Development of post-irradiation examination techniques for HTTR structural material

Post-irradiation examinations (PIEs) on heat resistant alloys used for the High Temperature Engineering Test Reactor (HTTR) which is now under construction, are one of major PIE works in the JMTR Hot Laboratory facility (JMTR HL). The structural materials tested are Alloy 800H for the control rod cladding, 2 1/4Cr-1Mo steel for the reactor pressure vessel and 1Cr-1Mo-0.25V steel for the bolts, etc.. PIE techniques developed mainly for the HTTR are creep tests to obtain high temperature creep property and low cycle fatigue tests to obtain high temperature fatigue property. Newly developed PIE techniques for the study of irradiation effects on reactor pressure vessel materials are carried out to clarify dynamic fracture toughness of reactor structural materials using an instrumented Charpy impact testing machine. This report describes the present status of material tests with emphasis on PIE techniques newly developed for the HTTR. (author)