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Nuclear decommissioning

Sellafield: atomic legacy

The world’s largest nuclear storage site is part-way through a 100-year-long decommissioning project.

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Words: Tina Weadick

The word “Sellafield” was guaranteed to strike fear into the hearts of children growing up on the east coast of Ireland in the 1980s. In the days before the Cold War began to thaw, anything to do with “the bomb” was frightening. But those of us living so close to Europe’s most complex nuclear site felt we had more to be worried about than most. 

Panorama or tunnel vision?

On 5 September, the BBC broadcast a Panorama documentary entitled Sellafield’s Safety Failings. It was largely based on the testimony of an ex-employee and whistleblower and included interviews with members of the management team of NMP – the British, French and American consortium that lost the £9bn contract to run the site earlier this year. Sellafield says it invited the documentary-makers to visit the site and speak to the new management and key personnel, but they declined.
Among the most serious accusations made by the programme were that there are not always enough workers to maintain safety levels, that staff routinely reset alarms without investigating the cause and that the site does not have the capability to respond to nuclear emergencies effectively. In addition the Magnox and storage ponds are beset by cracks, which, sooner or later, will lead to a catastrophic leak, the programme alleged.
IOSH Magazine put all of these points to Sellafield’s environment, health, safety and quality director, Euan Hutton, who had this to say:
  • Staffing levels: “Each facility has a minimum staff level. When we reach it – which does happen once or twice a week – we make a condition report. When auditing those reports, the key thing is: what did the plant manager do in that instance? Either, they won’t do the operation, or they’ll shut down. In the majority of cases, the delay is only for an hour or two until relief staff are found. The point is, we are actively managing this and acting on issues. The regulator would come down on us hard if we were operating below minimum safety manning levels. I would be sacked – and possibly sent to prison!”
  • Complacency about alarms: “A complex site like Sellafield has thousands of systems, which may all have their own individual alert or alarm procedures. Many of these are software-based alarms designed to notify plant operators of specific changes that are not safety-critical. Colour-coded visual signs help indicate changes in systems which require immediate attention. We have a robust training programme with instructions and procedures relating to any safety-critical alarm, whether that is site-wide or local to a specific building. These procedures are embedded in everyone who works on the site through regular drills and exercises. In addition, we are working constructively with ONR to simplify procedures for non-safety-related alarms.”
  • Emergency preparedness: “We have eight fully-manned emergency duty teams on an eight-week rota – 60 people per team. All are fully aware of whatever operations are going on on-site that week. We’ve been developing over a number of years our emergency preparedness to consider the worst case, taking into account the specific action that might be needed to manage our retrievals work, as well as learning from wider events, such as Fukushima and the flooding we have been unfortunate to have had in Cumbria over the last decade. As a member of the site emergency duty team I’ve seen a significant difference in the amount of time and resources we’re investing in making us ‘match ready’. The start of each of our emergency duty weeks is now a half-day session of briefing, training and exercising, as opposed to the half hour we used to diary.”
  • Deteriorating storage ponds and silos: “Some of these facilities contain around 1,000 different types of waste, including fuel, equipment and radioactive sludge. With regard to the silos, nuclear waste was tipped into them in the early days, when the site’s purpose was to create material to make weapons. Unfortunately, no plans were drawn up for how future generations would take out the waste when the building was at the end of its life. As for the first-generation Magnox storage pond, there are 257 cracks in it but these are closely monitored all the time.

Tales abounded of an Irish Sea so contaminated it glowed green at night. These stories were apocryphal but the environmental campaign group Greenpeace argues that the Irish Sea is one of the most radioactively contaminated bodies of water in the world. But having visited the erstwhile place of my nightmares I now know that risk management and emergency preparedness are integral to the Sellafield operation. 

The 6 sq km site in Cumbria sits on the doorstep of the beautiful Lake District National Park. It is one of Europe’s largest industrial complexes and stores more radioactive material than any other nuclear facility in the world. 

The site was built in the 1940s to create material for conventional weapons. After the end of the Second World War, it was developed into the UK’s first atomic energy site, producing plutonium for military purposes. In the 1950s, it diversified into energy production – the plant continued to generate electricity until 2003 – and fuel reprocessing. These were the mainstay of Sellafield’s operations until the early 1990s, when waste management – treating and disposing of the by-products of reprocessing and decommissioning operations – became a major part of the business.

While the plant was profiting from these activities, the older parts were beginning to deteriorate, and original treatment and storage facilities were becoming outdated and unfit for purpose. Consequently, a comprehensive, complex and – in many respects – pioneering clean-up and storage programme was devised. It is one that continues today.

Hundred-year plan

It will be well over 100 years before the site reaches the agreed end state, as specified in the Nuclear Decommissioning Authority’s (NDA) strategy (bit.ly/2dDmF3O). Such an extended timescale makes it difficult to predict how long the component stages will take, and how much they will cost. Because record keeping was historically poor, nobody knows what might be lurking in legacy buildings and structures that have been shut for 50 years. In many cases, before the old buildings can be knocked down, new ones have to be built on what is already a very crowded stretch of land.

Given the purpose of the site, it is easy to assume that its 15,000 workers are some of the most at-risk in the world. 

“We face significant challenges daily, involving nuclear, environmental, radiological, chemical and conventional safety hazards,” admits Euan Hutton, EHS&Q director at Sellafield. 

“This requires a constant and relentless concentration on safety. We need to create a safe working environment to enable our employees to undertake vital work on the operational and legacy buildings to ensure that every single one of our 11,000 employees and upwards of 4,000 contractors goes home safe, every day.”

The decommissioning process under way involves demolishing the site’s earlier structures. These include the 110 m chimney from the first Windscale nuclear pile chimney, which serviced reactors once used to make weapons grade plutonium but was mothballed in 1957. Another legacy item is the 7 m deep open-air pile fuel storage pond that cooled and stored spent fuel, first from Windscale and then from the neighbouring Calder Hall reactors. The pond’s “radiological inventory” includes thousands of cubic metres of oxide fuel, metal fuel and 300 sq m of radioactive sludge the consistency of tomato ketchup which will be retrieved and stored in drums before export for treatment. Other destinations include geological storage underground and, for the high- and intermediate-level waste that cannot be remediated, treatment, repackaging and storage at new facilities at Sellafield.

Low doses

You might think the bulk of the safety effort to protect workers amid these demolition programmes would revolve around radiation and the risk of leaks and explosions. In fact, the average worker at Sellafield receives a radiation dose of less than 1 millisievert (mSv) a year at work. The average person in the UK is exposed to 2.7 mSv per year from natural background radiation and other sources such as medical scans, according to Public Health England.

The removal of storage infrastructure is no more hazardous than some other demolition projects, because the external walls of many stores have not absorbed abnormal radiation levels. Handling and encapsulating the hazardous material is carried out remotely by crane, wherever possible. Where human intervention is needed, operators have full personal protective equipment, including air-fed suits.

People working with radiation are designated as “classified persons” if they are likely to receive a significant radiation dose. In the past, Sellafield has had up to 13,000 classified persons (including contractors), but current worker doses are low enough that the number has fallen from about 7,500 to 5,000 in the past year. All workers in controlled areas wear dosemeters whether they are classified persons or not.

It is more conventional health and safety issues that are of most concern at the site. According to information officer Haylee McCarron, slips, trips and falls are the biggest contributors to accidents. There is a plethora of signs urging people to hold the handrail when using steps and stairs, and I was tapped on the shoulder and reminded to do so several times during my visit. “We foster a positive challenging culture here,” says McCarron. “People will tell you when they think you are acting unsafely.”

Sellafield operates a peer observation programme, which has been in place for six years. Employees and contractors are encouraged to hold conversations directly with each other to prevent accidents and reinforce good safety practices. Employees can raise a condition report when they find something unexpected, including gaps in systems, processes, and procedures. For every observation report submitted the company donates £1 to charity. There is also an observation action board, displaying the concerns raised and actions to address them. 

Hutton adds: “A key part of a strong safety culture is having a healthy reporting culture to identify and resolve potential problems, at their lowest level of consequence, before they impact nuclear safety.”

No stopping

Despite this encouragement of employees to voice concerns about safety, a former site worker made claims about safety risks at Sellafield to the BBC. They formed the basis of a recent Panorama TV documentary (see our box above, Panorama or tunnel vision?). The company says: “We were disappointed that the ex-employee quoted in the programme took their concerns to the media rather than raising these issues via our well-established, independent and anonymous whistleblowing policy. 

“It ensures that our employees are confident that they can raise any matters of genuine concern relating to safety or behavioural safety without fear of reprisals, in the knowledge that they will be taken seriously and that matters will be investigated appropriately and regarded as confidential.”

The Panorama programme seemed to take the same stance as the many pressure groups and protesters, which is that the site is extremely dangerous, full of potentially catastrophic risks and hazards that are ignored, raising questions as to why it is allowed to continue operating. 

That Sellafield poses some of the biggest risks in the UK is a given – and openly acknowledged by its operator. What it denies are any suggestions that these risks are not dealt with and that the answer is as simple as shutting it.

“We can’t just stop and switch these things off,” says Hutton. “We have to keep going forward, and we are focused on accelerated risk and hazard reduction. To retrieve waste from our legacy ponds and silos we have to do things that have never been done before. We can’t employ a traditional, zero-based risk approach – we can’t switch off legacy plants. Therefore, to get work done with the urgency needed, we face the challenge of doing different work in a different way.

In order to retrieve waste from our legacy ponds and silos we have to do things that have never been done before

“This will involve balancing the transient increase in risk against reducing the overall risk and hazard while maintaining control. Time at risk is a critical factor in how we plan and execute the things that we have to do. We have to develop the boundaries that define nuclear safety in this context, deliver work closer to these boundaries than we have in the past, while providing governance that we are making the right decisions and not going too far.”

Carrying out construction work in old facilities that are in constant operation is a particular challenge. Hutton likens it to modifying a big ship, “changing it from a cruise liner to a freighter, say, while it is still at sea. We don’t have the option of putting it in dry dock.” 

Constant construction

Sellafield is one of the largest construction sites in the UK. New buildings often have to be put up to support the decommissioning and demolition of those already standing. In turn, these new structures will themselves have to be taken down. And all of this has to be done on a tightly packed site, where space is at a premium and planners and engineers have to navigate a 70-year-old tangle of buildings, storage ponds, pipework, utilities and equipment.

A good example is the project to build a new silo maintenance facility (SMF), which will support the retrieval of historic waste from earlier decades, stored in silos and ponds, some dating to the 1940s. One was the Magnox swarf storage silo, which stored cladding waste stripped from the reactors’ spent nuclear fuel before reprocessing. Another was the pile fuel cladding silo, which was constructed in 1952 and filled with intermediate level nuclear waste by 1964. There are some 3,000 cu m of waste in the silo’s six compartments that must be retrieved and transferred to new, more secure storage. 

The SMF, built as a joint venture between Balfour Beatty and Cavendish Nuclear and involving around 180 workers, is due to be completed in spring 2018. It is being built on the footprint of two of the old Calder Hall cooling towers, all four of which were safely demolished in 2007, after three years of planning. 

We don’t have the option of putting it in dry dock

Sellafield construction manager Maria Pennington, says the key objective on the site is safe access and exit for people. “That means managing logistics safely and keeping a tidy site. There are always a lot of mechanical activities going on – ductwork and electrics installation, for example. The modular structure of the building means there are myriad tradespersons on site at any one time. The variety of hazards is also huge – today, for example, we have confined spaces and restricted-access activities, noise and vibration, manual handling, lifting ops, work at height, plant movement and COSHH [hazardous substances].”

In response, there are colour-coding systems for lifting-equipment movements and a traffic-light system for noise levels. There are also colour-coded barriers to denote different walkways, as well as plenty of the aforementioned signs reminding people to hold handrails and warning of the risk of finger-trapping on steps and stairs. Meanwhile, a big safety dashboard at the SMF site entrance proclaims “1,075 days worked without incident”.

As a licensed nuclear site, Sellafield is under the auspices of the Office for Nuclear Regulation (ONR), which liaises with the installation’s personnel on how to comply with legal requirements, assessing the adequacy of documented safety cases and ensuring risks to workers and the public are reduced so far as is reasonably practicable. Hazard reduction and remediation at Sellafield legacy facilities is the ONR’s number-one priority in its 2015-16 work, and it is in the process of increasing front-line resources to cope with the “substantial growth” of the nuclear industry in general.

Between February 2012 and June 2015, the ONR issued Sellafield with nine enforcement notices, the most recent of which was for not ensuring that “all operations that may affect safety, including those subject to limits and conditions necessary in the interest of safety identified in the safety case, are carried out in accordance with written instructions”.

The company says it takes these events seriously, “carrying out management investigations where required and putting corrective action in place to take and share learning from events to strengthen and improve our arrangements”.

Two fires

In 1957, serious fires broke out at two separate nuclear plants within weeks of each other. In both cases, plumes of radioactive smoke escaped and dispersed into the air. After the first incident, which happened at a plant called Rocky Flats, near Boulder, in the US state of Colorado, authorities and the managers of the facility’s managers did not share the extent of the fire or the scale of the radiation hazard, with either local people or the media. There was no site public evacuation, nor any press coverage.  Operations ceased in 1989 but almost all underground contamination is still in place and concerns remain over the risks to public health.  

The second blaze was, until Chernobyl, Europe’s worst nuclear accident. It was front-page news, despite official efforts to play it down. Soon afterwards, livestock was quarantined, and dairy products were considered unsafe. This second incident happened at Windscale, or, as it is known today, Sellafield. 

We may never be told everything that did, or does, go on at this complex site, but its operator’s efforts to be as transparent as possible about what is happening there, as well as its obvious commitment to safety and risk management, mean I would rather live across the sea from Sellafield than down the road from Rocky Flats.

 

 

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