3.9.5 Shutdown Cooling (SDC) and Coolant Circulation - Low Water Level
LCO 3.9.5 Two SDC trains shall be OPERABLE, and one SDC train shall be in operation.
APP: MODE 6 with the refueling cavity water level < 647 ft elevation.
A. One SDC train inoperable.
-A.1 Initiate action to restore SDC train to OPERABLE status.-IMMEDIATELY
-A.2 Initiate action to establish the refueling cavity water level ≥ 647 ft elevation.
B. No SDC train OPERABLE or in operation.
-B.1 Suspend operations involving a reduction in primary coolant boron concentration. IMMEDIATELY
-B.2 Initiate action to restore one SDC train to OPERABLE status and to operation. IMMEDIATELY
-B.3 Initiate action to close all containment penetrations providing direct access from containment atmosphere to outside atmosphere. IMMEDIATELY
What is the purpose of the shutdown cooling system?
The SDC system is a portion of the safety injection system
-removes PCS decay heat during Rx S/D
-maintains suitable temperature for refueling and maintenance
Designed to cool the PCS from 300oF to refueling temperature assuming a CCW inlet temperature of 90oF.
What are the setpoints for RV-0402 and RV-0403, SDC HX tube side reliefs?
-protects the tube side of the SDC heat exchangers and piping from overpressure due to ambient temperature rise in the safeguards rooms.
-relieves to the safeguards sump.
What is the power supply for HIC-0325A/B, SDC temperature controllers?
What are the power supplies for MO-3015/3016, LPSI pump suctions from the PCS?
Why must power be maintained to at least one valve(MO-3015/3016) when the PCS is pressurized?
To maintain the ability to isolate RV-3164,SDC relief, if it fails open.
What are the SDC requirements when we are in reduced inventory?
Both trains of SDC shall be operable prior to entry into reduced inventory.
The operating SDC pump shall not be switched unless required by ONP-17 "loss of SDC"
-may be waived by the ops superintendent
CV-0937/0938, SDC Hx cooling inlets
Fail open on a loss of air/DC power
CV-0937 opens on right channel SIAS
CV-0938 opens on left channel SIAS
-valves cannot be closed until SIAS is reset
-ensures at least 1 SDC Hx is available during all accident scenarios
Operated from C-08 or C-33
3.9.4 Shutdown Cooling (SDC) and Coolant Circulation - High Water Level
LCO 3.9.4 One SDC train shall be OPERABLE and in operation.
1. The required SDC train may not be in operation for ≤ 1 hour per 8 hour period, provided no operations are permitted that would cause reduction of the Primary Coolant System boron concentration.
2. The required SDC train may be made inoperable for ≤ 2 hours per 8 hour period for testing or maintenance, provided one SDC train is in operation providing flow through the reactor core, and core outlet temperature is ≤ 200°F.
APP: MODE 6 with the refueling cavity water level ≥ 647 ft elevation.
A. One required SDC train inoperable or not in operation.
-A.1 Initiate action to restore SDC train to OPERABLE status and operation. IMMEDIATELY
-A.2 Suspend operations involving a reduction in primary coolant boron concentration. IMMEDIATELY
-A.3 Suspend loading irradiated fuel assemblies in the core. IMMEDIATELY
-A.4 Close all containment penetrations providing direct access from containment atmosphere to outside atmosphere. WITHIN 4 HOURS
What is the interlock for MO-3015/3016, LPSI pump suction valves from the PCS?
Prevents opening MO-3015/3016 if PCS pressure is greater than 275 psia (260 psig) as sensed by PS-0104A/B
-protects overpressurizing the low pressure injection piping (rated for 300 psig)
-will not auto close the valves if pressure goes back above 275 psia
What is the power supply for FIC-0306, CV-3006 SDC flow control valve controller?
What is the setpoint for RV-0401, SDC from PCS relief?
-protects the piping between MO-3015 and MO-3016 during a plant heatup/pressurization
-relieves to the PSDT
What is the setpoint for RV-3164, SDC suction relief valve?
-relieves to the quench tank T-73
-protects the SDC suction piping
Why must the PCS pressure be maintained <265 psia and PCS temperature <300oF while SDC is in service?
265 psia maintains your pressure less than the LTOP pretrip alarm
How does CV-3025, SDC temperature control valve, fail on a loss of air/loss of controller and why?
This is the safety position for containment spray during a CHP
How does CV-3055, inlet to SDC HX, fail on a loss of air?
Fails as is
How does CV-3006, SDC bypass valve, fail and why for a loss of air/controller?
This is the fail safe position for the LPSI pumps during a SIAS