Role of Radial Temperature Gradient in Outside - in Type Failure of High Burn - up Fuel Cladding Tubes during Power Ramp Tests

摘要

The role of radial temperature gradient in the outside - in type failure was examined by using unirradiated fuel cladding tubes. The temperature difference between the inner and outer surfaces of fuel cladding tube was approximately 60 K (LHGR=40kW/m). The results demonstrated that the radial temperature gradient caused the thermal difusion from the inner to the outer part of the fuel claddings and enhanced the radial cracking.