Annual report of Nuclear Science Research Institute, JFY2021

Nuclear Science Research Institute, Sector of Nuclear Science Research

JAEA-Review 2023-050, 178 Pages, 2024/03

JAEA-Review-2023-050.pdf:7.06MB

Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long- term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, belong to NSRI. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2021 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.

Annual report for FY2020 on the activities of Department of Decommissioning and Waste Management (April 1, 2020 - March 31, 2021)

Department of Decommissioning and Waste Management

JAEA-Review 2022-001, 112 Pages, 2022/06

JAEA-Review-2022-001.pdf:6.51MB

This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2020 to March 31, 2021. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM. In FY2020 radioactive wastes generated from R&D activities in NSRI were treated safely. They were about 267 m of combustible solid wastes and 233 m of noncombustible solid wastes and 78 m of liquid wastes. After adequate treatment, 1,448 waste packages (in 200 L-drum equivalent) were generated. The total amounts of accumulated waste packages were 130,604 as of the end of FY2020 due to efforts of the restitution of waste packages to the Japan Radioisotope Association and volume reduction treatments of the stored waste packages. Decommissioning activities were carried out for the JAEA's Reprocessing Test Facility (JRTF), the Liquid Waste Treatment Facilities, the Compaction Facilities, and Fusion Neutronics Source (FNS) facilities. As for the R&D activities, studies on radiochemical analyses of wastes for disposal were continued. In order to pass the conformity review on the New Regulatory Requirements for waste management facilities, the Approval of the design and construction method was applied sequentially for the Nuclear Regulation Authority. The ministry of the Environment and Tokai-mura office requested JAEA to dispose of the contaminated soil generated by the accident of the Fukushima Daiichi Nuclear Power Station. The monitoring work at the playground was conducted during this period.

Analysis of the radioactivity concentrations in radioactive waste generated from JPDR Facility

Tobita, Minoru*; Haraga, Tomoko; Endo, Tsubasa*; Omori, Hiroyuki*; Mitsukai, Akina; Aono, Ryuji; Ueno, Takashi; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2021-013, 30 Pages, 2021/12

JAEA-Data-Code-2021-013.pdf:1.47MB

Radioactive wastes generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried in the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes until the beginning of disposal. In order to contribute to this work, we collected and analyzed concrete samples generated from JPDR facility. In this report, we summarized the radioactivity concentrations of 21 radionuclides (H, C, Cl, Ca, Co, Ni, Sr, Nb, Ag, Cs, Eu, Eu, Ho, U, U, Pu, Pu, Pu, Am, Am, Cm) which were obtained from radiochemical analysis of the samples in fiscal year 2018-2019.

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JRR-3 and JPDR facilities

Tsuchida, Daiki; Haraga, Tomoko; Tobita, Minoru*; Omori, Hiroyuki*; Omori, Takeshi*; Murakami, Hideaki*; Mitsukai, Akina; Aono, Ryuji; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2020-022, 34 Pages, 2021/03

JAEA-Data-Code-2020-022.pdf:1.74MB

Radioactive wastes generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried in the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes until the beginning of disposal. In order to contribute to this work, we collected and analyzed concrete samples generated from JRR-3 and JPDR. In this report, we summarized the radioactivity concentrations of 22 radionuclides(H, C, Cl, Ca, Co, Ni, Sr, Nb, Ag, Ba, Cs, Eu, Eu, Ho, U, U, Pu, Pu, Am, Am, Cm) which were obtained from radiochemical analysis of the samples.

Study on the evaluation methodology of the radioactivity concentration in low-level radioactive wastes generated from post irradiation examination facility

Mitsukai, Akina; Haraga, Tomoko; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Technology 2019-015, 52 Pages, 2019/11

JAEA-Technology-2019-015.pdf:2.46MB

In the future, radioactive waste which generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. It is necessary to establish the method to evaluate the radioactivity concentrations of the radioactive wastes. In this work, we studied the evaluation method of radioactivity concentration based on radiochemical analysis data (H-3, C-14, Cl-36, Co-60, Ni-63, Sr-90, Mo-93, Nb-94, Tc-99, Ag-108m, Sn-126, I-129, Cs-137, Eu-152, Eu-154, U-233+234, U-238, Pu-238, Pu-239+240, Pu-241, Am-241, Am-243, Cm-244) which was generated from research facility Hot Laboratory. As a result of examining the application of the scaling factor method, the correlation with Key-nuclide in some nuclides which are Sr-90, I-129, Eu-154, U-233+234, Pu-238, Pu-239+240, Am-241, Cm-244 confirmed by the correlation coefficient and t-test. In the present radiochemical analysis data, the mean activity concentration method can be applied to all nuclides which could not be applied to the scaling factor method H-3, C-14, Cl-36, Ni-63, Mo-93, Nb-94, Tc-99, Ag-108m, Sn-126, Eu-152, U-238, Pu-241 and Am-243. Ni-63, Tc-99, Eu-152 and U-238 could be applied to the scaling factor method with getting several additional data, this study will be continued to review for the practical evaluation method.

Annual report for FY2016 on the activities of Department of Decommissioning and Waste Management (April 1, 2016 - March 31, 2017)

Department of Decommissioning and Waste Management

JAEA-Review 2018-008, 87 Pages, 2018/07

JAEA-Review-2018-008.pdf:2.67MB

This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2016 to March 31, 2017. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM.

Development of determination method of Mo content in metal waste generated at the Japan Power Demonstration Reactor

Shimada, Asako; Omori, Hiroyuki*; Kameo, Yutaka

Journal of Radioanalytical and Nuclear Chemistry, 314(2), p.1361 - 1365, 2017/11

AA2017-0285.pdf:0.49MB

https://doi.org/10.1007/s10967-017-5440-6

A separation method of Mo from Nb, Zr, and the matrix elements of rubble waste was modified to determine the content of Mo in metal waste. A separation scheme to treat 1 g of metal waste was established by optimizing the amount of ascorbic acid, the rinsing solution, and repeating of the procedure. A thin-layer source was prepared using direct drop deposition and evaporation to measure Mo content. Finally, Mo content in the metal waste generated at the Japan Power Demonstration Reactor was analyzed using the developed method.

Separation of Zr in the rubble waste generated at the Fukushima Daiichi Nuclear Power Station

Shimada, Asako; Kameo, Yutaka

Journal of Radioanalytical and Nuclear Chemistry, 311(3), p.1613 - 1618, 2017/03

AA2016-0191.pdf:0.23MB

https://doi.org/10.1007/s10967-016-5126-5

Separation method of Zr using trans uranium resin (TRU resin) was developed. Approximately 100% of Zr, Nb, Bi, Th, and U and a part of Mo and Hg were extracted on the TRU resin from 3 M HNO solution and separated from Li, Be, Mg, Al, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr,Ag, Cd, In, Cs, Ba. Approximately 100% of Zr, Nb, and U were striped from the TRU resin with 0.01 M HF and 10% of Mo, 7.1% of Hg, 77% of Bi, and 20% of Th were also included in the stripping solution. In order to measure Zr with inductively coupled plasma mass spectrometry (ICP-MS), Zr has to be separated from Nb and Mo to avoid isobaric interference. Therefore, further purification of Zr using tetra valent actinide resin (TEVA resin) was applied. The developed method was evaluated with the simulated rubble sample solution. Although a part of Zr was eluted during sample loading, most of Zr was extracted on the TRU resin and separated major elements of the rubble sample. Finally, Zr was separated from Nb and Mo with the TEVA resin.

Radiochemical analysis of rubble collected from Fukushima Daiichi Nuclear Power Station

Sato, Yoshiyuki; Tanaka, Kiwamu; Ueno, Takashi; Ishimori, Kenichiro; Kameo, Yutaka

Hoken Butsuri, 51(4), p.209 - 217, 2016/12

https://doi.org/10.5453/jhps.51.209

A large amount of contaminated rubbles were generated by the accident at the Fukushima Daiichi Nuclear Power Station (F1NPS). For safe decommissioning of F1NPS, it is important to evaluate the composition and concentration of radionuclides in the rubbles. In this paper, to characterize the rubbles collected at F1NPS in Unit-1, Unit-2 and Unit-3, radiochemical analysis was operated. As a result of radiochemical analysis, -ray-emitting nuclides Co, Cs and Eu, -ray-emitting nuclides H, C, Sr and Tc, and -particle-emitting nuclides Pu, Am and Cm were detected. In contrast, Nb and Eu concentrations were below the detection limit. Measured radioactive concentrations implied that H, C, Co and Sr concentrations depended on Cs concentration respectively. This analysis was characterized the radioactivity concentrations of the rubbles.

Study on radionuclide analysis of rubble and plants for decommissioning of Fukushima Daiichi Nuclear Power Station

Seki, Kotaro; Sasaki, Takayuki*; Akimoto, Yuji*; Tokunaga, Takahito; Tanaka, Kiwamu; Haraga, Tomoko; Ueno, Takashi; Ishimori, Kenichiro; Hoshi, Akiko; Kameo, Yutaka

JAEA-Technology 2016-013, 37 Pages, 2016/07

JAEA-Technology-2016-013.pdf:2.09MB

In this study, based on the simple and rapid analytical method established from the wastes from research facilities, we created analytical schemes which is applicable to rubble and plants collected at Fukushima Daiichi, then transported to Nuclear Science Research Institute of JAEA. We examined the applicability, and confirmed quantifiability of radioactivity concentration with high recovery rate without being affected by fission products such as Sr and Cs.