Irradiation Creep-Swelling Interaction in Modified 316 Stainless Steel up to 200 dpa

摘要

The irradiation creep-swelling interaction parameters were precisely derived for MONJU fuel pin cladding PNC316 by irradiation tests of pressurized tubes in FFTF. It was found out that a creep-swelling coupling coefficient decreased and asymptotically approached a constant value as the swelling progresses, although it was widely believed that the irradiation creep rate could be proportional to the swelling rate. This non-proportionality in the irradiation creep-swelling interaction was investigated by means of the rate theory analyses under sequential climb-controlled glide process of dislocation due to absorption of interstitial atoms. It was clarified through a constructed robust model that the presence of a precipitate sink should upset the proportionality of the net interstitial flux into dislocations to the net vacancy flux into the voids. In addition, irradiation creep parameters derived by material irradiation was demonstrated to be applicable for reasonably predicting the irradiation creep deformation in the fuel pins.