PURPOSE: To retain a pipe in a reactor core for a long time by heating it to a specific temperature range after a plurality of continuous rolling and annealing processes, rapidly cooling it to an ambient temperature, and homogenizing it with β phase.
CONSTITUTION: An alloy is made of zirconium group alloy, namely an alloy containing at least 90wt.% Zr, a plurality of continuous normal temperature rolling and annealing processes are included in a method for manufacturing a pipe for covering a fuel element used for a reactor, a pipe for covering fuel elements is heated between 950°C and 1,250°C as a final process, and the pipe is rapidly cooled to an ambient temperature within an inactive atmosphere, thus performing a heat treatment so that the entire pipe can be homogenized by β phase. This method especially has an advantageous application for creating a fuel assembly element covering made of zirconium group alloy for pressurized water reactor. Then, the covering that is treated in β phase and an entirely uniform metal crystalline structure has a high resistance against corrosion under corrosion due to application of light and stress due to the fuel elements.
JIYATSUKU DEKUURU
MISHIERU BUAITSU
JIYATSUKU PERUSHIYA
JIAN RU PAAPU
S N C YURANIYOMU PESHINE E FUR