The future of nuclear power in Wales Contents

5Decommissioning and waste

Decommissioning at Trawsfynydd

101.Trawsfynydd power station is in the process of decommissioning, after 26 years of operation. All Magnox nuclear power plants go through a similar decommissioning process, comprised of four steps:

102.Trawsfynydd has completed the defuelling stage and is currently undergoing preparations for the care and maintenance phase of decommissioning. The NDA has designated Trawsfynydd as one of two ‘Lead and Learn’ sites for accelerated entry into care and maintenance. The focus is on maintaining key assets, such as the reactor safe store and the intermediate level waste (ILW) store, and removing hazards, which will be treated, solidified, and placed in the ILW store.

103.Martin Moore, Trawsfynydd closure director, Magnox, told us that high hazard reduction would continue until 2022.122 Most of the intermediate level waste has been prepared for long-term storage and loading of the intermediate level waste store will be complete by 2022. The Trawsfynydd site contains wet ponds, which means there are a lot of waste streams and waste materials to be dealt with. For example, areas of concrete that the water has touched also need to be removed and stored as waste and ILW material must be removed from the ponds. Once store-loading is complete, from 2022–2028, work on site will focus on bringing down the height of the reactor buildings and weather-proofing them. When this is completed, the reactor buildings will be secured until 2074, when final site clearance will begin.123

104.There are currently around 150 permanent employees and 100 contractors on site at Trawsfynydd. It is intended that this will fall to around 100 employees in the 2020s and for it to be reduced further when the site enters care and maintenance in 2027–28.124 During our visit we were impressed by the resourcefulness of the management and employees on site, who are working together to retain as many jobs as possible. For instance, the innovative work of engineers on the site has enabled more decommissioning work to take place, which has in turn created jobs. One example of this includes building a bespoke engineering plant on site, which was necessary because the plant was not constructed with decommissioning in mind.

105.However, continued progress of decommissioning is dependent on stable funding from the NDA. In 2015/16, Magnox received £35m for the site and will receive £45m for 2016/17. However, funding is set on an annual basis and could easily fall, although David Batters, Chief Financial Officer, NDA, told us that funding should be stable, subject to any future spending reviews.125

106.Progress on decommissioning at Trawsfynydd has been good and demonstrates how decommissioning can take place quickly, efficiently, and safely. We were impressed by the determination of the management and staff at Trawsfynydd to find creative solutions to challenges on site. Their work has helped to improve decommissioning plans and save jobs.

Alternative decommissioning plan for Trawsfynydd

107.During the inquiry, we heard that the plan for Trawsfynydd might change to allow for more continuous decommissioning. This would see active decommissioning take place over a longer period, rather than the site entering ‘quiescence’ for around 30 years, with employment falling to a ‘minimal level’.126 Kenny Douglas explained how the plans could change:

“At Trawsfynydd, there was originally going to be an interim care and maintenance phase, which, with the revised plan, will disappear. The work…about fuel level debris…will run into the height reduction phase. That work then runs out to 2028–29.”127

108.Professor Gordon MacKerron, University of Sussex, described the prospect of an alternative plan for decommissioning:

“the NDA…are going to do a radical reconsideration of this notion of quiescence and see whether it may be possible to move towards a system whereby decommissioning is continuous. I think Trawsfynydd is one of those sites where this is most likely…the argument…is quite a strong one for not losing the knowledge, not losing the skills, possibly having further export opportunities, if the process of decommissioning is continuous rather than interrupted by a period of 30 years or more of, effectively, inactivity”128

109.The NDA’s annual strategy, published in April 2016, confirmed they would review their approach to decommissioning plans.129 Kenny Douglas, Managing Director, Magnox, confirmed they had been asked to carry out a study of the alternative plans, and that an initial concept project is underway.130

110.The NDA said that a number of factors made more continuous decommissioning possible. For example, the growing availability of remote decommissioning tools, more experience in remote handling and storage of waste, and new advice from the International Atomic Energy Agency all made the alternative plan an option. In addition, the NDA review found that the cost of the alternative decommissioning plan might be lower, and quicker decommissioning would make sites available for alternative use sooner. In the case of Trawsfynydd, this could include developing a small modular reactor at the site (see Chapter 6). David Batters, Chief Financial Officer, NDA, told us:

“A lot of the costs of decommissioning are ultimately related to the end use of the site. Once we know what the end use of the site is—whether it will be returned to a national park or used for future industry—that will impact on our costing and plans.”131

111.Under current plans, Trawsfynydd will lose most of its jobs within the next ten years. We heard there is a realistic plan for continuous decommissioning that could keep more jobs on site, which would be a major benefit to the local area. We recommend that, so long as that plan ensures that the high standards of safety continue, the NDA should implement it so that more people are employed for longer. We further recommend that, should additional funding be necessary, the UK Government should endeavour to make this available.

Future decommissioning at Wylfa A

112.Wylfa A closed at the end of 2015 and will begin decommissioning in three years’ time, once defuelling has completed. Defuelling involves removing the 88,000 fuel elements and shipping them in casks to Sellafield for reprocessing. Staff levels will fall from 377 full time employees to 150 at the end of the three year period. Magnox told us they are helping to provide staff with training opportunities and seeking their transfer to Horizon Nuclear Power.132

113.Wylfa A will have a much shorter period of initial decommissioning and will be easier to decommission because of its design. Stuart Law, Wylfa closure director, Magnox, explained why:

“we were fortunate at Wylfa. We do not have any ponds. We [have] primary dry store cells, which are…metal tubes that you stack fuel in. They do not have the same levels of contamination and the resins that you would use to keep pond water clean, so we do not have to deal with those. Also, we never had fuel element debris at Wylfa”133

114.Placing spent fuel from Wylfa in dry store cells cooled with carbon dioxide will reduce radioactive contamination and the amount of radioactive waste. Some non-nuclear hazards will also be removed from the site at the same time, but most decommissioning work will take place after defuelling is completed and will then last until 2026.

115.We welcome the fact that the process for decommissioning Wylfa A will be simpler and quicker than at Trawsfynydd. This should allow the site to be ready for the construction of Wylfa Newydd, and enable a smooth transition to take place.

Management of nuclear waste in Wales

116.Nuclear waste is divided into three categories: high, intermediate, and low-level. High-level waste accounts for a small volume of waste, but for most of the radioactivity. High-level waste and spent fuel is taken to be stored at Sellafield in specially designed flasks, which, for example, are able to withstand a fully engulfing fire of 800⁰C for 30 minutes, or being hit by a train at 100mph. Low-level waste makes up 90% of UK waste, but only 0.1% of the radioactivity. It is sent straight for storage in the Low-Level Waste Repository (LLWR) in Cumbria.

117.Intermediate-level waste (ILW) at Trawsfynydd is currently being stored on site. Further decommissioning at the Trawsfynydd site will fill the ILW store. David Batters Chief Financial Officer, NDA, said that the interim storage facilities will be secure for 150 years.134

118.The storage of nuclear waste at Trawsfynydd and Wylfa is a temporary solution. Ultimately, the high and intermediate-level waste is due to be moved to a geological disposal facility (GDF), though the Government has not yet identified a possible site. The site will store waste up to 1,000m underground with multiple barriers to contain the waste and prevent contamination. The surface facilities will be a secure industrial complex. The underground facilities would cover up to 20 square kilometres.135

119.The Committee on Radioactive Waste Management (a subsidiary of the NDA) has been carrying out preparatory work including geological screening (to identify a suitable site), public engagement, developing designs for the GDF, demonstrating safety, exploring international experience (particularly Sweden, Finland, Belgium, and Switzerland) and alternative disposal options.

120.Despite the Government’s position, that the GDF is the permanent solution and long-term goal for storing Britain’s nuclear waste,136 progress so far has been slow. Witnesses from Greenpeace and Friends of the Earth Cymru said that without a GDF, the storage of nuclear waste was too dangerous for nuclear power to be used. Both groups also doubted whether the GDF would be completed. Lee McDonough, Director, Office for Nuclear Development, DECC told us:

“our planning assumptions…we are basically looking at 2040 as the date for the first time that waste could go in. But that is an indicative date and it is not a target or a milestone. …[that] is not really [a long way off] in terms of the degree of engineering that needs to happen. As the Minister says, we want to go as soon as possible to get to a point where we can start to do the engineering work.” 137

121.The evidence we received is that nuclear waste is currently well-managed. The professionalism of staff on site, the technology deployed, and the flasks and storage facilities all support the view that nuclear waste is disposed of, transported and stored safely in Wales and the UK. Nonetheless, not enough has been done to enable the permanent disposal of the UK’s nuclear waste. While the temporary arrangements are both of a high standard and capable of storing the waste for a long time, progress on the geological disposal facility (GDF) and finding a final site is necessary. Without a site for the GDF, it is not clear that the UK Government has a permanent solution for waste. This is a concern, as we found that members of the public want reassurance that nuclear waste is dealt with appropriately.

122.We recommend the UK Government accelerate progress on identifying the site for the GDF, and make the necessary decisions. Speeding up the process would not only help the UK to begin dealing with waste more quickly, it would also make the future for nuclear power clearer.


122 Q193

123 Q196

124 Q201–202

125 Q197–198

126 Nuclear Decommissioning Authority (FNP 52)

127 Q222

128 Q106

129 Nuclear Decommissioning Authority, Strategy, April 2016

130 Q222

131 Q211

132 Q203 and Q219

133 Q217

134 Q237

135 Department for Energy and Climate Change, “Geological Disposal Facility (GDF) for higher-activity radioactive waste”, accessed 22 June 2016

136 Department of Energy and Climate Change (FNP 26)

137 Q305




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21 July 2016