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Sellafield's new discharge limits approved

Nuclear Monitor Issue: 
#522
10/12/1999
Article

(December 10, 1999) The UK government has approved new nuclear waste discharge limits for the Sellafield nuclear complex, including the two reprocessing plants. Some new limits are only slightly lower than the old ones, some are even higher. The Irish government was particularly disappointed that limits for technetium were not reduced as it had recommended to the UK government. The new limits are a slap in the face to Ireland, Norway, Sweden and Denmark, at which shorelines the waste washes up.

(522.5119) WISE Amsterdam - The UK had promised at a 1998 OSPAR conference to decrease its radioactive discharges significantly but is not doing so. The Oslo-Paris Agreement (OSPAR) with 15 member countries was signed in 1992, with the aim to reduce pollution of the Atlantic. In 1993 the UK government approved 900% and 1100% increases in Thorps liquid and atmospheric discharges, which led to protests and heavy pressure from the Nordic countries and Ireland on Great Britain to reduce its radioactive discharges. The Thorp reprocessing plant went into operation in 1994. In July 1998 OSPAR decided that nuclear discharges from La Hague and Sellafield should be reduced to "near-zero" by 2020. (see WISE News Communique 495.4888: 'OSPAR Convention: European reprocessing industry given deadline of year 2020') Owner and operator of Thorp, British Nuclear Fuel Limited, applied in November 1996 to the Environment Agency to "vary" some of its discharge licenses, it is to increase them. BNFL also applied to increase the discharge limit into the atmosphere for ruthenium with 70%.

In November 1998, the Environment Agency sent its proposed decisions to the government, which said they were in line with their obligations under OSPAR to reduce discharges to background levels by 2020. While over 40 radionuclides are released, the new limits only cover five radionuclides: tritium (H-3), carbon-14 (C-14), technetium-99 (Tc-99), ruthenium-106 (Ru-106) and jodium-129 (I-129). The new limits however are far from zero. Some new discharge limits are higher, to make it possible to treat old spent fuel from the Magnox reactors at the Solvent Treatment Plant (SRP) in Sellafield, some other limits are lower.

The new limits include provisions for increased discharges from the new BNFL MOX fabrication plant at the Sellafield complex, which did not yet get an operating license. Another plant that discharges radionuclides is the Enhanced Actinide Removal Plant (EARP), which discharges huge amounts of technetium. The new discharge limit for technetium-99 (90,000 billion becquerel/year = 90Tera Bequerel), is still nine times higher than it was in 1994. Tc-99 is accumulating enormously in the Irish Sea and along the Scandinavian coastlines, with very high levels found in lobsters, shellfish and seaweed. In 1992 Tc-99 levels in seaweed and lobsters in the Irish Sea were 800 and 400 Becquerel per kg (Bq/kg) respectively. In 1997 up to 180,000 Bq/kg in seaweed and 52,000 Bq/kg in lobsters were found.

The European Commission intervention level for foodstuffs after a nuclear accident is 1,250 Bq/kg. Both seaweed and lobsters are consumed; in England seaweed is traditionally used to make bread.

Especially the new tritium limits are still terribly high and are hardly lower than the old ones. Tritium is an isotope of hydrogen and can become part of water. As water molecules, which contain tritium, are built into organic tissues, those tissues will be damaged by irradiation, when tritium decays into deuterium, a non-radioactive hydrogen isotope.

The Environment Agency is to do a new full-scale review of all radioactive discharges from Sellafield as soon as possible, with the view of realizing the OSPAR deadlines. Its strategy is to reduce the future technetium discharge limits for Sellafield to 10,000 billion Bq per year.

The Sellafield site houses two reprocessing plants. The first is the very old B205 plant, dating from 1964, which reprocesses only metal spent fuel from the UK Magnox reactors. BNFL and the British government assure that spent Magnox fuel has to be reprocessed as quickly as possible, because the fuel is stored in water pools and will corrode in time. But if Magnox spent fuel should be dry-stored, as is the case at the Wylfa nuclear reactor, there would be no corrosion and reprocessing would not be necessary. The existing backlog of spent Magnox fuel is used as a excuse for higher discharge limits, for example for iodine-129, which radionuclide has a half-life of 17 million year!

The second reprocessing plant is the relatively new Thorp plant, which went into operation in 1994 and which reprocesses spent oxide fuel from British AGR reactors and mainly foreign LWRs.

Sources:

  • M2 Communications, 19 November
  • N-Base Briefing, 21 November
  • The Irish Times, 22 November 1999

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