High-pressure components structural steels

The primary system, the reactor coolant pressure boundary, the safety systems and the high-pressure components of the reactor auxiliary systems are enclosed in the primary containment, a cylindrical concrete structure with an embedded steel liner. The primary containment is a pressure-suppression type with two major compartments a drywell and wet well. The drywell includes the volume that surrounds the reactor pressure vessel and the second shutdown system rooms. A partition-floor and cylindrical wall separate the drywell from the wet well. The lower part of the wet well is filled with water that acts as the condensation pool and the upper part is a gas compression chamber. 

There is increasing interest in hose forms of construction as a route to manufacturing reinforced thermoplastic pipes (RTP) on a continuous production basis. The most widely used high pressure hoses are composite structures intended to create a flexible, tubular connection within high-pressure fluid systems. The pressure containment is achieved by incorporating textile fibres or steel wires which can carry high stresses whilst the elastomeric or plastic components essentially protect the fibre or wire structures and act as a seal against fluid permeation. 

The external case of the rocket motor supports the mechanically and thermally induced stresses, which are due to internal gas pressure, vibration, acceleration, thrust vector control, and differential thermal expansion of component materials. To accommodate these factors, the structural material should have high strength, adequate modulus, and resistance to buckling. Either a continuous glass filament wound epoxy plastic or a high temperature metal (steel, titanium, or aluminum) case serves as the exterior structural member. 

The primary coolant pipes carry pressurized sodium ( 0.8 MPa) from the pump header to the grid plate and thus, form a primary coolant pressure boundary. A rupture of the primary pipe is of great safety concern. Hence, structural reliability requirements are high for this component. In view of these considerations, a very ductile material, such as austenitic stainless steel type 316 LN, is selected and the pipe is designed as per Class 1 rules of RCC-MR [1]. 

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