Application of Fuel-In-Air Modelling For Various Fuel Handling Scenarios

Abstract

Recently, a number of fuel handling situations took place at Pickering NGS when fuel was exposed to air for prolonged time. These include incidents of fuel bundles jammed in the transfer mechanism elevator or residing in a disabled transfer mechanism magazine. In order to carry out an inspection and the subsequent repair work, if necessary, water cooling must be interrupted for a period of time. In a different situation, defective Unit 1 fuel was shipped following only relatively short cooling time. A new 12-bundle defuelling scheme for Units 3 and 4 retubing requires fuel bundles in the top transfer mechanism magazine tube to be exposed to air. In this paper; these different situations are discussed emphasizing the economic benefits of accurate analytical modelling of the specified fuel-in-air events. Validation and certain actual simulation results of the model THERMOS are presented.