[en] Pacific Northwest Laboratory (PNL) has developed and demonstrated a pilot process for trapping and storing ⁸⁵Kr recovered and purified from the dissolver off-gas stream of a nuclear fuel reprocessing plant. Ions produced in a low-pressure krypton discharge are implanted in a growing sputtered film of Cu/sub 0.67/Y/sub 0.25/Kr/sub 0.08/ deposited on the inner wall of a krypton trapping storage device (KTSD). A main objective of this work is to measure the release of ⁸⁵Kr implanted in a copper-yttrium alloy. The overall release characteristics of the deposits are quite favorable for long-term storage. Both the radioactive and nonradioactive test specimens stored at temperatures not exceeding 350/degree/C have shown that the release rates measured to date are <0.1% yr^-1. The release rates for the radioactive specimens were obtained for storage periods of 1.6, 1.1 and 0.4 yr for 150, 250 and 350/degree/C storage temperatures, respectively. The nonradioactive specimen has been held at temperatures ranging between 180 and 450/degree/C, but mainly at 350/degree/C, for a total storage time of 2.1 yr. Following the /approximately/10-yr monitoring period, the remaining Cu-Y-⁸⁵Kr waste form should be evaluated to better predict overall stability for the full storage period (50 to 100 yr). 5 refs., 6 figs., 2 tabs