Development of borated aluminum alloy with stability at high temperatures

Some spent fuels in nuclear power plants are ongoing plan to be stored in interim storage facilities by metal casks for about 50 years in Japan, until nuclear fuel reprocessing plants can accept these spent fuels. A stainless steel and aluminum alloy containing neutron-absorbing materials is used as a basket that is a component of a partition plate for the spent fuel in the metal cask. We have developed a high-performance borated aluminum alloy. This material has not only high heat conductivity, but also high strength at high temperatures. This strengthening is caused by stable precipitation at high temperatures, created by the addition of boron as a neutron absorber, and of Mn and Cr in the matrix of alloy A6082 to forcibly create the precipitation. The yield strength of the developed alloy is 74 MPa at 523 K and heat conductivity is 185W/m·K. An accelerated test based on the Larson-Miller parameter indicates that this material retains high strength for 50 years at 523 K. The developed alloy is stronger than traditional B-Al specified ASME code case. These results indicate the developed alloy is stable to heat aging ad useable for the components of metal casks. (author)