Issues and proposals for activation calculation of reactor decommissioning using recent evaluated nuclear data library

Okumura, Keisuke

Kaku Deta Nyusu (Internet), (133), p.63 - 67, 2022/10

http://www.aesj.or.jp/~ndd/ndnews/No133.html

no abstracts in English

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

Selection of important nuclides from the viewpoint of safety assessment for disposal of radioactive waste arising from research institute, 1; Evaluation of nuclide composition rates in waste generated from main research facilities

Sakai, Akihiro; Yoshimori, Michiro; Abe, Masayoshi

JAERI-Tech 2000-012, p.107 - 0, 2000/03

JAERI-Tech-2000-012.pdf:6.47MB

no abstracts in English

Re-evaluation of whole core nuclide inventory of the 1F; Development of detailed three-dimensional nuclide inventory data before the accident

Sakamoto, Masahiro; Okumura, Keisuke

no journal, , 

no abstracts in English

Present status of activation cross section data for nuclear reactor decommissioning, 4; Examination status of activation calculation of radioactive waste generated from research reactors for near surface disposal

Kochiyama, Mami; Sakai, Akihiro

no journal, , 

As part of the study on the burial disposal of waste from research facilities, we are studying a method for evaluating the radioactivity inventory of waste generated by the dismantling of research reactors. In the radioactivity evaluation of the research reactor, we have investigated the method of calculating the neutron transport in the reactor and using the obtained neutron spectrum to calculate the activation of the internal structure by the ORIGEN-S code. In recent years, we have introduced and evaluated libraries created based on JENDL-4.0 and JENDL/AD-2017, and we will introduce the status of their examination. And we will introduce how to apply the results obtained by the radioactivity evaluation calculation to burial disposal.

Present status and applications of activation cross section data for nuclear reactor decommissioning, 2; Points to note in activation calculations using recent evaluated nuclear data libraries

Okumura, Keisuke

no journal, , 

no abstracts in English

Development of sample radio-activity evaluation code at Materials and Life Science Facility in J-PARC

Harada, Masahide; Yamaguchi, Yuji; Hashimoto, Norimichi*; Ito, Taku*; Tajima, Takahiro*; Oku, Takayuki; Haga, Katsuhiro; Ikeda, Hiroshi*; Tamura, Satoshi*

no journal, , 

In Materials and Life Science Experimental Facility at J-PARC, carbon and mercury targets bombarded by 3 GeV and 1 MW proton beam produce muons and neutrons to provide to muon and neutron instruments. As the samples irradiated by muons and neutrons produce radioactive materials, an estimation of the radioactive materials produced in the irradiated samples is necessary for the stable operation and management of the facility. Therefore, a sample radio-activity evaluation code was developed using data from the DCHAIN-SP-2001 code. By selecting the irradiation conditions for each experiment and entering the information for each sample, the radio-activity of a sample can be calculated by multiplying the neutron flux by the activation cross section. The code is a servlet application, programed by JAVA, accessible on the Web, and can be used from the internal network. In the future, we will conduct activation experiments on various materials and validate this code.

Whole core three-dimensional nuclide inventory calculation of the Fukushima Daiichi Nuclear Power Station, 2; Calculation method and result for unit-2

Sakamoto, Masahiro; Okumura, Keisuke; Tada, Kenichi; Nishihara, Kenji; Mizokami, Shinya*; Mizokami, Masato*; Miki, Yosuke*; Kaneko, Seiji*

no journal, , 

no abstracts in English

Study on estimation of radioactivity concentration of biological shielding at Fukushima Daiichi Nuclear Power Station, 2; Contribution of activation processes and material composition in concrete

Ishigami, Tsutomu*; Koma, Yoshikazu; Okada, Takashi; Takahatake, Yoko; Sugita, Takeshi*; Okamoto, Tsutomu*; Seki, Masaya*; Nemoto, Hiroki*

no journal, , 

no abstracts in English

Applications of the methods used for nuclear reactor design to technology development for decommissioning of the Fukushima Daiichi Nuclear Power Station

Okumura, Keisuke

no journal, , 

As a part of human resource development for the decommissioning of the Fukushima Daiichi Nuclear Power Station(1F), I will give a lecture on the following contents to researchers who mainly specialize in reactor physics; (1) Activities of Collaborative Laboratories for Advanced Decommissioning Science (CLADS), (2) Activation calculation method for decommissioning of nuclear reactor, (3) Development of the method to predict dose rate distribution in 1F plant, (4) Simulation of the germanium detector, (5) Development of Non-Destructive Assay (NDA) technology for nuclear material accountancy of fuel debris canister by Monte Carlo simulation.