Development of a Methodology for Risk Analysis and Management in Sharing Electrical Power in Nuclear Power Plants

  • Jamila Khamis Alsuwaidi

    Student thesis: Doctoral Thesis

    Abstract

    The nuclear power plants (NPPs) in one site may share (Crosstie) Structures, Systems, and Components (SSCs) either in normal operation or in demand. For instance, the unit that has an event of Loss of Offsite Power (LOOP) with loss of its dedicated Emergency Diesel Generator (EDGs) will have a Station Blackout (SBO), and if the shared Alternate Alternating Current (AAC DG) is lost, the SBO is extended (Ex-SBO). SBO considered one of the highest risk contributors to the Core Damage Frequency (CDF). The crosstie of EDG from donor unit to the impacted unit could add advantages in reduction of the CDF risk if it's adopted. At the same time, the crosstie is associated with issues that can limit the shared systems from performing its intended functions. The limitations of EDG crosstie need to be identified systematically and the benefits from the EDG crosstie should be quantified considering the limitations. The research started with the research framework of the development of the methodology for risk analysis and management in the sharing of electrical power in Nuclear Power Plants. The potential issues associated with electrical crosstie are systematically identified as dependencies between multi-unit site. The Probabilistic Risk Assessment (PRA) approach in the risk analysis is illustrated. The KU-PRA model is developed for a realistic estimation of CDF with crosstie option in single unit PRA considering Multi-Unit Features. The factor of redundancy of AC sources on the CDF is examined by the addition of EDGs to KU-PRA base Model. The methodology and modelling of the crosstie are developed for multi-units PRA considering Common Cause Failure, Human Reliability Analyses, Battery load shedding, modelling of Multi-unit LOOP initiator and occupancy factors. The resources-based optimal mitigation strategy for Ex-SBO at the isolated multi-unit NPP site has been developed by conducting a PRA and deterministic analysis to quantify the risk and maximum accident mitigation time.
    Date of AwardDec 2020
    Original languageAmerican English
    SupervisorHo Joon Yoon (Supervisor)

    Keywords

    • Probabilistic Risk Assessment
    • SBO
    • Crosstie
    • Multi-Unit.

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