Radiation Chemistry in Nuclear Engineering

Takagi, Junichi; Mincher, Bruce J.; Yamaguchi, Makoto; Katsumura, Yosuke

doi:10.1201/b10389-35

Cited by 7 publications

(4 citation statements)

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“…At first, let us consider the reaction of OH • radical with undissociated nitric acid through reaction. If we consider the same value of the rate constant of reaction and an equilibrium constant for a 7 M nitric acid solution ( K = 12 M –1 ), , the reaction between OH • and undissociated nitric acid can occur partially, and the slight increase of the signal within the first 4 ns could be to that reaction (Figure ). Nevertheless, we cannot exclude a very low contribution of the reaction .…”

Section: Resultsmentioning

confidence: 99%

Picosecond Pulse Radiolysis Study of Highly Concentrated Nitric Acid Solutions: Formation Mechanism of NO₃^• Radical

et al. 2012

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The formation of nitrate radical, NO(3)(•), is observed for the first time directly by picosecond pulse radiolysis of highly concentrated nitric acid solutions. The experimental yield of NO(3)(-) ionization is deduced from the pulse-probe transient absorption measurements in the visible region where this radical absorbs. On the basis of the value of the extinction coefficient of nitrate radical at 640 nm equal to 1300 M cm(-1), the experimental yield of NO(3)(•) at 20 ps is found to be around 0.36 × 10(-7), 1.33 × 10(-7), and 2.85 × 10(-7) mol J(-1) for 1, 3.5, and 7 M nitric acid solutions, respectively. Relative to the dose absorbed by nitric acid by the direct effect, we find an unexpected high formation yield of the nitrate radical within the electron pulse. Therefore, we suggest that the trapping of the positive hole, H(2)O(•+), by NO(3)(-) also contributes to the formation of NO(3)(•) within the electron pulse. Moreover, after the pulse and within 4 ns, the beginning of the reaction of OH(•) radical with undissociated nitric acid is observed for the most concentrated nitric acid solution.

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Section: Resultsmentioning

confidence: 99%

Picosecond Pulse Radiolysis Study of Highly Concentrated Nitric Acid Solutions: Formation Mechanism of NO₃^• Radical

et al. 2012

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“…The cooling water operates at high pressure and temperature conditions (7-7.5 MPa, 285 • C in BWRs and ca. 15.5 MPa, 315 • C in PWRs) and is exposed to intense fluxes of gamma rays and fast neutrons [2] (pp. 960-1023).…”

Section: Introductionmentioning

confidence: 99%

“…331-364). The stable oxidants (H 2 O 2 and O 2 ) create a corrosive environment contributing significantly to stress corrosion cracking of the structural materials [1,2,[4][5][6]. The harmful effect of oxidants is strengthened by the low acidity (low pH) of water at the operating temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…A quantitative understanding of how these additives change a corrosive environment in the nuclear core is still insufficient but essential to control stress corrosion cracking and maintain the integrity of materials in reactor circuits. In particular, it is important to estimate critical hydrogen concentration (CHC), i.e., the amount of dissolved hydrogen gas needed to suppress the net production of O 2 and H 2 O 2 in the reactor circuit [2] (pp. 960-1023).…”

Section: Introductionmentioning

confidence: 99%

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A Numerical Simulation of Radiation Chemistry for Controlling the Oxidising Environment in Water-Cooled Nuclear Power Reactors

Swiatla-Wojcik

2022

Applied Sciences

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Maintaining the integrity of materials of light-water nuclear power reactors requires the development of effective methods to control and minimise the corrosive environment associated with the radiolysis of a coolant. In this study, the behaviour of the oxidising environment is simulated using a hybrid method. The hybrid method has advantages in that the production of radiolytic species under exposure of the coolant to ionising radiation is simulated while providing material and charge balances. Steady-state concentrations of stable and transient oxidising agents are calculated as a function of radiation composition and dose rate by numerical integration of the system of kinetic equations describing radiation chemistry of neutral water, the alkaline solution, and the hydrogenated systems at 300 °C. The importance of the reactions and equilibria constituting the radiolysis scheme of the coolant is assessed. The influence of the presence of a base and the injected H2 on the yield of key reactions responsible for the formation of the main oxidants H2O2 and O2 are discussed. Simulation indicated the synergic effect of H2 gas and base added to the coolant on diminishment of the steady-state concentration of oxidants.

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Material–Coolant Interactions

Katsumura

Muroya

2014

Supercritical-Pressure Light Water Cooled Reactors

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Radiation Chemistry in Nuclear Engineering

Cited by 7 publications

References 159 publications

Picosecond Pulse Radiolysis Study of Highly Concentrated Nitric Acid Solutions: Formation Mechanism of NO₃^• Radical

Picosecond Pulse Radiolysis Study of Highly Concentrated Nitric Acid Solutions: Formation Mechanism of NO₃^• Radical

A Numerical Simulation of Radiation Chemistry for Controlling the Oxidising Environment in Water-Cooled Nuclear Power Reactors

Material–Coolant Interactions

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Radiation Chemistry in Nuclear Engineering

Cited by 7 publications

References 159 publications

Picosecond Pulse Radiolysis Study of Highly Concentrated Nitric Acid Solutions: Formation Mechanism of NO3• Radical

Picosecond Pulse Radiolysis Study of Highly Concentrated Nitric Acid Solutions: Formation Mechanism of NO3• Radical

A Numerical Simulation of Radiation Chemistry for Controlling the Oxidising Environment in Water-Cooled Nuclear Power Reactors

Material–Coolant Interactions

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Product

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Picosecond Pulse Radiolysis Study of Highly Concentrated Nitric Acid Solutions: Formation Mechanism of NO₃^• Radical

Picosecond Pulse Radiolysis Study of Highly Concentrated Nitric Acid Solutions: Formation Mechanism of NO₃^• Radical