Investigation of the MSFR core physics and fuel cycle characteristics

Fiorina, Carlo; Aufiero, Manuele; Cammi, Antonio; Franceschini, Fausto; Krepel, Jiri; Luzzi, L.; Mikityuk, Konstantin; Ricotti, Marco Enrico

doi:10.1016/j.pnucene.2013.06.006

Cited by 74 publications

(23 citation statements)

References 13 publications

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“…The MSFR supports various fuel compositions; it can run on the same 235 U-238 U fuel used in most conventional LWRs. It can also run on a mixture of fresh and used uranium fuel containing reprocessed TRU isotopes [7]. However, the main configuration of the MSFR is a breeder reactor running on [4].…”

Section: Molten Salt Fast Reactormentioning

confidence: 99%

Safety Analysis of Molten Salt Fast Reactor Fuel Composition using Moltres

Park

Rykhlevskii

Huff

2019

Preprint

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The Molten Salt Fast Reactor (MSFR) has garnered much interest for its inherent safety and sustainbility features. The MSFR can adopt a closed thorium fuel cycle for sustainable operation through the breeding of 233 U from 232 Th. The fuel composition changes significantly over the course of its lifespan. In this study, we investigated the steady state and transient behavior of the MSFR using Moltres, a coupled neutronics/thermal-hydraulics code developed within the Multiphysics Object Oriented Simulation Environment (MOOSE) framework. Three different fuel compositions, start-up, earlylife, and equilibrium, were examined for potentially dangerous core temperature excursions during a unprotected loss of heat sink (ULOHS) accident. The six-group and total neutron flux distributions showed good agreement with SERPENT and published MSFR results, while the temperature distribution and total power showed discrepancies which can be attributed to known sources of error. For the transient behavior under the ULOHS scenario, while the transition time towards the new steady state core temperature is also in good agreement with existing MSFR simulations by Fiorina et al., Moltres underestimated the temperature rise by a factor of ten, due to the same sources of error affecting the steady state results. While an MSFR loaded with start-up fuel composition operates at a higher temperature than with the other two fuel compositions, all three cases were shown to be inherently safe due to the strong negative temperature feedback.

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Section: Molten Salt Fast Reactormentioning

confidence: 99%

Safety Analysis of Molten Salt Fast Reactor Fuel Composition using Moltres

Park

Rykhlevskii

Huff

2019

Preprint

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“…Closed Th-based fuel cycles are well known to have lower equilibrium radiotoxicity than U-based fuel cycles due to much lower TRU production from 232 Th than from 238 U (Franceschini et al, 2012;IAEA, 2005), although the period for which the radiotoxicity is lower is limited to~35,000 years, after which the radiotoxicity of 233 U and its daughters becomes most significant (Coates, 2011;Fiorina et al, 2013a). However, it is also well known that it takes a long time for the advantages of 'equilibrium' Th fuel cycles to be realised due to the long transition time to equilibrium (Hesketh and Thomas, 2013;Fiorina et al, 2013bFiorina et al, , 2013c. Franceschini et al (2013) compared Th-and U-based transmutation strategies from a point of view of fuel fabrication and reprocessing requirements.…”

Section: Introductionmentioning

confidence: 99%

The effectiveness of full actinide recycle as a nuclear waste management strategy when implemented over a limited timeframe – Part II: Thorium fuel cycle

Lindley

Fiorina

Gregg

et al. 2016

Progress in Nuclear Energy

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a b s t r a c tFull recycling of transuranic (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 timeframe, 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 Part I of this paper, TRU recycle over up to 5 generations of light water reactors (LWRs) or sodium-cooled fast reactors (SFRs) is considered for uranium (U) fuel cycles. 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. U-fuelled SFRs operating a breakeven fuel cycle are not particularly effective at reducing repository radiotoxicity as the final core load dominates over a very long timeframe. In this paper, the analysis is extended to the thorium (Th) fuel cycle. Closed Th-based fuel cycles are well known to have lower equilibrium radiotoxicity than U-based fuel cycles but the time taken to reach equilibrium is generally very long. Th burner fuel cycles with SFRs are found to result in very similar radiotoxicity to U burner fuel cycles with SFRs for one less generation of reactors, provided that protactinium (Pa) is recycled. Th-fuelled reduced-moderation boiling water reactors (RBWRs) are also considered, but for burner fuel cycles their performance is substantially worse, with the waste taking~3e5 times longer to decay to the reference level than for Th-fuelled SFRs with the same number of generations. Th break-even fuel cycles require~3 generations of operation before their waste radiotoxicity benefits result in decay to the reference level in~1000 years. While this is a very long timeframe, it is roughly half that required for waste from the Th or U burner fuel cycle to decay to the reference level, and less than a tenth that required for the U break-even fuel cycle. The improved performance over burner fuel cycles is due to a more substantial contribution of energy generated by 233 U leading to lower radiotoxicity per unit energy generation. To some extent this an argument based on how the radiotoxicity is normalised: operating a break-even fuel cycle rather than phasing out nuclear power using a burner fuel cycle results in higher repository radiotoxicity in absolute terms. The advantage of Th break-even fuel cycles is also contingent on recycling Pa, and reprocessing losses are significant also for a small number of generations due to the need to effectively burn down the TRU. The integrated decay heat over the scenario timeframe is almost twice as high for a break-even Th fuel cycle than a break-even U fuel cycle when using SFRs, as a result of much higher 90 Sr production, which subsequently decays into 90 Y. The peak decay heat is comparable. As decay heat at vitrification and repository decay heat affect repository s...

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“…This is a disadvantage to improve the utilization of nuclear fuels and to reduce the inventory of radioactive nuclear wastes. To solve the problems, there is growing emphasis on the study of transuranic (TRU) transmutation (Ignatiev et al, 2007;Fiorina et al, 2013). The Pu contained in the mixed-oxide (MOX) fuel can be reused in an appropriate thermal reactor.…”

Section: Introductionmentioning

confidence: 99%

“…Compared to a thermal MSR, MSFR has several potential unique merits such as large negative temperature feedback coefficient, simple fuel reprocessing and low TRU wastes production. The Th breeding characteristics for MSFR with different starter fuels ( 233 U, Pu, TRU, Pu + MOX and enr U + TRU) were investigated based on various reprocessing schemes (Fiorina et al, 2013;Heuer et al, 2014). In addition to the excellent fuel breeding potential, MSFR could also be applicable for MA transmutation due to its fast neutron spectrum.…”

Section: Introductionmentioning

confidence: 99%