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Nanjo, Kotaro; Shiotsu, Hiroyuki; Maruyama, Yu; Sugiyama, Tomoyuki; Okamoto, Koji*
Journal of Nuclear Science and Technology, 60(7), p.816 - 823, 2023/07
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Nanjo, Kotaro; Ishikawa, Jun; Sugiyama, Tomoyuki; Pellegrini, M.*; Okamoto, Koji*
Journal of Nuclear Science and Technology, 59(11), p.1407 - 1416, 2022/11
Times Cited Count：7 Percentile：90.45(Nuclear Science & Technology)Komiyama, Daisuke; Amaya, Masaki
JAEA-Research 2016-013, 20 Pages, 2016/08
JAEA-Research-2016-013.pdf:6.05MB
The boric acid in the coolant may precipitate on the fuel cladding surface in the case that the blockage of coolant flow path etc. occurs and/or the cooling of fuel becomes insufficient during a LOCA (Loss-Of-Coolant Accident) in PWRs. While there is much knowledge about the compatibility between Zircaloy-4 and boric acid under normal operation conditions, such knowledge under high temperature condition, e.g. LOCA, has not been sufficient. In this study, isothermal heating tests were carried out by using Zircaloy-4 plates with solid boric acid in various atmospheres at up to 900
C; and the stability of boric acid, the reaction between Zircaloy-4 and boric acid and the effect of solid boric acid on the high temperature oxidation behavior of Zircaloy-4 were investigated. From the results obtained, it was suggested that, if boric acid anhydride remained on the surface of Zircaloy-4, the boric acid anhydride prevented the surface of Zircaloy-4 from contacting oxidizing atmosphere and mitigated the high-temperature oxidation of Zircaloy-4. In the case that solid boric acid adhered to the surface of pre-oxidized Zircaloy-4 and they have been heated up to high temperature, it was indicated that the solid boric acid penetrated into the gaps in the pre-oxide layer and the penetrated solid boric acid mitigated the oxidation of Zircaloy-4 thereafter.
C control rod in severe accident of LWRShirasu, Noriko; Kurata, Masaki; Ogawa, Toru*
Proceedings of 2014 Water Reactor Fuel Performance Meeting/ Top Fuel / LWR Fuel Performance Meeting (WRFPM 2014) (USB Flash Drive), 6 Pages, 2014/09
In the accident of Fukushima-Daiichi Nuclear Power Plant, degraded fuels containing Zircaloy probably reacted with BC control blades containing stainless steel cladding or blade sheath. Since light elements like B and C are able to react easily with various elements and form various chemical species, several concerns are pointed out, such as variation in volatility and heat generation by oxidation of B and C. The chemical states of degraded fuel were evaluated on the assumption of thermodynamic equilibrium under various conditions of oxygen potential and temperature. The chemical behavior of B affects significantly the variation in oxygen potential with progressing severe accident, and many kinds of volatile compounds are formed by oxidation. The behavior of B causes the changes of volatility of FPs, such as Sr, Cs and Mo.
Journal of Radioanalytical and Nuclear Chemistry, 129(1), p.77 - 84, 1989/00
Times Cited Count：20 Percentile：86.79(Chemistry, Analytical)no abstracts in English
