Structural changes in pH-responsive gelatin/hydroxypropyl methylcellulose phthalate blends aimed at drug-release systems

Nogami, Satoshi*; Kadota, Kazunori*; Uchiyama, Hiromasa*; Arima-Osonoi, Hiroshi*; Iwase, Hiroki*; Tominaga, Taiki*; Yamada, Takeshi*; Takata, Shinichi; Shibayama, Mitsuhiro*; Tozuka, Yuichi*

International Journal of Biological Macromolecules, 190, p.989 - 998, 2021/11

https://doi.org/10.1016/j.ijbiomac.2021.09.074

Effect of magnetism on lattice dynamics in SrFeAs using high-resolution inelastic X-ray scattering

Murai, Naoki*; Fukuda, Tatsuo; Kobayashi, Tatsuya*; Nakajima, Masamichi*; Uchiyama, Hiroshi*; Ishikawa, Daisuke*; Tsutsui, Satoshi*; Nakamura, Hiroki; Machida, Masahiko; Miyasaka, Shigeki*; et al.

Physical Review B, 93(2), p.020301_1 - 020301_5, 2016/01

https://doi.org/10.1103/PhysRevB.93.020301

Production of criticality safety standard data with Monte-Carlo code MVP / nuclear data library JENDL-3.2 validated using ICSBE data

Tonoike, Kotaro; Suyama, Kenya; Okuno, Hiroshi; Miyoshi, Yoshinori; Uchiyama, Gunzo

Proceedings of 9th International Conference on Nuclear Criticality (ICNC 2011) (CD-ROM), 8 Pages, 2012/02

The 1st version of criticality safety handbook of Japan was published in 1988. A criticality safety analysis code system JACS was validated, and minimum critical mass and safety limit mass of various fissile materials were calculated. During more than two decades since then, new critical experimental data were taken in the Static Critical Experiment Facility (STACY), and more precise benchmark data of wider range of fissile materials were accumulated by the International Criticality Safety Benchmark Evaluation Project (ICSBEP). Computational capability has greatly grown, and new codes and nuclear data have been developed. The 2nd version of the handbook utilizes the results of validation of the criticality analysis method with a continuous energy Monte-Carlo code MVP and a nuclear data library JENDL-3.2 using the benchmark data chosen from the ICSBEP handbook. Results of the benchmark calculation were statistically studied, from which the safety limit value of multiplication factor was derived as 0.98. Based on the conclusion, minimum critical mass and safety limit mass were calculated. Future plan of research activities on the criticality safety in JAEA will be also overviewed.

Irradiation history of Itokawa regolith material deduced from noble gases in the Hayabusa samples

Nagao, Keisuke*; Okazaki, Ryuji*; Nakamura, Tomoki*; Miura, Yayoi*; Osawa, Takahito; Bajo, Kenichi*; Matsuda, Shintaro*; Ebihara, Mitsuru*; Ireland, T.*; Kitajima, Fumio*; et al.

Science, 333(6046), p.1128 - 1131, 2011/08

https://doi.org/10.1126/science.1207785

A steroid surface materials record regolith processes and a history of cosmic-ray irradiation. Noble gas isotopes in three rocky grains from Itokawa have been determined. High concentrations of solar He, Ne, and Ar, as high as those in lunar soils, are released at variable temperatures from each sample. The isotopic compositions are essentially identical to those of solar wind but distinguishable in He relative abundance. These noble gas characteristics can be explained by repeated implantation and preferential loss of solar He by removal of weathered He-rich rim on the grain surface through friction among regolith grains on Itokawa. Residence time of regolith materials on Itokawa is alculated to be shorter than 10 Myr, suggesting that regolith materials of small asteroids would escape easily to space.

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

http://accelconf.web.cern.ch/AccelConf/IPAC10/papers/tupe091.pdf

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Design of a 500kV electron gun for ERL light source at KEK

Yamamoto, Masahiro*; Honda, Yosuke*; Miyajima, Tsukasa*; Uchiyama, Takashi*; Kobayashi, Masanori*; Muto, Toshiya*; Matsuba, Shunya*; Sakanaka, Shogo*; Sato, Kotaro*; Saito, Yoshio*; et al.

Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.860 - 862, 2009/08

A newly 500 kV electron gun (2nd - 500 kV gun) for an ERL light source is designed at KEK. A new concept and state of-the-art technologies of vacuum system, ceramic insulators, high voltage power supply, photocathode and preparation system will be employed. The details are described in this report.

Nuclear criticality safety evaluation of a mixture of MOX, UO and additive in the most conservative concentration distribution

Okuno, Hiroshi; Sato, Shohei; Sakai, Tomohiro*; Uchiyama, Gunzo

Journal of Nuclear Science and Technology, 45(11), p.1108 - 1115, 2008/11

https://doi.org/10.3327/jnst.45.1108

For nuclear criticality safety evaluation of blenders at the mixed uranium-plutonium oxide (MOX) fuel plant, non-uniformity distributions of powders in three chemical components, i.e., MOX, uranium-dioxide (UO) and zinc-stearate, which is a fuel additive, should be taken into account. The model blender considered in this article contained a mixture of 33 wt% PuO-enriched MOX, depleted UO and zinc-stearate in a shape of an upside-down truncated cone, which was surrounded by 30 cm-thick polyethylene. For a limitation of the number of calculation cases, the fissile plutonium mass of the mixture was fixed to 98 kg, and the total concentration of MOX and UO was fixed to 4.0 g/cm. The most conservative fuel distribution in the aspect of nuclear criticality safety under these constraints was calculated with a two-dimensional optimum fuel distribution code OPT-TWO, so that the importance distribution of MOX and that of zinc-stearate should be individually flattened by conserving the mass of each component. The OPT-TWO calculation was followed by criticality calculation performed with the MCNP code to obtain the neutron multiplication factor of the fuel in the optimum fuel distribution. The most conservative fuel distribution obtained in this research was typically depicted as a shell of zinc-stearate embedded into the central MOX region surrounded by the peripheral UO region. An increase in the neutron multiplication factor was found 25% at most; non-uniformity of plutonium enrichment concentration and that of zinc-stearate concentration contributed to it in almost equal and independent ways.

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

Current status and potential needs of burn-up credit in Japan

Suyama, Kenya; Okuno, Hiroshi; Uchiyama, Gunzo; Yamamoto, Toru*

Need for Post Irradiation Experiments to Validate Fuel Depletion Calculation Methodologies, p.31 - 34, 2006/12

In Japan, burnup credit (BUC) has already been introduced into the criticality safety evaluation of Spent Nuclear Fuel (SNF) receiving pools and dissolver at Rokkasho Reprocessing Plant (RRP). BUC in other fuel cycle facilities including SNF transport is not considered. This is because the pressure of accumulation of SNF in Japan is decreased for a while since (1) the operation of spent fuel storage pools in RRP and (2) proposal of construction of an interim storage facility using dry-type metal casks by Recyclable-Fuel Storage Company (RFS) in Aomori. However, potential demands for adoption of BUC and improvement of related techniques have been still high. The technical development related to BUC is in progress continuously in the field of burnup analysis as post irradiation examinations (PIE) and reactor physics experiments. This concludes that BUC is an attractive concept and further adoption in spent fuel management process is expected in Japan.

Report of investigation on malfunction of reserved shutdown system in HTTR

Hamamoto, Shimpei; Iigaki, Kazuhiko; Shimizu, Atsushi; Sawahata, Hiroaki; Kondo, Makoto; Oyama, Sunao; Kawano, Shuichi; Kobayashi, Shoichi; Kawamoto, Taiki; Suzuki, Hisashi; et al.

JAEA-Technology 2006-030, 58 Pages, 2006/03

JAEA-Technology-2006-030.pdf:10.69MB

During normal operation of High Temperature engineering Test Reactor (HTTR) in Japan Atomic Energy Agency (JAEA), the reactivity is controlled by the Control Rods (CRs) system which consists of 32 CRs (16 pairs) and 16 Control Rod Drive Mechanisms (CRDMs). The CR system is located in stand-pipes accompanied by the Reserved Shutdown System (RSS). In the unlikely event that the CRs fail to be inserted, the RSS is provided to insert BC/C pellets into the core. The RSS shall be designed so that the reactor should be held subcriticality from any operation condition by dropping in the pellets. The RSS consists of BC/C pellets, hoppers which contain the pellets, electric plug, driving mechanisms, guide tubes and so on. In accidents when the CRs cannot be inserted, an electric plug is pulled out by a motor and the absorber pellets fall into the core by gravity. A trouble, malfunction of one RSS out of sixteen, occurred during a series of the pre-start up checks of HTTR on February 21, 2005. We investigated the cause of the RSS trouble and took countermeasures to prevent the issue. As the result of investigation, the cause of the trouble was attributed to the following reason: In the motor inside, The Oil of grease of the multiplying gear flowed down from a gap of the oil seal which has been deformed and was mixed with abrasion powder of brake disk. Therefore the adhesive mixture prevented a motor from rotating.