Determination of neptunium in neptunium-uranium-plutonium mixed oxide fuel by spectrophotometry.

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JNC TN8400 2001-026, 29 Pages, 2001/12

JNC-TN8400-2001-026.pdf:0.99MB

The measurement condition by spectrophotometry was evaluated to measure Np content in MOX fuel containing Np. The Np concentration was obtained by measuring the 727nm absorption peak, after the valence of Np in the sample solution was adjusted to the Np(Ⅳ). The calibration curve showed the linearity up to Np concentration 0.8mg/ml. Though Pu and U quantity were respectively added to the Np solution to 30 times and 60 times of Np concentration, there was no effect to the Np analysis. By using this method, relative standard deviation (RSD) of the analyzed values of Np content for 2%Np - MOX fuel was about 4%. In addition, It was confirmed that the Np content could be measured without separating Np from Pu and U. This method can be sufficiently applied as a quick simple method to analyze Np content in MOX fuel containing Np.

The Influence of Gd content on the properties of simulated fuel debris

Akashi, Masatoshi; Hirooka, Shun; Watanabe, Masashi; Komeno, Akira; Morimoto, Kyoichi

no journal, , 

Uranium oxide fuels containing GdO had been used to control fuel power in reactors of the Fukushima Daiichi Nuclear Power Plant where the severe accident occurred in 2011. JAEA has been evaluating physical properties of the molten fuel debris in the damaged core. However physical properties of the fuel debris containing Gd are not known, hence it is very difficult to select an appropriate debris removal method. Especially, it is important to know the distribution of Gd in the molten fuels for the evaluation of nuclear criticality safety during removal work. In this study, simulated samples of the molten fuel debris, which consisted of ZrO, UO and GdO, were prepared and their properties, which are density, crystal structure, thermal conductivity, thermal expansion and melting temperature, were investigated. This study includes results obtained under the research program entrusted to International Research Institute for Nuclear Decommissioning including Japan Atomic Energy Agency by Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry (METI) of Japan.