Category Archives: Study on Neutron Spectrum of Pulsed Neutron Reactor

Options of Principles of Fuel Debris Criticality Control in Fukushima Daiichi Reactors

Kotaro Tonoike, Hiroki Sono, Miki Umeda, Yuichi Yamane, Teruhiko Kugo, and Kenya Suyama Abstract In the Three Mile Island Unit 2 reactor accident, a large amount of fuel debris was formed whose criticality condition is unknown, except the possible highest 235U/U enrichment. The fuel debris had to be cooled and shielded by water in which the minimum critical mass is […]

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License Application and Schedule of the STACY Modification

The license application for the STACY modification was sent in February 2011 and has been under safety review by the Nuclear Regulation Authority (NRA) of Japan to comply with new safety standards for research reactors enforced in December 2013 [13]. In particular, the NRA will strictly demand prevention measures against natural disasters such as a tsunami from all reactors located […]

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Behavior of 14C in Rice Paddy Fields

From the aforementioned results, the behavior of 14C in rice paddy fields could be considered as follows (a conceptual diagram appears in Fig. 26.5). When irrigation water is contaminated by 14C-bearing sodium acetate, the 14C compound is taken up and metabolized by indigenous bacteria. A part of the 14C is assimilated by the bacterial cells, and the rest of the […]

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Current Status of HLW

HLW contains very toxic fission products. Fission products in the spent nuclear fuels are highly radioactive. Some countries such as Finland, Sweden, and USA directly dispose spent nuclear fuels as HLW after cooling at spent fuel storage. According to the conventional nuclear fuel cycle policy, spent nuclear fuels in Japan are reprocessed for separating fission products from uranium and plutonium, […]

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Volume Reduction of Municipal Solid Wastes Contaminated with Radioactive Cesium by Ferrocyanide Coprecipitation Technique

Yoko Fujikawa, Hiroaki Ozaki, Hiroshi Tsuno, Pengfei Wei, Aiichiro Fujinaga, Ryouhei Takanami, Shogo Taniguchi, Shojiro Kimura, Rabindra Raj Giri, and Paul Lewtas Abstract Municipal solid wastes (MSW) with elevated concentrations of radioac­tive cesium (rad-Cs hereafter) have been generated in some areas of Japan in the aftermath of the Fukushima Daiichi Nuclear Power Plant (F1 hereafter) accident. Both recycling and final […]

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