Last November, MAFF's monitoring uncovered a dramatic increase in radioactive contamination of shellfish caught off Cumbria (ENDS Report 262, pp 15-16 ). Levels of the radionuclide technetium-99 in lobsters have shot up since BNFL commissioned a new waste processing plant in 1994 - and far exceed an EC safety threshold which applies only after a nuclear accident.
A month later, BNFL applied to vary the authorisation for discharges from Sellafield, offering to reduce the annual limit for technetium-99 by 25%. MAFF called on the Agency to set a tougher limit and to order the fitting of abatement equipment. However, the Nuclear Installations Inspectorate argued that such requirements may slow BNFL's treatment programme and prolong on-site storage of liquid radioactive waste (ENDS Report 264, pp 5-6 ).
ENDS has now obtained correspondence showing that the Ministry has fought an uphill battle to make the Agency hold to a tough line. The outcome will become clear in June, when new draft authorisations for discharges to air and sea are sent out for consultation.
In March, MAFF told the Agency that "we strongly support the use of abatement plant and some timescale for an end-point to BNFL's deliberations might focus their endeavours." A month later, it repeated its "main concern" - "the lack of a requirement to install abatement for technetium-99 to a specified timescale in the improvement schedule. A requirement to produce a six-monthly statement...does not in our view place enough pressure on BNFL to fit abatement technology."
BNFL argues that technology to remove technetium-99 has not been proven at a large scale. It claims that an abatement plant would cost £100 million and could not begin operation before 2005.
MAFF accepts that the technology requires further development, but says that "this need not prevent" a firm duty being placed on the company. Should the technology not prove viable, it says, BNFL could apply to vary the authorisation - an approach which offers "the advantage of forcing BNFL to choose between fitting abatement or justifying not doing so in a rigorous public forum, rather than just by writing a report."
The argument carries strong echoes of an earlier dispute over emissions of the radioactive gas krypton-85 from BNFL's controversial THORP reprocessing facility (ENDS Report 214, pp 19-22 ). When planning permission for THORP was granted in 1978, BNFL was required to "pursue vigorously" research into krypton abatement. However, the company soon dropped active research into the issue, and merely "maintained a watching brief" on other studies. THORP was authorised in 1993 - without krypton abatement.
On 12 May, MAFF made another attempt to sway the Agency. It again called for abatement plant to be required - and warned that "Ministers may consider that such a robust requirement is necessary in the current climate."
However, environmentalists have already voiced fears that MAFF may back off under new Agriculture Minister Jack Cunningham. Friends of the Earth (FoE) has written to the Prime Minister calling for Dr Cunningham's resignation. The group says he is "fatally compromised" by "his long-standing support for, and association with, the nuclear industry."
The Sellafield works is the main employer in Dr Cunningham's Copeland constituency. As an MP, he often spoke in support of BNFL's activities and received financial support from the company for travel and accommodation overseas. He now shares responsibility with Environment Secretary John Prescott for the Sellafield authorisations.
The pressure to hold to a tough line on the technetium-99 issue will be increased by MAFF's assessment of the doses to the "critical groups" of highly exposed Cumbrian residents. This suggests that the substance is of greater radiological significance than at first thought.
Marine discharges at current limits would expose the critical group of Cumbrian seafood consumers to an annual dose of 155µSv. Technetium-99 accounts for 37% of the dose - rising to 47% in Morecambe Bay. BNFL's proposal to reduce the annual technetium limit from 200TBq to 150TBq would cut the total dose by less than 10%. MAFF calculates that a discharge of 90TBq - the limit likely to be proposed by the Agency - would reduce the total dose by 20%.
The Ministry's radiological assessments show that infants in the most exposed population near Sellafield would receive an annual dietary dose of 355µSv from discharges at BNFL's proposed limits, a 15% increase on the dose at current limits. These doses exclude the effect of direct irradiation from the site, which MAFF says may be 44µSv/year.
Adults and older children would also be exposed to considerably more than 300µSv/year, the official constraint on doses from a single source. However, the regulators maintain that Sellafield is covered by an alternative site dose constraint of 500µSv because the site's reprocessing activities and Calder Hall reactors are classed as separate sources.
Even so, MAFF's dose estimates are significantly higher than those put forward by BNFL. The Ministry has been forced repeatedly to defend its methods to the Agency - which appears more willing to set store by the company's figures.
In March, MAFF told the Agency that its own "cautiously realistic" assessments covered the upper bound of likely doses to the most affected population - but "in no way are these extreme scenarios, as they are described in the draft text [of the authorisation's explanatory memorandum]."
On 8 May, MAFF again defended its approach - telling the Agency that it was "prudent...to ensure that limits and relevant constraints will not be exceeded. This approach is consistent with the precautionary principle enshrined in Government policy. As a regulatory body you may also wish to reflect this."
MAFF has been angered by the Agency's plan to publish a statement by the National Radiological Protection Board alleging that MAFF's assessment relied on a "maximising approach". It argues that both BNFL and the NRPB are wrong to apply "modifying factors" for dose uptake based on environmental monitoring near Sellafield. MAFF insisted that if the NRPB's comments are included in the memorandum, it should be given space to respond.