Fukushima - what did we learn?

THE EARTHQUAKE AND TSUNAMI THAT hit the east coast of Japan on 11 March 2011 left about 19,000 dead, over a million buildings destroyed or partly collapsed, roads, railways and ports damaged and a large population in need of immediate assistance.

At the Fukushima Daiichi nuclear power station the tsunami left the site extensively damaged. This compromised cooling of the three operating reactors and the ponds where spent fuel was stored. The coordination of the response was made difficult by failures of reactor instrumentation and radiation monitoring equipment and the unreliable nature of communications between the site, nearby towns and the national response organisation.

Countermeasures to protect the public were imposed by the governor of Fukushima Prefecture who ordered a 2km evacuation. Shortly afterwards, Tokyo imposed 3km evacuation. Over the following days there were more countermeasures as the situation on site became clear and, despite heroic attempts, hydrogen explosions occurred, nuclear fuel melted and a significant off-site radiation release ensued.

The countermeasure strategy appeared to be struggling to catch up with events. There seemed to be understanding and trust problems within the decision making process that exacerbated the infrastructure failures. It appeared that the site’s safety cases were incomplete and the emergency plan inadequate. These impressions, whether fair or not, were to have a significant impact on the UK nuclear industry. The initial concern of the UK government had been to help UK nationals within the tsunami zone. Later there were concerns about the radiation situation in the area and problems arose from conflicting advice being given by different governments to their nationals.

On 14 March the UK’s Office for Nuclear Regulation (ONR) was asked to examine the circumstances of the Fukushima accident to see what lessons could be learnt by the UK nuclear industry. In addition, operators responded to the European Community’s ‘Stress Tests’, which concentrated on sites’ ability to cope with earthquake or flooding leading to station blackout (loss of all off-site power), loss of ultimate heat sink (failure of cooling), or both. Sites held workshops where they considered, for example, increasing levels of flood-water looking for “cliff edges” where safety suffers a dramatic fall. Following this exercise many diesel generators, fuel tanks and electrical circuits were raised, and doors and pipe-runs were sealed or waterproofed. On-site and off-site communications were hardened. More equipment was procured to ensure that nuclear plant sites could be cleared of rubble, electricity could be generated, lighting could be provided and reactor and pond cooling could be recovered.

Fukushima affected new UK nuclear projects, as questions were asked about their ability to survive such events. (See the discussion on Hinkley Point C in NNB Generation Company, (HPC) Ltd, Redacted Public Version, HPC PCRS3: Chapter 23 – Response To Fukushima Sub- Chapter 23.0 – Safety Approach For UK EPR (HPC Safety Requirements). Their response included adding sound powered telephones, more battery power, more water- proofing, more cooling, more hydrogen management and new procedures to manage severe accidents.

Prior to Fukushima off-site nuclear emergency planning in the UK was based on the Radiation (Emergency Planning and Public Information) or REPPIR 2001 regulations and the guidance issued by the Nuclear Emergency Planning Liaison Group (NEPLG). The philosophy was to plan in detail for event sequences considered to be ‘reasonably foreseeable’ and consider how this would expand to cope with a less-likely but more severe accident.

The plans envisaged:

• prompt declaration of an emergency when the situation warranted it, leading to the establishment of an emergency response organisation at the site, at the local coordination centre and in various national crisis centres; and
• pre-agreed, automatic countermeasures to protect the public with the systems and resources needed to implement them in place.

Thereafter, the role of off-site structures was to consider whether the countermeasures in place should be withdrawn, extended or left in place and to protect, inform and reassure the public.

The idea of ‘extendability’ was that the default plan brought together the right organisations to start the response. If this response was lacking then more resource could be bought to bear, including from neighbouring areas and national resources. In fact it was recognised that, even with a smaller event, the composition of the response would change according to need.

Post Fukushima the NEPLG, which had coordinated national nuclear emergency planning since 1990, was subsumed into a new government committee, known as the Nuclear Emergency Planning Delivery Committee (NEPDC) and answering to a new Nuclear Emergency Planning Board (NEPB). This system was more focused on government capabilities, more concerned with severe accidents and more directive. Essentially it was tasked with preparing the UK government for a Fukushima-scale event.

The UK local authorities were challenged to look in more detail at extendibility planning based on new advice. This initiated a series of multi-agency workshops considering the potential response to an extendibility scenario. Could it provide command and control, shelter wider areas and for longer, distribute iodine to more people and evacuate areas around nuclear sites? Updates of off-site plans followed.

Another post-Fukushima innovation was the development of ‘capability maps’ for emergency planning. These were developed by the industry and ONR in response to a demand from the NEPB for a dashboard-style report giving each site a red, amber or green rating on a range of capabilities.

Revising regulations

Currently the REPPIR regulations are being revised to implement a revised Basic Safety Standard, which all EU countries must implement. The draft regulations require revised risk assessments and reports and no longer contain the term “reasonably foreseeable” in the selection of the source terms used to scale the response. They also introduce an outline planning zone, set at 50km for sites “processing high level waste and/or storing in excess of 100 tonnes of plutonium” (ie Sellafield) and 30km for operating nuclear power plants. These regulations will herald a further risk review and an extension of emergency planning around UK sites.

In summary, the effect of Fukushima in the UK has been to take planning for response to severe accidents out of the ‘nice to have’ category of best practice and into the remit of good practice, mandated by regulation and guidance. It is likely that on a ‘risk for risk’ basis the nuclear industry will be spending considerably more than other industries and society. This may be seen as a prudent response to fears over radiation – or as poor use of resources that could be better used to improve, for example, flood defences, or resource the hard pressed local resilience forums that manage all types of resilience.

Nuclear sites have had to assess and improve their ability to survive earthquakes and floods and, in particular, loss of off-site power, on-site generation and cooling. This is a classic case of preparing for the last emergency. It is reminiscent of RIMNET, a system to detect and track radioactivity crossing UK borders, which was a response to the Chernobyl experience and which proved woefully inappropriate when faced with Fukushima.

We should take heed of the warning given by Rear Admiral E S J Larken, who said, “Despite efforts to the contrary, emergencies continue to outflank attempts at prediction, anticipation and prevention. Accidents, emergencies, and crises present by their nature an apparently endless ability to surprise”. Post Fukushima we have significantly improved our resilience and our ability to respond to disruptive events, but we also did that after Windscale, Three Mile Island, Piper Alpha, Buncefield, Chernobyl, 9/11 and many others. This is no guarantee that we have put in place the systems and resources needed to cope well with the next emergency. 

Author information: Keith Pearce, Director of Katwab Limited, a nuclear emergency planning specialist and author