Verification of the tables for control rods calibration at NSRR

Motome, Yuiko; Agake, Toshiki; Yanagisawa, Hiroshi

JAEA-Technology 2024-015, 30 Pages, 2025/01

JAEA-Technology-2024-015.pdf:1.36MB

The tables for calibration of control rods were verified, which is used positive period method and improved rod drop method of periodic inspection at Nuclear Safety Research Reactor (NSRR). Those tables are "DOUBLING TIME-REACTIVITY" and "DECAY OF NEUTRON FLUX AFTER INSTANTANEOUS REDUCTION OF REACTIVITY". They are prepared around 1975. Since those tables do not clearly express source of values and records of data used in calculations, the authors verified those tables again. For the verification, the tables were reproduced as follows. For the positive period method, the relationship between the period and reactivity was analytically evaluated by using the inhour equation with NSRR's parameters. For the improved rod drop method, the ratios of neutron flux after the rod drop with parameters of negative reactivities was calculated using the EUREKA- 2 code. As a result, the values described in the tables well agree with those by the present evaluation because it is confirmed that standard deviations of the differences in the value by between the present evaluation and the tables are less than 0.035%. For this reason, it is verified that these tables are valid in the practical use for NSRR operations.

Benchmark analyses on control rod worths of TRIGA reactor modeled in the ICSBEP handbook using continuous-energy Monte Carlo code MVP version 3

Yanagisawa, Hiroshi; Umeda, Miki; Motome, Yuiko; Murao, Hiroyuki

Proceedings of 12th International Conference on Nuclear Criticality Safety (ICNC2023) (Internet), 10 Pages, 2023/10

https://doi.org/10.11484/jaea-conf-2024-001

The benchmark analyses on the TRIGA reactor of the IEU-COMP-THERM-013 (ICT-013) in the ICSBEP handbook using the MVP version 3 code were carried out with the Japanese, US and European nuclear data libraries, including JENDL-5. The analyses on effective neutron multiplication factors (k's) were also performed for another TRIGA reactor defined in the ICT-003 as well as the ICT-013. As a result, it is confirmed that the calculated k's vary in the range of 0.8% with the libraries. The results also suggest that there might be unknown bias in the ICT-013 for the calculated k's. For the analyses on the control rod worths of the ICT-013, it is confirmed that differences in the worths among the libraries become smaller than those in k's. Most of the errors involved in k's are considered to be cancelled in the calculation of the worths since the worths are obtained by subtraction of the reciprocals of two sorts of k's. The differences in the worths by between the benchmark and alternative methods defined in the ICT-013 were tried to be examined from the aspect of the differences in horizontal flux distributions by between those methods. It is confirmed that the differences in the worths for two shim control rods, which are fully withdrawn at a delayed critical state, are well understood by that attempt, but on the other hand the differences are not sufficiently explained for a regulating control rod, which is partially inserted to attain delayed criticality.

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