Evaluation of the minimum critical amount for heterogeneous lattice systems composed of fuel rods utilized in low-power water-moderated research and test reactors by using continuous-energy Monte Carlo code MVP with JENDL-4.0

Yanagisawa, Hiroshi

JAEA-Technology 2021-023, 190 Pages, 2021/11

JAEA-Technology-2021-023.pdf:5.25MB

Computational analyses on nuclear criticality characteristics were carried out for heterogeneous lattice systems composed of water moderator and fuel rods utilized in low-power research and test reactors, in which the depletion of fuel due to burnup is relatively small, by using the continuous-energy Monte Carlo code MVP Version 2 with the evaluated nuclear data library JENDL-4.0. In the analyses, the minimum critical number of fuel rods was evaluated using calculated neutron multiplication factors for the heterogeneous systems of the uranium dioxide fuel rod in the Static Experiments Critical Facility (STACY) and the Tank-type Critical Assembly (TCA), and the uranium-zirconium hydride fuel rod in the Nuclear Safety Research Reactor (NSRR). In addition, six sorts of the ratio of reaction rates, which are components of neutron multiplication factors, were calculated in the analyses to explain the variation of neutron multiplication factors with the ratio of water moderator to fuel volume in a unit fuel rod cell. Those results of analyses are considered to be useful for the confirmation of reasonableness and validity of criticality safety measures as data showing criticality characteristics for water-moderated heterogeneous lattice systems composed of the existing fuel rods in research and test reactors, of which criticality data are not sufficiently provided by the Criticality Safety Handbook.

Nuclear fuel cycle, nuclear non-proliferation and nuclear security in Japan, 3; Challenges on technologies for nuclear non-proliferation/nuclear security and progressing credibility

Mochiji, Toshiro; Senzaki, Masao*; Tamai, Hiroshi; Iwamoto, Tomonori*; Ishiguro, Yuzuru*; Kitade, Yuta; Sato, Heigo*; Suehiro, Rie*; Taniguchi, Tomihiro*; Fukasawa, Tetsuo*; et al.

Enerugi Rebyu, 40(8), p.56 - 57, 2020/07

Strict application of IAEA safeguards and nuclear security should be implemented for Japan's full-scale nuclear fuel cycle. Based on the knowledge and experience of research and development in the nuclear fuel cycle, nuclear material management, the effective and efficient promotion of new technologies should be promoted with scientific and demonstrative measures to strengthen the world's nuclear non-proliferation and nuclear security. Development or sophistication of new technologies, human resource development, and reinforcement of the international framework are future challenge in the international community.

Nuclear fuel cycle, nuclear non-proliferation and nuclear security in Japan, 1; Peaceful nuclear use and nuclear non-proliferation

Mochiji, Toshiro; Senzaki, Masao*; Tamai, Hiroshi; Iwamoto, Tomonori*; Ishiguro, Yuzuru*; Kitade, Yuta; Sato, Heigo*; Suehiro, Rie*; Taniguchi, Tomihiro*; Fukasawa, Tetsuo*; et al.

Enerugi Rebyu, 40(6), p.58 - 59, 2020/05

In order to promote the peaceful use of nuclear energy, it is important not only to ensure safety but also to ensure nuclear non-proliferation and nuclear security. Japan has contributed to the international community through strengthening nuclear non-proliferation and nuclear security capabilities with technical and human resource development. However, in the wake of the accident at the Fukushima Daiichi Nuclear Power Plant in 2011, Japan's nuclear power plants have not restarted or plutonium use has not progressed smoothly. Concerns have been shown. Towards appropriate steps of Japan's nuclear fuel cycle policy, such concerns are examined and future efforts are summarized.

Magnetic anisotropy and thermodynamic anomaly in the superconducting mixed state of UBe probed by static dc magnetization measurements

Shimizu, Yusei*; Haga, Yoshinori; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*

Physical Review B, 93(2), p.024502_1 - 024502_8, 2016/01

https://doi.org/10.1103/PhysRevB.93.024502

X-ray backscattering study of crystal lattice distortion in hidden order of URuSi

Tabata, Chihiro*; Inami, Toshiya; Michimura, Shinji*; Yokoyama, Makoto*; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*

Philosophical Magazine, 94(32-33), p.3691 - 3701, 2014/00

https://doi.org/10.1080/14786435.2014.952701

Evaluation of nuclear characteristics of light-water-moderated heterogeneous cores in modified STACY

Izawa, Kazuhiko; Aoyama, Yasuo; Sono, Hiroki; Ogawa, Kazuhiko; Yanagisawa, Hiroshi; Miyoshi, Yoshinori

Proceedings of 9th International Conference on Nuclear Criticality (ICNC 2011) (CD-ROM), 11 Pages, 2012/02

For reactor physics and criticality safety researches, the Static Experiment Critical Facility (STACY) will be modified. In the modification, the present STACY, solution-fuel-type homogeneous cores, will be converted to fuel-pin-type heterogeneous cores moderated by light water. For nuclear safety design of the modified STACY, computational analyses have been carried out by using a Monte Carlo code MVP and a transport code system DANTSYS with cross-section data based on the JENDL-3.3. In the analyses, basic nuclear characteristics have been evaluated, such as criticality, water-level worth and reactor shutdown margin. By the results of these analyses, the feasibility of reactivity control mechanism and the sufficiency of reactor shutdown margin of the modified STACY were confirmed. In addition, temperature and void coefficients of reactivity and kinetic parameters were obtained to comprehend nuclear characteristics of the modified STACY.

Specific heat and magnetization studies of the superconducting mixed state of UBe

Shimizu, Yusei*; Ikeda, Yoichi*; Wakabayashi, Takumi*; Tenya, Kenichi*; Haga, Yoshinori; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*

Journal of the Physical Society of Japan, 80(Suppl.A), p.SA100_1 - SA100_3, 2011/07

https://doi.org/10.1143/JPSJS.80SA.SA100

Magnetization in the superconducting mixed state of the heavy-fermion compound UBe

Shimizu, Yusei*; Ikeda, Yoichi*; Wakabayashi, Takumi*; Tenya, Kenichi*; Haga, Yoshinori; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*

Journal of Physics; Conference Series, 273, p.012084_1 - 012084_4, 2011/02

https://doi.org/10.1088/1742-6596/273/1/012084

Evaluation of -ray dose components in criticality accident situations

Sono, Hiroki; Yanagisawa, Hiroshi*; Ono, Akio*; Kojima, Takuji; Soramasu, Noboru*

Journal of Nuclear Science and Technology, 42(8), p.678 - 687, 2005/08

https://doi.org/10.3327/jnst.42.678

Component analysis of -ray doses in criticality accident situations is indispensable for further understanding on emission behavior of -rays and accurate evaluation of external exposure to human bodies. Such dose components were evaluated, categorizing -rays into four components: prompt, delayed, pseudo components in the period of criticality, and a residual component in the period after the termination of criticality. This evaluation was performed by the combination of dosimetry experiments at the TRACY facility using a thermoluminescent dosimeter (TLD) made of lithium tetra borate and computational analyses using a Monte Carlo code. The evaluation confirmed that the dose proportions of the above components varied with the distance from the TRACY core tank. This variation was due to the difference in attenuation of the individual components with the distance from the core tank. The evaluated dose proportions quantitatively clarified the contribution of the pseudo and the residual components to be excluded for accurate evaluation of -ray exposure.

Analyses of neutronic characteristics of STACY heterogeneous core with 1.5-cm-lattice-pitch fuel pins

Sono, Hiroki; Fukaya, Yuji; Yanagisawa, Hiroshi; Miyoshi, Yoshinori

JAERI-Tech 2003-065, 61 Pages, 2003/07

JAERI-Tech-2003-065.pdf:3.11MB

A series of critical experiments using a heterogeneous core of the Static Experiment Critical Facility (STACY) in the Japan Atomic Energy Research Institute is planned in F.Y. 2003. In the experiment, the core is composed of uranyl nitrate solution (U enrichment 6 wt%) and 333 pins of uranium dioxide (U enrichment 5 wt%) loaded in lattice-pitch of 1.5 cm. Prior to the experiment, neutronic characteristics are analyzed to evaluate neutronic safety and criticality limitations of the core. The analyzed items are the parameters on criticality, reactivity and reactor shutdown margins. In the analyses, a Monte Carlo code, MVP, and a neutronics code system, SRAC, have been used with an evaluated nuclear data library, JENDL-3.3. By using the calculated characteristics, simplified equations to interpolate these values and criticality limitations of the core are evaluated. It has been also confirmed that the reactor shutdown margins will comply with safety criteria under all fuel conditions in the experiments.