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Title: Effectiveness of actinide management in fast reactors over a finite recycling period - 15123

Conference ·
OSTI ID:22822682

Long-lived nuclear waste primarily consists of transuranic (TRU) isotopes. Full recycling of TRU isotopes can, in theory, lead to a reduction in repository radiotoxicity to reference levels in as little as ∼500 years provided reprocessing and fuel fabrication losses are limited. However, over a limited time frame, the radiotoxicity of the 'final' core can dominate over reprocessing losses, leading to a much lower reduction in radiotoxicity compared to that achievable at equilibrium. In this paper, the fuel cycle code ORION is used to model the recycle of light water reactor (LWR)-produced TRUs in sodium-cooled fast reactors (SFRs). With full actinide recycling, at least 6 generations of SFRs are required in a gradual phase-out of nuclear power to achieve transmutation performance approaching the theoretical equilibrium performance. Break-even SFRs are much less effective from a point of view of reducing waste radiotoxicity. Thorium (Th)-burner fuel cycles are found to result in slightly lower radiotoxicity than U-burner fuel cycles for the same number of generations. Closed break-even Th fuel cycles require ∼3 generations of operation before their waste radiotoxicity benefits result in decay to the reference level in ∼1000 years, provided that Pa is recycled. While this is a very long time frame, it is substantially better than the time frame required by other strategies. The integrated decay heat over the scenario time frame is substantially higher for break-even Th-SFRs than break-even U-SFRs as a result of much higher {sup 90}Sr production. As decay heat affects repository sizing, this weakens the argument for the Th cycle. (authors)

Research Organization:
WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
OSTI ID:
22822682
Report Number(s):
INIS-US-19-WM-15123; TRN: US19V0672067597
Resource Relation:
Conference: WM2015: Annual Waste Management Symposium, Phoenix, AZ (United States), 15-19 Mar 2015; Other Information: Country of input: France; 28 refs.; Available online at: http://archive.wmsym.org/2015/index.html
Country of Publication:
United States
Language:
English