Coupled Thermo-Mechanical Creep Analysis for Boiling Water Reactor Pressure Vessel Lower Head
In this paper we consider a hypothetical severe accident in a Boiling Water Reactor (BWR) with molten core materials relocation to the lower head and subsequent debris bed and then melt pool formation. Efficiency of Control Rod Guide Tube (CRGT) cooling and external vessel wall cooling as severe accident management measures is investigated. The focus is on possibility of retention of decay-heated melt inside the reactor pressure vessel which is contingent upon the ultimate mechanical strength of the vessel structures under given mechanical and thermal loads and cooling conditions. Influence of pool depth and corresponding transient thermal loads on the reactor vessel failure mode is studied. First, efficiency of CRGT cooling is considered. A coupled thermo-mechanical creep analysis of the reactor vessel is performed revealing two different modes of vessel failure: (I) a ‘ballooning’ of the vessel bottom and (ii) a ‘localized creep’ concentrated within the vicinity of the top surface of the melt pool. It is important to note that these two modes of vessel failures may result in different consequences in the event of melt release and ex-vessel melt coolability. Second, possibility of in-vessel retention with CRGT and external vessel cooling is investigated. We found that up to certain pool depth the external vessel cooling was able to suppress the creep and subsequently prevent vessel failure.
Severe Accident Boiling Water Reactor In-vessel Coolability and Retention Thermo-Mechanical Creep Analysis
Walter Villanueva Chi-Thanh Tran Pavel Kudinov
Division of Nuclear Power Safety, Royal Institute of Technology (KTH), Roslagstullsbacken 21, Stockh Present address: Institute of Energy, 6 Ton That Tung, Dong Ha, Hanoi, Vietnam
国际会议
上海
英文
1699-1712
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）