Replacement of Moisture Separator Reheater

Replacement of Moisture Separator Reheater

As part of the planned outage of Unit 2 of the Temelín NPP, a complex project was implemented to replace moisture separator reheaters (MSR) with new, more efficient equipment. ŠKODA JS entered this event as the main local partner of the German equipment manufacturer. It designed the entire implementation process of the MSR replacement project, which included mapping the actual state of the technology and developing design and erection documentation. It also prepared transport and handling plans for large equipment in a limited space, manufacturing erection fixtures, coordinating and managing all assembly work, including, among other things, positioning the equipment in its final position with millimetre accuracy and connecting it to the existing technology.

During the preparation, ŠKODA JS created a 3D model, complete documentation, a construction organization project, up to technological procedures. In cooperation with the MSR manufacturer, a control assembly of the tube bundle into the separator body itself was carried out.

The implementation itself began with the transport of the separators to the power plant. This was the largest transport to the Temelín NPP since its construction. Two pieces of MSR casings, each weighing 114 t, 30 m long and 4.5 m high, were transported from the port in Bratislava to the Temelín NPP engine room.

Work on the planned shutdown of Unit 2 of the Temelín NPP began in March 2020, and ŠKODA JS had to complete the demanding pilot replacement of two separators in 40 days. After cutting off the attached technology, both existing separators were divided into two halves and transported from the engine room.

After the subsequent transport of two new separator casings and their placement in position along the turbine, the tube bundles were inserted. Each bundle weighing 32 tons is 14 m long. These manipulations required extremely high precision. After the heavy transports were completed, the follow-up technologies were connected. Approximately, 350 welds with diameter from DN 10 to DN 2200 were carried out. All welds were subjected to thorough ultrasound or X-ray inspection.

The schedule of ŠKODA JS assembly activities during this outage consisted of 488 sub-activities. The actual implementation was carried out by a ninety-member ŠKODA JS team, consisting of coordinators, inspection technicians, weld supervisors and 60 assembly workers – experienced pipe fitters and welders. External teams of scaffolders, insulators and electrical and I&C workers worked in parallel under the leadership of ŠKODA JS. After the physical replacement itself, a successful pressure test and connection of both new separators took place.

The identical replacement of two more separators took place one year later during the planned outage of Unit 1 of the Temelín NPP in March 2021. The duration of the entire project was reduced by two days compared to the previous replacement.

History of the project

2020replacement of moisture separator reheaters at Temelín NPP/2

2021replacement of moisture separator reheaters at Temelín NPP/1