ML20073P121
| ML20073P121 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 05/13/1991 |
| From: | ALABAMA POWER CO. |
| To: | |
| Shared Package | |
| ML19298E517 | List: |
| References | |
| REF-GTECI-070, REF-GTECI-094, REF-GTECI-NI, TASK-070, TASK-094, TASK-70, TASK-94, TASK-OR GL-90-06, GL-90-6, NUDOCS 9105200353 | |
| Download: ML20073P121 (9) | |
Text
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P ATTAODDir 1 Proposed Qianged Technical Specification Pages Unit 1 Revision Page 3/4 4-32 Replace Unit 2 Revision i
Page 3/4 4-32 Replace l
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l 9105200353 910513 PDR ADOCK 05000348 P
REACTOR COOLANT SYSTEM OVERPRESSURE PROTECTION SYSTEMS LIMITING CONDITIONS FOR OPERATION 3.4.10.3 At least one of the following overpressure protection systems shall be OPERABLE:
a.
Two RHR relief valves with:
1.
A lift setting of less than or equal to 450 psig, and 2.
The associated RHR relief valve isolation valves open; or b.
The Reactor Coolant System (RCS) depressurized with an RCS vent of greater than or equal to 2.85 square inches.
APPLICABILITY:
When the temperature of one or more of the RCS cold legs is less than or equal to 310'F, except when the reactor vessel head is removed.
ACTION:
With one RHR relief valve inoperable and the RCS not water-solid, l
a.
restore the inoperable valve to OPERABLE status within 7 days or depressurize and vent the RCS through a greater than or equal to 2.85 square inch vent within the next 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
b.
Vith one RHR relief valve inoperable and the RCS vater-solid, restore the inoperable valve to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or depressurize and vent the RCS through a greater than or equal to 2.85 square inch vent within the next 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, c.
Vith both RHR relief valves inoperable, within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> either:
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Restore at least one RHR relief valve to OPERABLE status, or 2.
Depressurize and vent the ECS through a greater than or equal te 2.85 square inch vent.
d.
In the event a RHR relief valve or a RCS vent is used to mitigate a l
RCS pressure transient, a Special Report shall be prepared and submitted to the Commission pursuant to Specification 6.9.2 vithin 30 days. The report shall describe the circumstances initiating the transient, the effect of the RHR relief valves or vent on the transient and any corrective action necessary to prevent recurrence.
e.
The provisions of Specification 3.0.4 are not applicable.
l FARLEY-UNIT 1 3/4 4-32 AMENDMENT NO.
i REACTOR COOLANT SYSTEM OVERPRESSURE PROTECTION SYSTEMS LIMITING CONDITIONS FOR OPERATION 3.4.10.3 At least one of the'following overpressure protection systems shall be OPERABLE:
a.
Two RHR relief valves with:
1.
A lift setting of less than or equal to 450 psig, and 2.
The associated RHR relief valve isolation valves opent or a
b.
The Reactor Coolant System (RCS) depressurized with an RCS vent of greater than or equal to 2.85 square inches.
APPLICABILITY:
When the temperature of one or more of the RCS cold legs is less l
than or equal to 310*F, except when the reactor vessel head is removed.
!i ACTION:
i a.
Vith one RHR relief valve inoperable and the RCS not water-solid, l
restore the inoperable valve to OPERABLE status within 7 days or depressurize and vent the RCS through a greater than or equal to 2.85 square inch vent within the next 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
l b.
Vith one RHR relief valve inoperable and the RCS vater-solid, restore the inoperable valve to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or depressurize and vent the RCS through a greater than or equal to 2.85 square inch vent within the next 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
c.
Vith both RHR relief valves inoperable, within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> either:
l 1.
Restore at least one RHR relief valve to OPERABLE status, or 2.
Depressurize and vent the RCS through a greater than or equal to 2.85 square inch vent.
d.
In the event a RHR relief valve or a RCS vent is used to mitigate a l
RCS pressure transient, a-Special Report shall be prepared and submitted to the Commission pursuant to Specification 6.9.2 within 3
30 days. The report shall describe the circumstances initiating the i
transient, the effect of the RHR relief. valves or vent on the transient and any corrective action necessary to prevent recurrence.
The provisions of Specification 3.0.4 are not applicable.
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Z FARLEY-UNIT 2 3/4 4-32 AMENDMENT NO.
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i ATTAODENT 2 1
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Significant liazards Evaluation s
Pursuant to 10 CFR 50.92 h
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19 CFR 50.92 EVALUATION 1
Pursuant to 10 CFR 50.92, each application for amendment to an operating license must be reviewed to determine if the proposed change involves a
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significant hazards consideration. The amendment, as defined below, describing the technical specification changes associated with the modification of j
j allowable outage times for residual heat removal system relief valves for cold overpressure protection has been reviewed and deemed not to involve significar t hazards considerations.
The basis for this determination follows.
Proposed Chances 4
4 The proposed amendment involves modification to the technical specification for everpressure protection systems. The allowable outage time (A0T) for one a
inoperable RHR relief valve with one or more of the RCS cold leg temperatures 0
less than or equal to 310 F is being modified.
For water-solid conditions the A0T is being decreased from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The required A0T for low temperature conditions other than water-solid will remain at 7 days.
1 Backcround On June 25, 1990, the NRC issued a Generic Letter (GL-90-06) in response to resolution of Generic Issue 70 (PORV and Block Valve Reliability) and Generic l
Issue 94 (Additional Low-Temperature Overpressure Protection for Light-Water Reactors).
In GL-90-06, the staff requested modification to the technical specifications to assure cold overpressure protection is afforded. As discussed in GL-90-06, the staff stated that the Reactor Coolant System (RCS) is most vulnerable to a low temperature overpressure (LTOP) transient at temperatures 0
less than 200 F when operating in a water-solid condition.
The following proposed modifications to the Joseph M. Farley Nuclear Plant Units 1 & 2 Technical Specification are in response to GL-90-06.
These modifications are being proposed based on GL-90-06 and a Farley specific study (WCAP-12933). The conclusions of this study are:
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- 1) The most vulnerable time for an overpressure transient is when the RCS is water-solid; therefore, a reduction in the allowed outage time while i
operating under water-solid conditions is appropriate.
(revised Action Statement - 3.4.10.3a) 2)
If the plant is not water-solid, reduction of the A0T from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is an insignificant contribution to the likelihood of brittle reactor pressure vessel failure (through wall crack), therefore the current A0T requirement of 7 days is appropriate.
This conclusion is censistent with the Staff recommendation of NUREG-1326 (Alternative 6).
Analysis Action statement (a) for technical specification 3.4.10.3 (overpressure protection systems) defines a maximum A0T for one inoperable RHR relief valve.
This proposed modification to the action statement would reduce the A0T from the current 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for one inoperable RHR relief valve during water-solid operation.
Modification of the A0T for non-water solid conditions is not needed since the risk from an overpressure event is insignificant.
These A0T's have been shown to be appropriate for the Farley Units based on Farley-specific work documented in WCAP-12933.
Associated Bases have also been appropriately modified.
Using information provided for the resolution of Generic Issue 70 and 94 (Generic Letter 90-06, NUREG-1326,and NUREG/CR-5186) and using specific inputs developed for the Farley Units, the most vulnerable time for an LTOP event has been confirmed to be the water-solid condition, A reduction in core damage frequency of approximately 54 percent can be acheived by reducing the allowable outage time for one RHR relief valve from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when operating in i
a water solid condition.
The reduction of A0T from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is appropriate for both of the Farley Units for water-solid operation.
A similar reduction in A0T from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> was analyzed for operation in low i
temperature conditions other than water-solid and
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it was found that the resulting contribution tri core damage frequency (i.e.,
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reactor pressure vessel fracture (through wall: crack)) was insignificant j
(approrimately 6'x 10-8 / year) and therefore need not be considered. The current A0T of 7 days for low temperature operation other than water-solid j _
operation is still appropiate.
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Based on the preceding evaluation and the analysis performed, the following conclusion with respect to 50.92 can be reached, j
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- 1) The proposed modification to the A0T for one. inoperable RHR relief valve with the RCS in a water-solid condition does not significantly increase the l
. probability or consequences of an accident previously evaluated in the FSAR. The proposed reduction in A0T is an_ enhancement to the_ existing j
technical specification, and affords increased protection for an LTOP event I
postulated during water-solid operation.-_As previously discussed, this 3
reduction in A0T is being proposed to assure proper overpressure protection
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is afforded for the most vulnerable situation (water-solid operation).
j This modification does not directly initiate an accident. Since no changes in relief valve design, setpoint or operation are-involved, the probability of brittle reactor vessel-failure has not significantly i
increased by the proposed change.
The consequences ~of accidents previously l
evaluated in the FSAR are unaffected by this proposed change.
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2)
The proposed change does not create the possibility of a new or different kind of accident than any accident _already evaluated in the FSAR, Cold overpressure events have been analyzed and their bases are presented in_the l
Bases to Technical Specification 3/4.4.10.
The reduction in the allowed outage time for one inoperable RHR relief valve will not alter the conclusion of the cold overpressure analysis.
This technical specif' cation change enhances the plant ability to prevent an overpressure event by j
applying greater restriction upon operations during times of highest risk-(i.e., water-solid conditions). No new accident scenarios, failure mechanisms, or limiting single failures are introduced as al result of this proposed change.
The proposed. technical specification modification'does
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-not challenge the performance or integrity of any safety-related systems.
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Therefore, the possibility of a new or different kind of' accident is not created.
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- 3) The proposed technical specification change does not involve a significant reduction in the margin of safety.
The proposed reduction in A0T for water j
solid conditions assures proper protection is afforded for all modes of low tempei3ture operation.
The margin of safety from an accident is impraved l
by significantly limiting the time allowed with one train of a protection feature inoperable during the time that the plant is in a vulnerable I
configuration.
The L10D basis for one RHR relief valve capacity has not changed.
Therefore there is no significant reduction in the margin of safety.
Based on the preceding information, it has been determined that this proposed change to the A0T for cold overpressure protection for water solid conditions does not involve a significant hazards consideration as defined in 10CFR50.92(C).
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l ATTACllHKfff 3 VCAP-12933 "Allovable Outage Yime Study for Residual llent Removal 1ves for Farley 14uclear Plas s 1 and 2" (proprietaty)
VCAP-12955 "Allovable Outage Time Study for itesidual lleat Removal Valves for Farley Nuclear Plant Units 1 and 2" (non-proprietary)
CAV-91-159 Vestinghouse Authorization Letter, Accompanying Affidavit,
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Proprietary Information tiotice, and Copyright tiotice i