12. Auxiliary and safety circuits

The auxiliary and safety circuits of naval propulsion PWRs differ in their design from those of land-based generator PWRs (see [B 3 100] REP. Description ), although the functions performed are the same.

On the ship :

• the greatest possible simplicity is sought (a French naval propulsion PWR with two loops has around five times fewer primary circuit valves than a land-based PWR with three loops). For example :

  • purification – filtration of the primary circuit generally operates at high pressure, which avoids the need for permanent lifting of the primary circuit,

  • control of reactivity by soluble poison is avoided (or its use is very limited),

  • ...