Effects ofWire Spacer Contact and Pellet-Cladding Eccentricity on Fuel Cladding Temperature under Natural Circulation Decay Heat Removal Conditions in Sodium-cooled Fast Reactor
Toward the commercialization of fast reactors, a design study of Japan Sodium Cooled Fast Reactor (JSFR) is being performed. In this design study, adoption of fully natural circulation system is being examined as the decay heat removal system. In order to confirm feasibility of the fully natural circulation system, we are developing a new evaluation method of core hot spot in transition from rated operation to natural circulation decay heat removal conditions, which requires uncertainty factor assessment for the natural circulation conditions as well as for the rated operation conditions. In this paper, we focus on effects of wire spacer contact and pellet-cladding eccentricity on the peak cladding temperature as typical uncertainty factors and evaluated these two effects under natural circulation conditions quantitatively. Three dimensional thermal-hydraulic analyses were carried out to obtain detailed sodium coolant flow and temperature fields and cladding tube temperature distribution in a wire-wrapped nineteen-pin fuel assembly using a commercial CFD code. As a result, it was found that the effects of these two uncertainty factors on peak temperature in the cladding tube are not negligible even under natural circulation conditions in which the reactor power is down to decay heat levels. In the case of loss-of-external-power event, increase of the maximum temperature in the cladding tube due to these effects is estimated to be a few degrees at the timing of when the second peak of coolant temperature appears just before natural circulation is caused by buoyancy force.
fast reactor natural circulation decay heat removal core hot spot uncertainty
Norihiro DODA Hiroyuki OHSHIMA Hideki KAMIDE OsamuWATANABE Yoshiyuki OHKUBO
Japan Atomic EnergyAgency 4002 Narita, O-arai, Ibaraki 311-1393, Japan Mitsubishi FBR Systems, Inc. 2-34-17 Jingumae, Shibuya-ku, Tokyo 150-0001, Japan Mitsubishi FBR Systems, Inc.2-34-17 Jingumae, Shibuya-ku, Tokyo 150-0001, Japan
国际会议
上海
英文
1831-1841
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）