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Journal Articles

Effect of re-oxidation rate of additive cations on corrosion rate of stainless steel in boiling nitric acid solution

Irisawa, Eriko; Yamamoto, Masahiro; Kato, Chiaki; Motooka, Takafumi; Ban, Yasutoshi

Journal of Nuclear Science and Technology, 56(4), p.337 - 344, 2019/04

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Journal Articles

Oxidation characteristics of lead-alloy coolants in air ingress accident

Kondo, Masatoshi*; Okubo, Nariaki; Irisawa, Eriko; Komatsu, Atsushi; Ishikawa, Norito; Tanaka, Teruya*

Energy Procedia, 131, p.386 - 394, 2017/12

 Times Cited Count:2 Percentile:10.14

The chemical behaviors of lead (Pb) based coolants in the air ingress accident of fast reactors were investigated by means of the thermodynamic considerations and the static oxidation experiments for Pb alloys at various chemical compositions. The results of the static oxidation tests for lead-bismuth (Pb-Bi) alloys indicated that Pb was depleted from the alloy due to the preferential formation of PbO in air at 773K. Pb-Bi oxide and Bi$$_{2}$$O$$_{3}$$ were formed after the enrichment of Bi in the alloys due to the Pb depletion. The oxidation rates of the alloys were much larger than that of the steels, and became larger with higher Pb concentration in the alloys. The compatibility of Pb-Bi alloys with stainless steel was worse when the Pb concentration in the alloys became low, since the dissolution type corrosion was promoted by the Bi composition in the alloy. The Pb-Li alloys were oxidized as they formed Li$$_{2}$$PbO$$_{3}$$ and Li$$_{2}$$CO$$_{3}$$. Then, Li was depleted from the alloy.

Journal Articles

Effect of oxidizing metallic ions on corrosion of stainless steel during concentration process simulating High-level Activity Liquid Waste (HALW) concentrator

Irisawa, Eriko; Kato, Chiaki; Kamoshida, Michio*; Hakamatsuka, Yasuyuki*; Ueno, Fumiyoshi; Yamamoto, Masahiro

Proceedings of European Corrosion Congress 2017 (EUROCORR 2017) and 20th ICC & Process Safety Congress 2017 (USB Flash Drive), 9 Pages, 2017/09

Journal Articles

Development of metal corrosion testing method simulating equipment of reprocessing of spent nuclear fuels

Matsueda, Makoto; Irisawa, Eriko; Kato, Chiaki; Matsui, Hiroki

Proceedings of 54th Annual Meeting of Hot Laboratories and Remote Handling (HOTLAB 2017) (Internet), 4 Pages, 2017/00

In the PUREX method, spent fuels are dissolved with nitric acid media. The reprocessing solution containing Fission Products derived from spent fuels is very corrosive to metal materials, the corrosion problem often appears on the surface stainless steel devices. The oxidizing metal ions such as Ruthenium (Ru) and Neptunium (Np) in the process solution is the key reason for severe corrosion of stainless steel. In order to obtain the corrosion rate of stainless steel, we installed the corrosion test apparatus inside an airtight concrete cell in a hot laboratory (the WAste Safety TEsting Facility (WASTEF) of the Japan Atomic Energy Agency), and performed the corrosion tests of stainless steel in the heated nitric acid solution containing Np. The corrosion tests were performed in the temperature range from room temperature to boiling point for 500 hours per batch. The results show that the presence of Np accelerate the stainless steel corrosion in the nitric acid solution.

Journal Articles

Effect of boiling of nitric acid solution on corrosion of Stainless steel-made concentrator in reduced pressure

Ueno, Fumiyoshi; Irisawa, Eriko; Kato, Chiaki; Igarashi, Takahiro; Yamamoto, Masahiro; Abe, Hitoshi

Proceedings of European Corrosion Congress 2016 (EUROCORR 2016) (USB Flash Drive), 7 Pages, 2016/09

In this study, we focused on the effect of the boiling of nitric acid solution on the corrosion of a stainless steel-made concentrator in reduced pressure in fuel reprocessing plant. In order to perform the simulation test in a non-radioactive condition, nitric acid solution with the addition of vanadium as an oxidizing metal ion were used. Corrosion tests were carried out under the conditions of boiling at reduced pressure, and of non-boiling at normal pressure and several temperatures. As a result, corrosion was accelerated by the solution boiling while it was not by non-boiling at the same temperature. It was found also that the temperature dependence of corrosion rate is the same in the both conditions of boiling and non-boiling. The corrosion accelerating effect will be discussed on the basis of the reaction among nitric acid, NOx and vanadium, etc.

Journal Articles

Effect of boiling under reduced pressure on corrosion of stainless steels in nitric acid solution simulating high-level radioactive liquid waste

Irisawa, Eriko; Ueno, Fumiyoshi; Kato, Chiaki; Abe, Hitoshi

Zairyo To Kankyo, 65(4), p.134 - 137, 2016/04

In order to investigate the effect of boiling under reduced pressure on corrosion of stainless steel in the nitric acid solution, the corrosion tests simulating the high-level radioactive liquid waste evaporator were performed. The results of immersion tests of stainless steels in the solution with and without boiling showed that the corrosion rates in boiling solution were larger than those in not boiling solution in case of same temperature of solution. Moreover, the cathode polarization curves showed that the corrosion potential of stainless steel in boiling solutions were shifted nobler, and the current intensity became larger than that in not boiling solutions. According to these results, it can be concluded that boiling of solution under reduced pressure accelerate the corrosion rates.

Journal Articles

Effect of nitrous ion on oxidation of oxidizing-metallic ion in nitric acid solution

Irisawa, Eriko; Seki, Masaharu*; Ueno, Fumiyoshi; Kato, Chiaki; Motooka, Takafumi; Abe, Hitoshi

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1108 - 1112, 2015/09

Journal Articles

Influence of seawater-component on corrosion of steel in nitric acid solution containing vanadium and ruthenium

Irisawa, Eriko; Ueno, Fumiyoshi; Uchida, Naoki; Taguchi, Katsuya

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 3 Pages, 2015/05

Oral presentation

Effect of sea water on corrosion of materials used in reprocessing process, 2; Corrosion in boiling nitric acid solution

Irisawa, Eriko; Ueno, Fumiyoshi; Yamamoto, Masahiro; Uchida, Naoki; Taguchi, Katsuya

no journal, , 

The effect of seawater added in the boiling nitric acid solution on the corrosion of steel used in the spent fuel reprocessing facility was investigated. The corrosion rates of 310 type austenitic stainless steel in the boiling nitric acid with containing of vanadium and chloride ion were obtained by the immersion corrosion tests under ordinary pressure. In case of the presence of the oxidizing cation (vanadium in this study) and the composition of seawater in the nitric acid solution, the corrosion rates were decreased compared with the case the absence of seawater.

Oral presentation

Study on temperature dependence of corrosion of stainless steel in the metal ion containing nitric acid

Ueno, Fumiyoshi; Irisawa, Eriko; Abe, Hitoshi

no journal, , 

The reprocessing components made of stainless steel appear intergranular corrosion in boiling nitric acid solution containing high oxidizing metal ions derived from spent nuclear fuel. In this paper, to clarify the corrosion mechanism in this environment, temperature dependence of corrosion rate of a stainless steel in boiling 3 molar nitric acid with added pentavalent vanadium was studied. As the results of investigation of the temperature dependence of the corrosion rate of the heat transfer surface using estimated temperature from a boiling curve, it was found that there was no effect of heat flux on corrosion rate because the dependence was consistent between heat transfer condition and non-heat-transfer. Also it was found that the activation energy was different between the boiling conditions of about 378 K or more and the non-boiling conditions of below 378 K.

Oral presentation

Influence of nitrite ion on oxidation of vanadium in nitric acid solution

Irisawa, Eriko; Ueno, Fumiyoshi; Abe, Hitoshi; Kumagai, Mikio*; Suzuki, Kazunori*; Hayashi, Shinichiro*

no journal, , 

no abstracts in English

Oral presentation

Study on corrosion of stainless steel in high activity liquid waste concentrator, 2; Effect of precipitates on corrosion

Ueno, Fumiyoshi; Irisawa, Eriko; Seki, Masaharu; Abe, Hitoshi

no journal, , 

no abstracts in English

Oral presentation

Study on corrosion of stainless steel in high activity liquid waste concentrator, 1; Effect of temperature and pressure

Irisawa, Eriko; Ueno, Fumiyoshi; Seki, Masaharu; Abe, Hitoshi

no journal, , 

no abstracts in English

Oral presentation

Influence of reduced pressure with boiling on stainless steel corrosion in simulated high-level radioactive liquid west

Irisawa, Eriko; Ueno, Fumiyoshi; Abe, Hitoshi

no journal, , 

no abstracts in English

Oral presentation

Chemical redox reaction simulation of metallic ions in nitric acid solution

Igarashi, Takahiro; Kato, Chiaki; Irisawa, Eriko; Ueno, Fumiyoshi

no journal, , 

It is known that corrosion rate of stainless steel in nitric acid solution is affected by the valence change of oxidizing metallic ions. In this study, we conducted redox reaction analyses using chemical reaction calculation model to clarify the mechanism of valence change. We obtained that the oxidization of metallic ions in the solution is not only caused by nitrus acid but also nitrogen oxides.

Oral presentation

Computer simulation of oxidation behavior of vanadium ion in nitric acid solution using chemical reaction calculation model

Igarashi, Takahiro; Irisawa, Eriko; Kato, Chiaki; Ueno, Fumiyoshi; Abe, Hitoshi

no journal, , 

It is known that existence of oxidizing metal ion in boiling nitric acid solution makes stainless steel more corrosive. In this study, in order to elucidate chemical species which promote oxidization of Vanadium(IV) ion, we conducted Redox reaction simulation in nitric acid solution using chemical reaction model. The results showed that nitrous acid and nitrogen dioxide affected oxidization of Vanadium(IV) ion, and rate constant of nitrogen dioxide was larger than that of nitrous acid.

Oral presentation

Relation between redox reaction of vanadium and nitrogen oxide in nitric acid solution

Irisawa, Eriko; Suzuki, Kazunori*; Kumagai, Mikio*; Kato, Chiaki; Ueno, Fumiyoshi; Abe, Hitoshi

no journal, , 

For the corrosion of stainless steels in the nitric acid solution containing oxidizing metallic ions, it is important factor that the relation between re-oxidation of metallic ions which is reduced with the corrosion reaction and the redox reaction of nitric acid. To make clear the effect of nitrogen oxides formed from nitric acid on oxidation behavior of tetravalent vanadium, changing of concentrations of nitrogen oxide discharged to gas phase from solution and nitrous acid in solution during oxidation reaction of vanadium were measured. The results showed that the nitrogen dioxide acted as oxidant on the oxidation reaction of vanadium.

Oral presentation

Intergranular corrosion simulation of stainless steel considering nitric acid solution condition

Igarashi, Takahiro; Irisawa, Eriko; Kato, Chiaki; Ueno, Fumiyoshi; Abe, Hitoshi

no journal, , 

Nuclear fuel reprocessing plants contain high-temperature condensed nitric acid solution for dissolution of spent nuclear fuel, and austenitic stainless steels are used as a main material for spent nuclear reprocessing systems. In such a highly oxidizing environment, stainless steel shows the morphology of an intergranular corrosion surface. It is known that grain dropping occurs with intergranular corrosion progress, accelerating the corrosion rate. To keep maintain the safety of the system, it is important to understand the intergranular corrosion behaviour. For understanding the mechanism, we constructed three-dimensional intergranular corrosion computational model of stainless steel considering nitric acid solution condition. Using the model, we showed that increase of face area and grain dropping affect acceleration behavior of total corrosion rate.

Oral presentation

Effect of re-oxidation rate of additive cation on corrosion rate of stainless steel in boiling nitric acid solution

Yamamoto, Masahiro; Kato, Chiaki; Motooka, Takafumi; Irisawa, Eriko; Ban, Yasutoshi; Ueno, Fumiyoshi

no journal, , 

Stainless steels used in nuclear fuel reprocessing plant occur intergranular corrosion by boiling nitric acid solution containing some cations. Reduction reaction of these cations accelerates corrosion rate of stainless steel, and then, they are re-oxidized to initial state in bulk nitric acid solution. These re-oxidized cations repeatedly concern corrosion reaction of stainless steel. The re-oxidation rates of typical cations were analyzed in the present work. As the result, Np ion accelerates corrosion of stainless steel in a little amount because it has both large reduction reaction rate and re-oxidation rate.

Oral presentation

Modelling of intergranular corrosion using cellular automata, 2

Igarashi, Takahiro; Irisawa, Eriko; Komatsu, Atsushi; Yamamoto, Masahiro; Kato, Chiaki; Ueno, Fumiyoshi

no journal, , 

Nuclear fuel reprocessing plants contain high-temperature condensed nitric acid solution for dissolution of spent nuclear fuel, and austenitic stainless steels are used as a main material for spent nuclear reprocessing systems. In such a highly oxidizing environment, stainless steel shows the morphology of an intergranular corrosion surface. To keep maintain the safety of the system, it is important to understand the intergranular corrosion behavior. According to our experiments, grain dropping occurred with intergranular corrosion progress and that lead accelerating the corrosion rate. To predict corrosion rate due to intergranular corrosion, it is necessary to consider not only dissolution of the metal surface but also grain dropping. In our previous study we developed computational intergranular corrosion propagation model by cellular automata method. In the model, simulation space is parted into three kinds of non-cubic cells: interior of grain (matrix) cell, grain boundary cell, and solution cell. The only matrix and grain boundary cell contacted with solution cell corrode and change into solution cells with local matrix and grain boundary dissolution rates. The corrosion rates were determined by dissolution rate ratio between grain boundary and matrix, and reaction rate theory with our experimental data. By setting appropriate dissolution rate ratio from experiments into the model, change of corrosion rate was estimated by the simulation and it was good agreement with that of real corrosion test.

23 (Records 1-20 displayed on this page)