Specification for strontium-90 500-watt(e) radioisotopic thermoelectric generator. Final report

Abstract

The Department of Energy (DOE) By-products Utilization Program (BUP) has the goal to develop and encourage the use of nuclear by-products produced in DOE defense operations. One of the byproducts is Strontivmi-90 (Sr-90), a beta-emitting isotope of value as a heat source. DOE has separated Sr-90 from defense wastes and doubly encapsulated it in storage capsules at the Hanford Waste Encapsulation and Storage Facility (WESF) for several years. Currently, several hundred capsules are stored at WESF. During the next ten years, significant additional quantities of Sr-90 will be separated, encapsulated and stored at Hanford.

Assessment of dynamic energy conversion systems for radioisotope heat sources

“…The reference heat source for the RDPS is a Sr heat source using nine 800-W(t) WESF capsules. This was the preliminary design for the 500-W(e) RTG by Teledyne, 12 and it would provide 7200 W(t) at beginning of life (BOL) and 6308 W(t) after 5.5 years or end of life (EOL). A five-year lifetime was chosen be-12 cause temperature data for the heat source was available from Je" ayne.…”

“…They are all based on the original Teledyne design for a 7200-W(t) 90 Sr isotcpic heat source. 12 This design used nine 800-W(t) WESF capsules; each capsule is a cylinder of hotpressed strontium-fluoride clad in 0.137-in.-thick Hastalloy C-276. The capsule has a diameter of approximately 2-1/4 in.…”

“…This is the temperature reduction predicted in the Teledyne calculations. 12 Another assumption is that heat losses through th<_ insulation would be 5%. This is the approximate heat loss calculated by Teledyne for their RTG design.…”