ML20135H809
| ML20135H809 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 05/29/1985 |
| From: | SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | |
| Shared Package | |
| ML20135H794 | List: |
| References | |
| CP.105, TAC-57558, NUDOCS 8509240251 | |
| Download: ML20135H809 (2) | |
Text
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1 05-29-85 Rev. l' WP0013F 0-0063P CP.105 l
TRANSIENT TERMINATION FOLLOWING AN OCCURRENCE THAT MAY i
REQUIRE PRESSURIZER RECOVERY $0LIO PLANT COOLDOWN
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WITH OTSG REMOVING HEAT AND RCS SUBCOOLED
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1.0 E THE HIGH POINT VENT VALVES HAVE BEEN OPENE0,' LEAVE OPEN UNTIL CORE '.. ;6 l :
1 COOLING IN DECAY HEAT MODE IS ESTABLISHED OR WHEN ON NATURAL CIRCULATION W 1
' THE RCS TEMPERATURE IS <212*F, THEN CLOSE HIGH POINT VENTS.
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- 6i j 2.0 IF THERE IS A BUBBLE IN THE PRESSURIZER, GO TO CP.102, OTHERWISE
.t CONTINUE.
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i,j 3.0 START RCPs.
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.1 E any RCPs are running, THEN go to Step 4.0, otherwise continue.
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.2 E natural circulation is in progress, THEN start RCPs per OP A.2,'RCP > -, : t.- >
System. One operating RCP per loop is desired.
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CONTROL HPI FLOW.
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4.0 a
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.1 Adjust HPI flow to remain as close as possible to the adequate subcooling margin in the RCS.
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.2 Close or verify closed. EMOV and EMOV block valve (HV-21505).
.3 Close or verify closed, pressurizer vent valves HV-21515 and HV-21517.
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.4 Close or verify closed, pressurizer vent valves HV-21528 and HV-21522 on panel H2SP.
.5 Establish letdown flow.
.6 Control HPI and letdown flow to remain as close as possible.to the adequate subcooling margin.
A 5.0 IF THE DECISICN IS MADE NOT TO TRY TO ESTABLISH A BUBBLE IN THE PRESSURIZER, THEN PROCEED WITH A SOLIO. PLANT COOLDOWN, STEP 8.0.
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6.0 ESTABLISH A BU88LE IN THE PRESSURIZER.
.1 Tu'rn ob all available pressurizer heaters.
.2 Maintain RCS pressure with HPI.
.3 Continue cooling down the RCS, 00 NOT exceed 100*F/hr. 00 NOT violate
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curves on Figure 1.
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.4 Mon'itor pressurize'r temperature and incore temperature. WHEN b
4 pressurizer water temperature is > 50* above incore temperature,; lower. "'
pressurizer level to form a steam bubble.-
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.5 WHEN a bubble is: established in the pressurizer, lower the pressurizer
. level to approximately 200 inches.
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7.0 GO TO CP.102.
i 8.0 CONTROL HPI.
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.1 Maintain the RCS about 30*F colder than the adequate subcooling margin
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I by throttling HPI.
.2 1[ the RCS temperature cannot be maintained about 30*F colder than the ;;; t:
adequate subcooljng margin, THEN maintain maximum HPI flow.
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.3 Close letdown. isolation valve (STV-22009), if needed, to maintain RCS
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7 temperature 30* colder than adequate subcooling margin.
.4 Rule 2.
1 9.0 BEGIN C00LDOWN.
.1 Using small incremental steps, open the turbine bypass valves to attain -
a cooldown rate such that adequate subcooling margin is not violated.
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.2 Further adjustment of HPI flow and turbine bypass valve position should be accomplished so as to maintain the cooldown rate less than 100*F/hr while maintaining adequate subcooling margin.
.3 IF a small break LOCA has occurred, THEN continue with CP.103, Step 11.0 as necessary.
.4 Continue cooldown while attending to overall plant cooldown per OP B.4, Section 5.0.
i END Rev. 1 CP.105-2 i
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