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Scottish radioactive particles still a mystery

Nuclear Monitor Issue: 

(January 17, 2003) Nineteen years after the first radioactive "hotspot" particle was found outside the Dounreay nuclear complex on the north coast of Scotland, operators UK Atomic Energy Authority have launched a consultation process on how the problem should be tackled.

(581.5482) N-Base - Since 1984, 216 particles have been found on the foreshore below Dounreay; 700 have been recovered from the seabed off Dounreay; 22 have been found on the Sandside beach three kilometers west of the site; and nine from the seabed eight kilometers east of the site.

The source, or sources, of the problem are still not properly known; the movement of the contamination through the environment is not understood; the extend and location of the contamination is not fully known; and no-one knows for sure whether or not more particles are still being released into the environment.

The UKAEA says it believes particles are not still being released and admitted last year that at least several hundred thousand of the tiny particles, which are the chopped-up casings of spent fuel rods, were released over several decades and probably only stopped about five or six years ago.

No-one knows where the particles are now, but they are probably either on the seabed, dispersed over a very wide area, at least along the Caithness coast and towards Orkney, and who knows how much further afield. The particles may also have found their way onto beaches and foreshores and not uncovered by the limited monitoring required by regulators, or even been carried onshore by storms and gales. The best the UKAEA can offer are computer models that suggest the particles may have moved eastwards and into deeper water.

Also, no one really knows their source. Two possibilities are the official favorites: the dispersion chamber on an old discharge pipeline; and the plant's drainage system. The UKAEA admits discharging the particles through the old pipeline and believes more were released when high-pressure hoses were used until a few years ago to flush parts of the plant's drainage system, so dislodging contamination lodged in the drains. The UKAEA would be prosecuted today for these actions. They only got away with it in the past because of lax regulatory supervision. Another possible source is the controversial waste shaft, which is unlined, flooded and subject to tidal movement, showing there is a connection between the groundwater and the sea. The UKAEA, however, insists the shaft is not "leaking" particles into the environment.

The criticisms of the monitoring required by the Scottish Environment Protection Agency at Sandside have been well documented, not least in N-Base Briefings over recent years, and these argument continue today. Sandside estate owner Mr. Geoffrey Minter and his scientific consultants believe inadequate equipment and techniques are uncovering only one per cent of possible particles on the beach.

After the first seabed survey in 1997 when 35 particles were found, a 2km fishing exclusion zone was introduced. Although particles have now been found outside this zone, the authorities have refused to extend its limits.

While the UKAEA has boasted of the 1 million pound (US$1.57 million) annual diving surveys it has commissioned in recent summers, the work has in fact covered a tiny area of the seabed - but still found over 700 particles. This summer the divers surveyed five areas outside the exclusion zone between Strathy Point and Brims Ness, 8km east of the plant, and each only the size of a football pitch. Nine particles were found off Crosskirk and east of Brims Ness. The five areas represent a tiny fraction of the seabed in the Pentland Firth - let alone further afield. The present diving contract is limited and divers are prevented from going deeper than 25 meters for technical and safety reasons.

The UKAEA's options for action
The UKAEA has started a public exhibition in Caithness and published a newsletter with details of the options it sees for future action. After public discussion of these, a "stakeholder panel" will consider the options and responses and recommend what action should be taken. These proposals will then be subject to a formal public consultation. The present exercise is the first example of the UKAEA's new "openness".

The options range from continuing as at present, with some monitoring and removing any particles which are found, at an annual cost of about 250,000 pounds, through to spending possibly tens of millions of pounds dredging and cleaning the seabed over a wide area.

Source: N-Base Briefing 355, 11 January 2003

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