Stress minimization procedure for stainless steel tube produced by phase transition of solidified lead-bismuth eutectic

Ohdaira, Naoya; Saito, Shigeru; Wan, T.; Obayashi, Hironari; Sasa, Toshinobu

no journal, , 

J-PARC plans to install a lead-bismuth eutectic (LBE) spallation target to study the irradiation effects of structural materials in flowing LBE environment. A freeze seal valve is to be used for the LBE circulation system. LBE is known as a material which expands after solidification; hence the solidified LBE in freeze seal part will be deformed and tube in freeze seal part might be broken by the imposed stress consequently. To minimize the stress at freeze seal valve, deformation of stainless steel (SS) generated by LBE expansion in different cooling conditions were studied. It was found that annealing at a certain temperature for 24 hours is effective to reduce the stress.