METHOD FOR DETECTING SINGLE FLAW IN FUEL ELEMENT Russian patent published in 2001 - IPC

FIELD: checking nuclear-reactor fuel element cans for depressurization. SUBSTANCE: activity of reference long- and short-living fission products contained in coolant is measured with reactor running at full power, constant of nuclide outlet from coolant is determined, and conclusion on presence of depressurized fuel elements in reactor core is made by their activity. Used as reference radionuclide is fission product whose constants of decay and deposition on surfaces are much lower than nuclide outlet constant at coolant cleaning filters; lifetime of nuclide is much shorter than hold time at cleaning filter and much longer than lifetime of predecessors in chain of radioactive transforms. Potential reference nuclides are Br, Rib, I, Cs; actually used are iodine isotopes I¹³¹, I¹³³, I¹³⁵. EFFECT: enhanced radiation safety. 5 cl, 2 dwg