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Title: Parametric Studies on Plutonium Transmutation Using Uranium-Free Fuels in Light Water Reactors

Journal Article · · Nuclear Technology
OSTI ID:20822186
 [1];  [2];  [2];  [1]
  1. Tokyo Institute of Technology (Japan)
  2. Japan Atomic Energy Research Institute (Japan)

To compare the once-through use of U-free fuels for plutonium burnup in light water reactors (LWRs), plutonium transmutation, minor actinide (MA) and long-life fission product (LLFP) buildup and radiotoxicity hazards were compared for PuO{sub 2} + ZrO{sub 2} (rock-like oxide: ROX) and PuO{sub 2} + ThO{sub 2} (thorium oxide: TOX) fuels, loaded in a soft-to-hard neutron spectrum LWR core (a moderator-to-fuel volume ratio V{sub m}/V{sub f} is from 0.5 to 3.0). For better understanding and proper improvement of the reactivity coefficient problem of ROX, the fuel temperature coefficient, the void coefficient, and the delayed neutron fraction were also studied. A mixed-oxide (MOX)-fueled LWR was considered for reference purposes.From the result of the cell burnup calculation, ROX fuel transmutes 90% of net initially loaded weapons-grade Pu, and 2.5% of initially loaded Pu is converted to MAs when V{sub m}/V{sub f} is 2.0 and discharge burnup in effective full-power days is equivalent to that of 33 GWd/t in MOX fuel. Reactor-grade Pu-based ROX fuel transmutes 80% of net initially loaded Pu, and 6.7% of initially loaded Pu converts to MAs with the same condition as the weapons-grade Pu ROX fuel. TOX fuel also has a good Pu transmutation capability, but the {sup 233}U production amount is approximately a half of the fissile Pu transmutation amount. The MA production amount in TOX fuel is lower than that in MOX and ROX fuels. The LLFP production amount in ROX fuel is lower than that in MOX and TOX fuels. The radiotoxicity hazard of ROX spent fuel is lower compared to that in TOX and MOX spent fuels.The thermal neutron energy region is important in ROX fuel for fuel temperature coefficient and void coefficient problems. From these calculations, 15 to 20% {sup 232}Th-added ROX fuel seems the best to use as a once-through Pu-burning fuel compared to TOX and MOX fuels in conventional LWRs, because of its higher Pu transmutation, lower radiotoxicity hazard.

OSTI ID:
20822186
Journal Information:
Nuclear Technology, Vol. 131, Issue 2; Other Information: Copyright (c) 2006 American Nuclear Society (ANS), United States, All rights reserved. http://epubs.ans.org/; Country of input: International Atomic Energy Agency (IAEA); ISSN 0029-5450
Country of Publication:
United States
Language:
English