Radiolysis of Sub- and Supercritical Water Induced by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li Recoil Nuclei at 300–500 °C and 25 MPa

(1) Background: Generation IV supercritical water-cooled reactors (SCWRs), including small modular reactor (SCW-SMR) variants, are pivotal in nuclear technology. Operating at 300–500 °C and 25 MPa, these reactors require detailed understanding of radiation chemistry and transient species to optimize...

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Main Authors: Md Shakhawat Hossen Bhuiyan, Jintana Meesungnoen, Jean-Paul Jay-Gerin
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Journal of Nuclear Engineering
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Online Access:https://www.mdpi.com/2673-4362/6/2/17
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author Md Shakhawat Hossen Bhuiyan
Jintana Meesungnoen
Jean-Paul Jay-Gerin
author_facet Md Shakhawat Hossen Bhuiyan
Jintana Meesungnoen
Jean-Paul Jay-Gerin
author_sort Md Shakhawat Hossen Bhuiyan
collection DOAJ
description (1) Background: Generation IV supercritical water-cooled reactors (SCWRs), including small modular reactor (SCW-SMR) variants, are pivotal in nuclear technology. Operating at 300–500 °C and 25 MPa, these reactors require detailed understanding of radiation chemistry and transient species to optimize water chemistry, reduce corrosion, and enhance safety. Boron, widely used as a neutron absorber, plays a significant role in reactor performance and safety. This study focuses on the yields of radiolytic species in subcritical and supercritical water exposed to <sup>4</sup>He and <sup>7</sup>Li recoil ions from the <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li fission reaction in SCWR/SCW-SMR environments. (2) Methods: We use Monte Carlo track chemistry simulations to calculate yields (<i>G</i> values) of primary radicals (e<sup>−</sup><sub>aq</sub>, H<sup>•</sup>, and <sup>•</sup>OH) and molecular species (H<sub>2</sub> and H<sub>2</sub>O<sub>2</sub>) from water radiolysis by α-particles and Li<sup>3</sup>⁺ recoils across 1 picosecond to 0.1 millisecond timescales. (3) Results: Simulations show substantially lower radical yields, notably e<sup>−</sup><sub>aq</sub> and <sup>•</sup>OH, alongside higher molecular product yields compared to low linear energy transfer (LET) radiation, underscoring the high-LET nature of <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li recoil nuclei. Key changes include elevated <i>G</i>(<sup>•</sup>OH) and <i>G</i>(H<sub>2</sub>), and a decrease in <i>G</i>(H<sup>•</sup>), primarily driven during the homogeneous chemical stage of radiolysis by the reaction H<sup>•</sup> + H<sub>2</sub>O → <sup>•</sup>OH + H<sub>2</sub>. This reaction significantly contributes to H<sub>2</sub> production, potentially reducing the need for added hydrogen in coolant water to mitigate oxidizing species. In supercritical conditions, low <i>G</i>(H₂O₂) suggests that H<sub>2</sub>O<sub>2</sub> is unlikely to be a major contributor to material oxidation. (4) Conclusions: The <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li reaction’s yield estimates could significantly impact coolant chemistry strategies in SCWRs and SCW-SMRs. Understanding radiolytic behavior in these conditions aids in refining reactor models and coolant chemistry to minimize corrosion and radiolytic damage. Future experiments are needed to validate these predictions.
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spelling doaj-art-df29210f828b4f6785019b2046c4b93f2025-08-20T02:20:58ZengMDPI AGJournal of Nuclear Engineering2673-43622025-06-01621710.3390/jne6020017Radiolysis of Sub- and Supercritical Water Induced by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li Recoil Nuclei at 300–500 °C and 25 MPaMd Shakhawat Hossen Bhuiyan0Jintana Meesungnoen1Jean-Paul Jay-Gerin2Department of Medical Imaging and Radiation Sciences, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue Nord, Sherbrooke, QC J1H 5N4, CanadaDepartment of Medical Imaging and Radiation Sciences, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue Nord, Sherbrooke, QC J1H 5N4, CanadaDepartment of Medical Imaging and Radiation Sciences, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue Nord, Sherbrooke, QC J1H 5N4, Canada(1) Background: Generation IV supercritical water-cooled reactors (SCWRs), including small modular reactor (SCW-SMR) variants, are pivotal in nuclear technology. Operating at 300–500 °C and 25 MPa, these reactors require detailed understanding of radiation chemistry and transient species to optimize water chemistry, reduce corrosion, and enhance safety. Boron, widely used as a neutron absorber, plays a significant role in reactor performance and safety. This study focuses on the yields of radiolytic species in subcritical and supercritical water exposed to <sup>4</sup>He and <sup>7</sup>Li recoil ions from the <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li fission reaction in SCWR/SCW-SMR environments. (2) Methods: We use Monte Carlo track chemistry simulations to calculate yields (<i>G</i> values) of primary radicals (e<sup>−</sup><sub>aq</sub>, H<sup>•</sup>, and <sup>•</sup>OH) and molecular species (H<sub>2</sub> and H<sub>2</sub>O<sub>2</sub>) from water radiolysis by α-particles and Li<sup>3</sup>⁺ recoils across 1 picosecond to 0.1 millisecond timescales. (3) Results: Simulations show substantially lower radical yields, notably e<sup>−</sup><sub>aq</sub> and <sup>•</sup>OH, alongside higher molecular product yields compared to low linear energy transfer (LET) radiation, underscoring the high-LET nature of <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li recoil nuclei. Key changes include elevated <i>G</i>(<sup>•</sup>OH) and <i>G</i>(H<sub>2</sub>), and a decrease in <i>G</i>(H<sup>•</sup>), primarily driven during the homogeneous chemical stage of radiolysis by the reaction H<sup>•</sup> + H<sub>2</sub>O → <sup>•</sup>OH + H<sub>2</sub>. This reaction significantly contributes to H<sub>2</sub> production, potentially reducing the need for added hydrogen in coolant water to mitigate oxidizing species. In supercritical conditions, low <i>G</i>(H₂O₂) suggests that H<sub>2</sub>O<sub>2</sub> is unlikely to be a major contributor to material oxidation. (4) Conclusions: The <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li reaction’s yield estimates could significantly impact coolant chemistry strategies in SCWRs and SCW-SMRs. Understanding radiolytic behavior in these conditions aids in refining reactor models and coolant chemistry to minimize corrosion and radiolytic damage. Future experiments are needed to validate these predictions.https://www.mdpi.com/2673-4362/6/2/17subcritical and supercritical water<sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li fission reaction<sup>4</sup>He and <sup>7</sup>Li recoil ionslinear energy transfer (LET)radiolysisMonte Carlo track chemistry simulation
spellingShingle Md Shakhawat Hossen Bhuiyan
Jintana Meesungnoen
Jean-Paul Jay-Gerin
Radiolysis of Sub- and Supercritical Water Induced by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li Recoil Nuclei at 300–500 °C and 25 MPa
Journal of Nuclear Engineering
subcritical and supercritical water
<sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li fission reaction
<sup>4</sup>He and <sup>7</sup>Li recoil ions
linear energy transfer (LET)
radiolysis
Monte Carlo track chemistry simulation
title Radiolysis of Sub- and Supercritical Water Induced by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li Recoil Nuclei at 300–500 °C and 25 MPa
title_full Radiolysis of Sub- and Supercritical Water Induced by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li Recoil Nuclei at 300–500 °C and 25 MPa
title_fullStr Radiolysis of Sub- and Supercritical Water Induced by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li Recoil Nuclei at 300–500 °C and 25 MPa
title_full_unstemmed Radiolysis of Sub- and Supercritical Water Induced by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li Recoil Nuclei at 300–500 °C and 25 MPa
title_short Radiolysis of Sub- and Supercritical Water Induced by <sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li Recoil Nuclei at 300–500 °C and 25 MPa
title_sort radiolysis of sub and supercritical water induced by sup 10 sup b i n i α sup 7 sup li recoil nuclei at 300 500 °c and 25 mpa
topic subcritical and supercritical water
<sup>10</sup>B(<i>n</i>,α)<sup>7</sup>Li fission reaction
<sup>4</sup>He and <sup>7</sup>Li recoil ions
linear energy transfer (LET)
radiolysis
Monte Carlo track chemistry simulation
url https://www.mdpi.com/2673-4362/6/2/17
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AT jeanpauljaygerin radiolysisofsubandsupercriticalwaterinducedbysup10supbiniasup7suplirecoilnucleiat300500cand25mpa