Decommissioning state of Plutonium Fuel Fabrication Facility; Dismantling the glove box W-9 and equipment interior, and a part of tunnel F1

Nagai, Yuya; Shuji, Yoshiyuki; Kawasaki, Takeshi; Aita, Takahiro; Kimura, Yasuhisa; Nemoto, Yasunori*; Onuma, Takeshi*; Tomiyama, Noboru*; Hirano, Koji*; Usui, Yasuhiro*; et al.

JAEA-Technology 2022-039, 117 Pages, 2023/06

JAEA-Technology-2022-039.pdf:11.96MB

Japan Atomic Energy Agency (JAEA) manages wide range of nuclear facilities. Many of these facilities are required to be performed adjustment with the aging and complement with the new regulatory standards and the earthquake resistant, since the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Station accident. It is therefore desirable to promote decommissioning of facilities that have reached the end of their productive life in order to reduce risk and maintenance costs. However, the progress of facility decommissioning require large amount of money and radioactive waste storage space. In order to address these issues, JAEA has formulated a "The Medium/Long-Term Management Plan of JAEA Facilities" with three pillars: (1) consolidation and prioritization of facilities, (2) assurance of facility safety, and (3) back-end countermeasures. In this plan, Plutonium Fuel Fabrication Facility has been selected as primary decommissioned facility, and dismantling of equipment in the facilities have been underway. In this report, size reduction activities of the glove box W-9 and a part of tunnel F-1, which was connected to W-9, are presented, and the obtained findings are highlighted. The glovebox W-9 had oxidation & reduction furnace, and pellet crushing machine as equipment interior. The duration of activity took six years from February 2014 to February 2020, including suspended period of 4 years due to the enhanced authorization approval process.

Antiferromagnetic-to-ferromagnetic transition induced by diluted Co in SrFeCoO:Magnetic circular X-ray dichroism study

Okamoto, Jun*; Mamiya, Kazutoshi*; Fujimori, Shinichi; Okane, Tetsuo; Saito, Yuji; Muramatsu, Yasuji*; Yoshii, Kenji; Fujimori, Atsushi*; Tanaka, Arata*; Abbate, M.*; et al.

Physical Review B, 71(10), p.104401_1 - 104401_5, 2005/03

https://doi.org/10.1103/PhysRevB.71.104401

The antiferromagnetic-to-ferromagnetic transition in SrFeCoO (0.15) induced by Co doping has been studied by magnetic circular X-ray dichroism. The orbital and spin magnetic moments of the Fe and Co 3 states under the magenetic field of 2 T are found to show different dependences: The spin polarization of Fe 3 gradually increases with Co concentration; On the other hand, a large spin polarization of Co 3 is induced already in the antiferromagnetic phase, indicating that the Co moment is nearly fully alligned already in the antiferromagnetic phase. This suggests that the alignment of the Fe magnetic moment in SrFeCoO is induced by interaction with doped Co magnetic moment. Possible formation of ferromagnetic Co rich region is discussed.

Study on an application of Powered Air Purifying Respirator (PAPR) half mask to -ray radiation management at a MOX fuel facility

Tamura, Ken; Hatanaka, Nobuhiro; Nemoto, Shuji; Kimura, Yasuhisa; Hirano, Hiroshi*; Kawasaki, Takashi

no journal, , 

no abstracts in English

Improving the efficiency of vehicle screening during a nuclear emergency using portable radiation portal monitors, 1; Time and manpower savings expected from simultaneous screening of tires and wiper area

Kawasaki, Kohei*; Hiraoka, Hirokazu; Ezaki, Iwao*; Kameda, Shuji*; Kimura, Masanori; Saito, Shota

no journal, , 

In the current contamination screening plan, the vehicle's tires are measured using a portable radiation portal monitor, while wiper area is measured by an inspector using a survey meter. These two measurements confirm that contamination levels are below the screening thresholds. However, if both areas could be screened simultaneously using the portal monitor, it would improve the efficiency of the screening process. In this study, the degree of efficiency that can be expected from simultaneous screening by the portal monitor was verified through simulated screening using actual vehicles. The results showed that this screening method can contribute to a 9.4 second time reduction, from an average of 29.5 seconds to 20.1 seconds per vehicle, and a reduction of two inspectors per lane.