RELATIONSHIP BETWEEN SWELLING AND IRRADIATION CREEP IN COLD-WORKED PCA STAINLESS-STEEL IRRADIATED TO SIMILAR-TO-178 DPA AT SIMILAR-TO-400-DEGREES-C

The eighth and final irradiation segment for pressurized tubes constru cted from the fusion Prime Candidate Alloy (PCA) has been completed in FFTF. At 178 dpa and similar to 400 degrees C, the irradiation creep of 20% cold-worked PCA has become dominated by the ''creep disappearan ce'' phenomenon. The total diametral deformation rate has reached the limiting value of 0.33%/dpa at the three highest stress levels employe d in this test. The stress-enhancement of swelling tends to camouflage the onset of creep disappearance, however, requiring the use of sever al non-traditional techniques to extract the creep coefficients. No fa ilures occurred in these tubes, even though the swelling ranged from s imilar to 20 to 40%.