Journal of Radiation Protection and Research

The Korean Association for Radiation Protection (대한방사선방어학회)
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Derivation of the Cathodic Current Density around the HLW Canister Due to the Radiolysis of Groundwater

고준위 폐기물 처분용기 주변에서의 지하수의 방사분해에 의한 음 전류 밀도 유도

  • Published : 2006.06.30
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Abstract

The oxidizing species are generated from the radiolysis of groundwater in the pore of buffer material around the canister used for the disposal of spent fuels. A mathematical model was introduced to calculate the cathodic current density induced by the oxidant around the canister, which determined the corrosion of carbon steel. An analytical solution was derived to get the cathodic current density in the cylindrical coordinate. The cathodic current densities from both the rectangular coordinate and cylindrical coordinate were compared with each other. The source terms and absorbed dose rate for the calculation of the radiolysis were calculated using the ORIGEN2 and MCNP computer code, respectively. The radius of the canister was determined with the new model in order to prevent the local corrosion. The results showed that the new solution made the cathodic current density around 25 % lower than the Marsh model.

사용후핵연료의 처분을 위해 사용되는 캐니스터 주변 완충재의 공극 내 지하수는 방사분해에 의해 산화제를 발생한다. 캐니스터 주변의 탄소강의 부식을 결정하는 산화제에 의해 야기된 음 전류 밀도를 계산하기 위하여 수학적 모델을 이용하였다. 실린더 좌표계에서 음 전류 밀도를 구할 수 있는 해석해를 유도하였다. 직교 좌표계와 실린더 좌표계에서 구한 음 전류 밀도를 서로 비교하였다. 방사분해 계산을 위한 선원항 및 흡수선량률은 ORIGEN2와 MCNP 컴퓨터 코드를 이용하여 계산하였다. 새로운 모델을 이용하여 부식을 억제할 수 있는 처분용기 반경을 결정하였다. 계산 결과 실린더 좌표계에서의 해를 이용할 경우 기존의 Marsh 모델보다 음 전류 밀도 값을 25 % 감소시켰다.

Keywords

References

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