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Patwary MM, Sanguanmith S, Meesungnoen J, Jay-Gerin JP. Formation of Local, Transient “Acid Spikes” in the Fast Neutron Radiolysis of Supercritical Water at 400 °C: A Potential Source of Corrosion in Supercritical Water-Cooled Reactors? JOURNAL OF NUCLEAR ENGINEERING AND RADIATION SCIENCE 2020. [DOI: 10.1115/1.4044409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abstract
The use of supercritical water (SCW) in GEN IV reactors is a logical approach to the ongoing development of nuclear energy. A proper understanding of the radiation chemistry and reactivities of transients in a reactor core under SCW conditions is required to achieve optimal water chemistry control and safety. A Monte Carlo simulation study of the radiolysis of SCW at 400 °C by incident 2 MeV monoenergetic neutrons (taken as representative of a fast neutron flux in a reactor) was carried out as a function of water density between ∼150 and 600 kg/m3. The in situ formation of H3O+ by the generated recoil protons was shown to render the “native” track regions temporarily very acidic (pH ∼ 1). This acidity, though local and transitory (“acid spikes”), raises the question whether it may promote a corrosive environment under proposed SCW-cooled reactor operating conditions that would lead to progressive degradation of reactor components.
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Affiliation(s)
- Md Mohsin Patwary
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Sunuchakan Sanguanmith
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Jintana Meesungnoen
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Jean-Paul Jay-Gerin
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
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Sultana A, Meesungnoen J, Jay-Gerin JP. Yields of primary species in the low-linear energy transfer radiolysis of water in the temperature range of 25–700 °C. Phys Chem Chem Phys 2020; 22:7430-7439. [DOI: 10.1039/d0cp00601g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Monte Carlo track chemistry simulations were used to calculate the yields (G values) for the radical (eaq−, H˙, ˙OH) and molecular (H2, H2O2) species formed in low-LET water radiolysis from ∼1 ps to 1 ms between 25 and 700 °C, at 25 MPa pressure.
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Affiliation(s)
- Abida Sultana
- Département de Médecine Nucléaire et de Radiobiologie
- Faculté de Médecine et des Sciences de la Santé
- Université de Sherbrooke
- Sherbrooke
- Canada
| | - Jintana Meesungnoen
- Département de Médecine Nucléaire et de Radiobiologie
- Faculté de Médecine et des Sciences de la Santé
- Université de Sherbrooke
- Sherbrooke
- Canada
| | - Jean-Paul Jay-Gerin
- Département de Médecine Nucléaire et de Radiobiologie
- Faculté de Médecine et des Sciences de la Santé
- Université de Sherbrooke
- Sherbrooke
- Canada
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Meesungnoen J, Jay-Gerin JP. Radiolysis of supercritical water at 400 °C: density dependence of the rate constant for the reaction of hydronium ions with hydrated electrons. Phys Chem Chem Phys 2019; 21:9141-9144. [PMID: 31033971 DOI: 10.1039/c9cp01190k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rate constant, k(eaq- + H3O+), for the reaction of hydronium ions with hydrated electrons in supercritical water (SCW) at 400 °C has been evaluated as a function of water density using Monte Carlo track chemistry simulations of the radiolysis of SCW over the range of 0.15-0.6 g cm-3. Results are consistent with recent predictions using the so-called "cage effect" model.
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Affiliation(s)
- Jintana Meesungnoen
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12ème Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada.
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Patwary MM, Sanguanmith S, Meesungnoen J, Jay-Gerin JP. “Acid spike” formation in the fast neutron radiolysis of supercritical water at 400 °C studied by Monte Carlo track chemistry simulations. CAN J CHEM 2019. [DOI: 10.1139/cjc-2018-0505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A reliable understanding of radiolysis processes in supercritical water (SCW) cooled reactors is required to ensure optimal water chemistry control. In this perspective, Monte Carlo track chemistry simulations of the radiolysis of pure, deaerated SCW at 400 °C by 2 MeV mono-energetic neutrons were carried out as a function of water density between 0.15 and 0.6 g/cm3. The yields of hydronium ions (H3O+) formed at early time were obtained based on the G values calculated for the first three generated recoil protons. Combining our calculated G(H3O+) values with a cylindrical track model allowed us to estimate the concentrations of H3O+ and the corresponding pH values. An abrupt, transient, and highly acidic pH response (“acid spikes”) was observed at early times around the “native” fast neutron and recoil proton trajectories. This intra-track acidity was found to be strongest at times of less than a few tens to a hundred of picoseconds, depending on the value of the density considered (pH ∼ 1). At longer times, the pH gradually increased for all densities, finally reaching a constant value corresponding to the non-radiolytic, pre-irradiation concentration of H3O+, due to the autoprotolysis of water. Interestingly, the lower the density of the water, the longer the time required to reach this constant value. Because many in-core processes in nuclear reactors critically depend on the pH, the present work raises the question whether such highly acidic pH fluctuations, though local and transitory, could promote or contribute to corrosion and degradation of materials under proposed SCW-cooled reactor operating conditions.
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Affiliation(s)
- Md Mohsin Patwary
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Sunuchakan Sanguanmith
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Jintana Meesungnoen
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Jean-Paul Jay-Gerin
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
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Patwary MM, Kanike V, Sanguanmith S, Meesungnoen J, Islam MM, Jay-Gerin JP. Low linear energy transfer radiolysis of supercritical water at 400 °C: in situ generation of ultrafast, transient, density-dependent "acid spikes". Phys Chem Chem Phys 2019; 21:7137-7146. [PMID: 30888004 DOI: 10.1039/c9cp00790c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
There is growing interest in the radiation chemistry of supercritical water (SCW), as its use as a coolant in a nuclear reactor (Generation IV) is the logical evolution of the current (Generation III or less) water-cooled reactors. However, current knowledge about the potential effects of water radiolysis in a Gen-IV supercritical water-cooled reactor (SCWR) is incomplete. In this work, Monte Carlo track chemistry simulations of the low linear energy transfer (LET) radiolysis of SCW (H2O) at 400 °C are used in combination with a spherical "spur" model to study the effect of water density on the in situ radiolytic formation of H3O+ ions and the corresponding abrupt, transient, highly acidic pH response ("acid spikes") that is observed immediately after irradiation. The magnitude and duration of this acidic pH effect depend on the water density in the considered range of 0.15-0.6 g cm-3. It is strongest at times less than a few tens of picoseconds with the pH remaining nearly constant at ∼1.6 and 1.9 for the highest ("liquid-like") and lowest ("gas-like") density, respectively. At longer times, the pH gradually increases for all densities and finally reaches a constant value corresponding to the non-radiolytic, pre-irradiation concentration of H3O+, due to the autoprotolysis of water. Our results show that the lower the density of the water, the longer the time required to reach this constant value, ranging from ∼50 ns at 0.6 g cm-3 (pH ∼ 5.6) to ∼1 μs at 0.15 g cm-3 (pH ∼ 8.5). The generation of these highly acidic pH fluctuations around the "native" radiation tracks, though local and transient, raises questions about the potential implications of this effect in proposed Gen-IV SCW-cooled reactors regarding corrosion and degradation of materials.
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Affiliation(s)
- Md Mohsin Patwary
- Département de Médecine Nucléaire et de Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada.
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Sanguanmith S, Meesungnoen J, Guzonas DA, Stuart CR, Jay-Gerin JP. Radiolysis of Supercritical Water at 400°C: A Sensitivity Study of the Density Dependence of the Yield of Hydrated Electrons on the (eaq−+eaq−) Reaction Rate Constant. JOURNAL OF NUCLEAR ENGINEERING AND RADIATION SCIENCE 2016. [DOI: 10.1115/1.4031013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The temperature dependence of the rate constant (k) of the bimolecular reaction of two hydrated electrons (eaq−) measured in alkaline water exhibits an abrupt drop between 150°C and 200°C; above 250°C, it is too small to be measured reliably. Although this result is well established, the applicability of this sudden drop in k(eaq−+eaq−)) above ∼150°C to neutral or slightly acidic solution, as recommended by some authors, still remains uncertain. In fact, the recent work suggested that in near-neutral water the abrupt change in k above ∼150°C does not occur and that k should increase, rather than decrease, at temperatures greater than 150°C with roughly the same Arrhenius dependence of the data below 150°C. In view of this uncertainty of k, Monte Carlo simulations were used in this study to examine the sensitivity of the density dependence of the yield of eaq− in the low–linear energy transfer (LET) radiolysis of supercritical water (H2O) at 400°C on variations in the temperature dependence of k. Two different values of the eaq− self-reaction rate constant at 400°C were used: one was based on the temperature dependence of k above 150°C as measured in alkaline water (4.2×108 M−1 s−1), and the other was based on an Arrhenius extrapolation of the values below 150°C (2.5×1011 M−1 s−1). In both cases, the density dependences of our calculated eaq− yields at ∼60 ps and 1 ns were found to compare fairly well with the available picosecond pulse radiolysis experimental data (for D2O) for the entire water density range studied (∼0.15–0.6 g/cm3). Only a small effect of k on the variation of G(eaq−)) as a function of density at 60 ps and 1 ns could be observed. In conclusion, our present calculations did not allow us to unambiguously confirm (or deny) the applicability of the predicted sudden drop of k(eaq−+eaq−) at ∼150°C in near-neutral water.
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Affiliation(s)
- Sunuchakan Sanguanmith
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada e-mail:
| | - Jintana Meesungnoen
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada e-mail:
| | - David A. Guzonas
- Canadian Nuclear Laboratories, Reactor Chemistry and Corrosion, 20 Forest Avenue, Deep River, ON K0J 1P0, Canada e-mail:
| | - Craig R. Stuart
- Canadian Nuclear Laboratories, Reactor Chemistry and Corrosion, 20 Forest Avenue, Deep River, ON K0J 1P0, Canada e-mail:
| | - Jean-Paul Jay-Gerin
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada e-mail:
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Butarbutar SL, Meesungnoen J, Guzonas DA, Stuart CR, Jay-Gerin JP. Modeling the Radiolysis of Supercritical Water by Fast Neutrons: Density Dependence of the Yields of Primary Species at 400°C. Radiat Res 2014; 182:695-704. [DOI: 10.1667/rr13715.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Butarbutar SL, Sanguanmith S, Meesungnoen J, Causey P, Stuart CR, Jay-Gerin JP. Self-radiolysis of tritiated water. 2. Density dependence of the yields of primary species formed in the radiolysis of supercritical water by tritium β-particles at 400 °C. RSC Adv 2014. [DOI: 10.1039/c4ra02761b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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