Study On Cancelling Secondary Source Assemblies During Refuling Cycles

Chinese government developed nuclear power industry in the early 1970 s and spectacular progress has been made till now.With the continuous development of nuclear power in China,the trend of fleet/base for nuclear power is becoming more and more obvious.Most of nuclear power plants adopt secondary source assembly to provide basic source intensity and safety surveillance(surveillance of SRC counts)for reactor during the process of loading/unloading and core start-up.However,activation of secondary source assembly is one of the main ways to provide and exhaust tritium.Meanwhile,the cladding of secondary source assembly will degrade because of long time operation.So cladding damage may happen and hit against the fuel rod cladding.The author has investigated the status of secondary source assembly used in America and France.Compared with problems related with secondary source assembly used in China,author decided to choose the topic “cancelling secondary source assembly during refueling cycles”.By expounding the structure/function/disadvantage of secondary source assembly,analyzing its working principles and mechanism of producing and exhausting tritium by secondary source assembly,demonstrating feasibility of replacing secondary source assembly by spent fuel assemblies,testing the implementation plan and evaluating core safety when cancelling secondary source assembly,author confirms that cancelling secondary source assembly is necessary and feasible.Considering that most of nuclear power plants adopt the design of PWR with secondary source assemblies and long fuel cycles,the researching result can well guide nuclear power operators to cancel secondary source assembly.Thus,tritium effluent will be reduced significantly and the clean-ability of nuclear power will be improved.