PSAM 16 Conference Paper Overview
Welcome to the PSAM 16 Conference paper and speaker overview page.
Lead Author: Shuhei Matsunaka
| Seismic Probabilistic Risk Analysis of Transmission Systems for Kashiwazaki-Kariwa NPS using Deaggregation Hazard taking account of Non-Specified Source Faults |
|---|
| In the 2011 Fukushima Dai-ichi nuclear power plants accident, power transmission facilities were damaged due to the earthquake, and the emergency diesel generators failed to perform their intended function due to the subsequent tsunami, resulting in the station blackout (SBO) scenario. Although the seismic reliability of offsite AC power supply has been evaluated in the conventional Seismic Probabilistic Risk Assessment (SPRA), in the United States, the generic fragility has been applied in the typical practical evaluation. Previous Kashiwazaki-Kariwa (KK) NPS SPRA has incorporated the plant-specific fragility of seismically weakest onsite power generation components (i.e., ceramic insulator), but it could be a non-conservative evaluation. Although there are evaluation examples of the transmission system, there are some assumptions and limitations that may become key in actual plant evaluation (such as insufficient consideration of non-specified source faults). In this study, the seismic reliability of the offsite power supply for the actual plant was evaluated in detail by calculating the frequency of the loss of offsite power (LOOP) using deaggregation 3-D hazard for each faults, modeling the transmission system as Boolean logic, and considering non-specified source faults. Compared with the conventional method (i.e., generic fragility in the United States and representative fragility by onsite facilities), the degree of conservative/optimistic were quantitatively confirmed respectively. As a plant characteristic of KK NPS, there are 3 power supply routes containing 5 lines (one route of which has a substantially different direction). Therefore, earthquakes of source faults that are close to one power transmission route (e.g., switching station) but far from the power plant is likely to be supplied from the other power transmission route. In this study, the effectiveness of transmission route redundancy was evaluated, and potential risk insights were gained by reviewing the positional relationship of the source faults, the power plant, and the transmission facilities including transmission network and switching station. Furthermore, since the importance of earthquakes of non-specified source faults was estimated, in addition to the conventional evaluation using logarithmic linear approximation based on the Gutenberg-Richter law, sensitivity analysis was also performed using the method of moments and other probability distribution forms including Generalized Extreme Value (GEV) distribution and Log-Pearson Type III distribution. |
Paper MA57 Preview
Author and Presentation Info
Presentation only, a full paper is not available.
Lead Author Name: Shuhei Matsunaka (matsunaka-shuuhei@tepsys.co.jp)
Bio: I studied Nuclear Engineering at Osaka University in Japan and received master degree of engineering in 2011. I have been working on the development of design basis of external events for several years. I have also been studying Seismic PRA, Tsunami PRA, and Dynamic PRA.
Country: Japan
Company: TEPCO SYSTEMS CORPORATION
Job Title: Deputy Manager
Bio: I studied Nuclear Engineering at Osaka University in Japan and received master degree of engineering in 2011. I have been working on the development of design basis of external events for several years. I have also been studying Seismic PRA, Tsunami PRA, and Dynamic PRA.
Country: Japan
Company: TEPCO SYSTEMS CORPORATION
Job Title: Deputy Manager