Improvements to the protection of the parts made of zirconium alloy to the formation of hydrides encontrede

摘要

1,153,606. Reactors. ATOMIC ENERGY OF CANADA Ltd. 28 Nov., 1966 [3 Dec., 1965], No. 53100/66. Heading G6C. In a nuclear reactor, the zirconium pressure tube is protected against the absorption of hydrogen and precipitation of zirconium hydride which causes structural weakening. The pressure tube is mounted within and is spaced from a calandria tube. An organic or aqueous coolant flows within the pressure tube and carbon dioxide gas acts as a thermal insulant in the annular space between the two tubes. Hydrogen diffuses into the pressure tube wall from the coolant and passes into zirconium fins fixed to the tube outer surface because of the temperature gradient between the wall and fins. In the fins, the hydrogen is precipitated as zirconium hydride owing to the reduced solubility in the metal at the low fin temperature. The fins may be either bonded to the pressure tube or formed integrally with it.