ML20246Q348
| ML20246Q348 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 04/29/1998 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20246Q347 | List: |
| References | |
| NUDOCS 9805050189 | |
| Download: ML20246Q348 (1) | |
Text
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oc EMERGENCY CORE COOLING SYSTEM B 3/4.5 j
BASES l
3/4.5.C Suppression Chamber The suppression chamber is required to be OPERABLE as part of the ECCS to ensure that a sufficient supply of water is available to the HPCI and CS systems and the LPCI subsystem in the event of a LOCA. This limit on suppression chamber minimum water volume ensures that sufficient water is available to permit recirculation cooling flow to the core. The OPERABILITY of the suppression chamber in OPERATIONAL MODE (s) 1, 2 or 3 is also required by Specification 3.7.K.
Repair work might require making the suppression chamber inoperable. This specification will permit those repairs to be made and concurrently provide assurance that the irradiated fuel has an adequate cooling water supply when the suppression chamber must be made inoperable, including draining, in OPERATIONAL MODE (s) 4 or 5.
In OPERATIONAL MODE (s) 4 and 5 the suppression chamber minimum required water volume is reduced because the reactor coolant is maintained at or below 212*F. Since pressure suppression is not required below 212'F, the minimum water volume is based on not positive suction head (NPSH), recirculation volume and vortex prevention plus a safety margin for conservatism. With j
the suppression chamber water level less than the required limit, all ECCS subsystems are j
inoperable unless they are aligned to an OPERABLE condensate storage tank. When the -
suppression chamber level is less than 7 feet, the CS system or the LPCI subsystem is considered OPERABLE only if it can take suction from the condensate storage tank, and the condensate storage tank water level is sufficient to provide the required NPSH for the CS or LPCI pumps.
Therefore, a verification that either the suppression chamber water levelis greater than or equal to i
7 feet or that CS or LPCI is aligned to take suction from the condensate storage tank and the I
condensate storage tank containsEeater than or equal to 140,000 gallons o 14r,4rdurbo P
c s
wated to the reactor pr asure vessel.
/
men.e up dev, AvdMe 3/4.5.D Reactor Core Isolation Coolina The Reactor Core isolation Cooling (RCIC) system is provided to supply continuous makeup water to the reactor core when the feedwater system is isolated from the turbine and when the feedwater system is not available. Under these conditions, the pumping capacity of the RCIC system is sufficient to maintain the water level above the core without any other water system in 3
operation. If the water level in the reactor vessel decreases to the RCIC initiation level, the system I
automatically starts. The system may also be manually initiated at any time. The RCIC system is conservatively required to be OPERABLE whenever reactor pressure exceeds 150 psig even though the LPCI mode of the residual heat removal (RHR) system provides adequate core cooling up to 350 psig.
' The RCIC system specifications are applicable during OPERATIONAL MODE (s) 1,2 and 3 when reactor vessel pressure exceeds 150 psig because RCIC is the primary non-ECCS source of core cooling when the reactor is pressurized.
i i
QUAD CITIES - UNITS 1 & 2 B 3/4.5-3 Amendmen Nos.
171 a ur i
9805050189 980429 PDR ADOCK 05000254 p
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