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JAEA Reports

Operation, test, research and development of the High Temperature Engineering Test Reactor (HTTR) (FY2019)

Department of HTTR

JAEA-Review 2021-017, 81 Pages, 2021/11

JAEA-Review-2021-017.pdf:2.53MB

The High Temperature Engineering Test Reactor (HTTR) is the first High-Temperature Gas cooled Reactor (HTGR) constructed in Japan at the Oarai Research and Development Institute of the Japan Atomic Energy Agency with 30MW in thermal power and 950 $^{circ}$ C of outlet coolant temperature. The purpose of the HTTR is to establish and upgrade basic technologies for HTGRs. The HTTR has accumulated a lot of experience of HTGRs' operation and maintenance up to the present time throughout rated power operations, safety demonstration tests, long-term high temperature operations and demonstration tests relevant to HTGRs' R&Ds. In the fiscal year 2019, we continued to make effort to restart operations of the HTTR that stopped since the 2011 off the Pacific coast of Tohoku Earthquake. It is necessary for the HTTR reoperation to prove conformity with the new regulatory requirements for research reactors enacted in December 2013. So we might cope with government agency to pass the inspection of application document for the HTTR licensing. This report summarizes the activities carried out in the fiscal year 2019, which were the situation of the new regulatory requirements screening of the HTTR, the operation and maintenance of the HTTR, R&Ds relevant to commercial-scale HTGRs, the international cooperation on HTGRs and so on.

Journal Articles

Pressure resistance thickness of disposal containers for spent fuel direct disposal

Sugita, Yutaka; Taniguchi, Naoki; Makino, Hitoshi; Kanamaru, Shinichiro*; Okumura, Taisei*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 19(3), p.121 - 135, 2020/09

https://doi.org/10.3327/taesj.J19.007

A series of structural analysis of disposal containers for direct disposal of spent fuel was carried out to provide preliminary estimates of the required pressure resistance thickness of the disposal container. Disposal containers were designed to contain either 2, 3 or 4 spent fuel assemblies in linear, triangular or square arrangements, respectively. The required pressure resistance thickness was evaluated using separation distance of the housing space for each spent fuel assembly as a key model parameter to obtain the required thickness of the body and then the lid of the disposal container. This work also provides additional analytical technical knowledge, such as the validity of the setting of the stress evaluation line and the effect of the model length on the analysis. These can then be referred to and used again in the future as a basis for conducting similar evaluations under different conditions or proceeding with more detailed evaluations.

JAEA Reports

Operation, test, research and development of the High Temperature Engineering Test Reactor (HTTR) (FY2018)

Department of HTTR

JAEA-Review 2019-049, 97 Pages, 2020/03

JAEA-Review-2019-049.pdf:4.66MB

The High Temperature Engineering Test Reactor (HTTR), a graphite-moderated and helium gas-cooled reactor being able to get 950 $^{circ}$ C temperature of the outlet coolant with 30 MW of thermal power, constructed at the Oarai Research and Development Institute of the Japan Atomic Energy Agency is the first High- Temperature Gas-cooled Reactor (HTGR) in Japan. The purpose of the HTTR is to establish and upgrade basic technologies for HTGRs. The HTTR has accumulated a lot of experience of HTGRs' operation and maintenance up to the present time throughout rated power operations, safety demonstration tests, long-term high temperature operations and demonstration tests relevant to HTGRs' R&Ds. In the fiscal year 2018, we made effort to pass the inspection of application document for the HTTR licensing to prove conformity with the new regulatory requirements for research reactors that took effect since December 2013 in order to restart operations of the HTTR that stopped since the 2011 off the Pacific coast of Tohoku Earthquake. This report summarizes the activities carried out in the 2018 fiscal year, which were the situation of the new regulatory requirements screening of the HTTR, the operation and maintenance of the HTTR, R&Ds relevant to commercial-scale HTGRs, the international cooperation on HTGRs and so on.

Journal Articles

Magnetic field induced phenomena in UIrGe in fields applied along the axis

Pospil, J.*; Haga, Yoshinori; Kohama, Yoshimitsu*; Miyake, Atsushi*; Kambe, Shinsaku; Tateiwa, Naoyuki; Valika, M.*; Proschek, P.*; Prokleka, J.*; Sechovsk, V.*; et al.

Physical Review B, 98(1), p.014430_1 - 014430_7, 2018/07

https://doi.org/10.1103/PhysRevB.98.014430

Times Cited Count：16 Percentile：61.77(Materials Science, Multidisciplinary)

JAEA Reports

Evaluation items to attain safety requirements in fuel and core designs for commercial HTGRs

Nakagawa, Shigeaki; Sato, Hiroyuki; Fukaya, Yuji; Tokuhara, Kazumi; Ohashi, Hirofumi

JAEA-Technology 2017-022, 32 Pages, 2017/09

JAEA-Technology-2017-022.pdf:3.59MB

As for the design of commercial HTGRs, the fuel design, core design, reactor coolant system design, secondary helium system design, decay heat removal system design and confinement system design are very important and quite different from those of LWRs. To contribute the establishment of the safety standards for commercial HTGRs, the evaluation items to attain safety requirements in fuel and core designs were studied. In this study, the excellence features of HTGRs based on passive safety or inherent safety were fully reflected. Additionally, concerning the core design, the stability to spatial power oscillation in reactor core of HTGR was studied. The evaluation items as the result of the study are applicable to the safety design of commercial HTGRs in the future.

Journal Articles

Safety requirements expected for the prototype fast breeder reactor "Monju"

Saito, Shinzo; Okamoto, Koji*; Kataoka, Isao*; Sugiyama, Kenichiro*; Muramatsu, Ken*; Ichimiya, Masakazu*; Kondo, Satoru; Yonomoto, Taisuke

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 10 Pages, 2015/05

Journal Articles

The dHvA experiment under pressure in UIr

Shishido, Hiroaki*; Yamamoto, Etsuji; Haga, Yoshinori; Ikeda, Shugo; Nakashima, Miho*; Settai, Rikio*; Onuki, Yoshichika

Journal of the Physical Society of Japan, 75(Suppl.), p.119 - 120, 2006/08

https://doi.org/10.1143/JPSJS.75S.119

Times Cited Count：1 Percentile：11.03(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

High temperature magnetic properties of UIr single crystals

Galatanu, A.; Haga, Yoshinori; Yamamoto, Etsuji; Matsuda, Tatsuma; Ikeda, Shugo; Onuki, Yoshichika

Journal of the Physical Society of Japan, 73(3), p.766 - 767, 2004/03

https://doi.org/10.1143/JPSJ.73.766

Times Cited Count：17 Percentile：65.19(Physics, Multidisciplinary)

High-temperature magnetic susceptibilities of ferromagnetic UIr have been measured up to 800 K. The small saturation moment 0.5 $mu_{rm B}$ as well as the large electronic specific heat coefficient suggest itinerant ferromagnetic characteristics of this compound. We have found that the paramagnetic effective moment approarches to the value expected for free uranium ion above room temperature. This result suggests that magnetic moments at high temperature behave like localized moments.

Journal Articles

Magnetic and electrical properties of UIr

Yamamoto, Etsuji; Haga, Yoshinori; Matsuda, Tatsuma; Nakamura, Akio; Settai, Rikio*; Inada, Yoshihiko*; Sugawara, Hitoshi*; Sato, Hideyuki*; Onuki, Yoshichika

Journal of Nuclear Science and Technology, 39(Suppl.3), p.187 - 190, 2002/11

http://www.tandfonline.com/doi/abs/10.1080/00223131.2002.10875440

We succeeded in growing a high-quality single crystal of UIr with the monoclinic PbBi-type structure by the Czochralski pulling method in a tetra-arc furnace. The magnetization measurement indicates that UIr is an Ising-like ferromagnet with the Curie temperature $T_{rm C}$ = 46 K. The magnetic moment is found to be oriented along the [1 0 $=1] direction in the (010) plane. The saturated moment is 0.5 $mu_{rm B}$$ /U. The magnetic property, reflected in the magnetic susceptibility, electrical resistivity, Hall coefficient and thermoelectric power, is highly anisotropic. We also observed the de Haas-van Alphen (dHvA) oscillation. All the detected branches have large cyclotron effective masses ranging from 9.6 to 32 . They are consistent with the electronic specific heat coefficient =49 mJ/Kmol.

Journal Articles

X-ray reflectivity and diffraction studies on lipid and lipopolymer Langmuir-Blodgett films under controlled humidity

Bolze, J.*; Takahashi, Masamitsu; Mizuki, Junichiro; Baumgart, T.*; Knoll, W.*

Journal of the American Chemical Society, 124(32), p.9412 - 9421, 2002/08

https://doi.org/10.1021/ja0265308

Times Cited Count：13 Percentile：46.01(Chemistry, Multidisciplinary)

Synchrotron X-ray reflectivity and grazing incidence diffraction were applied to study the structures of phospholipid Langmuir-Blodgett films under controlled humidity. DSPE and DSPE-PEO lipopolymers, in which a PEO chain with n= 8, 17, or 45 EO units is covalently linked to the polar headgroup of DSPE, were used. When the relative humidity was changed from below 2 to 97%, the phosphate headgroup in a DSPE film was hydrated with a concomitant thickness increase of 0.42 nm. The swelling of the monolayer was found to be a reversible process without any significant roughening of the film. Subtle differences in the film thickness could be detected for DSPE monolayers transferred under various lateral pressures. The degree of lateral ordering of the alkyl chains in DSPE monolayers increased considerably when the humidity was raised. In the case of DSPE-PEO with eight EO units, the hydration of the monolayer was also found to be reversible, but the water uptake was larger due to the presence of the hydrophilic polymer interlayer.

Journal Articles

De Haas-van Alphen effect in UIr

Yamamoto, Etsuji; Haga, Yoshinori; Shishido, Hiroaki*; Nakawaki, Hirokazu*; Inada, Yoshihiko*; Settai, Rikio*; Onuki, Yoshichika

Physica B; Condensed Matter, 312-313, p.302 - 303, 2002/03

https://doi.org/10.1016/S0921-4526(01)01331-X

Times Cited Count：16 Percentile：61.17(Physics, Condensed Matter)

We have succeeded in growing a high-quality single crystal of UIr with the monoclinic structure by the Czochralski pulling method in a tetra-arc furnace. UIr is a ferromagnetic compound. Its Curie temperature is 46 K and the magnetic moment is found to be oriented along the [1 0 $=1] direction by the magnetization measurement. The magnetic moment is 0.5 $mu_{rm B}$$ /U. We have observed the de Haas-van Alphen (dHvA) oscillation. All the detected branches have heavy cyclotron effective masses ranging from 9.6 to 32 . They are consistent with the electronic specific heat coefficient =48.5 mJ/Kmol.

JAEA Reports

Design of high temperature irradiation materials inspection cells (spent fuel inspection cells) in the High Temperature engineering Test Reactor

Ino, Hiroichi*; Ueta, Shohei; Suzuki, Hiroshi; Tobita, Tsutomu*; Sawa, Kazuhiro

JAERI-Tech 2001-083, 46 Pages, 2002/01

JAERI-Tech-2001-083.pdf:6.31MB

no abstracts in English

Journal Articles

High-quality single crystal growth and anisotropic magnetic properties of UIr

Yamamoto, Etsuji; Haga, Yoshinori; Nakamura, Akio; Tokiwa, Yoshifumi; Aoki, Dai*; Settai, Rikio*; Onuki, Yoshichika

Journal of the Physical Society of Japan, Vol.70, Supplement A, p.37 - 39, 2001/05

https://doi.org/10.1143/JPSJ.70.37

Times Cited Count：21 Percentile：69.9(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Alternate multilayer deposition from ammonium amphiphiles and titanium dioxide crystalline nanosheets using the Langmuir-Blodgett technique

Yamaki, Tetsuya; Asai, Keisuke*

Langmuir, 17(9), p.2564 - 2567, 2001/05

https://doi.org/10.1021/la0016423

Times Cited Count：41 Percentile：92.2(Chemistry, Multidisciplinary)

A new type of TiO $_{2}$ nanosheet-organic complex multilayer film was successfully prepared by the Langmuir-Blodgett technique. Surface pressure-area curves demonstrated that a stable monolayer of dioctadecyldimethylammonium bromide (DODAB) was formed on an aqueous suspension of TiO $_{2}$ nanosheets derived from an exfoliated layered titanate, H $_{x}$ Ti $_{2-x/4}$ □ $_{x/4}$ O $_{4}$ ・H $_{2}$ O (x0.7; □, vacancy). The hybrid monolayer of the ammonium amphiphiles and the TiO $_{2}$ nanosheet was quantitatively transferred onto a hydrophobic quartz plate to form a multilayer film. X-ray diffraction measurements confirmed the formation of an ordered structure of DODAB/TiO $_{2}$ with an interlayer distance of 3.4 nm.

JAEA Reports

Migration behavior of actinide colloids in near-field

Nagasaki, Shinya*

JNC TJ8400 2000-004, 32 Pages, 2000/02

JNC-TJ8400-2000-004.pdf:0.69MB

Equilibrium and kinetics of sorption of NpO $_{2}^{+}$ on illite were investigated at pH = 6 by using the differential pulse anodic stripping voltammetry method and the spectroscopic method, respectively. It was found that the sorption isotherm obtained was fitted better by the Langmuir-Freundlich type equation than by the Langmuir equation. The heterogeneity coefficient was 0.89 0.05 and the half width at half maximum (HWHM) of affinity spectrum was 0.19 log unit, indicating that the surfacc of illite used has a low degree of heterogeneity. The kinetic spectra indicated that the sorption of NpO $_{2}^{+}$ occurs only at the outer surfacc. The mean HWHM of the kinetic spectra was 0.18 log unit. This also proves that the sorption kinetics of NpO $_{2}^{+}$ on the illite used is controlled by the same heterogeneity of the sorption sites. From the dependence of mean rate constants on temperature, a mean apparent activation enthalpy and a mean apparent activation entropy were evaluated at 373 kJ/mol and - 69 7 J/Kmol, respectively. This value of enthalpy suggests that the sorption is not controlled by diffusion through the hydrodynamic film around the illite. Equilibrium and kinetics of sorption of NpO $_{2}^{+}$ and Np(V) carbonate complexes (mainly NpO $_{2}$ CO $_{3}$ ) on Na-montmorillonite were also examined by using same technique.