ML20151F598
| ML20151F598 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 07/12/1988 |
| From: | UNION ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20151F594 | List: |
| References | |
| NUDOCS 8807270166 | |
| Download: ML20151F598 (2) | |
Text
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3/4.5 EMERGENCY CORE' COOLING SYSTEMS 3f/4. 5.1 ACCUMULATORS LIMITING CONDITION FOR OPERATION Each Reactor Coolant System accu-ulator shall be OPERASLE with:
3.5.1 The isolation valve open and power removed, a.
A contained corated =atar volume of between 6051 and 6655 gallons, l
b.
A boren concentration of bet =een 1500 and 2100 ppm, and c.
A nitrogen cover pressure of between 602 and 643 psig.
d.
APPLICA5ILITY:
M30E5 1, 2, and 3".
ACTION:
With one accumulaton inoperable, except as a result of a closed
~
isolation valve, restore the inoperable accu =ulator to OPERABLE a.
our or be in at least HDT STANDBY vithin the next status wit in g MOY SHL'TC0"" within the felicwina 6 hoore _.1000 P6V 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> a (A b o u. ac.s pressuft +o tess +han inoperable due to the isolation valve being oneqccmulatoicce 'ately open the isolation valve or be in at b.
Vit cloedfe'the leas STA SY wi in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and k M0T 0"!!OO'J within the f
following 6 ho rs.
SURVEILLANCE REOUIREMENTS Each accumulator shall be demonstrated OPERA 8LE:
4.5.1.1 At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by:
a.
Verifying, by the absence of alarms, the contained borated 1) water volume and nitrogen cover pressure in the tanks, and J
2)
Verifying that each accumulator isolation valve is open.
osccu mvldo r i h a hb*on valve. mAy foe.
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- Pressurizer pressure above 1000 psig.
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f REVISION f
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3/4.5 EMERGENCY CORE COOLING SYSTEMS DASES 3/4.5.1 ACCUMULATORS The OPERABILITY of each Reactor Coolant System (RCS) accumulator ensures that a suf ficient volume of borated water will be immediately forced into the core through each of the cold legs in the event the RCS pressure falls below the pressure of the accumulators. This initial surge of water into the core provides the initial cooling mechanism during large RCS pipe ruptures.
The limits on accumulator volume, boron concentration and pressure ensure that the assumptions used for accumulator injection in the safety analysis are met.
The accumulator power operated isolation valves are considered to be "operating bypasses"' in the context of IEEE Std. 279-1971, which requires that bypasses of a protective function be removed automatically whenever permiss'ive In aodition, as these accumulator isolation valves conditions are not tiet.
fall to meet single. failure criteria, removal of power to the valves is iequired.
The limits for operation with an accumulator inoperable for any reason h
except an isolation valve closed minimizes the time exposure of the plant to a
%,M LOCA event occurring concurrent with failure of an additional ~ accumulator which may result in unacceptable peak cladding temperatures.
If a-closed-isolation valve cannot be immediately opened, the full, capability of one-accumulator is not available and prompt action 'is required to place the 1
reactor in a MODE where this capability is not required. 4 l
The requirement to verify accumulator isolation valves shut.with power removed from the valve operator when the pressurizer is solid ensures the-accumulators will not inject water and cause a pressure transient when the l
Reactor Coolant System is on solid: plant pressure control, i
,3/4.5.2, 3/4.5.3, and 3/4.5.4 ECCS SUBSYSTEMS The OPERABILITY of two independent ECCS subsystems ensures that sufficient emergency core cooling capability will be available in the event of a LOCA d55uming the loss of one subsystem through any single failure consideration.
Ilther subsystem operating in conjunction with the accumulators is capable of supplying sufficient core cooling to limit the peak cladding temperatures within acceptable limits for all postulated break sizes ra,1ging from the double ended break of the ' largest RCS cold leg pipe downward.
In addition, each ECCS subsystem provides. long-term core cooling capability in the recirculation mode during the accident. recovery period.
With the RCS temperature below 350*F, one OPERABLE ECCS subsystem is acceptable without single failure consideration on the basis of the. stable reactivity condition of the reactor and the limited core cooling requirements.
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