Sellafield Ltd is expected to ask the Environment Agency (EA) for an almost 5-fold increase in gas discharge limit for Antimony 125 (Sb-125) so that the Magnox reprocessing plant can continue to operate. Sb-125 has a radioactive half-life of 2.75 years and emits beta radiation.
Disclosed in its Quarterly Report to the local West Cumbria Sites Stakeholder Group meeting scheduled for 1st October, the EA confirms that Sellafield wants the limit to be raised from its current level of 6.9 to Gigabequerels (GBq) to 30GBq. The bulk of Sellafield’s Sb-125 gas discharges arise during the de-canning (removal of the fuel’s outer casing) of spent Magnox fuel, particularly the higher burn-up fuel, in the site’s Fuel Handling Plant prior to its transfer to the reprocessing plant.
In early 2008 the Sb-125 discharge limit stood at just 2.3GBq but later had to be raised to its current level of 6.9GBq when the discharge chimney sampling equipment was found to be under-reporting. In October 2008 Sellafield Ltd indicated to the EA that, as part of its Periodic Review submission, it would be seeking to increase the limit from 6.9GBq to 11.6 GBq. In a spectacular misjudgement of its discharge requirements, Sellafield now needs to raise the limit to 30GBq to allow the de-canning and subsequent reprocessing of the larger volumes of higher burn-up fuel being received in the Fuel Handling Plant from UK’s Magnox power stations.
Since 2007, processing higher burn-up fuel in the Fuel Handling Plant has lead to Sellafield breaching its discharge Quarterly Notification Level on a number of occasions, and in late 2008 exceeding the site’s internal trigger level. Subsequently, in April this year, as releases of Sb-125 from the Fuel Handling Plant threatened to breach the Sellafield site limit itself, Magnox reprocessing had to be abandoned for several weeks. Currently, the EA expects the current discharge limit to be breached again but is permitting Magnox reprocessing to continue – as the lesser of two evils.
CORE’s spokesman Martin Forwood said today: “This mega miscalculation on how much Antimony they expect to discharge speaks volumes about Sellafield’s disturbing lack of technical competence and, with the request for such a large increase in limit, its complete disdain for the environment. We deplore any increase in environmental discharge, but have some sympathy with the Environment Agency who is faced, as always with nuclear issues, with ‘no good options’.
In its Briefing on Sb-125 published earlier this year, the EA considered that the overall impact associated with the liquid discharges of Antimony that would result from prolonged underwater storage of Magnox fuel would outweigh any benefit from stopping the current gas discharges. There is also concern that, with the industry’s historic failure to come up with any viable ‘Plan B’ for dealing with un-reprocessed Magnox fuel, further delays to processing the fuel will result in a stockpile of un-reprocessed fuel in 2016/17 when the worn out reprocessing plant will have to close. CORE’s spokesman added: “ Sellafield has got the Agency over a barrel. We are all now paying the price for the industry’s abject failure to develop an alternative to reprocessing Magnox fuel – such as dry storage – despite years of lobbying by NGO’s and other stakeholders to adopt such an option”.
The proposed increase in site discharge limit to 30GBq is unlikely to be authorised until April next year when approval from the European Commission, under Euratom Article 37, is expected be given. Whilst the current limit of 6.9GBq is likely to be breached between now and then, it is understood that discharges of other fission products released during the de-canning of Magnox fuel in the Fuel Handling Plant, whilst also on the increase, will remain within their respective site discharge limits