Project updates
This section provides snapshots of the progress on the particles project. In addition quarterly reports are produced which are distributed to the Dounreay Stakeholder Group and made available here.
Progress reports
Project updates
15th April 2008
Investigations at the old diffuser continues
Divers took to the sea on April 15 to investigate the old subsea diffuser system that was used to discharge radioactive effluent from Dounreay until 1998.
The work will produce information about the rock above the old diffuser chamber and contamination levels to permit assessment on how to decommission the structure.
Investigations began last summer when divers from Fathoms UK Ltd sent a video camera 22 metres down one of the risers before it was stopped by a lead plug installed after the diffuser was taken out of service.
The work is expected to take place over a four-day period when divers will take more images inside the diffuser risers and check radiation levels. The divers will obtain marine samples, seek access via one of the other risers, inspect the new diffuser located nearby and collect rock samples.
Phil Cartwright, contaminated land and particles manager said: "The information will help us understand the conditions from the seabed to the diffuser chamber. Before a final decision is taken on how to remediate the old diffuser we need to understand the potential effect remediation of the discharge system may have on the marine environment. We cannot rule out the possibility that there are particles in the old diffuser system and the options for remediation will take this into account. This project is integral to the clean-up of particles on the seabed which we intend to start this summer. We are currently proposing to target particle clean-up on the seabed over a three year period and then tackle the remediation of the old diffuser, followed by a further three years of re-monitoring and recovery."
20th March 2008
Trials for second particles clean-up system
A second company will trial a particle detection and retrieval system fitted to a remotely operated vehicle for the clean-up of particles from the seabed. The trial will be carried out by Land and Marine Project Engineering Ltd and will be conducted on the seabed close to Dounreay within about 1km of the coast. It is expected to take about three days within a 15-day weather window, commencing March 15.
Meanwhile, what appears to be a plastic item, contamination with low levels of radioactive caesium, was recovered from the beach at Dunnet on March 18 and is now being analysed.
11th January 2008
Trials demonstrate seabed clean-up device
Offshore trails during December demonstrated that removal of particles from the seabed can be carried out by a remotely operated vehicle. Two companies were chosen to deploy and demonstrate their respective remote particle retrieval system offshore of Dounreay and the second company will test its system in February.
12th December 2007
COMARE report on particle detection system
The Committee on Medical Aspects of Radiation in the Environment has published its report of field trials carried out at Dunnet beach in June this year to test the performance of particle detection systems. The report confirms that the system in use meets the current requirements of the regulator and scans deeper in the sand than its predecessor. See: http://www.comare.org.uk/comare_docs.htm#otherdocs.
4th December 2007
Particle clean-up companies to trial their systems
Two contracts have been awarded to test retrieval systems for remotely operated vehicles for the proposed clean-up of particles from the seabed. Caithness firm Fathoms and a consortium of Land & Marine and Nukem have been awarded contracts to test their systems. Trials are expected to take place over the winter months.
20th November 2007
Particles offshore mapping survey
A new report on offshore surveys carried out this year lends support for the emerging picture of particles on the seabed. It points to a very limited spread of high-activity particles (categories as ‘significant’) and a wider but more diffuse spread eastwards of lower-activity particles (‘relevant’ and ‘minor’), with a number moving west into Sandside Bay, and a seaward limit to the detected contamination at about 30 metres’ depth. A computer model predicted the presence of particles at the headland at Brims Ness but none was found. See: LRP_07_P025 Issue%202.pdf.
9th October 2007
Dounreay announces particles clean-up
The clean-up operations for radioactive particles offshore could be substantially complete within seven years while onshore monitoring with removal of detected particles would continue for a longer period if the site’s recommended way forward is accepted. See press release.
24th July 2007
COMARE reports on beach monitoring equipment trials
The Committee on Medical Aspects of Radiation in the Environment carried out field trials of the beach monitoring equipment at Dunnet at the end of June. The purpose was to see how the monitoring vehicles, which have been improved since the last trials, performed under test conditions on a beach. While the full results are expected to be reported at COMARE’s Dounreay Working Group, preliminary results show that the monitoring vehicle performed well under the trial conditions. Prof Alex Elliot, COMARE chairman, recorded his thanks to site personnel for their co-operation and to the drivers of the monitoring vehicles.
Meanwhile, a third survey of Dunnet beach is now complete and no particles were detected. The scan took place between May and July. Further re-assurance that no particles were present came from the monitoring of 400 bags of rubbish and bigger items from the beach clean which saw over 50 volunteers from the site clean up the beach as part of the Dounreay Environment Week.
Monitoring of Melvich beach started this month and is expected to be complete by the end of July.
