초록 ▼

본 연구에서는 혹심한 자연재해에 대한 원자력발전소의 대응능력 평가 규제기술 개발을 위하여 원전 부지의 자연재해, 원전의 전력계통 비상대응능력과 신뢰성, 중대사고 안전현안 및 사고관리전략에 대한 평가기술을 연구하였으며 주요 연구결과는 다음과 같다.
○ 극한자연재해에 대한 안전성평가 규제기술 개발
- 동일본 대지진 후 지진해일 관련 신규 규제현안 분석
- 성능기반 설계지진 관련 규제기술 및 연구현황 분석
○ 전력계통 안전성 확보 규제기술개발
- 소외전력계통의 설계자료, 고장이력 및 침수 취약부위 등 현장 자료

본 연구에서는 혹심한 자연재해에 대한 원자력발전소의 대응능력 평가 규제기술 개발을 위하여 원전 부지의 자연재해, 원전의 전력계통 비상대응능력과 신뢰성, 중대사고 안전현안 및 사고관리전략에 대한 평가기술을 연구하였으며 주요 연구결과는 다음과 같다.
○ 극한자연재해에 대한 안전성평가 규제기술 개발
- 동일본 대지진 후 지진해일 관련 신규 규제현안 분석
- 성능기반 설계지진 관련 규제기술 및 연구현황 분석
○ 전력계통 안전성 확보 규제기술개발
- 소외전력계통의 설계자료, 고장이력 및 침수 취약부위 등 현장 자료조사
- 지진해일로 인한 소내 교류 및 직류 전력계통 설계자료 및 각국의 전원상실 대응 분석
- 침수선로 절연케이블의 전기저항률과 유전상수 측정, 담수 세척을 통한 절연성능 평가
○ 중대사고 안전현안 평가 규제기술 개발
- APR1400원전의 정전사고 분석용 MELCOR 상세분석 예비입력 개발
- OECD-SFP 1×4 사용후연료집합체의 손상시 거동 평가(MELCOR 코드 활용)
- OECD-STEM 핵분열생성물 거동 실험자료 확보, RAIM 코드 개선 및 Phébus FPT3 분석
- EOP/SAMG/EDMG 등 국내·외 사고관리지침서 체계 현황 분석
○ 중대사고 대처설비를 고려한 사고관리전략 평가기술 개발
- TEXAS-V 코드 도입, APR1400 원자로공동의 증기폭발 하중 및 건전성 예비계산
- APR+ 원자로공동 침수시 용융노심-콘크리트 반응 평가(미국 BNL 공동, MELCOR 활용)
- 격납건물 여과배기설비 관련 해외 현황, 규제요건 및 요소기술 조사
- 원자로용기 외벽냉각시 용기 내외부 열전달 특성 조사, 용기의 구조적 건전성 예비평가

Abstract ▼

I. Title of the Project
Development of Regulatory Assessment Technology for the Response Capability of NPPs against Accidents Due to Extreme Natural Hazards
II. Objectives and Justification of the Project
After the Fukushima accident caused by the Great East Japan Earthquake, safety inspect

I. Title of the Project
Development of Regulatory Assessment Technology for the Response Capability of NPPs against Accidents Due to Extreme Natural Hazards
II. Objectives and Justification of the Project
After the Fukushima accident caused by the Great East Japan Earthquake, safety inspection for the domestic plants resulted in fifty recommendations to improve their response capability. On the other hand, there are issues raised during licensing review of new plants concerning the effectiveness of the severe accident safety features and accident management strategies. Therefore, the purpose of this study is to develop the regulatory technology with respect to evaluation of the response capability against an accident at a nuclear power plant induced by an extreme natural disaster like the one at Fukushima. In order to fulfill this objective, regulatory technology should be developed for evaluation of the safety against an extreme natural hazard, emergency response capability and reliability of the electric power systems, and safety issues on a severe accident and accident management strategies.
Due to large uncertainties in the prediction of the occurrence and propagation of earthquakes, it is necessary to transit from the deterministic approach to the probabilistic approach that can be used to develop the performance-based approach for the evaluation of design earthquakes. And it is urgent to set up the new regulatory methodology based on the analysis of the new regulatory issues identified by Japan and other countries after the Fukushima accident. Also necessary is the improvement of the evaluation models and the regulatory techniques.
Although there is no study about the effects of flooding on the electric power systems of nuclear power plants due to natural hazard at home and abroad, protective measures against flooding are widely being searched in many countries after the Fukushima accident. In fact the need to improve the response capability of eletrical facilities against such a hazard is increasing in order to mitigate a catastrophe. Therefore, it is necessary to study to provide the measures of supplying emergency power at an accident at the plant due to a natural hazard beyond design basis and strengthen the accident mitigating capability. It is also needed to investigate the failure modes of on-site and off-site electric power systems and develop technical guidelines for evaluation and validation of the power supply facility designs.
In order to make an in-depth review of the follow-up actions of the safety inspection requiring to strengthen the effectiveness of the severe accident management strategies, it is necessary to develop a detailed MELCOR input model for a realistic analysis of the APR1400 NPPs' capability to cope with severe accidents due to station blackout. There are also needs to develop the assessment techniques for the OECD-SFP experiment on the spent fuel behavior during a Loss-of-coolant accident and for fission product behavior during a severe accident, which should be adapted to applications to a real plant. In addition, it is required to examine the status of corrective actions at home and abroad to the existing accident management guideline system which revealed not so effective to deal with a complex severe accident at various plants in the same site; Such a study will be useful to provide a measure to strengthen the guideline system in the future. With respect to the unresolved safety issues on the severe accident coping designs for the evolutionary N.P.Ps, it is necessary to develop regulatory evaluation methods for external reactor vessel cooling and steam explosion, and identify the vulnerabilities in the accident management strategies involving them and then finally develop the regulatory evaluation guidelines concerning the items; the similar approach is required for the containment filtered venting system which are being installed as one of the Fukushima actions.
III. Scopes of the Project
A. Development of the regulatory technology for the safety assessment of extreme natural hazards
(1) Analysis of new regulatory issues on the safety evaluation of tsunami derived from the Fukushima accident
(2) Analysis of the performance-based approach for the evaluation of design earthquakes with account taken of uncertainties in earthquake occurrence and propagation
B. Development of the regulatory technology for safety of the electric power system
(1) Prediction of the off-site electrical power system failures caused by earthquakes and tsunami
(2) Prediction of the on-site DC and AC power facility failures caused by earthquakes and tsunami
(3) Evaluation of the integrity of the insulation cables contaminated by flooding of sea-water
C. Development of the regulatory assessment technology for the safety issues concerning a severe accident
(1) Development of the MELCOR input model for a realistic analysis of the APR1400 NPPs' capability to cope with severe accidents due to station blackout
(2) Development of the assessment techniques for the OECD-SFP experiment on the spent fuel behavior during a beyond-design accident
(3) Experimental data acquisition and evaluation of the fission product behavior during severe accidents in NPPs
(4) Evaluation of the status of the accident management guideline system at home and abroad
D. Development of the assessment technology for the accident management strategies in association with the severe accident mitigation features
(1) Evaluation of the TEXAS code applicability to assessment of the accident management strategies associated with the steam explosion through sample calculations and sensitivity studies
(2) Survey of the design status and the regulatory requirements related to the CFVS
(3) Survey of the state-of-the-art technologies for External Reactor Vessel Cooling
IV. Results of the Project
Research results for the detailed areas are as follows;
A. Development of the regulatory technology for the safety assessment of extreme natural hazards
(1) Analysis of new regulatory issues on the safety evaluation of tsunami
i. Analysis of the new regulatory issues related to tsunami after the 2011 Fukushima accident
ii. Investigation of the post actions taken by the IAEA and foreign countries concerning the tsunami safety evaluation
(2) Analysis of the performance-based approach for the evaluation of design earthquakes with account taken of uncertainties in earthquake occurrence and propagation
i. Analysis of the status-of-the-art of the performance-based approach for design earthquake evaluation
ii. Investigation of the current status of the IAEA and foreign countries on the probabilistic evaluation of design earthquakes
B. Development of the regulatory technology for safety of the electric power system
(1) Prediction of the off-site electrical power system failures caused by tsunami
i. Investigation of the off-site electric power system design and safety analysis documents, the effects of interactions among the facilities
ii. Investigation of on-site installation location and the weakness areas against flooding and evaluation of failure data
(2) Prediction of the on-site DC and AC power facility failures caused by tsunami
i. Investigation of the on-site AC and DC electric power system design and safety analysis documents
ii. Analysis of the foreign countries’ responses to station blackout after the Fukushima accident
(3) Evaluation of the integrity of the insulation cables contaminated by flooding of sea-water
i. Measurement of volume electrical resistivity and dielectrical constant
ii. Evaluation of insulation capacitance through fresh water cleaning
C. Development of the regulatory assessment technology for the safety issues concerning a severe accident
(1) Development of the MELCOR input model for a realistic analysis of the APR1400 NPPs' capability to cope with severe accidents due to station blackout
i. Development of the MELCOR input model for natural-circulation analysis of the APR1400 RCS at station blackout
(2) Development of the assessment techniques for the OECD-SFP experiment on the spent fuel behavior during a beyond-design accident
i. Assessment of the behavior of the OECD-SFP 1x4 spent fuel assembly (using MELCOR)
(3) Experimental data acquisition and evaluation of the fission product behavior during severe accidents in NPPs
i. Acquisition and evaluation of the experimental data of the OECD-STEM fission product behavior
ii. Improvement of the RAIM code and benchmark analysis of Phébus FPT3 of the EU-SARNET2
(4) Evaluation of the status of the accident management guideline system at home and abroad
I. Investigation of the accident management guideline system EOP/SAMG/EDMG at home and abroad
ii. Trial use of the Objective Provision Tree method to induce the way to strengthen the accident management guideline system
D. Development of the assessment technology for the accident management strategies in association with the severe accident mitigation features
(1) Evaluation of the TEXAS code applicability to assessment of the accident management strategies associated with the steam explosion through sample calculations and sensitivity studies
i. Acquisition and installation of the TEXAS code
ii. Assessment of the steam explosion load in the APR1400 reactor cavity and preliminary calculation of its integrity (Conduct an international cooperative research with U.S.BNL using the MELCOR code)
(2) Survey of the design status and the regulatory requirements related to the CFVS
i. Investigation of the design status in the foreign countries and the regulatory requirements and elementary techniques related to the CFVS
(3) Survey of the state-of-the-art technologies for External Reactor Vessel Cooling
i. Study of the characteristics of heat transfer between metal and ceramic layers inside the reactor vessel and the critical heat flux outside the vessel during external reactor vessel cooling
ii. Preliminary assessment of structural integrity of the reactor vessel during external reactor vessel cooling
V. Application Plan for the Research Results
The technologies, developed by this study, such as those for evaluation of the safety of the plant site against an extreme natural hazard, emergency response capability and reliability of the electric power systems, and safety issues on a severe accident and accident management strategies, are to be used for review of new NPPs and regulatory issues. The detailed plans are as follows;
ㆍ Application to development of the regulatory guides related to the performance-based approach (probabilistic approach) for the evaluation of the design earthquakes that can replace the current deterministic approach
ㆍ Application to resolving the new regulatory issues on tsunami and development of the relevant regulatory guides
ㆍ Application to analysis of the failure modes of the on-site and off-site electric power system, and development of the regulatory guides related to validation of the electricity supply facility design and emergency power supply capability
ㆍ Application to analysis of the APR1400 NPPs' capability to cope with severe accidents due to station blackout and the behavior of the spent fuel pool
ㆍ Application to development of the strengthening measures for the accident management guideline system and the evaluation guidelines for the realistic source term
ㆍ Application to establishment of the regulatory positions on steam explosion, containment venting facilities and external reactor vessel cooling, and development of evaluation guidelines and confirmatory analysis methodology
ㆍ Application to confirmation of the follow-up actions of the safety inspection such as “Strengthening of the effectiveness of the accident management strategies”

목차 Contents

• 표지 ... 1
• 제출문 ... 3
• 보고서 요약서 ... 5
• 요약문 ... 7
• SUMMARY ... 11
• CONTENTS ... 17
• 목차 ... 18
• 표목차 ... 19
• 그림목차 ... 20
• 제 1 장 연구개발과제의 개요 ... 21
• 제 1 절 연구개발의 필요성 ... 21
• 제 2 절 연구개발의 내용 및 범위 ... 23
• 제 2 장 국내ㆍ외 기술개발 현황 ... 24
• 제 1 절 해외 기술현황 ... 24
• 제 2 절 국내 기술현황 ... 40
• 제 3 장 연구개발수행 내용 및 결과 ... 46
• 1. 극한자연재해에 대한 안전성평가 규제기술 개발 ... 46
• 2. 전력계통 안전성 확보 규제기술개발 ... 46
• 3. 중대사고 안전현안 평가 규제기술 개발 ... 47
• 4. 중대사고 대처설비를 고려한 사고관리전략 평가기술 개발 ... 50
• 제 4 장 목표달성도 및 관련분야에의 기여도 ... 52
• 제 5 장 연구개발결과의 활용 계획 ... 54
• 제 6 장 연구개발과정에서 수집한 해외과학기술정보 ... 55
• 제 7 장 참고문헌 ... 56
• 부록 1 극한자연재해에 대한 안전성평가 규제기술 개발 ... 75
• 부록 2 전력계통 안전성 확보 규제기술개발 ... 287
• 부록 3 중대사고 안전현안 평가 규제기술 개발 ... 347
• 부록 4 중대사고 대처설비를 고려한 사고관리전략 평가기술 개발 ... 579
• 수정ㆍ보완 요구사항 반영내역 ... 808
• 첨부 1 ... 811
• 첨부 2 ... 812
• 끝페이지 ... 813