Scottish CND
Safety of Trident Scottish CND
Safety of Trident
The used fuel cores from submarine reactors are high level nuclear waste and are transported across Britain. The Trident programme produces large quantities of low and intermediate level nuclear waste and there are problems with disposal and storage.
Used Fuel Cores
After the fuel cores have been used in submarine reactors they cannot be reprocessed. Although there is one facility in the US which can do this work there is none in the UK and it is unlikely that the US would take used fuel from British submarines. All used fuel cores which have been in service in naval reactors to date are stored at Sellafield. Although they are classified as used fuel for reprocessing they should be considered as high level waste.
Used Fuel Core Transport
Used fuel cores have been assessed in the US as the most hazardous form of material which is transported. There have been delays in defuelling US submarines because transport and storage arrangements may be inadequate.
On the planned Trident programme there will be 12 used cores which will have to be transported from Devonport to Sellafield and 3 used cores from Dounreay to Sellafield. It is anticipated that these will be carried by rail with 2 containers used to transport each core . Parts of cores, modules, from submarine reactors have in the past been taken to Dounreay for post operation inspection. From Dounreay the modules should be returned to Sellafield. These modules have been moved using the same containers as for half cores. This may continue with the PWR 2 reactors.
There are serious grounds for concern about the safety of this part of the programme. From the late 1960s until 1991 used fuel from submarines was carried in Used Core Transport Packages (UCTPs). In October 1991 the Department of Transport refused to renew the special arrangement with the MoD which covered UCTPs. This was in compliance with IAEA guidelines published in 1985. Replacement containers were expected to take several years to be designed, produced and approved. A large team is currently working within the Department of Transport to resolve the issue. Temporary use is being made of existing civil containers and a new replacement for the MoD is being designed.
There could be a major disaster, not unlike that described in Section 4.3, if there was a used core transport accident. This could occur anywhere on the rail routes from Devonport to Sellafield and from Dounreay to Sellafield. Privatisation of British Rail could reduce maintenance and could lead to closure of part of the rail link to Dounreay. Rail routes go through major towns and cities. UCTPs were derailed on several occasions and the problem of vandalism suggests that this is likely to occur again.
Processing residues
During the reprocessing of used fuel at Sellafield high level waste is produced. Some of this reprocessing has been to process plutonium for weapons purposes. High level waste will also be produced during the removal of decay products from weapons grade plutonium which is being recycled from old nuclear weapons - the MoD state that over 90% of this material is recovered but does not say what happens to the remainder.
The high level waste from reprocessing is in a liquid form. If a major accident occurred in the storage tanks at Sellafield then large amounts of long lived radionuclides could be dispersed over a wide area. If 10% of the caesium 137 was dispersed with the wind blowing towards Glasgow then there could be 14,000 deaths and 25,000 cases of cancer over a 30 year period, even assuming evacuation and relocation took place. There would be restrictions on agricultural produce from Dumfries to the Highlands for 20 - 30 years and severe economic disruption.
Dismantled nuclear weapons
After nuclear weapons are scrapped there will be substantial volumes of plutonium and HEU which result. Possibly 0.4 tonne of plutonium and twice as much HEU. This could be considered as high level waste resulting from the Trident programme.
Intermediate waste and low level waste associated with Trident has been produced at: Aldermaston, Devonport, Faslane, Chapelcross, Sellafield and will be produced when submarines are decommissioned.
Total waste associated with Trident
NIREX has said that nuclear waste from defence sources could be equivalent to one sixth of all the waste in Britain. The volume of low level waste which is expected to come from defence sources from 1988 to 2030 would be around 3 x 105 m3 . The volume of intermediate level waste from defence sources in the same period would be around 4 x 104 m3. These figures would include waste from hunter killer and Polaris submarines, but not waste produced at Springfields, Capenhurst, Chapelcross, Calder Hall and Sellafield when BNF is carrying out work for the MoD. If these factors balance each other out, then around one sixth of all the nuclear waste produced in Britain can be related to the Trident programme.
Low level waste is likely to consist of clothing, wrapping materials and worn out or damaged plant, tools and equipment. Waste of this type, related to Trident, has been or will be produced at Dounreay, Faslane, Coulport, Chapelcross, Sellafield, Calder Hall, Cardiff, Aldermaston, Burghfield, Devonport, Capenhurst and Springfields. Low level waste from MoD and other establishments is transported to the BNF site at Drigg near Sellafield. In the case of Devonport, low level waste is transported to Drigg up to 8 times a year. Most low level waste is transported by road. Some low level waste from Dounreay may be transported by sea from Thurso to Barrow and then by road to Drigg. Rail transport is used to take waste from Sellafield to Drigg.
Intermediate level waste has an activity higher than low level waste. It is likely to consist of reactor fuel cladding, reactor components, chemical process residues, ion exchange resins and filters. At the moment intermediate level waste is stored on site. Intermediate waste generated from the PWR 2 prototype reactor at HMS Vulcan will be stored at Dounreay. Intermediate waste from the refuelling and refitting of Trident submarines at Devonport will be stored in a new facility. Some intermediate waste from submarines is stored at Faslane.
The Advisory Committee on the Safety of Nuclear Installations, part of the Health and Safety Commission, have expressed concern that delays in the NIREX proposal for a deep depository for waste could compromise safety. There could be risks to workers at nuclear installations and the risk of accidental releases could be increased. There are two grounds for the Committees concern. One is that waste is being stored on site for a longer period than previously envisaged and "some of the waste storage facilities are unsuitable for long term storage, they are deteriorating ....". The other is that delays in agreeing on what type of packaging is required has created problems.
The Pochin inquiry in 1978 found that there were fundamental problems with the design of plants for handling nuclear waste. Contamination was building up within these facilities and the health of workers was being put at risk. There was also poor management with containers of waste lying abandoned at various parts of the site. The Pochin inquiry recommended that new plants be built for liquid waste and solid waste as well as a waste compaction facility. The solid waste and compaction plants have not been built. The liquid waste facility, A91, has been built, however there are serious corrosion problems in the pipework. This has been attributed to the use of tap water rather than demineralised water during tests. No date has been set for the commissioning of A91. There would need to be major replacement work before it could be brought into service. The old facilities which were severely criticised in the Pochin report in 1978 are still in use 15 years later and are likely to continue to be used for years to come.
Delays in the NIREX deep storage plans have been used to justify the lack of progress at Aldermaston. It is argued that the new solid waste compaction and storage facilities have been delayed because NIREX has not yet defined the type of packaging required.
In the early stages of a submarine refit work is carried out to reduce the levels of radiation in the reactor pipework. This MODIX process creates 10 containers of of resin per year at Devonport. Some resin is low level waste and some is intermediate level waste. The resin also has chemical contamination, due to the MODIX process. Most of the resin is stored in Resin Catch Tanks (RCTs) which were designed to be used to dump waste at sea. In July 1992, Devonport was storing 12 full RCTs in the storage building plus 7 full Magnox flasks outside the building, each holding the equivalent of 2 RCTs.
Because of the volume of intermediate level waste produced by MODIX, the MoD expect that the current storage facilities will be full by 1995. Devonport has been named in association with concerns about the how nuclear safety may be compromised by delays in the NIREX deep repository proposal. There are plans to enlarge the current intermediate level waste storage facility. Storage vessels will be built from stainless steel and stored in 3 new pits. The design of this facility has been criticised because it may not provide adequate shielding and because it is being built below ground level. There is also concern about the establishment of a long term nuclear waste store in the middle of a large town.
There will be space for 210 vessels in the proposed storage area. The MoD anticipate that 180 full vessels would be stored by 2010. Assuming a fleet of 4 Trident submarines and 12 hunter killer submarines, Trident would be responsible for one third of the total. This would be equivalent to 60 vessels of intermediate waste stored at Devonport in 2010. The actual number may be more due to the increased power and size of the PWR 2 reactor. Some liquid waste is deliberately discharged into the River Tamar after treatment. There have also been a number of occasions in the past when coolant has been spilt accidentally at Devonport.
There will be discharges into the sea of low level liquid waste from Trident submarines at Faslane. Water in the primary circuit is removed from the submarine into tanks and transferred to an Effluent Disposal Plant. The coolant is then conditioned to reduce the level of activity. At the end of this process the coolant is discharged into the sea. Intermediate level waste, including ion exchange resins, will be stored at the Northern end of the base.
At Chapelcross methods used for the discharge of liquid effluent in past years have been unsatisfactory. In 1992 particles of uranium were discovered near the end of the outflow pipe into the Solway Firth. This was explained as the result of earlier practice which allowed liquid effluent to be discharged before adequate time had been allowed for particles to settle so they could be removed.
Discharges from Sellafield are the largest source of radioactive isotopes released into the environment in the UK. The material discharged is dispersed by tidal currents to the North around the coast of Britain and to the South in the Irish Sea. Routine analysis of patients from North Uist in the Outer Hebrides showed that they had caesium 134 in their blood. This analysis was carried out in Glasgow and the radioactive isotope was not found in the blood of patients resident in Glasgow. It was established that caesium 134 was being discharged from Sellafield and carried on tidal currents to the Outer Hebrides. The isotope may have found its way into the human food chain through the consumption of local sheep which graze on the foreshore. Traces of plutonium and americium have also been found at a number of sites on the shore of North Uist. These too are believed to have come from Sellafield. It had previously been argued that while lighter elements, such as caesium, would travel long distances, this would not apply to heavy metals.
In addition to the widespread distribution of radioactive discharges there is a high concentration in areas near the site, in particular on coast in West Cumbria and the Solway Firth. A survey conducted by the Scottish Universities Reactor and Research Centre is reported as having found that there are radioactive hot spots in the Cree, Nith, Dee, Urr and Fleet estuaries in the Solway Firth. Fishermen, nature wardens, bird watchers and children playing in the banks of the rivers could be particularly at risk. Around a dozen coastal Sites of Special Scientific Interest may be polluted with caesium 137 beyond the accepted NRPB limits. The Royal Society for the Protection of Birds (RSPB) is concerned about the effect on birdlife in the estuary which has 120,000 visiting birds in Winter including the world population of Scalbard barnacle geese and half of the British population of Scaup duck. Chris Rollie of the RSPB has said "the Solway Firth ... is undoubtedly the most radioactively polluted in Scotland".
Discharges from Sellafield have included substantial quantities of plutonium. A BNF report written in 1992 showed that levels of Pu 239 in the 1950s and early 1960s were more than 200 times the figures which had previously been revealed.
When Trident submarines are withdrawn from service there will be a considerable problem with what to do with them. The initial part of decommissioning is similar to defuelling during refit. However this leaves the long term problem of what to do with the reactor itself and the surrounding hull. It is possible to reduce substantially the levels of radiation in components of the reactor. This can partly be done by time and partly by chemical processes. The chemical processes produce nuclear waste. At the end of this there will be a large volume of low level waste and a smaller volume of intermediate waste. Large parts of the submarine hull will remain radioactive. A number of solutions have been proposed. The MoD would like to fill the submarines with concrete and sink them in the Atlantic but future monitoring would be difficult, recovery virtually impossible and there would be international objections. Shallow burial on land is another option, a number of American submarines have been dumped this way. Cutting the submarine up into small sections could be carried out and the sections then packaged and dumped in the NIREX deep depository. Cutting work would expose workers to higher levels of radiation than the other options. There is no easy answer to the question of what to do with a decommissioned submarine. When the Royal Navy first introduced nuclear powered submarines they did not even consider this issue. Almost 30 years later, they have still not been able to find a solution.
Scottish CND Safety of Trident