Behavior of Type 316 stainless steel under simulated fusion reactor irradiation

Abstract

NOTrCE-Hik itport wii prepared u «n accoim of wock tponiorcd by the Uniud SlaleaGoitnunenl. Neither At United Suiei noi Die tfciiled Slatci Department of Etttiff, nor iny or thtk employees, IKX any or their contrition, ubconfraclon, or (heir employ*!, imkn uiy unrnnty, expreit or implied, or iKtimes any left! lUbililyoi teiponeibOity for IheKcuncy.compfeleMK or UKfulntn of iny inrormttion, •pDaraiui, product or proceM dkckwd, or fepretenu that lit u» would not infringe privately owned ri|[t1l. ABSTRACT Fusion reactor irradiation response in alloys containing nickel can be simulated in thermal-spectrum fission reactors, where displacement damage is produced by the high-energy neutrons and helium is produced by the capture of two thermal neutrons in the reactions: 58 Ni + n -*• 59 Ni + y; S9 Ni + n -• 56 Fe + a. Examination of type 316 stainless steel specimens irradiated in HFIR has shown that swelling due to cavity formation and degradation of mechanical properties are more severe than can be predicted from fast reactor irradiations, where the helium contents produced are far too low to simulate fusion reactor service. Swelling values are greater and the temperature dependence of swelling is different than in the fast reactor case. The property change most restrictive for fusion reactor performance is the low values of ductility that result from irradiation. These results imply limitations on the operating conditions and useful lifetimes of stainless steel first-wall and high flux region structural components of fusion reactors. *0perated for the U.S.