Pressure vessel for reactor - using pressurised water - cooling with separate upper pressure chamber

摘要

The top plate of the support structure for the reactor core assembly is sealed and above it is a separate chamber isolated from the main chamber containing the reactor core except for pressure relief channels through which coolant passes into the top chamber in the event of a sudden pressure rise. Non return drain valves are fitted in this plate to allow return of the coolant when the main pressure again falls.