Review of recent irradiation creep results

Abstract

Materials deform faster under stress in the presence of irradiation by a process known as irradiation creep. This phenomenon is important to reactor design and has been the subject of a large number of experimental and theoretical investigations. This purpose of this work is to review the recent experimental results to obtain a summary of these results and to determine those research areas that require additional information. The investigations have been classified into four subgroups based on the different experimental methods used. These four are: (1) irradiation creep using stress relaxation methods; (2) creep measurements using pressurized tubes; (3) irradiation creep from constant applied load; and (4) irradiation creep experiments using accelerated particles. Measurement of irradiation creep is a difficult task because of the small strains involved and the uncertain and hostile radiation environment. Each of the above techniques was chosen because of some advantage overcoming the difficulties. Each method also has important limitations. As yet, no single method for measuring irradiation creep has provided consistently accurate data over wide temperature, stress, and time ranges. In this review the available data are considered and the strengths and deficiencies of each method evaluated. New areas for further work are suggested, including further analysis of the dependence of creep on swelling, temperature, stress state, and alloying additions. Recent publications in each of these areas have shown unexpected or unexplained results.