TRANSPORT NUCLEAR POWER PLANTS IRRADIATED FUEL ASSEMBLIES FUEL ELEMENT CLADDING TIGHTNESS MONITORING METHOD Russian patent published in 2023 - IPC G21C17/00 G21C17/07 

FIELD: nuclear power plant fuel element cladding radiation tightness monitoring method.

SUBSTANCE: invention relates to nuclear power plant fuel element cladding radiation tightness monitoring method. An irradiated fuel assembly is placed in a leak-tight case, the case and circulation circuit are filled with a gaseous medium with oxygen concentration of 0,5 to 1,0% vol. The case is heated up to a temperature of 300°C and the gas is pumped through a closed circulation loop passing through a chiller, droplet eliminator, aerosol filter, iodine-129-selective filter, and carbon dioxide absorber, Krypton-85 activity is measured and the fuel assembly cladding tightness is determined by comparing the measured value of krypton-85 activity with the established criteria for rejection of defective fuel assemblies, after the measurement gas is discharged from the container. Before measuring the activity, gas is pumped through a catalyst, where hydrogen containing tritium is oxidized to water and through drying agent to absorb water vapour containing tritium, dry absorber is used as absorber of carbon-14 contained in carbon dioxide, and the gas is dumped through aerosol cleaning filter and carbon filter to absorb krypton-85 after completing the measurement.

EFFECT: invention increases fuel element cladding tightness monitoring accuracy and reliability.

4 cl, 3 dwg, 4 tbl