A parametric study of helium retention in beryllium and its effect on deuterium retention

作者：Alegre D^*; Baldwin M J; Simmonds M; Nishijima D; Hollmann E M; Brezinsek S; Doerner R P

来源：Physica Scripta, 2017, T170: 014028.

DOI：10.1088/1402-4896/aa8c99

• beryllium
• helium retention
• deuterium retention
• helium and deuterium mix
• ITER tritium retention
• high-Z contamination

Beryllium samples have been exposed in the PISCES-B linear plasma device to conditions relevant to the International Thermonuclear Experimental Reactor (ITER) in pure He, D, and D/He mixed plasmas. Except at intermediate sample exposure temperatures (573-673 K) He addition to a D plasma is found to have a beneficial effect as it reduces the D retention in Be (up to similar to 55%), although the mechanism is unclear. Retention of He is typically around 10(20)-10(21) He m(-2), and is affected primarily by the Be surface temperature during exposition, by the ion fluence at <500 K exposure, but not by the ion impact energy at 573 K. Contamination of the Be surface with high-Z elements from the mask of the sample holder in pure He plasmas is also observed under certain conditions, and leads to unexpectedly large He retention values, as well as changes in the surface morphology. An estimation of the tritium retention in the Be first wall of ITER is provided, being sufficiently low to allow a safe operation of ITER.

• 出版日期2017-12