EDF's fleet of 58 reactors needs upgrades 'as quickly as possible' to be sufficiently robust in extreme situations, said France's nuclear safety regulator.
The utility has already started work to meet some of the requirements, which emerged from the 'stress tests' it carried out on the orders of President Nicolas Sarkozy and the European Commission.
France's 58 nuclear power reactors and fuel cycle facilities "have a sufficient level of safety" that means none of them should be closed, said the Autorité De Sûreté Nucléaire (ASN), but "their continued operation requires increasing as quickly as possible their robustness in the face of extreme situations beyond safety margins they already have." The results refer to a prioritised list of 79 of the country's 150 nuclear facilities.
Announcing yesterday's report, ASN head André-Claude Lacoste said the Fukushima accident "marks nuclear history" in the same way as the only other nuclear power accidents that have affected the public: at Three Mile Island and Chernobyl. "There will be a before and after Fukushima," said Lacoste.
The focus of additional safety in response to previous accidents was to develop universal excellence in nuclear operation, first across the USA as facilitated by the Institute of Nuclear Power Operations (INPO) and then globally through its sister, the World Association of Nuclear Operators (WANO). By contrast, Fukushima could not have been prevented by better operation but rather by better appreciation of external risks and their on-site consequences. For this reason two of the fundamental drives in ASN's requirements are improvements in earthquake and flood protection.
This enhanced preparation for natural disasters is to be complimented by prevention of risk from nearby industrial activity. Nuclear power plants may be located near major and potentially dangerous industries such as chemical processing, liquid natural gas storage or hydroelectric power generation. EDF will have to prepare itself and its sites for potentially enormous failures at nearby facilities like these.
In an accident situation the ASN wants French reactors to be able to rely on what it calls a 'hard core' set of safety requirements. These arrangements would protect safety-critical structures and equipment to ensure that vital functions can be maintained in the face of demands beyond the design basis of the plant, such as earthquakes, fires, or the prolonged loss of power or emergency cooling. Among the 'hard core' set-up would be robust emergency centres, improved communication and hardened supplies of water, diesel generators and dosimetry supplies for workers.
At the same time, a 'rapid action' force should be available to support any plant in the country within 24 hours, coming complete with highly capable staff and equipment such as mobile diesel generators and even a helicopter. This idea was suggested by EDF and a trial exercise has already been carried out at the Cruas-Meysse nuclear power plant. The nuclear group will compliment another national crisis group dubbed 'FIRE' that supports grid restoration.
ASN also wants all French operators to examine their options to construct a barrier to prevent the contamination of surface or groundwater under any circumstance. Operators using pools to store used nuclear fuel are to strengthen their protection against losing water.
Lacoste said France should guard against the temptation to add more and more technical systems in a drive to increase safety. This can be counter-productive, he said, because "nuclear safety rests fundamentally with people." In that respect, a major effort will be required on an ongoing basis to ensure proper supervision of subcontractors: Nuclear licensees will have to directly oversee subcontractors undertaking safety-related work, and no more than three levels of subcontracting will be allowed. It is also necessary to ensure that subcontractors are ready and willing to fulfill potentially vital roles should an accident situation develop.
ASN's announcement came when its 524-page report on the stress tests was passed on to government for transmission to the European Council. Every nation involved in the stress test program is keeping the same schedule.
The next step in the process will see national regulators peer-review each others' reports. They may then be accepted by the European Nuclear Safety Regulators Group (ENSREG) by late June, when the European Commission concludes the project with a summary report to European Council.
At the same time, the commission will make suggestions on how the bloc may standardise some aspects of nuclear regulation. It said in November that "an EU-wide set of basic principles and requirements could be envisaged, together with associated minimum technical criteria in the areas of siting, design, construction and operation of nuclear power plants."
Researched and written
by World Nuclear News