Decommissioning a nuclear power plant is no minor matter. From dismantling the pressure reactor vessel and other structures, to restoring the site and managing the waste, it takes time, resources and most importantly - knowhow. Doing the job better, faster and more economically needs sustained international cooperation and knowledge sharing.
The IAEA plays a key role in sharing such knowhow, including among countries that operate a type of pressurized water reactor known as WWER, of which there are more than 70 in operation in 12 countries, some near the end of the design life. At a recent IAEA workshop held in collaboration with the European Commission and the European Bank for Reconstruction and Development, countries decommissioning WWERs shared knowledge and experience with countries that currently operate such reactors and will have to dismantle them one day.
Decommissioning is the process that leads to the removal of regulatory controls on a nuclear site, so that it can be reused. Getting there involves conducting a set of technical activities which "need to be well planned and managed by the knowledgeable experts and staff," according to Pavol Stuller, CEO of JAVYS, the Slovakian nuclear and decommissioning company that hosted the event in mid-May.
"Sharing experiences and solutions helps to improve the efficiency of the overall decommissioning process," Stuller added.
As part of the event, some 50 participants from 15 countries spent a day at the Bohunice V1 nuclear power plant, where two WWERs are being decommissioned. Highlights included viewing work at the Radioactive Waste Treatment Centre, the V1 Reactor Hall where the remote cutting of reactors is ongoing, and the V1 Turbine Hall where the remote cutting of steam generators is under way.
The acronym WWER (water, water, energy, reactor) refers to Soviet designed water cooled, water moderated reactors. The first WWER came online at Novovronezh in 1963, while the latest model was connected to the grid in Belarus in November 2020. In addition to Slovakia, there are two ongoing WWER decommissioning projects, including two reactors at Novovoronezh in Russia and four reactors in Bulgaria at Kozloduy.
The IAEA initiated its activities on WWER decommissioning knowledge transfer in 1994 when it launched a regional technical co-operation project. During the recent IAEA workshop, experiences of radiological characterization, dismantling of auxiliary structures and secondary circuit components were considered..
"All activities, including applied safety practices, benefit from knowledge sharing," said Chantal Mommaert from Bel V, a technical support organization to the Belgian nuclear safety regulator.
A guided brainstorming session was also held on technical aspects and on planning, organizational and managerial issues during the workshop, which was supported by three IAEA Collaborating Centres on decommissioning, including JAVYS. Information from the workshop will be used by the Agency to plan follow-up activities.
"This workshop was a nice example of putting together decommissioning planners, implementers and international organizations to discuss good practices, trends and challenges," said Olena Mykolaichuk, Head of the IAEA's Decommissioning and Environmental Remediation Section. "Such cooperation will go a long way to helping our Member States address the upcoming opportunities and challenges of decommissioning their WWERs."
