Nuclear Power Information
Measures against Potential Massive Earthquakes
Basic Seismic Design
In earthquake-prone Japan, nuclear power stations are taking various measures to assure seismic safety, while constantly striving to achieve higher standards of safety. As new scientific and technical findings are acquired, they are incorporated into safety measures for all nuclear power stations throughout Japan.
The plant design has been configured based on thorough investigations to ensure that the plant can withstand the maximum earthquake ground motion.
The major facilities of a nuclear power station are designed to be able to withstand the maximum level of earthquake that is predicted based on past earthquakes and the results of detailed geological investigations.
Boring surveys, surface geological investigations, trench excavation surveys, offshore acoustic exploration, literature surveys, aerial photographic interpretation, airborne gravity surveys, etc.
Demonstration of seismic safety and identification of seismic safety threshold
Vibration tests are conducted using the world’s largest-class shaking table to demonstrate the seismic safety of important safety components, such as the containment vessel.
The seismic safety of such components is verified by applying a greater seismic force than that assumed in the design stage to a full-scale model or a detailed model placed on a shaking table.
A nuclear power station is built on a robust foundation.
A nuclear power station is built on a foundation that provides solid support by digging deep into the ground, rather than on subsurface ground in which earthquake-induced vibration would be significantly amplified.
The nuclear power plant will automatically shut down in response to a strong earthquake ground motion.
Multiple seismoscopes are installed at a nuclear power station. When a seismoscope detects a large seismic acceleration, it sends a signal to a control device which automatically and safely shuts the reactor down.