Thermal expansion of Zr, Zr-4 alloys and new zirconium alloys

Zirconium alloy has high corrosion resistance. Radiation stability、good thermal properties and comprehensive mechanical properties, as nuclear reactor fuel cladding material. In recent years, new zirconium alloys have been developed in some countries in order to meet the performance requirements of cladding materials under high fuel consumption. The fuel rods made of these new zirconium alloys show better performance than Zr-4 alloy after reactor irradiation. Two new zirconium alloys of Zr-Sn-Nb series N18 and N36 have also been developed in China. Among them, N18 alloy has excellent corrosion resistance not only in high temperature and high pressure water, but also in superheated steam, which may be widely used as a new fuel cladding material in nuclear reactors.

In order to accurately predict the fuel cladding geometry size and the size of the fuel cladding clearance, need to know the size of the fuel cladding during heating and cooling change, especially the new type of cladding material to more accurately know the thermal expansion behavior, therefore, the measured with a differential type quartz dilatometer alloy and Zr, Zr -4 by pilot scale process preparation of N18 and N36 new zirconium alloy thermal expansion.

The thermal expansion behavior of Zr, Zr-4, N18 new zirconium and N36 new zirconium alloys has been measured by differential quartz dilatometer in the range of room temperature to 800℃. The empirical formula of the measurement results has been given and the thermal expansion behavior of these materials has been compared. The measurement results show that. The thermal expansion of Zr,Zr-4 alloy, N18 new zirconium alloy and N36 new zirconium alloy bar is basically the same, and the thermal expansion of Zr, Zr-4 alloy and new zirconium alloy plate is anisotropic.