The effect of fast neutron radiation on the impact strength of two precipitation hardening stainless steels has been determined using full-size Charpy V-notch specimens. The brittle-ductile impact transition temperature of type 17-4 PH stainless steel aged at 1100 F was found to increase from approximately room temperature to values above 300 F after irradiation at 545 F to exposures in excess of 5 x 10¹⁹ neutrons per sq cm > 1 Mev. The impact strength of doubly aged austenitic type A-286 stainless steel was found to increase from about 30 ft-lb in the unirradiated condition to approximately 50 ft-lb after irradiation.

A technique for performing in-reactor slow-cycle fixed range fatigue tests on thin-walled tubing is described. Results of preliminary work on type 304 stainless steel tubing are presented. Irradiation in a core position in the General Electric Test Reactor during tests was found to produce a threefold decrease in strain cycle life of type 304 stainless steel in a configuration similar to that of fuel element cladding.