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THORP troubles

Nuclear Monitor Issue: 

(December 4, 1997) If BNFL's THORP reprocessing plant in Sellafield operates at a capacity of 900 metric ton/year as planned, it will discharge far more radioactive substances than allowed. That may be one of the reasons why THORP reprocessed only 680 ton in the first three years, 1994-1997, instead of the 1780 tons planned.

(482.4783) WISE Amsterdam -THORP's baseload contracts for the first decade amount to 7,000 tons (1 ton = 1,000kg) of spent fuel, which calls for an average throughput of 700 tons a year. To reach this average, THORP must reach an output of 900 tons a year in the next seven years (see also WISE NC 458.4539: THORP; lame duck and loser). Seventy percent of its contracts are with foreign customers, thirty percent with British utilities. The Consortium of Opposing Local Authorities (COLA) calculated that at the current discharge limit for tritium, a radioactive hydrogen isotope, BNFL can reprocess 440 ton annually at most. This would mean that it would take another 14 years before the baseload contracts are completed, which would be very embarrassing for BNFL and very costly. BNFL may be obliged to change its contracts. The most likely option is to store the spent fuel for a longer period, without extra costs. That's why BNFL applied to the Environment Agency (EA) in November 1996 for variable discharge limits, which proposed tritium gas discharges about six times higher than current levels. Probably due to increasing concerns over THORP's discharges and a possible legal challenge from environmental organisations, the EA appears to have persuaded BNFL to reduce its application for increased tritium discharges in July 1997.

Another point of concern is the increase of radioactive contamination levels in shellfish and seaweed by up to 40 times over the past three years. Especially alarming is the contamination levels in lobsters for technetium-99 (Tc-990) which has a half-life of 210,000 years. These levels are 14 times higher than European safety levels for the aftermath of a nuclear emergency. However no action has been taken because the levels are the result of authorised discharges from Sellafield.

The signing of the OSPAR convention by Britain this summer (see WISE NC 477.4734: UK and France promise end to sea discharges), which aims to reduce radioactive emissions to `close to zero', will force BNFL to reduce its discharges. This makes it very unlikely that THORP will achieve a throughput of 900 metric tons a year in its first decade. Foreign utilities will probably be content if their spent fuel could remain some decades at Sellafield and not be reprocessed. In this way they prevent difficult BNFL denies that operation of THORP will be affected by the new discharge limits the Environment Agency is considering for the Sellafield site. Increased discharges stem from a separate waste-treatment facility, not from THORP, it says.


  • COLA Special Briefing, September 1997
  • NFLA Bulletin, September 1997
  • Nuclear Fuel, 25 August 1997

Contact: COLA, South Sommerset District Council, Council Offices, Brympton Way, Yeovil, Somerset BA20 2HT, UK. Tel: +44-1935-462 576; Fax: +44-1935-462 188