate effects of the point source elevation on the horizontal variability of the concentration field and on the ground level concentration as function of distance from the source.

36000250
Chip shape and secondary fragmentation through TBM excavation (in Japanese)
Tsusaka, Kimikazu; Tanimoto, Chikaosa*; Nakane, Tatsuto*; Ueno, Takaaki*; Koizumi, Yu*
Dai-37-Kai Ganban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM) , p.31-36(2008) ; (JAEA-J 03586)

In the construction of geological repository of high-level radioactive waste, TBM excavation could be one of the most usable tunneling methods to minimize the loosening of rock. The secondary fragmentation has been recognized to have unfavorable influence on the driving, which is defined as a phenomenon that rock pieces between a cutter head and face are fragmented. The chips in the tunneling are well-known for one of useful indices to reflect the geological conditions. The flat and elongated chips indicate the cutting face with less joints and good practice with less secondary fragmentation rate. Through a case history in granitic rock, the authors proposed the new index to estimate the shape of chips and studied the relationship between the index and the excavation efficiencies. In conclusion, it was clarified that chips with the new index over 3.5 were generally observed when a TBM drove with less than 30% the secondary fragmentation rate.

36000251
Study on mass transport in single fracture using tracer transport data measured by optical method (in Japanese)
Sato, Hisashi; Sawada, Atsushi
Dai-37-Kai Ganban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM) , p.263-268(2008) ; (JAEA-J 03587)

The fracture aperture and tracer concentration within a single fracture was measured quantitatively, by using optical method with the transparent replica of a single fracture, to study how flow and transport is affected by the aperture spatial pattern. Two dimensional groundwater flow analysis was applied with the transmissivity estimated from measured aperture data, according to the assumption that cubic law could be applicable locally. The evaluated flow rate through the fracture was 1.6 times larger than the hydraulic test result. The mass balance aperture calculated from the mean travel time of tracer migration with groundwater flow rate was equivalent to the arithmetic mean value of the aperture data.

36000252
Determinaion of parameters for a stress-strain constitutive equation considering time-dependent behavior of Toki granite (in Japanese)
Hirano, Toru; Seno, Yasuhiro; Nakama, Shigeo; Okubo, Seisuke*
Dai-37-Kai Ganban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM) , p.397-402(2008) ; (JAEA-J 03588)

Toki granite was tested to obtain parameters for the constitutive equation and numerical simulations were carried out. The testing method was uniaxial compressive loading at the moderate a constant strain rate that is decreased after yielding to obtain the complete stress-strain curve. In addition, two kinds of the strain rate were alternately switched to obtain the parameter n from one specimen. The n represents the strength time-dependence in the constitutive equation. Based on n and the complete stress-strain curve, second parameter m can be calculated by numerical simulations. The m accounts for the behavior after yielding. According to the results, Toki granite has n=52 and m=60. Thus shows relatively low time-dependence.

36000253
The Early realization of fast breeder reactor cycle (in Japanese)
Mukai, Kazuo
Genshiryoku Sogo Shimpojiumu 2007 Koen Rombunshu , p.111-118(2007) ; (JAEA-J 03589)

The Japanese government assessed the result of "Feasibility Study on Commercialized FR Cycle System 2nd Phase" and a major concept that is the combination of a sodium cooled FBR(oxide fuel), an advanced aqueous reprocessing and a simplified pelletizing was selected. From now on, the JAEA invests the development resource to a major concept intensively, and aims to put it to practical use by new project, "FaCT". With "FaCT" project, the adoption of innovative technology is going to be judged in 2010. The result of "Fact" are going to be presented in 2015 that is the systematized technologies based on R&D and the conceptual designs of demonstration facility and commercial facility. In order to start the demonstration reactor operation in 2025 by the result of "FaCT", the project is carried with international cooperation.

36000254
Recent progress of fusion research (in Japanese)
Ikeda, Yoshitaka
Nippon Genshiryoku Gakkai Dai-39-Kai Robutsuri Kaki Semina "Robutsuri Shiken No Kiso To Jissen" Tekisuto , p.160-177(2007) ; (JAEA-J 03590)

The recent progress of the fusion plasma is reviewed. The developments of profile diagnostics and large-scale simulation methods have clarified the self-organized plasma characteristics. These progresses contribute to predict the ITER performance with high accuracy. The key issues of the fusion plasma towards the demo reactor plasma, which will demonstrate the economically attractive energy source, are also presented.

36000255
Statistical evaluation of cross flow in a tight-lattice rod bundle (in Japanese)
Zhang, W.; Yoshida, Hiroyuki; Ose, Yasuo*; Onuki, Akira; Akimoto, Hajime
Nippon Kikai Gakkai 2007-Nendo Nenji Taikai Koen Rombunshu, Vol.3 , p.145-146(2007) ; (JAEA-J 03591)

In relation to the thermal-hydraulic design of FLWR, this study presents a statistical evaluation of numerical simulation results obtained by a detailed two-phase flow simulation code (named TPFIT). In order to clarify mechanisms of cross flow in such tight lattice rod bundles, the TPFIT was used to simulate water-steam two-phase flow in two modeled subchannels. Attention was focused on instantaneous fluctuation characteristics of cross flow. With the calculation of correlation coefficients between the differential pressure and gas/liquid mixing coefficients, the time scales of cross flow were evaluated, and the effects of mixing section length, flow pattern and gap spacing on correlation coefficients were investigated. The difference in mechanism between gas and liquid cross flows was pointed out.

36000256
Interoperability establishment between two different GRIDs (in Japanese)
Kushida, Noriyuki; Suzuki, Yoshio; Minami, Takahiro; Aoyagi, Tetsuo; Nakajima, Norihiro
Zen NEC C&C Shisutemu Yuzakai Heisei-19-Nendo Rombunshu (CD-ROM) , 10p.(2007) ; (JAEA-J 03592)

Interoperability establishment between two different GRIDs.

36000257
Incorporating the electromagnetic field in the EGS5 code
Torii, Tatsuo; Sugita, Takeshi*
KEK Proceedings 2007-5 , p.43-49(2007) ; (JAEA-J 03599)

In recent years, radiation bursts called terrestrial γ-ray flashes (TGFs) have been observed over thunderclouds by X- and γ-ray observation satellites. Accordingly, a set of modules designed to analyze the effects of electrons on the thundercloud electric field and global electric fields was developed, and the subroutine ELECTR was modified. These modules and the modified subroutine were then incorporated into the EGS5 code. Furthermore, in the EGS5 the density of substances was set for each computational region, but the code was modified to allow the density to be changed continuously by simulating the global atmosphere. The magnetic field was compared with the user code UCBEND and it was confirmed to agree well.

36000258
Development of dose assessment method for high-energy neutrons using intelligent neutron monitor
Sato, Daiki; Sato, Tatsuhiko; Endo, Akira; Takada, Masashi*; Matsufuji, Naruhiro*; Sato, Shinji*
NIRS-M-203 (CD-ROM) , p.198-199(2007) ; (JAEA-J 03600)

An innovative intelligent neutron monitor named "DARWIN" was applied to measuring dose in a high-energy neutron field produced through nuclear spallation by 800-MeV/u Si-ion bombardment with a thick graphite target. The measured dose was compared with calculated dose from neutron spectrum in the field. The comparison validated the reliability of DARWIN for dose measurement against high-energy neutrons.

36000259
Improvement of analytical activities in the Tokai reprocessing plant, Japan, by measuring destructive and non-destructive assays
Surugaya, Naoki; Taguchi, Shigeo; Kurosawa, Akira; Watahiki, Masaru
STI/PUB/1298 (CD-ROM) , p.673-679(2007) ; (JAEA-J 03601)

We have been analyzing nuclear materials at the Tokai pilot reprocessing plant, Japan, since 1977. To obtain reliable measurements for nuclear material such as uranium and plutonium, we have developed various kinds of measurement techniques and implemented effective ones for accountability and verification analyses in a nuclear material accountancy system. One of our role as a pilot plant has been successfully accomplished with the effort put into various analytical activities. Now, it is time to transfer the experience gained with our technology to the next large-scale commercial plant in Rokkasho. This paper presents our analytical methods and their results obtained using analytical techniques we have applied over recent years.

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JAEA > JAEA Library > JOPSS > Papers Published in Journals [Back Issues] > February 2008