초록 ▼

본 세부과제의 목표는 사용 중 및 사용 후 핵연료 피복관의 기계적 열화성능 특성을 평가하고, 건전핵연료 및 손상핵연료의 기계적 열화성능 예측을 위한 기초 모델을 제시하여, 사용 중 및 사용 후 핵연료의 신뢰성 확보에 있다. 본 세부과제의 연구실적은 다음과 같음.
▪ 노외 핵연료봉 크립 성능열화자료 및 분석
▪ 노내 핵연료봉 크립 성능열화자료 분석 및 모델 개발
▪ 비조사시편 및 하나로 조사시편의 기계적성능열화 실험조건 도출
▪ 노외 피복관 기계적성능열화 1, 2차 실험 수행 및 기계적성능열화 결과 분석
▪

본 세부과제의 목표는 사용 중 및 사용 후 핵연료 피복관의 기계적 열화성능 특성을 평가하고, 건전핵연료 및 손상핵연료의 기계적 열화성능 예측을 위한 기초 모델을 제시하여, 사용 중 및 사용 후 핵연료의 신뢰성 확보에 있다. 본 세부과제의 연구실적은 다음과 같음.
▪ 노외 핵연료봉 크립 성능열화자료 및 분석
▪ 노내 핵연료봉 크립 성능열화자료 분석 및 모델 개발
▪ 비조사시편 및 하나로 조사시편의 기계적성능열화 실험조건 도출
▪ 노외 피복관 기계적성능열화 1, 2차 실험 수행 및 기계적성능열화 결과 분석
▪ 노외 기계적 열화시험 자료 및 하나로 조사시편 열화시험자료 DB 구축
▪ 산화막 특성 및 합금성분 산화물 (ZrO2, SnO2, NiO등)의 미세/나노구조 분석
▪ 피복관 크립열화성능 향상을 위한 금속열처리기술 개선방안 도출
▪ 피복관의 기계적 성능열화 예측 모델 개발

Abstract ▼

Ⅱ. Objectives and necessities of R & D
○ The objectives of this research is to produce out-of-reactor mechanical performance degradation data by simulating high burn-up nuclear power plant operation conditions.
○ Based on the mechanical performance degradation data, the mechanical performance

Ⅱ. Objectives and necessities of R & D
○ The objectives of this research is to produce out-of-reactor mechanical performance degradation data by simulating high burn-up nuclear power plant operation conditions.
○ Based on the mechanical performance degradation data, the mechanical performance degradation models will be developed for intact and damaged nuclear fuels in order to evaluate the mechanical failure risk driven by the increasing burn-ups of nuclear fuels and more aggressive environments in nuclear power plants.
○ The mechanical performance degradation data of spent fuels restored in fuel reservoir of nuclear power plants and in dry interim storage facilities out of nuclear power plants will be produced
○ The basic mechanical performance degradation models for the intact and damaged nuclear fuels in dry and/or wet storage conditions will also be developed.

Ⅲ. Contents of R & D
In order to secure the long term reliability of nuclear fuels and enhance the nuclear power plant operation efficiency, the understanding of mechanical performance degradation of the intact and damaged nuclear fuels in reactor operating conditions and in wet/dry storage conditions is imperative. In order to achieve the goals of this research, the studies will be carried out.
○ Data acquisition and analyses of mechanical performance degradation for high burn-up and damaged nuclear fuels and establishing mechanical degradation testing conditions and mechanical failure mechanisms.
○ Performance of out-of reactor mechanical experiments and creep deformation analyses.
○ Development of basic creep mechanical performance models.
○ Analyses of irradiation creep model and mechanical performance degradation for high burn-up and damaged nuclear fuels.
○ Performance of out-of reactor creep experiments and developing the basic in-reactor creep performance models.
○ Establishment of in-reactor creep degradation testing conditions.
○ Development of basic in-reactor creep performance models.
○ Proposal of creep degradation remedies through annealing.

Ⅳ. Outcome of the study
○ Collection and evaluation of mechanical performance degradation data of high burnup fuel claddings.
○ Determination of high burnup fuel operation conditions for in-reactor, plant wet storage and interim dry storage and establishment of out-of-pile test conditions to simulate high burn fuel performance.
○ Completion of the first HANARO capsule irradiation tests and mechanical degradation tests for irradiated specimens
○ Completion of the second HANARO capsule irradiation tests and mechanical degradation tests for irradiated specimens
○ Development of cladding mechanical degradation models.
○ Nanostructural analyses of various oxides of alloying elements in Zr alloys.
○ Creep life prediction models of oxidized cladding tubes.
○ Proposal of remedies to alleviate cladding creep degradation models through annealing.

Ⅴ. Expected contribution
○ Mechanical performance degradation models can be used to optimize the operation conditions of nuclear reactors for the minimization of the nuclear fuel damage and to secure the safety and reliability of advanced nuclear fuels.
○ The understanding of mechanical degradation of the intact and damaged nuclear fuels in reactor operating conditions would lead to the establishment of the long term reliability of fuels and the enhancement of the power plant operation efficiency.
○ Mechanical performance degradation models in wet reservoir and dry storage facilities can be used to find the ways to establish the safe wet/dry storage conditions for the spent fuels.
○ The database on the mechanical performance degradation for damaged fuels can be utilized for developing the appropriate performance models.