Rewriting the nuclear safety rulebook

Monday, 17 December 2012

Nuclear safety will be more holistic in the post-Fukushima era, as technical requirements broaden, regulators welcome more peer review and emergency planning is deepened.

The Ministerial Conference on Nuclear Safety concluded today in Koriyama, Fukushima prefecture. Organised by the International Atomic Energy Agency (IAEA) and the government of Japan, it heard from every IAEA member state and held working sessions for international discussion of changes in regulation, emergency preparation and protection of the public.

Every country in the world has reconsidered nuclear safety in the year and nine months since a major accident was caused at Fukushima Daiichi by severe tsunami flooding. "It is reassuring to note," said the UK's chief nuclear inspector Mike Weightman, "that despite different terminology and emphases, the efforts have largely converged on the same conclusions."

The most significant change is a new approach to regulation that adds serious consideration of external events of a scale significantly greater than ever considered by plant designers - events that are beyond design basis. Nuclear power plants and their operators are now required to cope with as-yet unimagined natural disasters and local difficulties that challenge safety systems. And if an accident cannot be avoided, operators are expected to mitigate its effects and limit radiation release.

Beyond design-basis requirements are necessarily generalised, and quite different from the detailed rules and regulations that typically govern nuclear operations. Successfully combining the two represents a major challenge, but national regulators are not alone. There was much enthusiasm for sharing and peer review between safety authorities - the kind of interaction that could have exposed the flaws in Japan's previous system which allowed weaknesses to linger and a crisis to become an accident. There was unanimous praise for Japan's new Nuclear Regulatory Authority, which has been established with the proper level of independence.

Readiness for response

Many delegates declared sincere determination to prevent any future nuclear accident occurring on the scale of that at Fukushima Daiichi, but this can never be guaranteed. Important changes in emergency response are to be implemented to improve readiness should a major accident happen again.

Going further than checking on safety, regulators should see their work in a broader context, said Weightman. A nuclear accident can have a major social cost even in the absence of health impact on the public - Fukushima being a case in point.

Alumanda dela Rosa, director of the Philippine Nuclear Research Institute, said nations using nuclear power should develop policies for dealing with an accident causing contamination of public areas "at an early stage of their program." This should include guidance on cleaning-up urban and rural areas under a wide range of conditions, covering all the legal, technical and environmental issues. To support this, countries need to share experience in radiation monitoring and decontamination.

Deputy director general of the European Commission's Joint Research Centre Vladimir Sucha emphasised that planning for nuclear emergencies should draw on the full range of science. It is important, he said, to understand the psychology that determines behaviour in stressful circumstances such as an evacuation, as well as cultural and communication issues - particularly when considering an accident with effects in more than one country.

In Europe there are 177 nuclear reactors in use across 30 countries, and some degree of harmonisation in emergency response is important said Sucha. Juan Carlos Lentijo of the IAEA said existing safety standards could inform a benchmark on response to a nuclear accident, while the IAEA has launched a project to compare the approaches and methodologies in various countries.

Similarly, international monitoring of contamination in food after a nuclear accident will be strengthened by a program involving the UN Scientific Committee on the Effects of Atomic Radiation. A range of international bodies will review global generic standards under which food is traded internationally.

Researched and written
by World Nuclear News