[3H07-09] Severe Acident

[3H08] Effect of heating during the severe accident on the microstructure and the strength of LWR structural steels

(2)Change of microstructure of austenitic alloys for the core internals by ion-irradiation and annealing

*Takumi Hashimoto¹, Kento Takahashi, Hayato Ueda, Shiro Jitsukawa (1. National Institute of Technology, Fukushima College)

Keywords:Fukushima daiichi, Reactor decommissioning, Light water reactor, Fine structure, heating

Microstructure of the core internal components would be affected by both the neutron irradiation during service and the heating to elevated temperatures by the severe accident. The microstructure, therefore, seems to be applicable to estimate the temperature history of the components during the accident. Microstructure of 316 stainless steel after ion-irradiation + annealing has been examined. Ion-irradiation produced dislocation loops. Annealing induced the growth in size and the reduction in the number density of loops, as well as the formation of the vacancy clusters.