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DYNAMIC SEISMIC PROBABILISTIC RISK ASSESSMENT OF NUCLEAR POWER PLANTS

Kasapoglu, Baris
http://orcid.org/0000-0001-6098-0010
http://rave.ohiolink.edu/etdc/view?acc_num=osu1713295585488882

Abstract Details

2024, Doctor of Philosophy, Ohio State University, Civil Engineering.
The history of probabilistic risk assessment (PRA) in the nuclear industry goes back to the 1960s. Traditional PRA procedures use the fixed event tree/fault tree approach and only qualitatively account for the time dependence of events. Dynamic PRA is regarded as an advanced approach over traditional PRA with the advantage of its ability to incorporate time dependency. For assessing the seismic risk of nuclear power plants (NPPs), seismic PRA has been used since the 1980s. In recent years, concerns have been raised over the potential conservatism in current practice since it contains significant uncertainties quantified by engineering judgment. To overcome this problem, research has been conducted to modernize tools and methods to provide more realistic seismic risk assessment approaches, so-called computational risk assessment. However, there are some issues that have not been addressed yet, such as integration of state-of-the-art structural modeling and analysis techniques into SPRA procedure for failure estimation of safety-critical equipment and time dependency into accident progression during and after an earthquake. This study aims to investigate the potential conservatism in the current approaches used for seismic fragility evaluation of NPP structure and components (e.g., separation of variables and hybrid methods) and integrate the state-of-the-art techniques (e.g., dynamic PRA, detailed finite element models, explicit time history analysis, etc.) into the traditional SPRA. To achieve this on a real-world problem, a hypothetical scenario is created. A representative NPP is developed for three case studies that research objectives are addressed. The first case study estimates the core damage probability (CDP) of the NPP for a beyond design basis earthquake using state-of-the-art structural models within a dynamic probabilistic risk assessment framework. Randomness of seismic excitation and uncertainty of structural parameters are considered using a simulation-based approach. Finite element models are developed for the structure and a liquid container (hydro-accumulator), and fluid-structure interaction is considered with the arbitrary Lagrangian-Eulerian method. The CDP is evaluated through a time-dependent event tree. Also, correlation among multiple hydro-accumulators is investigated. The second case study investigates the impact of choice of fragility approaches on seismic fragilities of safety-critical components and conditional core damage probability of the plant analyzed. The third case study demonstrates a novel methodology for accounting for the seismic-induced dependency among safety-critical components. The observations indicate the following: 1) it is necessary to adopt a dynamic approach to determine the available time for recovery action and core damage timing probabilistically, 2) failure probability of components conditional to seismic intensity can be reduced by integrating the state-of-the-art methods, and 3) seismic-induced dependency can be accounted for CDP quantification using simulation-based seismic fragility approaches.
Halil Sezen (Advisor)
Richard Denning (Committee Member)
Ali Nassiri (Committee Member)
Tunc Aldemir (Committee Member)
230 p.
Civil Engineering
Seismic Probabilistic Risk Assessment (SPRA), Dynamic Probabilistic Risk Assessment (DPRA), Fluid-Structure Interaction (FSI), Arbitrary Lagrangian-Eulerian (ALE) Method, Conditional Core Damage Probability (CCDP), Seismic Fragility Analysis.

Recommended Citations

Citations

  • Kasapoglu, B. (2024). DYNAMIC SEISMIC PROBABILISTIC RISK ASSESSMENT OF NUCLEAR POWER PLANTS [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1713295585488882

    APA Style (7th edition)

  • Kasapoglu, Baris. DYNAMIC SEISMIC PROBABILISTIC RISK ASSESSMENT OF NUCLEAR POWER PLANTS . 2024. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1713295585488882.

    MLA Style (8th edition)

  • Kasapoglu, Baris. "DYNAMIC SEISMIC PROBABILISTIC RISK ASSESSMENT OF NUCLEAR POWER PLANTS ." Doctoral dissertation, Ohio State University, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=osu1713295585488882

    Chicago Manual of Style (17th edition)

osu1713295585488882
86
© 2024, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.