Compatibility of helium- and soidum-bonded hyperstoichimetric (U,Pu)C with advanced cladding alloys

Out-of-pile tests were conducted for 1000 h at 6000C and 7250C to determine the compatibility of helium- and sodium-bonded (U,Pu)C + 9-12 vol percent (U,Pu)2C3 with austenitic alloys Type 330 stainless steel, A286, M813, PE-16, Inconel 706, and Inconel 718. The compatibility of ferritic alloy HT-9 was determined only in the sodium-bonded tests. As a reference alloy, Type 316 stainless steel was also tested. At 6000C, none of the alloys showed evidence of carburization in the sodium-bonded tests and only Inconel 706 and 718 showed significant compatibility effects in the helium-bonded (contact) tests. at 7250C, carbide precipitation was observed in the matrix and grain boundaries of the alloys to depths of 50 to 150 μm in the helium-bonded tests. In the sodium-bonded tests, no effects were observed in alloys M813, PE-16, and HT-9; there was precipitation in the matrix and grain boundaries to depths of 45 to 125 μm in the remaining alloys