Experiments With WER Fuels to Confirm Safety Criteria

During loss-of-coolant (LOCA) accidents the primary reactor coolant system shall be maintained in a safe state so that the coolability of fuel rods was maintained and the emergency core cooling criteria must be met. These criteria were accepted originally for Western design reactors and the same criteria were applied in Hungary to the Paks NPP as well. However the WER type reactor has different core materials and geometrical arrangement, so the Western experimental results may not be directly applied. That is why experimental series were conducted to check the following safety criteria: "* peak cladding temperature (PCT) is not allowed to exceed 12000C, "* during oxidation the equivalent cladding reacted (ECR) is limited to 17% of the total cladding thickness at any local position on the fuel rod, * fuel rods must keep a coolable geometry.