Fragmentation of the final 12th steam generator started in the decommissioned V1 NPP in Jaslovské Bohunice

Becoming a member of the European Union, the Slovak Republic took on the commitment to shut down both units of V1 NPP in Jaslovské Bohunice in 2006 and 2008. Furthermore, it is obliged to finish the decommissioning until 2027.

One of the key parts of the commitment is the implementation of the project D4.2 Dismantling of V1 NPP reactor coolant system large components.  Pavol Štuller, director general of JAVYS, a. s., asserts that the project is an important milestone in the entire process of safe and economic decommissioning of the nuclear facilities in Slovakia. The project is managed by the Westinghouse – VUJE consortium.

This unique and complex solution for decommissioning of all components of the VVER-440 type of NPP is implemented in the way that the primary circuit parts are fragmented in-situ.   

VUJE, a. s. performs the fragmentation (cutting) of steam generators (SG) and in cooperation with the Technical University of Košice the two prototypes of special remote-controlled cutting devices were developed. The team of 20-30 workers ensures the process of SG cutting in 24/7 operating mode.   

The weight of a single SG is approximately 155 tonnes. The shell and auxiliary structures make up the bulk of 105 tonnes, almost 30 tonnes belong to the heat exchange tubes, and finally the collectors comprise 20 tonnes of the weight. 

Matej Korec, director general of VUJE, a. s. pointed out: “A significant and very important result of the project is that two thirds of the steam generator can be released to environment for further processing. Such released materials are radiologically clean, to be used without any restrictions”.

Fragmentation of the first steam generator started in December 2019. The process involves several steps, explains Matej Zachar, project manager from VUJE, a. s.: “The steam generator shell is removed first. Further it is fragmented to the size that fit into box pallets 1,2 m x 0,8 m x 0,8 m, resp. 1-tonne at maximum. Subsequently, the heat exchange tubes are fragmented by the manipulator, and finally the collector is fragmented by the band saw.

The research of materials and their degradation after being used in the nuclear power plant operation is also important part of the project. Matej Zachar reports on the following: “Material samples taken from the steam generators and other parts of the primary circuit are collected by our colleagues and further evaluated. This study can help in improvement of the operation parameters of nuclear power plants, and / or in developing of new large components for NPPs. The research outcomes are of particular interest both in Slovakia and abroad”.

VUJE had to face several technical challenges throughout the process of fragmentation of twelve steam generators. Nevertheless, all the issues have been successfully managed, hence if no other unexpected issues will come, we estimate that the fragmentation will be completed two months earlier than scheduled.

Pavol Štuller, director general of JAVYS, a. s., concludes: “The fact that our Contractor achieve such a significant milestone proves the quality of Slovak industry and quality of contractors in the field of nuclear power engineering”.

Reported by TV JOJ:

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Transport of the last twelfth steam generator to the fragmentation workplace.From left: Pavol Štuller, director general of JAVYS, a. s., and Matej Korec, director general of VUJE, a. s. 

From left: Matej Korec, director general of VUJE, a. s., together with Matej Zachar, project manager from VUJE, a. s.

Manipulators for fragmentation of steam generator developed in cooperation with the Technical University of Košice.