Progress in conceptual design of a pool-type sodium-cooled fast reactor in Japan

Kato, Atsushi; Kubo, Shigenobu; Chikazawa, Yoshitaka; Miyagawa, Takayuki*; Uchita, Masato*; Suzuno, Tetsuji*; Endo, Junji*; Kubo, Koji*; Murakami, Hisatomo*; Uzawa, Masayuki*; et al.

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 11 Pages, 2022/04

The authors are carrying out conceptual design studies for a pool-type sodium-cooled fast reactor. There are main challenges such as measures against severe earthquake in Japan, thermal hydraulic in a reactor vessel (RV), a decay heat removal system design. When the JP-pool SFR of 650 MWe is installed in Japan, it shall be designed against the severe seismic conditions. Additionally, a newly three-dimensional seismic isolation system is under development.

Research on factor analysis and technical process for achieving denuclearisation; Investigation on Libya's case

Tamai, Hiroshi; Tazaki, Makiko; Shimizu, Ryo; Kimura, Takashi; Nakatani, Takayoshi; Suda, Kazunori

JAEA-Review 2021-073, 19 Pages, 2022/03

JAEA-Review-2021-073.pdf:1.51MB

As a part of "Research on Factor Analysis and Technical Process for Achieving Denuclearisation", investigation on Libya's cases of nuclear development and denuclearisation, and analysis of its characteristics have been conducted. Libya had been suspected that dictator Qadaffi had an interest in the acquisition of weapons of mass destruction (WMD) since early 1970s after his revolution. US and UK intelligence were focusing on Libya's situation; however, actual status was not revealed for a long time. In 1980s, Libya faced to economic exhaustion due to sanctions from the international community against Libya's supporting terrorism. Libya decided to abandon WMD development and its denuclearisation in early 2000s. Several factors to prompt Libya's decisions can be highlighted; economic sanctions; witnessing regime collapse of President Hussein due to Iraq War who aimed at WMD; revealing secret procurement of centrifuge equipment through the inspection of German-flagged ships by US. Libya's denuclearisation was rapidly implemented to prevent Libya from reverting to nuclear development through well-coordinated roles among main players, quick decisions by Libyan side, and warning effect of Iraqi case. International Atomic Energy Agency (IAEA) played a central role in the verification of all related facilities and activities in Libya. Through safeguards activities beyond those permitted by Additional Protocol (AP), IAEA evaluated the whole Libya's nuclear programme. The denuclearisation was successfully completed by removal of nuclear materials and related equipment from Libya. It was also revealed that Libya's technological capabilities had not well developed to utilize procured materials and equipment. Libya's case is regarded in the international community as a good practice of denuclearisation. On the other hand, Qadaffi administration was overthrown by the democratisation movement that occurred after denuclearisation. It might be understood as a miserable end

Study of rational safeguards for the treatment of radioactive waste containing nuclear materials

Nakatani, Takayoshi; Shimizu, Ryo; Tazaki, Makiko; Kimura, Takashi; Tamai, Hiroshi; Suda, Kazunori

Dai-42-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2021/11

Currently, JAEA is in the advancing of decommissioning own nuclear facilities, and some facilities have been handling nuclear materials. In decommissioning, it is necessary to consider rational methods while keeping nuclear non-proliferation and transparency, including treatment of radioactive waste generated from these facilities and methods for terminating safeguards. In this study, we considered the above issues regarding waste treatment with reference to the guidance of Safeguards by Design (SBD) published by the International Atomic Energy Agency (IAEA).

Research on factor analysis for achieving denuclearization, 10; Summary of research; Analysis of denuclearization factors of target countries and lessons learned from the analysis

Tazaki, Makiko; Shimizu, Ryo; Kimura, Takashi; Nakatani, Takayoshi; Tamai, Hiroshi; Suda, Kazunori

Dai-42-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2021/11

no abstracts in English

Carrying-out of whole nuclear fuel materials in Plutonium Research Building No.1

Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.

JAEA-Technology 2021-001, 144 Pages, 2021/08

JAEA-Technology-2021-001.pdf:12.98MB

Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.

Discrimination between active and non-active faults based on the chemical composition of fault gouge; An Attempt using linear discriminant analysis

Tateishi, Ryo*; Shimada, Koji; Shimizu, Mayuko; Ueki, Tadamasa*; Niwa, Masakazu; Sueoka, Shigeru; Ishimaru, Tsuneari

Oyo Chishitsu, 62(2), p.104 - 112, 2021/06

https://doi.org/10.5110/jjseg.62.104

We attempted to discriminate between active and non-active faults by linear discriminant analysis using the chemical composition data of fault gouges in Japan, and then examined the elements that represent the difference between them and better discriminants. As a result, the multiple discriminants obtained could discriminate between them with high probability. In addition, the generalization performance of these discriminants is discussed, and the discriminants that can be expected to have high discriminant performance for unknown samples are presented. Also, from the combination of elements common to these discriminants, we narrowed down the number of elements that represent the difference between active and non-active faults to 6, and showed that the combination of TiO and Sr contributing the most to the discrimination. The method applied in this study is an innovative one that can discriminate the activity by chemical analysis of fault rocks that are universally present in the bedrock.

Morphological reproductive characteristics of testes and fertilization capacity of cryopreserved sperm after the Fukushima accident in raccoon ()

Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.

Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03

https://doi.org/10.1111/rda.13887

We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.

Discriminative measurement of absorbed dose rates in air from natural and artificial radionuclides in Namie Town, Fukushima Prefecture

Ogura, Koya*; Hosoda, Masahiro*; Tamakuma, Yuki*; Suzuki, Takahito*; Yamada, Ryohei; Negemi, Ryoju*; Tsujiguchi, Takakiyo*; Yamaguchi, Masaru*; Shiroma, Yoshitaka*; Iwaoka, Kazuki*; et al.

International Journal of Environmental Research and Public Health, 18(3), p.978_1 - 978_16, 2021/02

https://doi.org/10.3390/ijerph18030978

Research on factor analysis for achieving denuclearization, 6; Denuclearization of former republics of the Soviet Union

Kimura, Takashi; Tazaki, Makiko; Nakatani, Takayoshi; Shimizu, Ryo; Tamai, Hiroshi; Suda, Kazunori

Dai-41-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 3 Pages, 2020/11

Following the collapse of the Soviet Union in 1991, Ukraine, Kazakhstan, and Belarus (the former three Soviet Union countries) unintentionally deployed nuclear weapons within their territory. The former three Soviet Union countries achieved denuclearization by transferring the deployed warheads and the delivery system of the nuclear weapons to Russia for disposal. This report gives our analysis of the success factors for achieving denuclearization by investigating the efforts towards denuclearization of such countries, the relevant frameworks such as the Treaty on the Reduction of Strategic Arms, etc.

Research on factor analysis for achieving denuclearization, 7; Framework on the non-proliferation of weapons scientists and engineers

Suda, Kazunori; Kimura, Takashi; Nakatani, Takayoshi; Shimizu, Ryo; Tazaki, Makiko; Tamai, Hiroshi

Dai-41-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 3 Pages, 2020/11

The disintegration of central control in the former Soviet Union (FSU) prompted concerns among western countries that weapons scientists and engineers would flee to countries to acquire know-hows of weapons of mass destruction. To reduce this threat, the International Science and Technology Center (ISTC) was established at Moscow aimed at engaging weapons scientists and engineers from the FSU in peaceful use of nuclear technologies. In order to contribute the denuclearization study, it was discussed on contributions and good practice of the ISTC including non-proliferation measures of weapons scientists and engineers, deploying research results.