Jacobs is supporting Slovakia’s nuclear and decommissioning company JAVYS in its pioneering work to decommission the Jaslovské Bohunice V1 nuclear power plant.

This is the first time a VVER-440 reactor has ever been decommissioned and the project consortium, led by Westinghouse and VUJE, reached a key milestone in June 2020 when it safely removed the Unit 1 reactor pressure vessel (RPV).

Using the main 250 tonne crane in the reactor hall, the RPV was placed on a prepared platform in a specially built pool, where segmentation work is being carried out by Westinghouse. As subcontractor to Westinghouse, Jacobs designed and manufactured remotely operated equipment to carry out underwater handling, baskets to hold fragments of the RPV components, and equipment for radiological characterization.

“This is a significant milestone in the decommissioning process,” said a JAVYS spokesperson. “One of the main tasks of the project is the dismantling and fragmentation of RPVs and internal parts of reactors, whose radioactivity represents almost 100% of the total radioactivity of the power plant.

“Before dismantling activities began, the project team, comprising Westinghouse, VUJE and Jacobs, conducted extensive tag-out and lock-out activities, asbestos removal, radiological characterisation, sampling and decontamination to ensure that operations could be conducted as safely as possible. Removal of the RPV was preceded by months of preparations, technical negotiations, design, production of handling equipment and approval of the necessary documentation by supervisory authorities.”

The RPV removal was performed with additional health and safety regulations in place to prevent the spread of COVID-19.

In awarding the contract, JAVYS required bidders to have proven decontamination, dismantling and waste packaging expertise, and to be innovative in planning and meeting a very tight schedule, while meeting the highest safety standards.

The overall project includes: studies and procedures; designing and manufacturing new tools and equipment; site preparation; and decontamination, dismantling, segmentation, packaging and management of waste arising from 9,500 tonnes of contaminated and activated components.

These components include the primary circuits (steam generators, main circulation pumps, main insulation valves, pressurisers, bubble tanks and primary piping), reactor vessel internals, reactor vessels, auxiliary equipment, plant systems and other elements such as the annular water tank. They also include high-activated operational waste, which is stored in a dedicated location.

Jacobs’ scope of work includes complete waste management of the project including delivery of containers and radiological measuring equipment, regulatory and engineering support.

Helena Mrázová, Jacobs Project Manager, said: “We have achieved a very significant milestone, thanks to the hard and effective work of all the team members. I am really glad to have the opportunity to work with such professionals and see the results of their hard work.

“COVID-19 interrupted our operations in March and early April 2020, when we introduced restrictions to safeguard the project team. We did this successfully and returned to site in early April, with strict measures in place to ensure that everyone remained safe.”

Marek Mečiar, Jacobs Business Unit Director, said: “The professional decommissioning skills and high level of safety culture of the Jacobs team have impressed the nuclear regulator’s representatives and all the organisations we are working with.”

The Jacobs team at Bohunice is able to reach back to specialists at the company’s suite of laboratories in Trnava, which has extensive experience of developing analysis methods and decontamination technologies for surface treatment, including electrochemical sampling and scanning electron microscopy. The laboratories are also responsible for the development and deployment of SIAL, Jacobs’ proprietary waste solidification and encapsulation technology.

Bohunice’s two VVER-440 V-230 reactors were connected to the grid in 1978 and 1980 and operated until they were shut down in 2006 and 2008.

Decommissioning of Bohunice V1 NPP, led by JAVYS, is co-financed from the sources of the European Union through the Bohunice International Decommissioning Support Fund administered by the European Bank for Reconstruction and Development (EBRD).