A fast reactor transmutation system for 6 LLFP nuclides

Wakabayashi, Toshio; Takahashi, Makoto; Chiba, Satoshi; Takaki, Naoyuki; Tachi, Yoshiaki

doi:10.1016/j.nucengdes.2020.110667

Cited by 10 publications

(11 citation statements)

References 14 publications

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“…As shown in Fig. 1 (c), 169 pins in the form of mixed ZnSe 41,42 and YD2 were arranged in the assembly 30,31 . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Based on these studies, a system that further improves the transmutation efficiency of the six nuclides was explored. A fast reactor LLFP transmutation system that achieves a support ratio of 1 or more for the entire system was constructed by combining three fast reactors, in addition to using one reactor 31 . From these studies, a significant amount of information about the LLFP transmutation system was obtained.…”

Section: Introductionmentioning

confidence: 99%

“…Here, the support ratio (SR) was defined as the ratio of the amount of each nuclide transmuted by the fast breeder reactor to the amount of each nuclide (MA and LLFP) produced by the fast breeder reactor 28,30,31 .…”

Section: Introductionmentioning

confidence: 99%

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Concept of a Fast Breeder Reactor To Transmute MA and LLFP

Wakabayashi

2021

Preprint

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The long-term issues of nuclear power systems are the effective use of uranium resources and the reduction of radioactive waste. Important radioactive wastes are minor actinides (MA: 237 Np, 241 Am, 243 Am, etc.) and long-lived fission products (LLFP: 129 I, 99 Tc, 79 Se, etc.). The purpose of this study was to show a system that can simultaneously achieve the breeding of fissile materials and the transmutation of MA and LLFP in one fast reactor. Transmutation was carried out by loading innovative Duplex type MA fuel in the core region and LLFP containing moderator in the first layer of the radial blanket. Breeding was achieved in the core and axial blanket. As a result, it was clarified that in this fast breeder reactor, a breeding ratio of about 1.1 was obtained, and MA and LLFP achieved a support ratio of 1 or more. The transmutation rate was 10.3%/y for 237 Np, 14.1%/y for 241 Am, 9.9%/y for 243 Am, 1.6%/y for 129 I, 0.75%/y for 99 Tc, and 4%/y for 79 Se. By simultaneously breeding fissile materials and transmuting MA and LLFP in one fast reactor, it will be possible to solve the long-term issues of the nuclear power reactor system, such as securing nuclear fuel resources and reducing radioactive waste.

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“…As shown in Fig. 1 (c), 169 pins in the form of mixed ZnSe 41,42 and YD2 were arranged in the assembly 30,31 . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Concept of a Fast Breeder Reactor To Transmute MA and LLFP

Wakabayashi

2021

Preprint

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“…There have been many studies on the transmutation of MAs and LLFPs in pressurized water reactors 8 , fast reactors 9 – 13 , accelerator-driven sub-critical systems (ADS) 14 , 15 and other systems 16 , 17 . Particularly, the lead-cooled fast reactor (LFR) produces a fast neutron spectrum which is suitable for transmuting both the LLFPs and MAs.…”

Section: Introductionmentioning

confidence: 99%

Transmutation of MAs and LLFPs with a lead-cooled fast reactor

Sun

Han

et al. 2023

Sci Rep

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The management of nuclear wastes has long been a problem that hinders the sustainable and clean utilization of nuclear energy since the advent of nuclear power. These nuclear wastes include minor actinides (MAs: 237Np, 241Am, 243Am, 244Cm and 245Cm) and long-lived fission products (LLFPs: 79Se, 93Zr, 99Tc, 107Pd, 129I and 135Cs), and yet are hard to be handled. In this work, we propose a scheme that can transmute almost all the MAs and LLFPs with a lead-cooled fast reactor (LFR). In this scheme, the MAs and the LLFPs are loaded to the fuel assembly and the blanket assembly for transmutation, respectively. In order to study the effect of MAs loading on the operation of the core, the neutron flux distribution, spectra, and the keff are further compared with and without MAs loading. Then the LLFPs composition is optimized and the support ratio is obtained to be 1.22 for 237Np, 1.63 for 241Am, 1.27 for 243Am, 1.32 for 79Se, 1.53 for 99Tc, 1.02 for 107Pd, and 1.12 for 129I, respectively, indicating that a self-sustained transmutation can be achieved. Accordingly, the transmutation rate of these nuclides was 13.07%/y for 237Np, 15.18%/y for 241Am, 13.34%/y for 243Am, 0.58%/y for 79Se, 0.92%/y for 99Tc, 1.17%/y for 107Pd, 0.56%/y for 129I. Our results show that a lead-cooled fast reactor can be potentially used to manage nuclear wastes with high levels of long-lived radioactivity.

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“…Nevertheless, however, the transmuted amount of 135 Cs for the above two methods is still less than that produced in the reactor itself. Wakabayashi et al 13 improved the transmuted amount of 135 Cs in a new fast reactor transmutation concept consisting of three MONJU‐class fast reactors by increasing the loaded amounts of 135 Cs in the radial blanket regions and shielding regions of the three cores, and the transmuted amount of 135 Cs was evaluated to be about 33.30 kg/(GWe∙y). In addition, Chiba et al 14 further improved the 135 Cs transmutation rate up to 57.04 kg/(GWe∙y) by using the irradiation‐cooling repeating method in the radial blanket region of the core.…”

Section: Introductionmentioning

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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A fast reactor transmutation system for 6 LLFP nuclides

Cited by 10 publications

References 14 publications

Concept of a Fast Breeder Reactor To Transmute MA and LLFP

Concept of a Fast Breeder Reactor To Transmute MA and LLFP

Transmutation of MAs and LLFPs with a lead-cooled fast reactor

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

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A fast reactor transmutation system for 6 LLFP nuclides

Cited by 10 publications

References 14 publications

Concept of a Fast Breeder Reactor To Transmute MA and LLFP

Concept of a Fast Breeder Reactor To Transmute MA and LLFP

Transmutation of MAs and LLFPs with a lead-cooled fast reactor

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

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