Radiological environmental impact analysis of a 2-MW thorium molten salt reactor during an accident

Changqi, Chen; Xia, Xiaobin; Cai, Jun; Li, Chang-Yuan

doi:10.1007/s41365-019-0605-3

Cited by 7 publications

(2 citation statements)

References 19 publications

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“…Major actinides like Np, Pu, Am, and Cm are the most influencing elements on the neutron balance and radioactivity in the core 30 . TRU is contained in feeding fuel and will be burned over burn‐up time.…”

Section: Resultsmentioning

confidence: 99%

Ex‐core transition to thorium cycle in a small modular heavy‐water moderated molten salt reactor with unchanged concentration of heavy metal nuclides in the fuel salt

Zhang

Chen

et al. 2021

Int J Energy Res

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Summary Ex‐core transition to thorium fuel cycle is an effective way to address the issue of the lacking of the 233U in nature. It consists to extract online the thorium bred 233Pa from the core and store it outside. The obtained 233Pa stockpile will decay into the 233U (T1/2 = 27 days), and when enough 233U is cumulated, a new 233U‐based reactor can be loaded. However, this approach will inevitably provoke the heavy nuclides (HN) concentration in the core during the extraction operation, which would affect the chemical stability of fuel salt and subsequently endanger the safety of the core operation. In this study, an improved ex‐core transition with unchanged HN concentration is proposed for a 500‐MWth small modular heavy‐water moderated molten salt reactor (SM‐HWMSR). To achieve this, two operating stages are needed. In the first stage, transuranic (TRU) from the spent fuel of LWRs is used to feed the low enrichment uranium (LEU, 19.75 wt% 235U/U) started core with 300 operating days to ensure negative temperature reactivity coefficient (TRC). In the second stage, the thorium bred 233U from the first stage is mixed with TRU to refuel the core. The proposed ex‐core transition scheme aims to burn TRU, meanwhile breed 233U to start new MSRs. The fuel cycle performance over 60‐years' operation is analyzed. The results demonstrate that it is possible to realize ex‐core transition with unchanged concentration of HN in the fuel salt. As the fraction of 233U in the mixed fuel is set to be 15 mol%, it only takes 3 years to start a new reactor with the stored 233U. The radiotoxicity of TRU‐based fuel is decreased after 60 years' burning in the SM‐HWMSR core. Novelty Statement “Ex‐core transition to thorium cycle in an SM‐HWMSR with unchanged concentration of heavy metal nuclides in the fuel salt” was investigated by Yapeng Zhang, Jianhui Wu, Jingen Chen, and Xiangzhou Cai. The results demonstrate that it is possible to realize ex‐core transition with unchanged concentration of HN in the fuel salt. As the fraction of 233U in the mixed fuel is set to be 15 mol%, it only takes 3 years to start a new reactor by the stored 233U.

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Section: Resultsmentioning

confidence: 99%

Ex‐core transition to thorium cycle in a small modular heavy‐water moderated molten salt reactor with unchanged concentration of heavy metal nuclides in the fuel salt

Zhang

Chen

et al. 2021

Int J Energy Res

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“…Accurate estimation of the dose received by astronauts is an essential precondition for successful manned deep-space exploration missions. In addition, with the wide use of nuclear technology in material physics and medical physics [38][39][40][41][42][43][44][45][46], it is also important to be able to calculate the radiation dose received by a typical human in the corresponding radiation environment. Based on the prior simulation results, we calculated the radiation dose that would have been received by astronauts on the Mars surface.…”

Section: Radiation Dose Received By a Typical Human Bodymentioning

confidence: 99%

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

et al. 2022

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The radiation environment on the surface of Mars is a potential threat for future manned exploration missions to this planet. In this study, a simple geometrical model was built for simulating the radiation environment on the Mars surface caused by galactic cosmic rays; the model was built and studied using the Geant4 toolkit. The simulation results were compared with the data reported by a radiation assessment detector (RAD). The simulated spectra of neutrons, photons, protons, $$\alpha$$ α particles, and particle groups $$Z=3$$ Z = 3 –5, $$Z=6$$ Z = 6 –8, $$Z=9$$ Z = 9 –13, and $$Z=14$$ Z = 14 –24 were in a reasonable agreement with the RAD data. However, for deuterons, tritons, and $$\,^{3}{\mathrm{He}}$$ 3 He , the simulations yielded much smaller values than for the corresponding RAD data. In addition, the particles’ spectra within the $$90^{\circ }$$ 90 ∘ zenith angle were also obtained. Based on these spectra, we calculated the radiation dose that would have been received by an average human body on Mars. The distribution of the dose throughout the human body was not uniform. The absorbed and equivalent doses for the brain were the highest among all of the organs, reaching 62.0 ± 1.7 mGy/y and 234.1 ± 8.0 mSv/y, respectively. The average absorbed and equivalent doses for the entire body were approximately 44 mGy/y and 153 mSv/y, respectively. Further analysis revealed that most of the radiation dose was owing to $$\alpha$$ α particles, protons, and heavy ions. We then studied the shielding effect of the Mars soil with respect to the radiation. The body dose decreased significantly with increasing soil depth. At the depth of 1.5 m, the effective dose for the entire body was 17.9 ± 2.4 mSv/y, lower than the dose limit for occupational exposure. At the depth of 3 m, the effective dose to the body was 2.7 ± 1.0 mSv/y, still higher than the accepted dose limit.

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Experimental study on the penetration characteristics of leaking molten salt in the thermal insulation layer of aluminum silicate fiber

et al. 2021

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Radiological environmental impact analysis of a 2-MW thorium molten salt reactor during an accident

Cited by 7 publications

References 19 publications

Ex‐core transition to thorium cycle in a small modular heavy‐water moderated molten salt reactor with unchanged concentration of heavy metal nuclides in the fuel salt

Ex‐core transition to thorium cycle in a small modular heavy‐water moderated molten salt reactor with unchanged concentration of heavy metal nuclides in the fuel salt

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

Experimental study on the penetration characteristics of leaking molten salt in the thermal insulation layer of aluminum silicate fiber

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