Inspection of radioactive waste packages stored in the Waste Storage Facility L; Planning and trial operation

Kawahara, Takahiro; Suda, Shoya; Fujikura, Toshiki; Masai, Seita; Omori, Kanako; Mori, Masakazu; Kurosawa, Tsuyoshi; Ishihara, Keisuke; Hoshi, Akiko; Yokobori, Tomohiko

JAEA-Technology 2023-020, 36 Pages, 2023/12

JAEA-Technology-2023-020.pdf:2.79MB

We have been storing drums containing radioactive waste (radioactive waste packages) at waste storage facilities. We have been managing radioactive waste packages along traditional safety regulations. However, over 40 years has passed from a part of them were brought in pit-type waste storage facility L. Most of them are carbon steel 200 L drums, and surface of them are corroded. For better safety management, we started to take drums out from the pit and inspect them in FY 2019. After each inspection, we repair them or remove the contents of the drum and refill new drums if necessary. In this report, we will introduce the planning, the review of the plan, and the trial operation of this project.

Development of separation technology of transuranium elements and fission products by using new extractants and adsorbents; Development of separation technology of Cs and Sr (Contract research)

Hoshi, Harutaka; Kikuchi, Takahiro; Asakura, Toshihide; Morita, Yasuji; Kimura, Takaumi

JAEA-Research 2010-016, 70 Pages, 2010/07

JAEA-Research-2010-016.pdf:2.31MB

We have studied selective separation of Cs and Sr, which are included in high level liquid waste (HLLW) generated from reprocessing of spent nuclear fuel and are major heat generators, by using extractant impregnated adsorbents. Cs adsorbent using calix arane derivatives showed excellent selectivity for Cs. It also showed significant stability against -irradiation. Sr adsorbent using crown ether derivatives also showed high selectivity for Sr from nitric acid solution, except for Ba and Tc. Dynamic capacity decreased ca. 30% after -irradiation. Hot test using genuine HLLW stored in NUCEF was performed for separation of Cs and Sr through columns, respectively. Each Cs and Sr was separated from other typical fission product elements as well as the results obtained in preliminary experiments. Finally, Cs and Sr were separated according to a supposed separation scheme. Although some complexing agents were added in simulate HLLW, no negative effect was found.

Study on stability of CsSr solvent impregnated resin against irradiation

Hoshi, Harutaka; Kikuchi, Takahiro; Morita, Yasuji; Kimura, Takaumi

JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 24, 2009/12

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2009-041.pdf

Minimization of radioactive waste from reprocessing process of spent nuclear fuel is strongly desired. We develop an advanced technology for separation of heat generating elements (Cs and Sr) from high level waste to optimize radioactive waste by its characteristics. Some novel solvent impregnated resins (SIRs) were prepared and these SIRs indicated promising ability to separate Cs and Sr from other typical fission products dissolved in nitric acid solution. These adsorbents contacting with nitric acid solution were exposed to ray in a vial. After the irradiation, adsorbents were filtrated through a membrane filter. The adsorption capacity was examined by using irradiated adsorbents after drying. It is concluded that both SIRs maintained their high selectivity for Cs and Sr, respectively, after irradiation. Decreasing ratio of adsorption capacity by irradiation can be estimated from these results. It contributes significantly for conceptual design of separation plant.

Study on stability of CsSr solvent impregnated resin against irradiation

Hoshi, Harutaka; Kikuchi, Takahiro; Morita, Yasuji; Kimura, Takaumi

no journal, , 

Novel solvent impregnated resins (SIR), which have significant selectivity for Cs or Sr, were examined their stability against irradiation. SIR was soaked in nitric acid solution and was irradiated by Co source. After the irradiation, resin was filtrated and air-dried. The capacity of Cs or Sr was examined by batch method. The capacity reduced with nitric acid concentration, however, it was mainly caused by elution of impregnated extractant into aqueous phase. Thus, these resins indicated rather stability against irradiation. Selectivity was also examined through a column packed with irradiated resin. Cs or Sr was effectively separated from other typical fission products by using simulated high level liquid waste.

Emergency safety measures at the Tokai Reprocessing, 2

Ouchi, Masayuki; Hoshi, Takahiro; Sasaki, Shunichi; Isobe, Hiroyasu; Nagaoka, Shinichi; Kurabayashi, Kazuaki; Obu, Tomoyuki

no journal, , 

Plutonium nitrate solution is stored in tanks that have cooling system to prevent boiling accident by decay heat and scavenging system to prevent explosion of hydrogen generated by radiolysis. These systems are designed to be provided power from emergency power generators at the Tokai Reprocessing Plant (TRP) when commercial power is lost. In addition, some apparatus (mobile power generators and nitrogen gas cylinder to scavenge hydrogen, etc.) are recently deployed at TRP on the basis of power loss in Fukushima Daiichi nuclear accident. In this report, these safety measures for emergency are shown.

Measurement of the hydrogen concentration in the vessel off-gas generated radiolytically from Pu storage tanks

Hoshi, Takahiro; Nagaoka, Shinichi; Kudo, Atsunari; Ouchi, Masayuki; Isobe, Hiroyasu; Obu, Tomoyuki; Kurabayashi, Kazuaki

no journal, , 

no abstracts in English

Solidification and stabilization for Pu nitrate solution at TRP, 1; Confirmations for equipment and facilities soundness after The Great East Japan Earthquake, and emergency safety measures

Takahashi, Naoki; Nakamura, Yoshinobu; Obu, Tomoyuki; Samoto, Hirotaka; Namatame, Toshihiro; Hoshi, Takahiro; Kurabayashi, Kazuaki; Mukai, Yasunobu; Kimura, Yuichi; Kurita, Tsutomu

no journal, , 

no abstracts in English