Reactor vessel inner shaft

The in-vessel chessboard (hereinafter referred to as the ICV) provides design placement and orientation in plan view of the fuel assembly shanks in the supports installed in the fixed cells of the VVER reactor vessel distancing grid.
The design of the bottom and supports of the fuel assemblies provides stabilisation and equalisation of the coolant flow at the entrance to the core and at the reactor exit due to:
- smooth reduction of the gap between the bottoms of the PWC and the reactor vessel;
- uniform distribution of holes in the bottom, supports and perforated shell;
- flow throttling at the holes in the bottom and supports.
The PMC takes weight loads from the fuel assembly, the baffle, and also takes the force from the clamping device and spring blocks of the fuel assembly, from the pressure drop and hydrodynamic forces from the coolant.
The CVC is a vertical cylindrical shell with a flanged extension at the top, a spacing grid and an elliptical bottom welded on. CVC shells are made of sheet metal.
Between the bottom and the grille...