Radiation-Induced Volumetric Expansion and Temperature Effects on the Structural Integrity of Concrete Biological Shield Wall

Jinbok Choi; Daegi Hahm

doi:10.7734/COSEIK.2024.37.6.371

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2024 Vol.37, Issue 6 Preview Page Next Page

Research Paper

Radiation-Induced Volumetric Expansion and Temperature Effects on the Structural Integrity of Concrete Biological Shield Wall 방사선조사 유발 체적팽창과 온도가 콘크리트 생체 차폐벽의 구조 건전성에 미치는 영향

31 December 2024. pp. 371-378

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Abstract

This study assesses the structural integrity of concrete biological shield (CBS) walls in nuclear power plants, considering the effects of radiation-induced volumetric expansion (RIVE). The research focuses on the impact of neutron irradiation on concrete material properties, particularly in the context of extending nuclear power plant lifespans beyond their original operating license period. This study outlines a method to estimate neutron fluence levels in CBS walls using data from reactor pressure vessel surveillance programs. It describes the process of calculating fluence attenuation starting from the inside surface of the reactor pressure vessel (RPV) to the CBS wall outside and presents a model for radiation-induced volumetric expansion (RIVE) in concrete. The effect of temperature rise of the CBS wall during the operation is considered in addition to the RIVE effects because the stress state of the CBS wall can be affected by elevated temperature. A finite element analysis was conducted to evaluate the effects of RIVE and temperature on the CBS wall structure. The results indicate that compressive stresses in the inner region of the CBS wall can exceed the compressive strength limit of the concrete, while tensile stresses in the outer region may lead to cracking. The stress distribution shows an increasing trend with accumulated neutron fluence over time. The temperature also affects the stress state of the CBS wall but its influence is not that significant compared to the effect of RIVE because the level of thermal strain and its gradient through CBS wall is less than those of RIVE. Further research considering more practical geometries, fluence distributions, and the inclusion of reinforcing rebar elements in CBS wall models will be performed and the assessment of radiation effects on reactor pressure vessel support structures and anchor systems will also be considered in the future.

Keywords

radiation-induced volumetric expansion

concrete biological shield wall

temperature effects

nuclear power plant

본 연구에서는 방사선조사 유발 체적팽창(RIVE)이 원자력 발전소의 콘크리트 생체 차폐벽의 구조 건전성에 미치는 영향을 확인하고자 하였다. 이를 위해 원자로 압력용기 감시 프로그램의 데이터를 사용하여 콘크리트 생체 차폐벽의 누적 중성자 조사 수준을 추정하는 방법으로 원자로 압력용기(RPV) 내부 표면에서 차폐벽 외부까지의 누적 조사량의 감쇠를 계산하는 과정을 설명하고 콘크리트의 방사선 조사 유발 체적팽창에 대한 모델을 제시하였다. 콘크리트 생체 차폐벽의 응력 상태는 온도의 영향을 받을 수 있기 때문에 방사선조사유발 체적팽창 효과와 더불어 운전 중 차폐벽의 온도 상승 효과도 고려하였다. 콘크리트 생체 차폐벽 구조에 대한 방사선 조사 유발 체적팽창과 온도의 영향을 평가한 결과, 차폐벽의 안쪽 표면 부근 영역의 압축 응력이 국부적으로 콘크리트의 압축 강도 한계를 초과할 수 있으며, 외부 영역의 인장 응력은 균열을 유발할 가능성이 있음을 확인할 수 있었다. 또한 중성자 누적 조사량이 증가하면 응력도 증가하는 경향을 보였다. 온도도 차폐벽의 응력 상태에 영향을 미치지만, 그 영향은 방사선조사 유발 체적팽창의 효과에 비해 그다지 크지 않았다. 향후 추가 연구를 통해 차폐구조물의 보다 현실적인 기하학적 구조, 중성자 조사량 분포, 그리고 차폐벽 내부 보강 철근 요소 등을 포함하는 상세 모델을 바탕으로 콘크리트 생체 차폐벽에 설치되는 압력용기 지지 구조물 및 앵커 시스템에 대한 영향 평가를 수행할 계획이다.

키워드

방사선조사 유발 체적팽창

콘크리트 생체 차폐벽

온도 효과

원자력 발전소

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Information

Publisher :Computational Structural Engineering Institute of Korea
Publisher(Ko) :한국전산구조공학회
Journal Title :Journal of the Computational Structural Engineering Institute of Korea
Journal Title(Ko) :한국전산구조공학회 논문집
Volume : 37
No :6
Pages :371-378
Received Date : 2024-07-05
Revised Date : 2024-09-03
Accepted Date : 2024-09-09
DOI :https://doi.org/10.7734/COSEIK.2024.37.6.371

Journal of the Computational Structural Engineering Institute of Korea ISSN:1229-3059(Print) 2287-2302(Online) 한국전산구조공학회 논문집

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