Many of the world’s first-generation nuclear reactors will reach the end of their lives by 2025. Nuclear specialists Scott Sax and Frank Wigley discuss how the growing fleet of retired plants present a unique opportunity to change the narrative around decommissioning from risky and expensive to responsible and innovative.
Shutting down a nuclear reactor site is complex. It requires detailed management, stringent technical understanding of the site and the highest of safety standards. It’s also a costly undertaking. International Energy Agency suggests half of the world’s 434 reactors currently in use will cease operations by 2040. They will need to be closed down and cleaned up— a task industry experts estimate will cost hundreds of billions of dollars. Safe, well executed and cost-effective clean-up programmes show that taking these nuclear facilities out of service can contribute to a cleaner environment and effective waste management programmes.
Another benefit of remediating retired facilities is it reduces the cost of maintaining the facilities. The savings can then be reinvested into cleaning up the site and returning it back to the community for future uses.
Start with the end in mind
President of AECOM-led Washington Closure Hanford Company, Scott Sax, project manages the Hanford River Corridor Closure project — the US’s Department of Energy’s (DOE) largest environmental clean-up closure project. Scott Sax has been at the forefront of pioneering decommissioning projects in both the US and the UK for nearly three decades.
“Nuclear is still a relatively young industry,” says Sax. “Back when first generation plants were being built, they didn’t really consider plans for shutting them down, but things are different now. It’s all about discipline and delivery. You need to put a detailed programme in place and then strive steadily towards closure goals,” he says.
“Decommissioning should be included in the very earliest plans for a plant. Waiting until the reactor has stopped generating is a mistake because you’re making no money at the back end — you’re just spending money cleaning it up. The longer you leave it, the worse it will get. There will be more hazards, more investigations, more waste and ultimately more cost,” says Sax.
A good approach is to start decommissioning assessments and financial modelling while the reactor is still generating revenue, to offset clean-up costs early, and build a clearer idea of liabilities and uncertainties when it’s time to start tearing things down.
The plan’s the thing
Of course, this isn’t an option for sites currently or just about to go into decommissioning. But good programme management can keep operators and their decommissioning partners on track and on budget.
A good example of this is AECOM’s work at the Hanford River project. The 586-square-mile site was established to develop the first nuclear weapons as a key part of the Manhattan Project during World War II.
Over 10 years, Scott and his team have taken down 324 buildings and cleaned up 572 waste burial grounds along the site’s 220-square-mile river corridor, meeting all 49 of the programme’s regulatory milestones on or ahead of schedule.
“It was a big contract, but we did it,” says Sax. “Our client also added US$1.1 billion (approximately £700 million) of works, about three years of work scope, which we achieved by only extending the end date by just one year, and came in US$330 million (approximately £230 million) under budget.”
Exporting expertise
Working on projects like Hanford, which are much larger and more complex than a standard nuclear reactor decommission, provides an essential grounding in cutting-edge best practice and enables AECOM’s decommissioning teams to transfer their experience.
Frank Wigley, AECOM’s technical director for radioactive waste and contamination, agrees. “The UK’s nuclear industry, which includes the Sellafield site in Cumbria, where we have 35 years’ design experience, has learned a lot from the US, where the process of decommissioning is more advanced. AECOM has also been able to act as a conduit for a reversal of this process, by harnessing best practices from other geographies back to the US as well.”
“Because of our experience in working on these major sites, we’re able to bring expertise to countries such as Germany, which need to get their decommissioning programmes up and running quickly, and to support safe and efficient waste disposal in places like Slovakia, the Czech Republic and Bulgaria,” says Wigley.
Of course, regulatory regimes are different in each country. Governments and their operators will want to take ownership of their own decommissioning programmes. “This is where we can help, by providing local teams with an in-depth understanding of regulations coupled with global best practice,” says Wigley.
Out of harm’s way
Regardless of the project, operational safety is a major area of attention. “Regulators tend to be focused on radiological safety during decommissioning,” says Sax. “That’s understandable, but in reality, most of the safety issues we encounter on a reactor site are around chemical and industrial safety. You need to balance all areas. One approach is to remove people from hands-on decommissioning by using heavy equipment such as bulldozers and huge shears to tear down buildings.”
“Our approach is to protect our workforce first. They are the first to be impacted by any event so by ensuring their safety, we ultimately also protect the environment and the public,” adds Sax.
To date, demolition and remediation activities have typically been completed as an extension to the safety procedures used to manage the removal of spent fuel and nuclear critical materials.
In the UK these procedures are governed under a documented safety case regime, which ensures that the safety and management of nuclear materials is paramount. Once these materials are removed, much of the risk is removed with them. The strict safety cases that govern the business-as-usual running of a nuclear plant are a good example of the need for a more holistic approach to safety.
“At another nuclear site in the UK, we designed a hierarchy of safety cases to reflect the reality of the clean-up, increasing the flexibility to deal with unforeseen circumstances such as localised contamination hotspots in areas that it would not be practicable to conduct thorough characterisation before demolition. This could include, for example, the ground beneath operational facilities. We believe it will be crucial in helping our client hit their accelerated decommissioning deadlines,” says Wigley.
In the interim
Ultimately, decommissioning is all about the end state. “When do you stop decommissioning? When the site is completely clear? Do you put it into long-term management?” asks Wigley. De-licensing is often an attractive option on paper, especially with the potentially positive economic and social benefits of redeveloping the land. But it can be a long, arduous process. An alternative is to move to what’s known as an interim end state — where you clean-up the site to agreed concentrations of contaminants. After that, a site is still protected, enabling the remaining substances to decay and naturally reduce.
Uncomplicating waste
The question of what to do with the waste is also a contentious one. For remediation teams it’s the low-level waste left after the more radioactive material has been removed and the extra low-level waste produced by the decommissioning itself.
“I’ve seen operators run complicated waste segregation schemes, but these can be self-defeating,” says Sax. “It takes a long time, and you need lots of different facilities to store the different categories of material. Ultimately, the equipment and packaging used to segregate and sort the waste add to the waste volume.
This impacts storage or disposal space and increases the cost dramatically. Too often this cost is hidden from the project life cycle by accumulating it in its own standalone project so it’s not necessarily considered in any cost benefit analysis.”
Sax believes less segregation and larger facilities may be better —Wigley agrees that while this may be the case for facilities in the US, in the UK and Continental Europe, space in these facilities is critical for the performance of the whole decommissioning programme.
Setting the focus
“The adoption of traditional waste management hierarchy arrangements for low level waste has been proven to work well, and by starting with the end waste form in mind it will focus the decommissioning process,” says Wigley. “You can use standard techniques developed for other types of waste to streamline the process and save your operator money. Repair and maintenance is also much more straightforward.”
A better nuclear future
With our global, multidisciplinary skill set and understanding of tricky decommissioning projects, AECOM is positioned to support operators and license-holders as they navigate the complex shutdown and decommissioning process. “Exemplary decommissioning projects can help change public perception of nuclear power to something more positive,” says Sax. “And that’s good for operators, governments and the whole industry.”
To address the concerns of the public and regulators alike, it’s important to listen to their concerns and provide timely information. “Establishing relationships and confidence has proven to be an important element in executing our work,” says Sax.
“On the River Corridor Closure project, while preparing to remediate an extremely hazardous burial ground of radiological and chemical laboratory waste, we expected to find uranium oxide powder stored in barrels which could burst into flames when exposed to the air,” says Sax.
“Our stakeholders were aware of these risks and were very concerned. Before operations began, we invited community members from a citizen advisory board and the media to a series of briefings and demonstrations by our team, where our emergency response preparations, team’s readiness preparations and drills were demonstrated. This built public confidence in our planning and procedures, and our ability to address the potential risks that might occur during clean-up.”
Protecting the Columbia River
The Columbia River corridor in southeast Washington State contains nine retired plutonium production reactors and buildings. Used to conduct experiments and manufacture nuclear equipment, and as toxic waste sites and burial grounds during World War II and the Cold War, it is now known as the Hanford site and is the US Department of Energy’s largest environmental clean-up closure project.
Plutonium is a known radioactive substance that can harm humans and the environment, and requires careful and expert clean-up and disposal. Decommissioning and cleaning up the site is a complex and massive job.
Washington Closure Hanford (WCH), a limited liability company led by AECOM with partners Bechtel and CH2M, is providing decommissioning and closure, engineering, environmental services, and risk management and resilience to safely clean-up and close the corridor, located on the Hanford site.
Along with safely decommissioning buildings, and cleaning up waste sites and burial grounds, our teams are placing two deactivated plutonium production reactors and one nuclear facility into interim safe storage, and disposing of more than four million tonnes of contaminated material in the environmental restoration disposal facility, which WCH operates.
Since 2005, we have transported and disposed of 11.4 million tonnes of hazardous waste from the Columbia River site with 11 years of work scope completed in less than 10 years, as well as completing more than US$400 million (approximately £280 million) in additional clean-up work. We’ve also helped save more than an estimated US$230 million (approximately £160 million) through efficiencies and have reinvested back into the project. Our teams have achieved more than six million hours without a lost-time work injury — an outstanding safety performance under very hazardous conditions that is among the very best in the DOE complex.
Decommissioning the UK’s nuclear legacy
One of the most complex and challenging nuclear sites in the world, Sellafield in Cumbria in the north west of England is also the largest decommissioning project in the UK.
The site is home to the nation’s first full-scale nuclear reactors, the Windscale Piles, built for national defence purposes. It’s also home to the world’s first commercial-scale nuclear power station, Calder Hall, two nuclear fuel storage ponds and two nuclear waste silos, all built in the 1940s and 1950s.
From 2008-2015, the AECOM-led consortium, Nuclear Management Partners (NMP) was responsible for safely managing and decommissioning legacy and redundant facilities on the site on behalf of the Nuclear Decommissioning Authority (NDA). Our other work on the site over this period included reprocessing used fuel from nuclear power stations, manufacturing mixed oxide fuel, managing and storing nuclear materials, and the processing and storage of low, intermediate and high‑level nuclear wastes.
During our time leading the project, NMP helped Sellafield Ltd achieve some significant decommissioning and hazard reduction milestones, such as removing spent fuel from one of the site’s legacy storage ponds for the first time in 50 years. In total, more than 100 tonnes of radioactive material has now been removed from the pond, equivalent to the weight of a blue whale or a Boeing 757 aircraft.
NMP also introduced global best practices and proven processes to improve performance and improve safety standards. Over the past three years we have consecutively recorded the site’s best ever overall safety performance.
Other achievements under NMP’s leadership include the first returns of high-level waste to countries of origin, safely completing one of Europe’s largest asbestos removal projects and delivering over a billion dollars of operational efficiency savings.
It was announced in 2015 that the NDA would take direct management responsibility for Sellafield as a result of a change to the commercial model. With the program in healthy shape, AECOM and its partners are now working with the NDA to ensure an effective handover.