Abstract
In the present study, a RELAP5/Mod3 input deck for the spent fuel pool of the Chinshan Nuclear Power Station of Taiwan Power Company is developed. Chinshan nuclear power station employs a Boiling Water Reactor (BWR IV) designed by General Electric and Mark I containment. The input deck is used to analyze the loss of cooling event of spent fuel pool. The work involved in the study includes：(1)Use the ASB-92 formula to calculate decay power of the spent fuels. The spent fules of the latest discharged cycle are calculated in detail. The decay power generated in these spent fuel depends on the final power of the spent fuels during operation. (2) The lumped parameter approach is adopted to model the spent fuel racks within the pool. The rack which contains maxmum numbers of the latest cycle of spent fuels is model in detail. (3) The radiation heat transfer model is built. (4) The impact of counter current flow limit (CCFL) and radation heat transfer model is assessed. (5) Sensitivity studies of the cooling effect of water spray on the heat up of spent fules are performed. The results indicate that spent fuel is uncovered at 6.75 days after accident takes place and the cladding temperature rises above 2200℉at 8.1 days after accident takes place 8.1 days. The time is about 13.2 hours less that the results predicted using simple energy balance method. The results also show that the impact of CCFL and radiation heat transfer model is marginal. The results indicate that the earlier take spray action, the shorter time to recover the spent fuel will take.If the capacity of spray is bigger, the cladding temperature will be decreased more effectively.