Plant Operating Standard

DK-48 Emergency Cooling

1. Emergency cooling system and emergency diesel generator are operable and are set up for remote operation and auto-start. The emergency cooling system is to be used only in the event that all other reactor heat removal systems are inoperable.
2. Emergency Makeup Pump is lined up to DC Heater with all inlet valves open. Discharge valve DK-17V is to be closed.
3. A routine check of the DK system Auto-Start, operation and head removal ability is to be conducted once each week and prior to each reactor startup which follows a maintenance outage.
4. Valves DK-19V, DK-20V, DK-21V, DK-32V and DK-4V are to be fully closed.

1. The reactor is shut down and no other method to remove decay heat is available.
2. The emergency cooler is operating to remove maximum decay heat from the reactor (4 million btu/hr).
[4 million btu/hour is 1,172,288 watts.]
3. The emergency canned pump DK-P2 is operating to provide a minimum of 200 gpm through the reactor vessel.
4. The emergency sea water pump DK-P1 is operating to provide sufficient flow to the emergency cooler to remove decay heat, to provide sufficient flow to the emergency containment cooling coil to keep the containment temperature less than 150 F. and to provide sufficient flow to the emergency canned pump to prevent the pump from overheating.
5. The emergency makeup pump DK-P3 is operating to provide sufficient water to the primary system to compensate for the contraction of the primary water if it is cooled. Maximum capacity of pump is 31 gph.
6. The remote operated throttle valve DK-20V is operating downstream of the emergency cooler, and the remote operated throttle valve DK-19V is operating in the emergency cooler bypass line to control the rate of decay heat removal.

1. The emergency cooling system and emergency diesel generator are operable and are set up for remote operation and auto start.