Cleaning up Hanford: A Deep Borehole Disposal Concept for the Cs/Sr Capsules - 16249
- Deep Borehole Disposal Research Group, Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom)
The Hanford site in Washington State is possibly the most radioactive-contaminated site in the USA presenting a major environmental problem requiring urgent clean-up. Sealed capsules containing halides of strontium (Sr) and cesium (Cs) account for over a third of the total radioactivity. Interim storage for a period of 10-half-lives is an unappealing option since many of the capsules contain Cs-135, which has a half-life of 2.3 million years, and the dose received from the shorter-lived isotopes would remain dangerously high for several generations. Deep geological disposal of the capsules would be a safer solution. We discuss a new and revised conceptual model for disposal of the entire Hanford capsule inventory in a single deep geological borehole with a diameter that could be as little as 31 cm. The concept involves placing thirty capsules inside a steel-disposal container. Holes up to this size are regularly drilled to depths much greater than 5 km by the hydrocarbon industry and are well within current drilling capabilities. Numerical modeling work demonstrates the feasibility of the conceptual model. In particular we examine the thermal envelope generated as a function of time enabling decisions to be made on possible fillings for the borehole annulus. Variations on the disposal concept include disposing different combinations of capsules to control the heat output and thus the temperature rise. The results lend support to a comment attributed to Secretary Moniz that the Hanford capsules could be the world's first HLW to be disposed of in a deep borehole. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 22838110
- Report Number(s):
- INIS-US-19-WM-16249; TRN: US19V1303083465
- Resource Relation:
- Conference: WM2016: 42. Annual Waste Management Symposium, Phoenix, AZ (United States), 6-10 Mar 2016; Other Information: Country of input: France; 10 refs.; available online at: http://archive.wmsym.org/2016/index.html
- Country of Publication:
- United States
- Language:
- English
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