ML20217G148
| ML20217G148 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 03/27/1998 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20217G140 | List: |
| References | |
| NUDOCS 9804020214 | |
| Download: ML20217G148 (2) | |
Text
P ATTACHMENT 1 Technical Specification Bases Page B/3.4.5-1 i
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EMERGENCY CORE COOLING SYSTEM B 3/4.5 BASES 3/4.5.A ECCS - Operatina 3/4.5.8 ECCS - Shutdown The Core Spray (CS) system, together with the Low Pressure Coolant injection (LPCI) subsystem, is provided to assure that the core is adequately cooled following a loss-of-coolant accident (LOCA) and provides adequate core cooling capacity for all break sizes up to and including the double-ended reactor recirculation line break, and for smaller breaks following depressurization by the Automatic Depressurization System (ADS).
The CS system is a primary source of emergency core cooling after the reactor vessel is depressurized and a source for flooding of the core in case of accidental draining.
The surveillance requirements provide adequate assurance that the CS system will be OPERABLE when required. Although all active components are testable and full flow can be demonstrated by recirculation through a test loop during reactor operation, a complete system functional test requires reactor shutdown. The pump discharge piping is maintained full to prevent water hammer
' damage to piping and to start cooling at the earliest moment.
The Low Pressure Coolant injection (LPCl) subsystem is provided to assure that the core is adequately cooled following a loss of coolant accident. The LPCI subsystem with a minimum of three pumps will provide adequate core flooding for all break sizes up to and including the double-ended reactor recirculation line break, and for small breaks following depressurization by the ADS.
The surveillance requirements provide adequate assurance that the LPCI subsystem will be OPERABLE when required. Although all active components are testable and full flow can be demonstrated by recirculation through a test loop during reactor operation, a complete system functional test requires reactor shutdown. The pump discharge piping is maintained full to prevent water hammer damage to piping and to start cooling at the earliest moment.
The High Pressure Coolant injection (HPCI) system is provided to assure that the reactor core is adequately cooled to limit fuel clad temperature in the event of a small break in the reactor coolant system and loss of coolant which does not result in rapid depressurization of the reactor vessel.
The HPCI system permits the reactor to be shutdown while maintaining sufficient reactor vessel water level inventory until the vessel is depressurized. The HPCI system continues to operate until reactor vessel pressure is below the pressure at which CS operation or LPCI subsystem operation maintains adequate core cooling.
p The capacity of the system is selected to provide the required core cooling. The HPCI pu designed to deliver greater than or equal to 5000 gpm at steam supply pressures between and 150 psig. Suction piping for the system is provided from the condensate storage tank the suppression pool., Pump suction for HPCl is normally aligned to the condensate storage tank source to minimize injection of suppression pool water into the reactor vessel. However, if the condensate storage tank water supply is low, an automatic transfer to the suppression pool water source ensures a water supply for continuous operation of the HPCI system.
QUAD CITIES - UNITS 1 & 2 B 3/4.5-1 Amendment Nos.
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