Emergency feed-water pump failure protection - by water from tank under gas pressure admitted through non-return valve

摘要

The after heat from a pressurised water reactor which has been cut out because of a failure of the main feedwater pumps for the steam generator is carried away by emergency pumps. If these should fail too, the drop in the feedwater supply line causes a non-return valve to open. A feedwater tank which is kept pressurised by a gas then takes over the water supply until the emergency or main pumps have resumed their function. This prevents the drying out of a steam generator during a limited interruption caused by a failure of the emergency feedwater pumps and creates an additional redundancy.