Canadian spent fuel storage canister: some materials aspects

Journal Article · Sat Jan 01 04:00:00 EST 1977 · Nucl. Technol.; (United States)

OSTI ID:7335279

Boase, D G; Vandergraaf, T T

Concrete canisters for interim dry storage of spent, irradiated CANDU fuel are being developed. The canisters are designed to contain fuel safely for periods of 50 to 100 y in carbon steel baskets sealed inside a steel- and lead-lined concrete shield. A demonstration program is utilizing four instrumented canisters to etablish the canister structural integrity when exposed to the thermal stresses generated by the decay heat of the stored fuel. Review of other potential materials problems identified three areas of concern: corrosion of the fuel basket and canister lining, fuel sheath oxidation, and UO/sub 2/ oxidation. The first of these may be minimized by the migration of moisture to the outside of the canister under the influence of the temperature gradient, and the second is predicted to be insignificant for periods up to 100 y. The third area was less well understood, and an experimental study was undertaken. The rates and mechanism of UO/sub 2/ oxidation were studied using powders, sintered pellets, and intentionally defected fuel elements. The oxidation in fuel elements proceeds by the formation of U/sub 3/O/sub 8/, swelling and splitting of the sheath and exposure of more fuel, and the release of finely powdered U/sub 3/O/sub 8/. Some data are given for the oxidation rates of irradiated fuel elements together with the approximate times required to oxidize a single fuel pin. In the present demonstration canisters, the possibility of oxidation of the fuel has been eliminated by storing it in helium-filled baskets. 14 figures. (DLC)

• Research Organization: Atomic Energy of Canada Ltd., Pinawa, Manitoba
• OSTI ID: 7335279
• Journal Information: Nucl. Technol.; (United States), Journal Name: Nucl. Technol.; (United States) Vol. 32:1; ISSN NUTYB
• Country of Publication: United States
• Language: English

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ACCIDENTS
ACTINIDE COMPOUNDS
BUILDING MATERIALS
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CONTAINERS
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KINETICS
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PRESSURE TUBE REACTORS
REACTION KINETICS
REACTOR ACCIDENTS
REACTORS
SPENT FUEL STORAGE
THERMAL REACTORS
URANIUM COMPOUNDS
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URANIUM OXIDES