MSR replacement project in Vandellós II Nuclear Power Plant

The project to replace the MSR was included as part of the continuous process of improvement of the Vandellós II nuclear power plant and to increase the reliability in the long-term operation. The project started in 2015, when the study of the thermal balance of the plant with the potential replacement of these equipment was performed. After this analysis, it was concluded that the replacement of the MSR would mean a benefit for the plant and its long-term operation so the project was incorporated into the ANAV strategic plan, identifying the following main objectives:

  • Increased long-term reliability: The original equipment had some degradations that already caused episodes of loss of the process efficiency.
  • Improving efficiency: The thermal design of the MSR corresponded to the original design of the plant, for a thermal power of 2775 MW compared to the current power of 2940 thermal MW
  • Erosion reduction in low pressure turbines: The increase in the temperature of the superheated steam has the consequence, in addition to the performance improvement, to reduce the erosion in the low pressure turbine.

Design and manufacture of the equipment: The design of the new MSR use the input data obtained from the performed thermal balance, in addition to all those physical and functional conditioning factors related to the configuration of the facilities in the turbine building, in order to minimize the affectations and potential modification to the already existing structures, systems and components.

Some of the most significant determining factors were: the maximum equipment’s weight allowed, in order to do not overload the resistant capacity of the structures that transmit the loads to the building, as well as maintaining the position and size of the main steam cycle inlet and outlet nozzles (Cross Under and Cross Over). The result of this design is the new equipment with main dimensions of: 30 meters in length, a body shell with 4 meters diameter and a maximum height of 4.2 meters, as well as a weight of 290 tons. Being the weight of each one of the equipment a very important and determining factor of the installation work, since the existing lifting crane in the turbine hall is not capable of lifting this load, so after completing the manufacturing of the MSR, they must be cut in two halves to allow its later lifting, location and assembly.

Installation during the Outage: The duration of the VR23 Outage program was set at 36 and a half days, a really tight time for the implementation of a project of this magnitude. This led to the optimization of the planning and all the activities necessary to carry out the MSR’s replacement, as well as an intense coordination between the responsible from the different areas involved, creating a “Hit team” dedicated to it. During the outage the progress of the activities, as well as the interactions and needs from the different specialties, were reviewed daily. Due to the multidisciplinary nature of the activities related to the MSR’s replacement, almost all areas from the organization were involved in the implementation, from mechanical, electrical and instrumentation maintenance, up to the general services groups responsible for scaffolding, painting and thermal insulation, passing through operation and inspection and testing. This complexity in the organizational reinforce, even more than usual, the main goal within the installation of any project, which is the safety of all people involve in the job.

The final result obtained with the MSR replacement in Vandellós II nuclear power plant allow us to have a more reliable and safer plant that encourages us to continue working to face the long-term operation of our plant.

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