Enhanced Seismic Protection System for an Emergency Diesel Generator Unit

Abstract

Nuclear power plants are required to maintain operation after an earthquake, leading to a safe shutdown if necessary. In the case of a loss of offsite power, the onsite emergency diesel generator is critical to ensure procedural operations of the nuclear power plant. As a means to reduce the overall seismic risk, a three-dimensional seismic protection system is proposed to enhance the seismic performance of the emergency diesel generator. The proposed seismic isolation system decouples the horizontal and vertical components of shaking and considers available hardware to achieve an effective isolation solution over the range of excitation frequencies considered. Numerical analysis of the proposed system demonstrates a reduction in seismic demands on the emergency diesel generator and provides a higher safety margin than conventional base installation procedures. Umbilical lines that cross the isolation plane are considered and impose additional constraints on the displacement capacity of the isolation system. However, increasing the displacement capacity of these components can significantly increase the safety margin against failure. The seismic protection system can be customized depending on the seismic hazard and application to different seismic regions.

A Comprehensive Review and Comparison of the Fragility Curves Used for Resilience Assessments in Power Systems

“…Towers (either distribution or transmission) [85,87,88] 2. Generation units [85,86,89,90] 3. Transformers [85,[91][92][93] 4.…”

“…In addition, a detailed vulnerability model of a diesel generator during earthquakes has been undertaken in [89]. In it, the FCs of the internal pieces are combined to obtain a final FC for the generator itself.…”

“…A discussion regarding the implications of assuming the previous criterion is detailed in Section III. TN-Poles and wires [80] Seismic events (Earthquakes) Towers (TN and DN) [85,87,88] Generators [85,86,89,90] Substations [85,94] Protective devices [92,94,95] Ice storms Lines [99][100][101][102] Flooding Substations, lines and generators [42] Wildfires Lines (Transmission) [2,106] Lightning Lines (Transmission) [113] 2…”