In the wake of events at Fukushima, on 24-25 March 2011 the European Council EC requested a review of safety at all European nuclear power plants (NPP) and the European Nuclear Safety Regulators Group (ENSREG) produced a specification and a plan for this review based on preliminary work carried out by the Western European Nuclear Regulators Association (WENRA). The reviews are commonly referred to as the 'stress tests'. Every nuclear power generating country in Europe agreed to carry out safety stress tests under request of the European Council. The tests, completed by licensees, involve a targeted reassessment of each stations safety margins in light of extreme natural events, such as earthquake and tsunami.
Given that the European Council stress tests only focus on NPPs HM Chief Inspector of Nuclear Installations decided to extend the stress test process to all other licensed nuclear installations within the UK.