Determination of the fission gas release in the segment N0204 and gas phase result of anoxic leaching experiment

This paper presents the current status of the experiments performed at INE within the Work-packages 2 and 3 of the EURATOM FP7 Collaborative Project, “Fast / Instant Release of Safety Relevant Radionuclides from Spent Nuclear Fuel (CP FIRST-Nuclides)”. The segment N0204 from the pressure water reactor of Gösgen (KKG) nuclear power plant was selected to carry out this project. In a first approach and before the performance of leaching experiment, the fission gas release of this segment was determined to be 8.35% (in vol.). Leaching experiment of a cladded fuel pellet in bicarbonate water (19 mM NaHCO3 + 1 mM NaCl) under an Ar and H2 atmosphere with a total pressure of (40 ± 1) bar (pH2: 3 ± 1bar) were started. After a cumulative contact time of 57 days, 4.3% of the Xe and 17% of the Kr inventories of the cladded fuel pellet segment was released into the gas phase.