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Kurata, Masaki; Shirasu, Noriko; Kawakami, Kazuto*
Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2015) (Internet), p.139 - 156, 2015/09
Thermodynamic database is a useful tool for evaluating preliminary chemical reactions during molten core concrete interaction and phase relations in fuel debris. Japan Atomic Energy Agency and Nippon Steel Sumitomo Metal Corporation are collaborating to develop an open thermodynamic database by combining their own nuclear- and steel/slag-databases. The phase diagrams of Al
O
-UO, AlO-ZrO, SiO-UO, and UO-ZrO sub-systems and those of AlO-UO, SiO-UO, and AlO-ZrO sub-systems were able to be drawn properly using the cell model parameters and the sub-lattice model parameters assessed in the present study, respectively. The concerns for improving accuracy on the assessment were extracted in several sub-systems.
Amaya, Masaki; Udagawa, Yutaka; Narukawa, Takafumi; Mihara, Takeshi; Sugiyama, Tomoyuki
Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2015), Part.2 (Internet), p.10 - 18, 2015/09
Advanced fuels which consist of cladding materials with high corrosion resistance and pellets with lower fission gas release have been developed by utilities and fuel vendors to improve fuel performance even in the high burnup region and also raise the safety level of current nuclear power plants to a higher one. In order to evaluate the adequacy of present safety criteria and safety margins in terms of such advanced fuels and provide a database for future regulation on them, Japan Atomic Energy Agency (JAEA) has started a new extensive research program called ALPS-II program (Phase II of Advanced LWR Fuel Performance and Safety program). This program is primarily composed of tests simulating a reactivity-initiated accident (RIA) and a loss-of-coolant accident (LOCA) on high burnup advanced fuels shipped from European nuclear power plants. This paper describes an outline of this program and some experimental results with respect to RIA and LOCA which have been obtained in this program.
Tokushima, Kazuyuki; Shibata, Hiroki; Kurata, Masaki; Sawada, Akihiko*; Sakamoto, Kan*
Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2015), Conference Proceedings, Poster (Internet), p.478 - 485, 2015/00
Two type tests were performed to examine the prevention effect of the oxide layers to liquefaction interaction between Zircaloy and core component materials. The oxide layer of Zircaloy was clearly confirmed to prevent the liquefaction interaction under the temperature of melting point of stainless steel even if the oxide layer on Zircaloy of approximately 30 micro meters, which is thinner than it is predicted to be formed under typical accident condition. The oxide layers were able to be formed even in the region where the gas flow is significantly limited by narrow arrangement. Although the oxide layers at the inner position of upper end plug was hard to form, the prevention effect of the oxide layers was sufficiently observed. The axial variation of the thickness of the oxide layers was observed. It suggested that variation of partial pressure of HO should be considered to evaluate the growth rate of the oxide layers for detail.
