Olkiluoto 3 Reactor Pressure Vessel internals arrived in  Finland

After an exceptional 26-day-transport through Czech Republic, Germany, and the Baltic Sea, the Olkiluoton3 reactor pressure vessel internals manufactured under the responsibility of the AREVA Chalon/Saint-Marcel plant reached Finland on December 21, 2010.

Key components of the reactor coolant system, the internals consist of three subassemblies each weighing nearly 100 tons:

• Core barrel
• Heavy reflector
• Upper internals

These components will be successively introduced and assembled inside the reactor pressure vessel at the beginning of next year.

The manufacturing of this “first of a kind” was entrusted to SKODA (Czech Republic), which has solid experience and acknowledged expertise in the manufacture of reactor pressure vessel internals, particularly for VVER reactors. SKODA is well reputed for its expertise in the machining of large components.

The manufacturing process of the internals is very complex; the precision required during the machining is expressed in tenths of a millimeter and fractions of a degree on a scale of several meters. The compliance with the dimensional requirements of this first of a kind constituted one of the major manufacturing challenges.

"This first manufacturing is a success for Saint-Marcel and SKODA teams! It has enabled the Saint-Marcel plant to develop new expertise in production engineering, and new methods for surface treatment and 3D dimensional inspection", explains Didier Desruelles, Project Manager at the Chalon/Saint Marcel plant.

Key figures:

• 8,000 integral stainless steel parts assembled
• Total weight: 260 tons
• 580 manufacturing documents, of which approximately 450 were submitted for approval to TVO and STUK (Finnish Nuclear Safety Authority)