Postirradiation examination of recently irradiated metallic fuel concepts

Conference · Tue Oct 16 04:00:00 EDT 2018

OSTI ID:1498078

Harp, Jason M ^[1]; Capriotti, Luca ^[1]; Cappia, Fabiola ^[1]

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1. Idaho National Laboratory

In fast neutron spectrum nuclear reactors, metallic uranium alloys have often been chosen because of their high uranium density, high thermal conductivity, and several reactor kinetic safety benefits. Metallic uranium is often alloyed to raise the melting temperature or to modify the microstructure which improves irradiation performance. Recent irradiations have explored additional alloys and geometric forms beyond what has historically been irradiated (U-10 weight % Zr, 75% smeared density, sodium bonded fuel). Postirradiation examination results and how these results can be incorporated into modelling and simulation will be presented. The evaluated fuels fall into four categories alternative alloying metals, additives, sodium bond removal, and alternative smear densities. For alternative alloys, Zr has been substituted for 10% Mo or 5% Mo, 4.3%Ti, 0.7%Zr to stabilize the cubic phase of U and prevent constituent redistribution seen in U-Zr alloys. Unfortunately these alloys have significant, undesirable interactions with cladding during irradiation. Additives, such as Pd, have been suggested to bind lanthanide fission products, which interact with cladding limiting fuel performance, into high temperature intermetallic compounds. Irradiation results indicate there may be targeted applications such as high burnup fuel or recycled fuel with lanthanide carry-over where additives are useful. Sodium bonding is considered undesirable at the back end of the fuel cycle where sodium bonded fuel must be treated to remove sodium prior to geological disposition. Helium bonded metallic fuel of several alloys has been irradiated to better understand the implications of removing sodium bonding. Current results show that with proper dimensional tolerances on the final fuel slug, helium bonding is feasible. Low smear density fuel is necessary to enable high (30 atom %) burnup. Both solid and annular low smear density fuels have also been examined, and their performance is also discussed.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Fuel Cycle Technologies (NE-5)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1498078
• Report Number(s): INL/CON-18-51782-Rev000
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
AFC
U-Mo Fuel
U-Zr Fuel
annular fuel
fast reactor fuel additives