Mechanical Property Degradation of Fast Reactor Fuel Cladding During Thermal Transients

Abstract

Temperature-transient-to-burst tests were performed on irradiated Type 316 stainless steel cladding. Special attention was paid to control the atmosphere for specimen preparation and testing to avoid possible change in the chemical state of the fission products which remained inside the fueled specimens. Under the controlled atmosphere, the burst temperature of the irradiated fueled cladding was not degraded at lower stress level by the ‘fuel adjacency effect (FAE)’. The so-called fuel adjacency effect was suspected to be caused, at least in part, by an atmospheric effect during post-irradiation examination. The transient burst temperatures of Type 316 stainless steels were fairly insensitive to the material conditions in a controlled testing environment, although the onset of swelling acted to decrease the failure temperature. Results were also presented for irradiated advanced austenitic stainless steel and ferritic/martensitic steel cladding.

Effects of Fast Reactor Irradiation Conditions on Tensile and Transient Burst Properties of Ferritic/Martensitic Steel Claddings

“…The temperature-transient-to-burst tests 5,7,[11][12][13] were performed on irradiated cladding specimens using the machine shown schematically in Fig. 4.…”

“…The post-irradiation examination results of irradiation creep, 4) tensile and temperature-transient-to-burst tests [5][6][7] for specimens irradiated at temperatures from 678 to 1013 K up to a neutron dose of 103 dpa (displacement per atom) were obtained using material testing rigs to clarify the effects of radiation on the mechanical properties of PNC-FMS claddings. There are, however, no published reports on the mechanical properties of PNC-FMS cladding irradiated as fuel pins.…”