CONFERENCE REPORT | NUCLEAR DECOMMISSIONING
New perspectives on decommissioning
As a growing number of reactors shut down and enter the decommissioning phase, Nuclear Engineering International held its second virtual conference exploring some of the technical developments, innovations and lessons learned from worldwide decontamination and decommissioning efforts
Above: Dounreay is a compact site but is one of the world’s more complex decommissioning challenges
AROUND A TENTH OF THE world’s operating nuclear fleet has been shut down since 2017, that’s more than 40 units. With more reactors set to follow this year alone, dozens are expected to end their operational life by 2030. With this in mind, Nuclear Engineering International held is second virtual event dedicated to decommissioning. Sharing some of the technical developments, innovations and lessons learned from decommissioning and radioactive waste management projects around the globe, delegates heard from power plant operators, those responsible for clean-up of hazardous legacy sites and key industry players who outlined emerging technologies which can support the decommissioning and decontamination. Jurij Šapoval, Head of Dismantling Projects Programme
SE Ignalina Nuclear Power Plant, started off the event proceedings with a presentation on decommissioning Lithuania’s Ignalina. Early closure was required to facilitate EU accession due to safety concerns as the plant features two RBMK-1500 water-cooled, graphite-moderated channel- type reactors. The reactors were closed in 2004 and 2009. Dismantling began in 2010 for unit 1 and in 2014 for unit 2 and decommissioning is scheduled for completion by the end of 2038 at a cost of some €3.4bn. To manage the large volume of waste, Ignalina is currently considering a facility to melt VLL/LL waste using two medium-frequency induction furnaces. A cost benefit analysis on this project is still required.
28 | July 2022 |
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Delegates also heard from Gordon Tait, Senior
Project Manager, Dounreay Site Restoration Ltd on decommissioning this large and complex site which dates back to the mid-1950s. Tait explained that the challenges of the site tend to be underestimated: “It is probably the most diverse nuclear site in the world in terms of breadth of capability. Other sites may be physically larger, but have a more focused product stream,” he said. Decommissioning has been underway at the site for
many decades, starting with the materials test reactor which was shut down in 1969. After fuel was removed in 1971 the reactor then lay until 1996. Inspection work inside the reactor supported the plan to defer the next phase of decommissioning for 20 years, by which time radiation would have decayed to an optimum point. Turning to the prototype FAST reactor, Tait noted
that techniques for the next phase of decommissioning are currently being determined, including removing components from the reactor vessel using cold cutting. The site is also exploring the use of plasma and laser cutting. “Laser cutting technology is rapidly reaching a level of maturity for active deployment in reactors and the airborne generation it causes is closer to 110th of that from plasma,” said Tait. Dounreay is also pursuing the potential of lasers to decontaminate heavily contaminated reprocessing plant vessels. The technique is starting to see early use in lightly contaminated metals, but the potential to deal with highly
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