The Interaction of Iodine with Organic Material in Containment

The leaching behavior of remaining solvent from an epoxy paint coating when it is submerged in water was experimentally studied. A leach kinetics model considering the equilibrium of the solvent concentration in the paint matrix and in water was developed. Three model parameters, equilibrium constant K, leaching rate k d , and initial concentration of the solvent in the paint C 0 p , were evaluated based on the experimental results, and empirical correlation equations for them were obtained. The model showed good qualitative and quantitative agreement with the observed evolution of the leached solvent mass in the present experiment. Also, the model showed consistency with experimental data in a different configuration.

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“…The overall rate constant, k Ã , can be evaluated based on them using Eq. (10). The evaluated values and experimental data are compared in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The leaching behavior of organic solvents from various types of paint layers has been studied by Wren et al 10,11) and Ball et al 12) They performed experiments on the leaching behavior of solvents remaining in paint layers submerged in water. Various kinds of paints, vinyl, epoxy, and polyurethane types, were tested.…”

Section: Introductionmentioning

confidence: 99%

Experiment and Modeling for Solvent Leaching from Paint Matrix Considering Equilibrium

Moriyama

Chiba

Tashiro

et al. 2011

Journal of Nuclear Science and Technology

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“…Despite considerable efforts in various studies, [31][32][33][34] the sources and rates of organic iodide formation in containment are not well characterized. It has been reported that an organic iodide (chiefly CH 3 I) may be formed in water with relatively higher concentrations of CH 4 and I 2 under gamma radiation.…”

Section: Organic Iodide Formation and Destructionmentioning

confidence: 99%

“…[32][33][34] In operating BWRs, iodine activities have been found to contain a large fraction of organic iodine in the offgas and gaseous effluent. 56,[59][60][61] The mechanism of organic iodine formation may be attributed to the adsorption of volatile inorganic species, e.g., I 2 , I, and HIO, on steel and/or painted surfaces.…”

Section: Surface Reactionsmentioning

confidence: 99%

Reassessment of Reactor Coolant and Iodine Chemistry under Accident Conditions

Lin

Chao

2009

Journal of Nuclear Science and Technology

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Under severe accident conditions, the chemistry of reactor coolant could be significantly different from that under normal operating conditions. Injection of standby liquid control (SBLC) solution, release of fission product cesium (Cs) from damaged fuel rods, and addition of NaOH and Na 2 S 2 O 3 in spray water will certainly enhance the alkalinity of water. In addition, oxidation of fuel cladding (zircaloy) by hightemperature water and steam would produce a significant amount of hydrogen, and hydrogen in water could effectively suppress water radiolysis and make the water more reducing. It is believed that the chemistry and transport behavior of iodine released from damaged fuel rods are strongly dependent on the chemistry of reactor water under accident conditions, and it is expected that the released iodine will most likely remain in nonvolatile forms in water. The chemistry of reactor coolant and the activities of iodine released from a damaged core are reviewed in detail in this paper.

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“…Such organic iodine production was experimentally investigated by Wren et al 10) and by Cantrel 11) in medium-scale facilities RTF and CAIMAN, respectively, and by Taghipour and Evans 8) in a small-scale apparatus. Wren et al observed a pH drop due to acid formation by the radiolytic decomposition of the organic compound.…”

Section: Introductionmentioning

confidence: 99%

Experiments on the Release of Gaseous Iodine from Gamma-Irradiated Aqueous CsI Solution and Influence of Oxygen and Methyl Isobutyl Ketone (MIBK)

Moriyama

Tashiro

Chiba

et al. 2010

Journal of Nuclear Science and Technology

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Volatile iodine production due to radiation chemical effects is known to be an important uncertainty source in the evaluation of the source term for severe accidents of light water reactors (LWRs). The gaseous release fractions of molecular iodine and organic iodine from gamma-irradiated 10 À4 mol/L cesium iodide aqueous solution were measured with the dose rate $ 7 kGy/h at room temperature. The solution was buffered with 0.1 mol/L boric acid and sodium hydroxide (pH $7) and contained up to 10 À3 mol/L methyl isobutyl ketone (MIBK) as an organic additive. The concentrations of MIBK in the solution and oxygen in the sweep gas were changed as experimental parameters. The total iodine release fraction of the original aqueous inventory and the fraction released as organic iodine were 2-47 and 0.02-1.5%, respectively, at the end of 2 h of irradiation. They were dependent on both the aqueous MIBK concentration and oxygen concentration in the sweep gas. Under a constant cover gas condition, the total iodine release showed a decreasing trend and the organic iodine release showed an increasing trend when the MIBK concentration increased. This behavior can be explained by the branching of the reaction path of radiolytic degradation of ketones depending on the availability of dissolved oxygen, and competition between iodine and organic compounds on the consumption of radicals produced by water radiolysis.

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The Interaction of Iodine with Organic Material in Containment

Cited by 35 publications

References 5 publications

Experiment and Modeling for Solvent Leaching from Paint Matrix Considering Equilibrium

Experiment and Modeling for Solvent Leaching from Paint Matrix Considering Equilibrium

Reassessment of Reactor Coolant and Iodine Chemistry under Accident Conditions

Experiments on the Release of Gaseous Iodine from Gamma-Irradiated Aqueous CsI Solution and Influence of Oxygen and Methyl Isobutyl Ketone (MIBK)

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