KERNBRANDSTOFELEMENT EN WERKWIJZE VOOR DE VERVAARDIGING DAARVAN.

摘要

1402496 Fuel elements ATOMIC ENERGY OF CANADA Ltd 10 Aug 1973 [1 Dec 1972] 37988/73 Heading G6C A nuclear fuel element having a sheath of Zr or a Zr-alloy is provided with a crosslinked siloxane lacquer coating on the inner surface of the sheath as an interlay between it and the fuel. A silicone grease is first applied as a thin layer in the sheath and then baked at 300‹ C. in a partial vacuum, with oxygen present, so that oxidative cleavage of the side chains of the grease occurs to form a crosslinked siloxane lacquer coating bonded to the sheath. The partial vacuum removes hydrocarbon products emitted by the silicone grease during the heating. Uranium dioxide fuel pellets are subsequently stacked in the sheath in an argon atmosphere. The siloxane lacquer coating retards cracking of the sheath by iodine vapour emitted by the fuel during burn-up and acts as a lubricant for the fuel to prevent rupture of the sheath by thermal ratchetting of the fuel against the sheath caused by differential thermal expansion between the fuel and the sheath.