ML20247D776

Proposed Tech Specs Page B 3/4.4-1,changing Administrative Error.Bases for Net Quantity of Gallons for Solution Is Changed from 3254 (Correct Quantity) to 3245

ML20247D776
Person / Time
Site:	Quad Cities
Issue date:	05/05/1998
From:	COMMONWEALTH EDISON CO.
To:
Shared Package
ML20247D775	List: ML20247D776 SVP-98-167, Forwards TS Page B 3/4.4-1,correcting Administrative Error. Bases for Net Quantity of Gallons for Solution Was Erroneously Changed from 3254 Gallons (Correct Quantity) to 3245
References
NUDOCS 9805180094
Download: ML20247D776 (2)

Text

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a ATTACHMENT A Technical Specification Bases SVP-98-167 Page 1 of B3/4.4-1 1

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.. SLCS B 3/4.4 BASES 3/4.4.A STANDBY LIQUID CONTROL SYSTEM The standby liquid control system consists of an unpressurized tank for low temperature sodium pentaborate solution storage, a pair of full capacity positive displacement pumps, two explosive i

actuated sheer plug valves, the poison sparger ring, and the necessary piping, valves and instrumentation. An OPERABLE standby liquid control system provides backup capability for reactivity control independent of normal reactivity control provisions provided by the control rods.

OPERABILITY of the system is based on the conditions of the borated solution in the storage tank and the availability of a flow path to the reactor pressure vessel, including the pumps and valves.

Two subsystems are required to be OPERABLE; each contains a pump, an explosive valve, and the l associated piping, valves, and necessary instruments and controls to ensure an OPERA 8LE flow

! path. A valve is also allowed to be in tne nonaccident position provided it can be aligned to the l

accident position from the coritrol room, or locally by a dedicated operator. Inoperability of a nonredundant component, such as the tank, affects both subsystems.

l l The standby liquid control system provides the capability for bringing the reactor from full power to a cold, xenon free shutdown assuming that none of the withdrawn control rods can be inserted.

To meet this objective, it is designed to inject a quantity of boron which produces a concentration of no less than 800 ppm of boron in the reactor core in less than 100 minutes. This boron 1

concentration is required to bring the reactor from full power to 3% Ak/k or a more subcritical

. condition, considering the hot to cold reactivity swing and xenon poisoning. An addstional margin of 25% boron is provide to compensate for possible losses and imperfect mixing of the chemical

! solution in the reactor water. This results in an avereg concentration of 750 ppm of boron in the reactor core assuming no losses. A not quantity of 3 allons of solution at less than or equal to 110*F and having a 14 weight percent sodium pentaborst (NA,8.0,. 10H 0) concentration is 3 required to meet this shutdown requirement. An additional of solution is contained below the pump suction and is not available for injection. Other

• lent combinations of increased concentration and reduced volume are also acceptable provided they have considered required temperatures and not positive suction head.

The specified pumping rate of 40 gpm will meet the above design objective. This insertion rate of boron solution will override the rate of reactivity insertion due to cooldown of the reactor following the xenon peak. Two pump operation will enable faster reactor shutdown for anticipated transients I

without scram (ATWS) events. The required minimum flow combined with the solution concentration requirements are sufficient to comply with the requirements of 10 CFR 50.62.

With redundant pumps and explosive injection valves and with a highly reliable control rod scram system, operation of the reactor is permitted to continue for short periods of time with the system l inoperable or for longer penods of time with one of the subsystems inoperable, i

Surveillance requirements are established on a frequency that assures a high reliability of the system. The standby liquid control system is operated by a five-position control switch which allows single pump operation for surveillance testing. This testing demonstrates the capability of t

firing the explosive trigger assemblies, and injects clean demineralized water from the test tank to l

the reactor vessel to demonstrate the injection line isn't plugged. Locally controlled testing circulates sodium pentaborate from the storage tank, through one suction line, through a pump,

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and back into the storage tank. This is done separately for each system to demonstrate that both OUAD CITIES - UNITS 1 & 2 B 3/4.4-1 Amendment Nos. 180, 178

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