Risk and hazard reduction at Sellafield 2015/16

25 April 2017

The Sellafield Annual Review of Safety 2015/16 highlights progress in cleaning up the site, the largest repository of nuclear waste in Europe. Major steps, outlined below, include significant advances in dealing with the contents of the site’s storage ponds, containing some of the most highly radioactive waste on the site.

Image: Sellafield Ltd

These steps include:

• Removal of the entire bulk stocks of historic nuclear fuel from the Pile Fuel Storage Pond, reducing radioactivity levels at the 68-year-old pond by 70%.

• Beginning of bulk sludge transfers from the legacy First Generation Magnox Storage Pond to the Sludge Packaging Plant (see article on page 22). This was followed by the start of bulk fuel exports from the pond at the beginning of this financial year. This achievement was the culmination of over a decade of planning, preparation and investment.

Thousands of people, both at Sellafield and in the nuclear supply chain, have been involved in starting the process of removing the highest hazard contents from the First Generation Magnox Storage Pond.

• Completion of the assembly of the first 11 modules of the Silo Emptying Plant, which will be used to grab radioactive waste from the compartments at the Magnox Swarf Storage Silo (completing the main mechanical build – 300 tonnes of the 360 tonne machine).

• The first delivery in March 2016 of equipment needed to install the huge, steel silo containment doors which will be attached to the Pile Fuel Cladding Silo. This marks progress towards retrievals starting in the last of the four legacy buildings, to get radioactive waste out and into a safer place.

• A new ventilation stack has been built at Sellafield – so an old one can be knocked down. Completion of the Separation Area Ventilation project has paved the way for the demolition of a stack on top of one of the site’s reprocessing plants. The new ventilation building will provide a modern state of the art aerial discharge route for existing facilities at Sellafield, and enable the removal of older facilities to be completed.

• The highly active liquor (HAL) stocks have been reduced achieving a regulator mandated milestone. Earlier work undertaken to secure long-term evaporative capacity is key to this success.

In a companion piece to Sellafield’s 2015/16 review of safety, EHS&Q Director Euan Hutton points to the organisation’s achievements over the year, and to areas of future focus:

When you look at the cold statistics you have to say that our performance was mixed, with good performance in nuclear, environmental and radiological safety, but we missed targets in our industrial performance. When I look at what we delivered across the site in the same period though, I have to say that, overall our safety performance was good.

We have built upon our previous strong environmental performance with no significant environmental events; overall discharges and disposals of waste are well within permit limits.

Doses to the most exposed members of the public from operations at Sellafield remain very low at approximately 100 microsieverts (µSv)/yr. This compares to the average annual UK dose of around 2,700 µSv, of which 2,230 (µSv)/yr is derived from natural sources.

Our radiological protection performance remains strong in a year of increased high hazard risk reduction work. All doses to the workforce remain less than 10 millisieverts (mSv)/yr with the average being less than 1 mSv.

We also recently collected nine awards – eight gold and one silver – at the Royal Society for Prevention of Accidents Occupational Health and Safety Awards 2016. Many of our contractor colleagues also won awards for their safety performance at Sellafield.

That said, while our industrial safety accident rates remain good when compared with comparable industry averages, it is disappointing that we missed the challenging targets that we set ourselves.

Euan Hutton, EHS&Q Director, Sellafield Ltd

We have a combined Sellafield Ltd and supply chain workforce of approximately 14,000 people. These people are delivering a wide range of work in a mix of office, radiological and industrial environments. During the year we had 45 recordable injuries. The majority of these injuries were strains and sprains, bone fractures and cuts, caused predominantly by slips, trips and manual handling. Our focus remains on preventing all injuries and near misses.

There were three events which were rated as Level 1 on the International Nuclear Events Scale which means that they are classed as anomalies with no release of radioactivity or increased dose to individuals. We have investigated these events and are sharing learning across our business.

Our industrial safety performance is an area that we’re focused on improving. We have a plan in place to enhance our industrial safety performance focusing on improving standards, preventing accidents and reducing human errors.

We have increased visibility of industrial safety with dashboards across our plants highlighting performance in this area; progress against gaps is also discussed at the management daily meeting.

We’re also looking to make improvements to the effectiveness of the environmental case process and increase visibility of Best Available Techniques (BAT) governance arrangements within project and programme areas.

We’re developing our management system to make it easier to use and to reduce the volume of documents, simplifying the process and aligning it to changing business needs.

The biggest improvement that we as a company can make to the continued safety of the site is to ensure that we continue to focus on looking after our site assets, accelerating the clean-up of our highest hazard facilities.

In order to retrieve waste from legacy ponds and silos we have to do things that have never been done before, and we have to find a balance between risk and safety. With some of our ageing assets 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. This will involve balancing the transient increase in risk against reducing the overall risk and hazard whilst 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 whilst providing governance that we are making the right decisions and not going too far.

We operate within a stringent and highly monitored environmental regulatory regime and are subject to exacting regulation and oversight from independent regulators including the Office for Nuclear Regulation and the Environment Agency.

We work with our regulators and key stakeholders to safely drive risk and hazard reduction to keep ourselves, our facilities and the environment safe. We measure our performance against industry best practice at a national and international level through our membership of the World Association of Nuclear Operators, helping us strengthen and improve our arrangements.

Our internal regulators provide an important role in helping us assess how we’re doing and where we need to centre our attention. They’re continually providing oversight on our performance and independent assessment of compliance with legal requirements under Site Licence and UK legislation.

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. We have a corrective action programme where employees can raise a condition report when they find something unexpected, including any gaps in our systems, processes and procedures. This supports safe and reliable operations at Sellafield.

We have also 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). There are also new tools to help us understand the situation more quickly – these range from electronic boards that are interlinked between our command facilities to the use of GIS (the Geographic Information System). The on-plant response teams have also seen significant changes in the amount and quality of preparation that is being undertaken and the associated time we are investing.

I am proud that our employees and contractors remained focused on safety throughout and that every single day I see people looking out for each other, challenging when things are unsafe, focused on continually improving safety.