Methods of fabricating metallic fuel from surplus plutonium
A method of fabricating metallic fuel from surplus plutonium may include combining plutonium oxide powder and uranium oxide powder to obtain a mixed powder with reduced proliferation potential. The mixed powder may be electroreduced in a bath of molten salt so as to convert the mixed powder to a first alloy. The first alloy may be pressed to remove a majority of the molten salt adhered to the first alloy to form a pressed alloy-salt mixture. The first alloy may be isolated from the salt by melting the pressed alloy-salt mixture. The first alloy may be further processed to fabricate a fuel rod. Accordingly, the metallic fuel produced may be used in a fast reactor system, such as a Power Reactor Innovative Small Module (PRISM).
1. A method of fabricating metallic fuel from surplus plutonium, the method comprising:
combining plutonium oxide powder consisting essentially of PuO 2 with uranium oxide powder to obtain a mixed powder, the plutonium oxide powder being present at a quantity of about 20% to 50% by weight relative to a total weight of the mixed powder, the uranium oxide powder having a 235 U enrichment of less than 5.0 wt %;
electroreducing the mixed powder in a porous basket immersed in a bath of molten salt so as to convert the mixed powder to a first alloy of plutonium and uranium, the first alloy being in a form of a porous metal sponge;
pressing the first alloy to remove a majority of the molten salt adhered to the first alloy to form a pressed alloy-salt mixture; and
isolating the first alloy from a remainder of the molten salt by melting the pressed alloy-salt mixture via electromagnetic induction in a furnace and discharging the first alloy from a bottom of the furnace.
2. The method of claim 1 , wherein the pressing includes removing at least 80% of the molten salt adhered to the first alloy.
3. The method of claim 1 , wherein the pressing includes a simultaneous application of heat to facilitate removal of the molten salt adhered to the first alloy.
4. The method of claim 1 , further comprising:
reintroducing the molten salt back into the bath of molten salt after the pressing and isolating the first alloy.
5. The method of claim 1 , wherein the plutonium oxide powder is from a can of a recovered product of reprocessed nuclear fuel or nuclear weapons.
6. The method of claim 1 , further comprising:
sampling the mixed powder to verify a quantity of the plutonium oxide powder therein prior to the electroreducing.
7. The method of claim 1 , wherein the plutonium oxide powder and the uranium oxide powder are not commingled until the combining to obtain the mixed powder.
8. The method of claim 1 , further comprising:
adding a Group 4 metal and uranium metal to the first alloy after the isolating so as to form a second alloy.
9. The method of claim 8 , wherein the adding a Group 4 metal and uranium metal is performed such that the second alloy has about 20% to 50% plutonium by weight.
10. The method of claim 8 , wherein the adding a Group 4 metal includes introducing zirconium to the first alloy.
11. The method of claim 8 , further comprising:
forming a fuel rod from the second alloy.