Could a single EMP cause nearly all USA reactors to "go Fukushima" - melt-down and explode?
- NRC policies have taken into account EMP since the late 1970s
- The USA has no nuclear reactors of the old design type used at Fukushima.
The Nuclear Regulatory Commission (NRC) have been studying the effect of EMP on nuclear power plants since the 1970s to ensure that these plants can shutdown safely after an EMP.
See Keeping U.S. Reactors Safe from Power Pulses
The NRC requires U.S. nuclear power plants to be able to shut down safely in the face of many extreme events – tornados, hurricanes and earthquakes. But the NRC also takes into account far more unusual events, like solar flares and electromagnetic pulse (EMP) caused by a certain type of nuclear weapon.
Here's an example study: Interaction of electromagnetic pulse with commercial nuclear-power-plant systems
was concluded that: (1) Diffuse fields inside Seismic Class I
buildings are negligible; (2) EMP signal entry points are identifi-
able; (3) Interior signal attenuation can be reasonably modeled;
(4) Damage thresholds, even for equipment containing solid state
components are high; (5) EMP induced signals at the critical
equipment in the example plant are much less than nominal operating
levels, but plant topology and cabling practice have a strong
influence on responses; (6) The likelihood that individual com-
ponents examined will fail is small; therefore, it is unlikely that
an EMP event would fail sufficient equipment so as to prevent safe
EMP from high altitude nuclear tests in the 1960s did cause significant damage to some sections of street lighting and other equipment at long range.
Since the continental USA is a large country, it would take an extraordinarily large nuclear explosion to create a single EMP pulse that affects both west and east coasts.
The containment failures at Fukushima were due to a combination of factors:
- The Tsunami knocked out the power grid in the region.
- The Tsunami flooded the standby generators at the power plant.
- The Reactors did not have a purely passive system for reaching cold-shutdown.
The Fukushima reactors are Boiling Water Reactors (BWR) designed by GE in the 1960s and now designated, by some people, as Generation-1 reactors. According to Wikipedia there are no Generation-1 reactors operating in the USA (they've all been decommissioned - the last was Big Rock Point in 1997). However this system of classification is not universally used.