• 제목/요약/키워드: containment performance

검색결과 148건 처리시간 0.022초

Proposal and Analysis of Hydrogen Mitigation System Guiding Hydrogen in Containment Building

  • Park, Kweonha;Lee, Khor Chong
    • Journal of Advanced Marine Engineering and Technology
    • /
    • 제39권5호
    • /
    • pp.516-521
    • /
    • 2015
  • This study is about a hydrogen mitigation system in a containment building like an offshore or a nuclear plant. A hydrogen explosion is possibly happened after condensation of steam if hydrogen releases with steam in a containment buildings. Passive autocatalytic recombiner is the one of the measures, but the performance of this equipment is not sure because the distribution of hydrogen is very irregular and is not predicted correctly. This study proposes a new approach for improving the hydrogen removing performance with hydrogen-guiding property. The steam is simulated and analysed. The results show that the shallow air containment reduced over 55% of the released hydrogen and the deep air containment type reduces over 80% of released hydrogen.

Development of analysis program for direct containment heating

  • Jiang, Herui;Shen, Geyu;Meng, Zhaoming;Li, Wenzhe;Yan, Ruihao
    • Nuclear Engineering and Technology
    • /
    • 제54권8호
    • /
    • pp.3130-3139
    • /
    • 2022
  • Direct containment heating (DCH) is one of the potential factors leading to early containment failure. DCH is closely related to safety analysis and containment performance evaluation of nuclear power plants. In this study, a DCH prediction program was developed to analyze the DCH loads of containment vessel. The phenomenological model of debris dispersal, metal oxidation reaction, debris-atmospheric heat transfer and hydrogen jet burn was established. Code assessment was performed by comparing with several separate effect tests and integral effect tests. The comparison between the predicted results and experimental data shows that the program can predict the key parameters such as peak pressure, temperature, and hydrogen production in containment well, and for most comparisons the relative errors can be maintained within 20%. Among them, the prediction uncertainty of hydrogen production is slightly larger. The analysis shows that the main sources of the error are the difference of time scale and the oxidation of cavity debris.

CONTAINMENT PERFORMANCE EVALUATION OF PRESTRESSED CONCRETE CONTAINMENT VESSELS WITH FIBER REINFORCEMENT

  • CHOUN, YOUNG-SUN;PARK, HYUNG-KUI
    • Nuclear Engineering and Technology
    • /
    • 제47권7호
    • /
    • pp.884-894
    • /
    • 2015
  • Background: Fibers in concrete resist the growth of cracks and enhance the postcracking behavior of structures. The addition of fibers into a conventional reinforced concrete can improve the structural and functional performance of safety-related concrete structures in nuclear power plants. Methods: The influence of fibers on the ultimate internal pressure capacity of a prestressed concrete containment vessel (PCCV) was investigated through a comparison of the ultimate pressure capacities between conventional and fiber-reinforced PCCVs. Steel and polyamide fibers were used. The tension behaviors of conventional concrete and fiber-reinforced concrete specimens were investigated through uniaxial tension tests and their tension-stiffening models were obtained. Results: For a PCCV reinforced with 1% volume hooked-end steel fiber, the ultimate pressure capacity increased by approximately 12% in comparison with that for a conventional PCCV. For a PCCV reinforced with 1.5% volume polyamide fiber, an increase of approximately 3% was estimated for the ultimate pressure capacity. Conclusion: The ultimate pressure capacity can be greatly improved by introducing steel and polyamide fibers in a conventional reinforced concrete. Steel fibers are more effective at enhancing the containment performance of a PCCV than polyamide fibers. The fiber reinforcementwas shown to bemore effective at a high pressure loading and a lowprestress level.

OVERVIEW OF CONTAINMENT FILTERED VENT UNDER SEVERE ACCIDENT CONDITIONS AT WOLSONG NPP UNIT 1

  • Song, Y.M.;Jeong, H.S.;Park, S.Y.;Kim, D.H.;Song, J.H.
    • Nuclear Engineering and Technology
    • /
    • 제45권5호
    • /
    • pp.597-604
    • /
    • 2013
  • Containment Filtered Vent Systems (CFVSs) have been mainly equipped in nuclear power plants in Europe and Canada for the controlled depressurization of the containment atmosphere under severe accident conditions. This is to keep the containment integrity against overpressure during the course of a severe accident, in which the radioactive gas-steam mixture from the containment is discharged into a system designed to remove the radionuclides. In Korea, a CFVS was first introduced in the Wolsong unit-1 nuclear power plant as a mitigation measure to deal with the threat of over pressurization, following post-Fukushima action items. In this paper, the overall features of a CFVS installation such as risk assessments, an evaluation of the performance requirements, and a determination of the optimal operating strategies are analyzed for the Wolsong unit 1 nuclear power plant using a severe accident analysis computer code, ISAAC.

Pretest analysis of a prestressed concrete containment 1:3.2 scale model under thermal-pressure coupling conditions

  • Qingyu Yang;Jiachuan Yan;Feng Fan
    • Nuclear Engineering and Technology
    • /
    • 제55권6호
    • /
    • pp.2069-2087
    • /
    • 2023
  • In nuclear power plant (NPP) accidents, the containment is subject to high temperatures and high internal pressures, which may further trigger serious chain accidents such as core meltdown and hydrogen explosion, resulting in a significantly higher accident level. Therefore, studying the mechanical performance of a containment under high temperature and high internal pressure is relevant to the safety of NPPs. Based on similarity principles, the 1:3.2 scale model of a prestressed concrete containment vessel (PCCV) of a NPP was designed. The loading method, which considers the thermal-pressure coupling conditions, was used. The mechanical response of the PCCV was investigated with a simultaneous increase in internal pressure and temperature, and the failure mechanism of the PCCV under thermal-pressure coupling conditions was revealed.

사용후연료 운반용기의 격납 성능에 미치는 항공기 엔진 충돌위치의 영향 고찰 (Investigation on Effect of Aircraft Engine Crash Location on Containment Performance of a Spent Nuclear Fuel Transport Cask)

  • 김종성;김창종
    • 한국압력기기공학회 논문집
    • /
    • 제19권2호
    • /
    • pp.69-74
    • /
    • 2023
  • The paper presents the results investigating the effect of aircraft engine impact location on the intended function evaluation results of spent nuclear fuel transport cask. As a result of the investigation, it is found that the structural integrity is maintained as the maximum accumulated equivalent plastic strain is below the acceptable criterion regardless of the collision location. It is identified that when the aircraft engine collided with the upper part of the transport cask without considering impact limiter the containment performance is weakened compared to when the aircraft engine collided with the central part.

Reliability Assessments and Design Load Factors for Reinforced Concrete Containment Structures of Nuclear Power Plant

  • Han, Bong-Koo
    • Nuclear Engineering and Technology
    • /
    • 제29권6호
    • /
    • pp.444-450
    • /
    • 1997
  • The current ASME code for reinforced concrete containment structures are not based on probability concepts. The stochastic nature of natural hazard or accidental loads and the variations of material properties require a probabilistic approach for a rational assessment of structural safety and performance. The paper develops design load factors for the serviceability limit state of reinforced concrete containment structures. The target limit state probability is determined and the load factors are calculated by the numerical analysis. Design load factors are proposed and carried out the reliability assessments.

  • PDF

Experimental investigation and design method of the general anchorage zone in the ring beam of prestressed concrete containment vessels

  • Chang Wu;Tao Chen;Yanli Su;Tianyun Lan;Shaoping Meng
    • Nuclear Engineering and Technology
    • /
    • 제56권2호
    • /
    • pp.485-497
    • /
    • 2024
  • Ring beam is the main anchorage zone of the tendons in the nuclear power prestressed concrete containment vessel (PCCV). Its safety is crucial and has a great influence on the overall performance of PCCV. In this paper, two half-scale ring beams were tested to investigate the mechanical performance of the anchorage zone in the PCCV under multidirectional pressure. The effect of working condition with different tension sequences was investigated. Additionally, a half axisymmetric plane model of the containment was established by the finite element simulation to further predict the experimental responses and propose the local reinforcement design in the anchorage zone of the ring beam. The results showed that the ultimate load of the specimens under both working conditions was greater than the nominal ultimate tensile force. The original reinforcement design could meet the bearing capacity requirements, but there was still room for optimization. The ring beam was generally under pressure in the anchorage area, while the splitting force appeared in the under-anchor area, and the spalling force appeared in the corner area of the tooth block, which could be targeted for local strengthening design.

가상적 중대사고에 대한 대형건식 가압경수로 격납용기의 반응해석 (A Large Dry PWR Containment Response Analysis for Postulated Severe Accidents)

  • Chun, Moon-Hyun
    • Nuclear Engineering and Technology
    • /
    • 제19권4호
    • /
    • pp.292-309
    • /
    • 1987
  • 미국 원자력 안전규제위원회(U.S. NRC)의 "원자로 위험도 참고문서(NUREG-1150)"에 입력자료로 제공하기 위해 실시한 Zion발전소 안전성 재평가 작입의 일환으로, 가상적 중대사고에 대한 대형건식 가압경수로 격납용기 반응해석을 수행하였다. 본 연구에서 사용한 방법론들은 Sandia 국립연구소에서 "중대사고 위험도 감소계획"의 일환으로 특히 Surry 발전소에 대한 연구를 위해 개발한 것이며, 이 방법론을 Zion발전소에 외삽법으로 적용하였다. 먹저, 원자력발전소의 위험도를 정량적으로 평가하는 주요절차를 개설하였다. 그리고, Zion발전소의 중대사고에 대한 격납용기 반응해석을 위해 사용한 방법론들을 상세히 기술하였다. 즉, 격납용기 반응해석을 위해 사용한 방법론들을 상세히 기술하였다. 즉, 격납용기 사건수목 해석 전산코드의 주요 특징과 격납용기 사건수목의 정량적 평가절차를 요약하여 높액다. 격납용기 반응해석에 있어서 중요한 발전소 고유의 특성과 본 연구의 불확실성 분석에 포함시킨 격납용기 하중과 성능에 관계되는 문제점들을 아울러 제시하였다. 끝으로, 가상적 증대사고에 대한 대형건식 가압경수로 격납용기의 반응에 대한 전망을 제공하기 위해서 결정적 및 통계학적 격납용기 사건수목 해설결과를 간단히 요약하여 제시하였다.설결과를 간단히 요약하여 제시하였다.

  • PDF

Improvement and validation of aerosol models for natural deposition mechanism in reactor containment

  • Jishen Li ;Bin Zhang ;Pengcheng Gao ;Fan Miao ;Jianqiang Shan
    • Nuclear Engineering and Technology
    • /
    • 제55권7호
    • /
    • pp.2628-2641
    • /
    • 2023
  • Nuclear safety is the lifeline for the development and application of nuclear energy. In severe accidents of pressurized water reactor (PWR), aerosols, as the main carrier of fission products, are suspended in the containment vessel, posing a potential threat of radioactive contamination caused by leakage into the environment. The gas-phase aerosols suspended in the containment will settle onto the wall or sump water through the natural deposition mechanism, thereby reducing atmospheric radioactivity. Aiming at the low accuracy of the aerosol model in the ISAA code, this paper improves the natural deposition model of aerosol in the containment. The aerosol dynamic shape factor was introduced to correct the natural deposition rate of non-spherical aerosols. Moreover, the gravity, Brownian diffusion, thermophoresis and diffusiophoresis deposition models were improved. In addition, ABCOVE, AHMED and LACE experiments were selected to validate and evaluate the improved ISAA code. According to the calculation results, the improved model can more accurately simulate the peak aerosol mass and respond to the influence of the containment pressure and temperature on the natural deposition rate of aerosols. At the same time, it can significantly improve the calculation accuracy of the residual mass of aerosols in the containment. The performance of improved ISAA can meet the requirements for analyzing the natural deposition behavior of aerosol in containment of advanced PWRs in severe accident. In the future, further optimization will be made to address the problems found in the current aerosol model.