Development of a prototype shielding-free radiation-resistant diamond neutron measurement system (Contract research); FY2023 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Hokkaido University*

JAEA-Review 2025-028, 66 Pages, 2025/11

JAEA-Review-2025-028.pdf:3.59MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2023. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (1F), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2023, this report summarizes the research results of the "Development of a prototype shielding-free radiation-resistant diamond neutron measurement system" conducted in FY2023. The present study aims to develop a prototype of a shielding-free neutron measurement system for 1F. The system consists of diamond neutron detectors and radiation-resistant silicon integrated circuits, and has radiation resistance of more than 10 MGy and 4 MGy, respectively, at the component level in terms of integrated dose, and has a track record of stable operation under -ray dose rate environment of 1.5 kGy/h. Future applications are expected to include neutron detectors for debris investigation, criticality proximity monitoring monitors, and neutron detectors for dry tube investigation in pressure vessels. In this development, a prototype consisting of 100 diamond detector elements of 5 mm square will be developed to obtain system construction technology and to evaluate system performance. In addition, a subcriticality evaluation method will be developed. This development will lead to the completion of system development, development of the actual system in collaboration with the manufacturer, and introduction of the system into 1F decommissioning project.

Updating fission product chemistry database based on recent investigation in Fukushima-Daiichi Nuclear Power Station, 2; Temperature effects on the deposition behavior of CsOH aerosols on concrete main phase-CaCO

Luu, V. N.; Nakajima, Kunihisa; Rizaal, M.; Miwa, Shuhei

Proceedings of International Topical Workshop on Fukushima Decommissioning Research 2024 (FDR2024) (Internet), 4 Pages, 2024/10

Experimental determination of deposition velocity of CsOH aerosols on CaCO at temperature range 170 - 290C

Luu, V. N.; Nakajima, Kunihisa

Nuclear Engineering and Design, 426, p.113402_1 - 113402_7, 2024/09

https://doi.org/10.1016/j.nucengdes.2024.113402

Surface analyses of CsOH chemisorbed on concrete and aggregate at around 200C

Luu, V. N.; Nakajima, Kunihisa

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 9 Pages, 2023/05

https://doi.org/10.1299/jsmeicone.2023.30.1940

Research and development of transparent materials for radiation shield using nanoparticles (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Kyushu University*

JAEA-Review 2020-036, 176 Pages, 2021/01

JAEA-Review-2020-036.pdf:9.55MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2019. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Research and Development of Transparent Materials for Radiation Shield Using Nanoparticles" conducted in FY2019. The present study aims to reduce radiation exposure of workers in debris retrieval/analysis and reduce deterioration of optical and electronic systems in remote cameras. For these purposes, we develop transparent radiation shield by making the shield materials into nanoparticles, and dispersing/solidifying them in epoxy resin. By making boride or heavy metal compounds into nanoparticles, we will also develop a radiation shield that shields both neutrons and gamma-rays, and also suppresses secondary gamma-rays produced from neutrons.

Shielding

Maekawa, Fujio

Hamon, 28(4), p.208 - 211, 2018/11

https://doi.org/10.5611/hamon.28.4_208

Adequate shielding of neutrons and associated -rays is of importance from viewpoints of the radiation safety of researchers and good experimental data taking by reducing the background. This article introduces basics of neutron shielding, physics and suitable materials for neutron and -ray shielding, and an example of conceptual shielding design for the 1-MW spallation neutron source of J-PARC MLF.

Design and nuclear analysis of the equatorial launcher for EC heating and current drive of ITER plasma

Takahashi, Koji; Abe, Ganji; Isozaki, Masami; Oda, Yasuhisa; Sakamoto, Keishi; Kobayashi, Noriyuki*; Iida, Hiromasa*; Abe, Teruo*; Komatsuzaki, Manabu*

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05

https://doi.org/10.1299/jsmeicone.2015.23._ICONE23-1_245

An ITER equatorial EC launcher has been designed to inject a 170GHz, 20MW millimeter (mm) wave beam to plasma with poloidal steering functionality in order to obtain more driven current at the peripheral region of plasma. The equatorial launcher has three sets of mm-wave beam row and each is composed of eight waveguide lines and a quasi-optical transmission region that is formed by a steering and fixed mirror, locating in front of the waveguide outlet. The millimeter wave design to accomplish the high transmission efficiency more than 99% and to compliant with the requirement (criteria) on heat load on the mirrors and beam size at the resonance location of plasma has been successfully developed. This optimized configuration of the millimeter wave components ensures that both mm-wave beams from the middle and bottom row pass through the same BSM opening and then, the feasible and reliable design of BSMs can be carried out. The nuclear analysis of this design modification shows that the residual dose rate at the launcher back end is reduced by 20%, compared to the previous design, which has three openings. This paper reports that the design optimization of the mm-wave design of the equatorial launcher with poloidal beam scan functionality, enhancing the off axis current drive is developed and ensures the effective mm-wave propagation, feasible design of the EL BSMs and nuclear shield structure. The design of the associated structural components such as the port plug and internal shield is also reported.

Measurement of depth distributions of H and C induced in concrete shielding of an electron accelerator facility

Endo, Akira; Harada, Yasunori; Kawasaki, Katsuya; Kikuchi, Masamitsu

Applied Radiation and Isotopes, 60(6), p.955 - 958, 2004/06

https://doi.org/10.1016/j.apradiso.2004.01.010

no abstracts in English

Japanese evaluated nuclear data library version 3 revision-3; JENDL-3.3

Shibata, Keiichi; Kawano, Toshihiko*; Nakagawa, Tsuneo; Iwamoto, Osamu; Katakura, Junichi; Fukahori, Tokio; Chiba, Satoshi; Hasegawa, Akira; Murata, Toru*; Matsunobu, Hiroyuki*; et al.

Journal of Nuclear Science and Technology, 39(11), p.1125 - 1136, 2002/11

https://doi.org/10.3327/jnst.39.1125

Evaluation for JENDL-3.3 has been performed by considering the accumulated feedback information and various benchmark tests of the previous library JENDL-3.2. The major problems of the JENDL-3.2 data were solved by the new library: overestimation of criticality values for thermal fission reactors was improved by the modifications of fission cross sections and fission neutron spectra for U; incorrect energy distributions of secondary neutrons from important heavy nuclides were replaced with statistical model calculations; the inconsistency between elemental and isotopic evaluations was removed for medium-heavy nuclides. Moreover, covariance data were provided for 20 nuclides. The reliability of JENDL-3.3 was investigated by the benchmark analyses on reactor and shielding performances. The results of the analyses indicate that JENDL-3.3 predicts various reactor and shielding characteristics better than JENDL-3.2.

Proceedings of the Symposium on the Joint Research Project between JAERI and Universities; Status and Perspective of the Advanced Radiation Technology Project, January 27, 1999, National Education Center, Tokyo, Japan

Committee for the Joint Research Project on the Advanced Radiation Technology; Committee for the Collaborative Research on the Advanced Radiation Technology

JAERI-Conf 2000-008, 113 Pages, 2000/06

JAERI-Conf-2000-008.pdf:11.5MB

no abstracts in English