Controlled release of radioactive krypton gas

Watanabe, Kazuki; Kimura, Norimichi*; Okada, Jumpei; Furuuchi, Yuta; Kuwana, Hideharu*; Otani, Takehisa; Yokota, Satoru; Nakamura, Yoshinobu

JAEA-Technology 2023-010, 29 Pages, 2023/06

JAEA-Technology-2023-010.pdf:3.12MB

The Krypton Recovery Development Facility reached an intended technical target (krypton purity of over 90% and recovery rate of over 90%) by separation and rectification of krypton gas from receiving off-gas produced by the shearing and the dissolution process in the spent fuel reprocessing at the Tokai Reprocessing Plant (TRP) between 1988 and 2001. In addition, the feasibility of the technology was confirmed through immobilization test with ion-implantation in a small test vessel from 2000 to 2002, using a part of recovered krypton gas. As there were no intentions to use the remaining radioactive krypton gas in the krypton storage cylinders, we planned to release this gas by controlling the release amount from the main stack, and conducted it from February 14 to April 26, 2022. In this work, all the radioactive krypton gas in the cylinders (about 7.110 GBq) was released at the rate of 50 GBq/min or less lower than the maximum release rate from the main stuck stipulated in safety regulations (3.710 GBq/min). Then, the equipment used in the controlled release of radioactive krypton gas and the main process (all systems, including branch pipes connected to the main process) were cleaned with nitrogen gas. Although there were delays due to weather, we were able to complete the controlled release of radioactive krypton gas by the end of April 2022, as originally targeted without any problems such as equipment failure.

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PNC TN8440 92-053, 110 Pages, 1992/09

PNC-TN8440-92-053.pdf:2.74MB

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PNC TN8440 91-032, 119 Pages, 1991/03

PNC-TN8440-91-032.pdf:2.82MB

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R&D on separation, concentration and recovery of Tc from Mo for commercial production

Shiina, Takayuki*; Tsuchiya, Kunihiko; Nagai, Yasuki; Morikawa, Yasumasa*; Takeuchi, Nobuhiro*

no journal, , 

According to statistical data reported by the Japan Radioisotope Association (JRIA) in 2014, the Mo/Tc generator and Tc injections (Tc labeled pharmaceuticals) continues to account for approximately 80% of the entire in-vivo supply in Japan. Furthermore, the number of Tc injection supplies is approximately four times larger than that of the Mo/Tc generator. Therefore, Chiyoda Technol Co. have performed a research and development (R&D) for the domestic production of Tc in cooperation with the Japan Atomic Energy Agency (JAEA) and FUJIFILM RI pharma Co., Ltd. to ensure a constant and reliable supply of Tc. CTC therefore has a plan to stably produce Tc from Mo, which can be produced by the Mo(n,) reaction using the Japan Materials Testing Reactor (JMTR) and by the Mo(n,2n) reaction using some new cyclotrons, and thereby to meet the Japanese demand for Tc together with pharmaceutical companies in Japan. These production methods of Mo were selected from viewpoints of safety, nuclear proliferation resistance and waste management. The specific activity of Mo produced by these methods, however, is very low compared with that of (n,f)Mo. Therefore, it is essential to develop some techniques for separation, concentration and recovery of Tc, and it will be necessary to choose the best methods such as a wet method by solvent extraction and a dry method by sublimation, finally. In future, we aim to provide to about 20% of the domestic demand for Mo using the JMTR and cyclotrons, 100-200 6-day Ci per week at the end of irradiation, and will carry out empirical studies for the commercial production of Tc.

Deterioration study of adsorbents for selective minor actinides separation using extraction chromatography under radiation

Miyazaki, Yasunori; Watanabe, So; Sano, Yuichi; Kofuji, Hirohide; Takeuchi, Masayuki; Ishigami, Ryoya*; Koka, Masashi*; Sato, Takahiro*

no journal, , 

no abstracts in English