European regulators have been publishing progress reports on the program of stress tests being carried out at nuclear power plants in response to the Fukushima accident. In the weeks following the Fukushima accident, the European Council (EC) requested a review of safety at European nuclear power plants when faced by challenging situations. The criteria for the reviews, now known as stress tests, were produced for the European Commission by the European Nuclear Safety Regulatory Group (ENSREG). Progress reports were due to be submitted to the European Commission by 15 September, and many nuclear regulators and in some cases plant operators have published summaries, including regulators in Belgium, France, Hungary, Romania, Slovakia, Slovenia, Spain, Sweden and the UK.