Keywords: spent fuel management, monitoring, condition, wet interim storage, VVER-440, leak tightness testing, nuclear fuel assemblies, fission product release, sorbent, Nifsil, leak tests, nuclear power plants, nuclear energy, Slovakia, online detection, VVER reactors, nuclear waste management
Leak tightness testing system for nuclear fuel assemblies in wet conditions of interim spent fuel storage
The Slovak wet Interim Spent Fuel Storage Facility in the Jaslovske Bohunice nuclear power plant was built and put in operation in 1986. Since 1999, leak tests of VVER-440 fuel assemblies have been provided by the special leak tightness detection system 'Sipping in Pool' delivered by the Framatome-anp facility, with external heating for the precise detection of active specimens. Although this system seems to be very effective, the detection time of all fuel assemblies in one storage pool is too long (several months). Therefore, a new online detection system, based on a sorbent KNiFC-PAN for effective 134Cs and 137Cs activity, was developed. This sorbent was compared with another type of sorbent, Nifsil, and results are presented in this paper. The design of this detection system and its possible application in the Slovak wet spent fuel storage facility are discussed. For completeness, the initial results of the new system are also presented.