Possible scenarios for the transition to thorium fuel cycle in molten salt reactor by using enriched uranium

Cui, De-Yang; Li, X.X.; Xia, Siyou; Zhao, Xuebing; Yu, Chenggong; Chen, J.G.; Xiang-Zhou, Cai

doi:10.1016/j.pnucene.2017.09.003

Cited by 41 publications

(18 citation statements)

References 15 publications

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“…It is found that the initial TRC increases from −7.7 pcm/K for the SVF = 4% to −3.5 pcm/K for the SVF = 15%, and then keeps an almost stable value for SVF between 15% and 30%. Although the initial TRC with different SVFs is negative enough for the safe demands of the SMMSR, the TRC with the reactor operation time increases and even becomes positive when both LEU and Th are fueled . Both the accumulation of 233 U and the reduction of 235 U in the fuel salt are adverse to graphite‐moderator temperature coefficient, especially for a small SVF situation.…”

Section: Resultsmentioning

confidence: 99%

“…Since there is no available 233 U in nature, various igniting fuels including LEU, Pu, or TRU have been investigated to achieve the transition to Th-U fuel cycle. 23,30 Because of its extensive uses in various commercial reactors, however, this work just focuses on the LEU as both starting and feeding fuel for the above three fuel cycle modes. In this simulation for nonproliferation consideration, 19.75 wt% ( 235 U/U) of LEU is adopted.…”

Section: Smmsr Systemmentioning

confidence: 99%

“…Although the initial TRC with different SVFs is negative enough for the safe demands of the SMMSR, the TRC with the reactor operation time increases and even becomes positive when both LEU and Th are fueled. 23 Both the accumulation of 233 U and the reduction of 235 U in the fuel salt are adverse to graphite-moderator temperature coefficient, especially for a small SVF situation. Therefore, the TRC with different SVFs is also simulated up to 10 years (see Figure 5) to prevent the FPs concentration in the fuel salt from exceeding its solubility limit (about 1%) during the whole operation.…”

Section: Once-through Fuel Cycle Modementioning

confidence: 99%

“…Therefore, the HN in the fuel salt would increase gradually, which is detrimental to the stability of the fuel salt. Besides, it is also necessary to pay more attention to the supply of ignition fuel of 233 U in both the FUJI‐U3 and the LFTR since there is no available 233 U in nature . This work focuses on the optimization of Th utilization in a 220‐MWe SMMSR, in which the fuel salt volume fraction (SVF), the fuel salt stability, and the fuel transition from LEU to 233 U are investigated for the progressive once‐through, batch and online processing fuel cycle modes, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…Besides, it is also necessary to pay more attention to the supply of ignition fuel of 233 U in both the FUJI-U3 and the LFTR since there is no available 233 U in nature. 23,24 This work focuses on the optimization of Th utilization in a 220-MWe SMMSR, in which the fuel salt volume fraction (SVF), the fuel salt stability, and the fuel transition from LEU to 233 U are investigated for the progressive once-through, batch and online processing fuel cycle modes, respectively. The SMMSR system, solubility of HN, and calculation method of Th energy contribution (ThEC) are described in Section 2.…”

Section: Introductionmentioning

confidence: 99%

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Thorium utilization in a small modular molten salt reactor with progressive fuel cycle modes

Zou

et al. 2019

Int J Energy Res

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Summary The thorium‐uranium (Th‐U) fuel cycle is considered as a potential approach to ensure a long‐term supply of nuclear fuel. Small modular molten salt reactor (SMMSR) is regarded as one of the candidate reactors for Th utilization, since it inherits the merits of both MSR and small modular reactor. The Th utilization in a 220‐MWe SMMSR with the once‐through fuel cycle mode is investigated first. Then, the SMMSR with batch and online fuel processing modes is investigated second for comparison, considering the progressive development of fuel reprocessing technology. To keep a negative temperature reactivity feedback coefficient (TRC), a configuration for fuel salt volume fraction (SVF) equal to 15%, with a mixed fuel of low enriched uranium (LEU) and thorium at an operation time of 5 years is recommended for the once‐through mode, corresponding to the Th energy contribution (ThEC) of 37.6% and natural U and Th utilization efficiency (UE) of 0.51%. Considering the solubility limit of heavy nuclide (HN) proportion (below 18.0 mol%) in the fuel salt, the total operation time of the SMMSR shall be less than 50 years for the batch reprocessing mode with a 5‐year reprocessing interval time. In this case, the ThEC and UE can be improved to about 47.4% and 0.99%, respectively. Finally, the Th utilization and fuel sustainability are analyzed at a lifetime of 50 years for the online reprocessing fuel cycle mode, including both the only online fission products (FPs) removing scheme and the fuel transition scheme from LEU to 233U. For the former scheme, the ThEC and UE can be further improved to 58.6% and 1.52%, respectively. For the latter scheme, 233Pa is extracted continuously from the core to breed and store 233U. If a total reactor lifetime of 50 years is assumed, the operation time using LEU as starting and feeding fuel for 6 years is required, and the bred 233U during this 6‐year operation can start and maintain the reactor criticality for the remaining 44 years. In this case, the ThEC is improved significantly to 89.1% corresponding to a UE of 2.74%.

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Section: Resultsmentioning

confidence: 99%

Section: Smmsr Systemmentioning

confidence: 99%

Section: Once-through Fuel Cycle Modementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thorium utilization in a small modular molten salt reactor with progressive fuel cycle modes

Zou

et al. 2019

Int J Energy Res

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Comparison of homogeneous and heterogeneous thorium fuel blocks with four drivers in advanced high temperature reactors

et al. 2020

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Thorium is an attractive potential fuel owing to its abundance and unique thermal, neutronic, and chemical properties. One way to utilize thorium in block-type advanced high temperature reactors (AHTRs) is to homogenously mix the driver fuel (eg, U-233) with thorium in every fuel kernel of the tristructural-isotropic particles in a fuel block, which is the mixed oxide fuel (MOX) concept. Application of the seed and blanket (S&B) concept, that is, driver fuel in the seed region of a fuel block and thorium in the blanket region, is also another method to utilize thorium. To investigate the differences in the utilization of thorium using the MOX and S&B concepts in AHTRs, their multiplication factors (k ∞ ), discharge burnups, conversion ratios, and reactivity temperature coefficients are compared. The investigated drivers include U-233 (U3), weapons-grade uranium (WU), weapons-grade plutonium (WPu), and reactor-grade plutonium (RPu). The results demonstrate that the MOX block with plutonium drivers has a higher discharge burnup in comparison with the S&B block. When the heavy metal mass is 6 kg and the initial mass of the fissile materials is 0.65 kg per block, the MOX block achieves 27% higher discharge burnup than the S&B block with the RPu driver. In contrast, the S&B block achieves higher discharge burnup in the case of uranium drivers (U3 and WU). The MOX block achieves a higher conversion ratio for all the drivers. Furthermore, the MOX block achieves a stronger negative moderator temperature coefficient of reactivity than the S&B block for all the driver fuels.

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The conceptual design of thorium‐based molten salt energy amplifier

et al. 2020

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Summary Thorium is a possible nuclear fuel to achieve the sustainable development of nuclear energy. The molten salt reactor (MSR) has great potential and advantages in realizing the efficient utilization of thorium resources. However, there are still many challenging technologies to be developed, such as the graphite lifetime problem, the complex online processing of the fuel salt. Therefore, the actual deployment timelines of thorium‐based MSR are still unpredictable. In this research, a Thorium‐based Molten Salt Fast Energy Amplifier (TMSFEA), which is based on the subcritical chloride salt fast reactor, is proposed. It adopts a single‐fluid, moderator‐free simple core design. A ternary molten salt system containing sodium chloride (NaCl), thorium tetrachloride (ThCl4), and plutonium trichloride (PuCl3) serves as both the spallation target and the fuel. A 1 GeV proton accelerator with maximum beam current of 4 mA is introduced to compensate the neutrons absorbed by fission products during operation. By adopting an offline fuel cycle scenario based on the multi‐generation reactor evolution, the utilization efficiency of thorium fuel is greatly improved. After four generations of TMSFEA operation, the total net 233U production is 2774.6 kg, the fission rate fraction of 233U rises from 0% to 89.3%, the energy fraction of thorium (EFT) can achieve the value of 66.6%, and the utilization efficiency of thorium (UET) can reach 25.9%.

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Possible scenarios for the transition to thorium fuel cycle in molten salt reactor by using enriched uranium

Cited by 41 publications

References 15 publications

Thorium utilization in a small modular molten salt reactor with progressive fuel cycle modes

Thorium utilization in a small modular molten salt reactor with progressive fuel cycle modes

Comparison of homogeneous and heterogeneous thorium fuel blocks with four drivers in advanced high temperature reactors

The conceptual design of thorium‐based molten salt energy amplifier

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