Common evaluation procedure radioactivity concentration by theoretical calculation for radioactive waste generated from the decommissioning of research reactors

Okada, Shota; Murakami, Masashi; Kochiyama, Mami; Izumo, Sari; Sakai, Akihiro

JAEA-Testing 2022-002, 66 Pages, 2022/08

JAEA-Testing-2022-002.pdf:2.46MB

Japan Atomic Energy Agency is an implementing organization of burial disposal for low-level radioactive waste generated from research, industrial and medical facilities in Japan. Radioactivity concentrations of the waste are essential information for design of the disposal facility and for licensing process. A lot of the waste subjected to the burial disposal is arising from dismantling of nuclear facilities. Radioactive Wastes Disposal enter has therefore discussed a procedure to evaluate the radioactivity concentrations by theoretical calculation for waste arising from the dismantling of the research reactors facilities and summarized the common procedure. The procedure includes evaluation of radioactive inventory by activation calculation, validation of the calculation results, and determination of the disposal classification as well as organization of the data on total radioactivity and maximum radioactivity concentration for each classification. For the evaluation of radioactive inventory, neutron flux and energy spectra are calculated at each region in the reactor facility using two- or three-dimensional neutron transport code. The activation calculation is then conducted for 140 nuclides using the results of neutron transport calculation and an activation calculation code. The recommended codes in this report for neutron transport calculation are two-dimensional discrete ordinate code DORT, three-dimensional discrete ordinate code TORT, or Monte Carlo codes MCNP and PHITS, and for activation calculation is ORIGEN-S. Other recommendation of cross-section libraries and calculation conditions are also indicated in this report. In the course of the establishment of the procedure, Radioactive Wastes Disposal Center has discussed the commonly available procedure at meetings. It has periodically held to exchange information with external operators which have research reactor facilities. The procedure will properly be reviewed and be revised by reflecting future situ

Experience in the implementation of physical protection measures of nuclear material at the JAERI Tokai Establishment

; ; Tsuruta, Harumichi

Physical Protection of Nuclear Materials:Experience in Regulation,Implementation and Operations, p.195 - 200, 1998/00

no abstracts in English

Present activities preparation of a Japanese draft of structural design guidelines for the experimental fusion reactor

Miya, Kenzo*; ; Takatsu, Hideyuki; Hada, Kazuhiko; Koizumi, Koichi; Jitsukawa, Shiro; ; Okawa, Yoshinao; Shimakawa, T.*; Aoto, Kazumi*; et al.

Fusion Engineering and Design, 31, p.145 - 165, 1996/00

https://doi.org/10.1016/0920-3796(95)00433-5

no abstracts in English

Design study of fusion experimental reactor tritium plant, I; Tritium safety systems for reactor building

Yoshida, Hiroshi; ; Okawa, Yoshinao; Tanemori, Nozomu*; Horikiri, Hitoshi*

JAERI-M 93-107, 112 Pages, 1993/05

JAERI-M-93-107.pdf:3.29MB

no abstracts in English

Present status and problems of decommissioning technology, 8; Radioactivity measurement techniques

*;

Nihon Genshiryoku Gakkai-Shi, 33(5), p.441 - 442, 1991/05

no abstracts in English

Study on optimization of amount of radioactive waste in radioactive level and worker exposure dose in decommissioning and dismantling work

Sasagawa, Tsuyoshi; Shimada, Taro; Takeda, Seiji

no journal, , 

IAEA standard document (GSR part6) requires appropriate dose control and minimization of radioactive waste for decommissioning of nuclear facilities. It is necessary to develop a method to optimize the amount of radioactive waste and the radiation dose. Therefore, we developed a code to evaluate the optimum conditions of dismantling work by calculating the amount of radioactive waste in radioactive level and the radiation dose according to the conditions of the decommissioning process and analyzing the cost-benefit of both results. Furthermore, based on the information of decommissioning of JPDR, the sensitivity analysis was performed for the case of decontamination and dismantling of three kinds of tanks and associated piping, focusing on the size of cut pieces and the type of container. As a result, different trends were observed for the minimum number of containers of the radioactive waste in radioactive level and the minimum dose to workers. The cost-benefit analysis was performed to derive the optimum conditions of the type of container and the size of cut pieces with cost as an index, and the optimization method by the cost-benefit analysis based on the results of the amount of radioactive waste generated in radioactive level and the radiation dose was shown to be applicable.