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

Yu, Chenggang; Wu, Jianhui; Zou, Chunyan; Xiang-Zhou, Cai; Ma, Yuanwei; Chen, Jingen

doi:10.1002/er.4511

Cited by 27 publications

(17 citation statements)

References 30 publications

(64 reference statements)

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“…Thus, the net 233 U production for scenario 1 is about 2.03 tons at the operation time of 60 years, which is about 2.39 tons smaller than that for scenario 0. In addition, the net 233 U production at the end of life is much larger than the initial 233 U loading amount of the SD‐TMSR (1.28 tons), which means that the online returning 135 Cs transmutation scenario 1 can transmute the 135 Cs produced by itself under a Th‐U breeding mode for a 60‐year operation 31,34 . For scenario 2, a large amount of nonsoluble gaseous and metallic FPs remain in the reactor, which requires a considerable amount of 233 U loading into the core to maintain the reactor criticality during the whole operation.…”

Section: Resultsmentioning

confidence: 99%

Transmutation of ¹³⁵ Cs in a single‐fluid double‐zone thorium molten salt reactor

Chen

et al. 2020

Int J Energy Res

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Summary The single‐fluid double‐zone thorium molten salt reactor (SD‐TMSR) allows for online reprocessing fission products and adding nuclear fuel, which provides a high Th‐U breeding capability for thorium utilization. Although 135Xe in the core can be online extracted by the helium bubbling system during reactor operation to improve the reactor neutron economy, it would decay to the long‐lived 135Cs with a half‐life of 2.3 × 106 years, which is undesired from the viewpoint of the development of nuclear energy. The total production of 135Cs decayed from the extracted 135Xe is about 1.83 tons for the SD‐TMSR after 60 years operation. To reduce the significant accumulation of 135Cs, we propose a cooling transmutation method, by which the produced 135Cs is reinjected into the core for transmutation. First, a separation and multigroup cooling system in the SD‐TMSR is adopted to enhance the mass fraction of decayed 135Cs in the total Cs isotopes from 29% to 75%. Then, the separated Cs isotopes with optimized mass fraction of 135Cs are online injected into the core for transmutation. The total transmuted mass of 135Cs is about 0.61 tons after 60 years operation, corresponding to the transmuted fraction of about 37.42% and the transmutation rate of 10.17 kg/(GWe y). Moreover, the net 233U production is about 2.03 tons which is much larger than the initial 233U loading inventory of the SD‐TMSR, indicating that the Th‐U breeding mode for the transmutation of 135Cs in the SD‐TMSR can be achieved over 60 years. Novelty Statement “Transmutation of 135Cs in a single‐fluid double‐zone thorium molten salt reactor” was investigated by Kunfeng Ma, Chenggang Yu*, Jingen Chen*, and Xiangzhou Cai. A cooling transmutation method is performed to reduce the 135Cs decayed from 135Xe outside of core. It is found that a separation and multigroup cooling system improves the mass fraction of 135Cs in the total Cs isotopes from 29% to 75% and an online returning 135Cs transmutation scenario transmutes about 0.61 tons of 135Cs over 60 years.

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Section: Resultsmentioning

confidence: 99%

Transmutation of ¹³⁵ Cs in a single‐fluid double‐zone thorium molten salt reactor

Chen

et al. 2020

Int J Energy Res

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“…The single‐cell parameters in an existing SM‐TMSR 20‐22 design are used in this article. The lattice half‐pitch is 9 cm, and the volume fraction of fuel molten salt over graphite is 15% to ensure a negative temperature reactivity feedback coefficient 23‐25 . The fuel power density at the center of the SM‐TMSR core is 100 MW/m 3 .…”

Section: Calculation Model and Methodologymentioning

confidence: 99%

A new structure design to extend graphite assembly lifespan in small modular molten salt reactors

et al. 2021

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Summary Dimensional change of the graphite assemblies due to irradiation is a key factor in limiting the service lifespan of the reactor core in small modular molten salt reactors. The graphite assembly structure, determining the fast neutron flux distribution and temperature distribution, has a notable impact on its dimensional change and hence its lifespan. In this article, we put forward an innovative solid hexagonal prism assembly (HPA) surrounded by fuel salt to prolong the lifespan of the graphite assemblies and compare it with the traditional hexagonal round channel assembly (RCA) with fuel salt flowing through its central round channel. Under the single‐cell model, the calculation results prove that the neutron flux distribution and temperature distribution in the HPA are more uniform than those in the RCA. The HPA deforms more slowly than the RCA under the same operating conditions. The lifespan of the RCA, defined as when it expands back to its original size, is 7.5 years under the 100 MW/m3 power density of fuel salt, while the lifespan of the proposed HPA is 8.4 years. The HPAs also allow a further expansion in the radial direction due to its noncontact arrangement in the core. It will take 14.9 years for the HPA assemblies to contact each other, which displays a significant improvement in lifespan.

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“…In various MSR projects, many different carrier salts have been proposed, such as Flibe, Fli, and Flinak 38 . The Flibe salt with 99.995% of Li‐7 enrichment has excellent neutron economy, and has been widely used in various MSRs for Th breeding 24,39‐41 . With the fuel compositions of 77% LiF–17% BeF 2 –6% ThF 4 , the PuF 3 solubility limit is 4.0% at 923 K. The Fli carrier salt removes BeF 2 and accommodates higher actinide tetrafluorides, and has been selected as the fuel compositions in the molten salt fast reactor (MSFR) (78% LiF–22% ThF 4 ) for Th breeding and MA transmutation 18 .…”

Section: Tmsr Transmutation Core Designmentioning

confidence: 99%

Parametric study on minor actinides transmutation in a graphite‐moderated thorium‐based molten salt reactors

Zou

et al. 2021

Int J Energy Res

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Summary Transmutation of minor actinides (MAs) is an effective solution to reduce the long‐term radiotoxicity of nuclear waste. Online refueling and no fuel rod fabrication in thorium‐based molten salt reactors (TMSR) are two remarkable advantages of MA transmutation. However, MA solubility limit of the fuel salt and the neutron spectrum in the core are two key parameters that have a strong impact on MA transmutation capability. In this paper, three types of carrier salt with different MA solubility limits and various salt volume fractions (SVFs) are introduced in a TMSR core to evaluate the MA transmutation characteristics. The results indicate that the Flibe salt with the best neutron economy can obtain the highest MA transmutation rate (TR), while the Flinak salt with the largest MA inventory can achieve the highest specific MA transmutation consumption (STC). STC and TR for the case with the Flibe salt and 5% SVF are about 200 kg/GWth.yr and 82%, respectively, which indicates that it can consume the annual MA yields from about 3.37 typical pressurized water reactors (PWRs). Meanwhile, the STC and TR for the case with the Flinak salt and 40% SVF are about 366 kg/GWth.yr and 75%, respectively, which indicates that it can consume the annual MA yields from about 50 typical PWRs. In addition, the total radiotoxicity of MAs after 50‐year operation in TMSR can be lowered by as high as about 50%. The significant production of Pu isotopes can be reused as nuclear fuel in fast reactors. In particular, Pu‐238, with the mass fraction of more than 60% in Pu isotopes, is a useful material for many nuclear applications. In conclusion, it is feasible to transmute MAs in TMSR and thus achieve the goals of reduction of MA's long‐term radioactive hazards.

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

Cited by 27 publications

References 30 publications

Transmutation of ¹³⁵ Cs in a single‐fluid double‐zone thorium molten salt reactor

Transmutation of ¹³⁵ Cs in a single‐fluid double‐zone thorium molten salt reactor

A new structure design to extend graphite assembly lifespan in small modular molten salt reactors

Parametric study on minor actinides transmutation in a graphite‐moderated thorium‐based molten salt reactors

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

Cited by 27 publications

References 30 publications

Transmutation of 135 Cs in a single‐fluid double‐zone thorium molten salt reactor

Transmutation of 135 Cs in a single‐fluid double‐zone thorium molten salt reactor

A new structure design to extend graphite assembly lifespan in small modular molten salt reactors

Parametric study on minor actinides transmutation in a graphite‐moderated thorium‐based molten salt reactors

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Transmutation of ¹³⁵ Cs in a single‐fluid double‐zone thorium molten salt reactor

Transmutation of ¹³⁵ Cs in a single‐fluid double‐zone thorium molten salt reactor