초록 ▼

O 본 연구의 주요 목표는 원자로심, 발전소저장조 및 건식중간저장시설 내 핵연료의 손상기구 및 열화를 평가할 수 있는 기술 개발로 요약할 수 있음.
O 본 보고서에는 총 3단계(2009. 4 ~ 2015. 3) 연구결과를 기술하였으며, 연구결과는 다음과 같이 요약할 수 있음.
- 노외 및 상용로 고연소핵연료의 열화성능, 손상원인 및 손상기구 등의 핵심자료수집 및 분석
- Autoclave 부식특성시험과 상온 프레팅마모 특성시험 수행
- 냉각재 방사능 준위 이력을 토대로 주요 손상기구 예측모델 개발
- 건식

O 본 연구의 주요 목표는 원자로심, 발전소저장조 및 건식중간저장시설 내 핵연료의 손상기구 및 열화를 평가할 수 있는 기술 개발로 요약할 수 있음.
O 본 보고서에는 총 3단계(2009. 4 ~ 2015. 3) 연구결과를 기술하였으며, 연구결과는 다음과 같이 요약할 수 있음.
- 노외 및 상용로 고연소핵연료의 열화성능, 손상원인 및 손상기구 등의 핵심자료수집 및 분석
- Autoclave 부식특성시험과 상온 프레팅마모 특성시험 수행
- 냉각재 방사능 준위 이력을 토대로 주요 손상기구 예측모델 개발
- 건식중간저장 연료봉 손상 예측을 위한 노외 핵연료 열화성능시험 수행 및 평가
- 하나로 1차 및 2차 캡슐조사시험을 통한 조사열화 DB 생산
- 원자로심 연소, 발전소내 저장 및 건식중간저장에 따른 핵심 핵연료 손상기구(프레팅마모, 수소화 재배열 등)에 대한 핵연료 열화속도 예측모델 개발

Abstract ▼

Nowadays high burnup fuel, power up-rating and plant lifetime extension have been employed by world-leading nuclear vendors to enhance nuclear power plant economy. To provide some solutions for anticipated fuel integrity problems caused by the aforementioned aggressive fuel usage, the following obje

Nowadays high burnup fuel, power up-rating and plant lifetime extension have been employed by world-leading nuclear vendors to enhance nuclear power plant economy. To provide some solutions for anticipated fuel integrity problems caused by the aforementioned aggressive fuel usage, the following objectives have been established for this project and the corresponding activities have been performed:
○ Develop key failure mechanisms of high burnup fuel during in-reactor operation, plant wet storage and interm dry storage
○ Develop degradation characteristics of high burnup fuel during in-reactor operation, plant wet storage and interm dry storage
○ Develop technologies for the prediction of high burnup fuel degradation during the dry interim storage
To achieve the aforementioned objectives, the results obtained through the phases 1 through 3 activities (April 2009 through March 2015) are summarized in the following;
○ Collection and evaluation of performance degradation data of high burnup fuel
- Collected fuel failure mechanisms, mechanical performance degradations and hydride-induced degradations through domestic and foreign journals, international fuel performance conferences, and IAEA-TECDOC
○ Setup of out-of-pile test conditions and HANARO capsule test matrix
- Determined high burnup fuel operation conditions for in-reactor, plant wet storage and interim dry storage
- Established out-of-pile test conditions to simulate high burn fuel performance degradation with the use of a commercial fuel performance code
- Established the first and second HANARO capsule test matrix, and manufactured test specimens
○ On-going fuel performance degradation out-of-pile tests
- Evaluated the results of hydride reorientation tests using Zr alloy cladding tubes simulating plant wet storage and interim dry storage conditions
- Evaluated the results of mechanical degradation tests and fractured surface examinations for hydride reoriented cladding specimens
- Evaluated grid-to-rod fretting wear test results
○ Completion of the first and second HANARO capsule irradiation tests and mechanical degradation tests for irradiated specimens
- Completed the first and second HANARO tests: 56 days irradiation
- Performing mechanical degradation tests for irradiated ring and plate specimens:tensile tests, short-term creep tests, microstructure examination, hardness tests, etc.
○ Development of preliminary versions of fuel degradation prediction models for key high burnup fuel failure mechanisms
- Developed preliminary prediction models for fuel failure mechanisms with the use of reactor coolant activity histories
- Developed cladding oxidation-dependent PCI-induced fuel rod failure simulation model
- Developed grid-to-rod fretting wear-induced failure simulation model
- Developed hydride reorientation-induced cladding tube failure simulation model

The aforementioned results may be utilized as basic data for 1) emergency core design required in the case of fuel failure and failure remedy establishment, 2) establishment of reuse criteria for spent fuel in in-site wet storage pits and 3) prediction of interim dry storage period for spent fuel and establishment of optimized interim dry storage conditions.