ML19332C396

Application for Amends to Licenses NPF-68 & NPF-81,revising Tech Specs 3/4.4.1.2 & 3/4.9.1 to Allow for Periodic Chemical Addition Via Chemical Mixing Tank

ML19332C396
Person / Time
Site:	Vogtle
Issue date:	11/21/1989
From:	Hairston W GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19332C397	List: ML19332C396 ML19332C399
References
ELV-01077, ELV-1077, NUDOCS 8911280073
Download: ML19332C396 (7)

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W. G. Hairston, Hi sena v a presoent ELV-01077 Nuclew Oweons 0122 L Docket Nos. 50-424 50-425

U. S. Nuclear Regulatory Commission ATTN

Document Control Desk Washington, D.~C. 20555 Gentlemen:

V0GTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS 3/4.4.1.4.2 AND 3/4.9.1 In accordance with the provisions of 10 CFR 50.90 and 10 CFR 50.59, Georgia Power Company (GPC) hereby proposes to amend the Vogtle Electric Generating Plant (VEGP) Unit I and Unit 2 Technical Specifications, Appendix A to Operating Licenses NPF-68 and NPF-81.

L The proposed amendment would revise Technical Specifications 3/4.4.1.4.2 and ,,

' 3/4.9.1 to allow for periodic chemical addition via.the chemical mixing tank. /

The existing specifications require that the reactor makeup water storage tank be isolated from the CVCS by fou- locked closed valves in Mode 5 with the Reactor Coolant System loops not filled and in Mode 6. The proposed amendment l would allow two of these valves to be opened periodically under administrative l control so that. chemical additions may be made in these modes of operations.

l-The proposed amendment and its basis is described in Enclosure 1. Our evaluation pursuant to 10 CFR 50.92 showing that the proposed change doe:, not

-involve a significant hazards consideration is provided as Enclosure 2.

l Instructions for incorporation of the proposed change into the Technical I. Specifications and revised pages are provided as Enclosure 3.

L GPC requests approval of the proposed amendment by February 16, 1990. In 1:- accordance with 10 CFR 50.91, the designated state official will be sent a copy of this letter and all enclosures.

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U. S. Nuclear Regulatory Co:anission .

ELV-01077 Pace Two ,

Mr. W. G. Hairston, III states that he is a Senior Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power Company and that, to the best of his knowledge and belief, the facts set forth in this letter and enclosure are true.

GEORGIA POWER COMPANY By: M. I . M ,m+

W. G. Hairston, 111 Sworn to and subscribed before me this 4/ " day of 7% v. t /~ , 1989.

Nbnwflun1[07Y NotaryJ Public p s a g a W 3 0:C 15 l *,

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Enclosures:

1. Basis for Proposed Changes

2. 10 CFR 50.92 Evaluation

3. Instructions for Incorporation c(w): Georaia Power Comoany Mr. C. K. McCoy Mr. G. Bockhold, Jr.

Mr. P. D. Rushton .

Mr. R. M. Odom .

NORMS U. S. Nuclear Reaulatory Commission Mr. S. D. Ebneter, Regional Administrator Mr. J. B. Hopkins, Licensing Project Manager, NRR l

Mr. J. F. Rogge, Senior Resident Inspector, Vogtle i State of Georoia l Mr. J. L. Ledbetter, Commissioner, Department of Natural Resources

r ENCLOSURE 1 V0GTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS 3/4.4.1.4.2 AND 3/4.9.1 BASIS FOR PROPOSED CHANGE Proposed Chanae Technical Specification 3/4.4.1.4.2, " Reactor Coolant System - Cold Shutdown -

Loops Not Filled," presently requires Reactor Makeup Water Storage Tank (RMWST) discharge valves (1208-U4-175,1208-U4-176,1208-U4-177, and 1208-U4-183) to be closed and secured in position. The proposed amendment would allow valves 1208-U4-176 and 1208-U4-177 to be opened under administrative control provided:

1. The Shutdown Margin requirements of Specification 3.1.1.2 are met, and

2. The source range high flux at shutdown alarm is operable with a setpoint of 2.3 times background in accordance with Note 9 of TS Table 4.3-1.

Technical Specification 3/4.9.1, " Refueling Operations - Boron Concentration,"

also requires the RMWST discharge valves to be closed. Similarly, the proposed amendment would allow valves 1208-U4-176 and 1208-U4-177 to be opened unde-administrative control provided:

1. The Reactor Coolant System (RCS) is in compliance with the requirements of Specification 3.9.1, and

2. The source range high flux at shutdown alarm is operable with a setpoint of 2.3 times background. For the purpose of this Specification, the source range high flux at shutdown alarm will be demonstrated operable pursuant to the surveillance requirements cf Specifiat ha 4.9.2.

Basis In order to make chemical additions to the RCS during Mode 5b (cold shutdown, loops not filled) and Mode 6 (refueling) to maintain proper water quality, GPC is proposing to use the flowpath via the RMWST discharge through the chemical mixing tank. This requires that valves 1208-U4-176 and 177 be opened periodically under administrative control. The requisite boron dilution analyses for this specific dilution path have been performed in accordance with NUREG-0800, Standard P.aview Plan (SRP), Section 15.4.6. The results indicate that, for Mode 5b (loops not filled), at least fifteen minutes are available for operator action between the time of receipt of the high flux at shutdown alarm and total loss of shutdown margin (criticality). For Mode 6, at least 30 minutes are available for operator action between the time of receipt of the high flux at shutdown alarm and complete loss of shutdown margin. Therefore, the SRP acceptance criteria are met for the chemical addition flowpath via valves 1208-U4-176 and 1208-U4-177.

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ENCLOSURE 2 i V0GTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS i 3/4.4.1.4.2 AND 3/4.9.1 .

y 10 CFR 50.92 EVALUATION 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 significant  ;

hazards consideration. The amendment, as defined below, describing a  !

non-borated chemical addition activity during Modes 5b (loops not filled) and 6 (refueling), has been reviewed and deemed not to involve a significant hazards consideration. The basis for this determination follows:  ;

Backaround l In order to provide for the capability to make non-borated chemical additions to  !

the RCS during Modes 5b (loops not filled) and 6 (refueling) for proper water chemistry control, it was necessary to' perform boron dilution analyses for the specific dilution path to be utilized in these modes. The injection of non-borated water into the RCS for chemistry control during shutdown modes  !

results in a dilution of the RCS boron concentration. The current boron dilution analysis for Vogtle is presented in FSAR Section 15.4.6. Dilution flow  :

paths during shutdown have been identified for Modes 3, 4, and Sa (loops filled) configurations. The analyses are performed in accordance with NUREG-0800, Standard Review Plan (SRP), Section 15.4.6 to demonstrate that at least fifteen -

minutes are available, between the high flux at shutdown alarm and complete loss  :

of shutdown margin (criticality), for operator action time to terminate the dilution flow. Therefore, boron dilution analyses have been performed which verify that the anticipated dilution flow rates will still permit adequate time l

for operator action in accordance with the acceptance criteria. However, analyses do not exist for dilution flow in Modes 5b or 6. Instead, boron dilution is precluded by verifying that the possible dilution flow paths are ,

I closed and secured in position in accordance with Technical Specifications l-3/4.4.1.4 and 3/4.9.1. In order to verify that chemical addition in Modes 5b and 6 will not violate the acceptance criteria, specific analyses were performed y to demonstrate adequate operator action time is available. Note that the acceptance criteria identified in SRP 15.4.6 for Mode 6 boron dilution is 30 minutes for operator action time.

P Analysis A review of the accident analyses in the Vogtle FSAR has determined that the only transient which is affected by this chemical addition procedure is the boron dilution event. Since all applicable technical specifications for RCS boron concentrations will continue to be met by surveillance and the recommended RCS chemistry will not be changed, there is no adverse effect on any other accident analyses or system or component performance.

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I ENCLOSURE 2 i

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10 CFR 50.92 EVA!UATION (CONTINUED) l During Mode 6, reactivity conditions of the RCS must be maintained at the most c restrictive of the two: RCS boron concentration above 2000 ppm or a Kerr of l 0.95 or less per Technical Specification 3.9.1. Technical Specification 3.1.1.2  !

controls the variable shutdown margin in Mode 5. These boron requirements have '

not changed as a result of the Modes 5b and 6 boron dilution analyses. Rather, the analyses have been performed such that they adhere to and are in conformance with these existing requirements. Also, the Modes 5b and 6 analyses have assumed the operability of the high flux at shutdown alarm in these modes, with a flux multiplier alarm setpoint of 2.3. This setpoint is defined in Technical '

Specification Table 4.3-1, Note 9, and is consistent with the Modes 3, 4 and Sa analyses.

The injection of unborated chemical solution into the RCS for coolant chemistry control results in a dilution of the core bcron concentration. A prolonged and unmonitored addition of the unborated solution can be postulated to eventually '

result in the complete loss of shutdown margin. The current boron dilution .

analysis for Vogtle is presented in FSAR Section 15.4.6. Dilution flow paths have been identified for Modes 3, 4, and Sa (loops filled) configurations. The analyses were performed in accordance with NUREG-0800, Standard Review Plan l (SRP) 15.4.6., to demonstrate that at least fifteen minutes is available, between an alarm and complete loss of shutdown margin, for operator action time to terminate the dilution flow. Per the FSAR, boron dilution in Modes 5b and 6 is currently administrative 1y precluded by verifying that possible dilution flow paths are isolated and the appropriate valves are secured in position in I accordance with Technical Specifications 3/4.4.1.4.2 and 3/4.9.1. Therefore, l calculation of operator action time in Modes 5b and 6 is not currently required for the FSAR.

L Analysis of the boron dilution event for Modes 5b and 6 with a minimum cold drained reactor vessel volume has now been performed assuming a maximum dilution flow rate of 3.5 gpm to determine the minimum operator action time. This flow rate is the maximum that can be achieved via the proposed flow path under any operating condition. In addition to using the minimum cold drained reactor vessel volume, the active RCS volume was further minimind by making the following assumptions: only one residual heat removal train is in operation, miniflow and bypass lines are considered empty, and no reactor coolant loop E volumes are assumed. The analyses also assume the operability of the high flux at showdown alarm such that the instrumentation annunciates a neutron flux level which is 2.3 times greater than that occurring at the initiation of the boron dilution event.

The results of the analysis demonstrate that for a dilution flow rate of 3.5 gpm or less there is sufficient operator action time available to terminate the flow after the high flux at shutdown alarm. The SRP acceptance criteria of fifteen

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ENCLOSURE 2 10 CFR 50.92 EVALUATION (CONTINUED) minutes in Mode 5b and thirty minutes in Mode 6 for minimum operator action time is met and exceeded. No other non-LOCA safety analysis assumptions, methods or results are affected by the proposed procedure.

Results Based on the information presented above, the following conclusions can be reached with respect to 10 CFR 50.92,

1. This chemical addition procedure does not increase the probability of an accident previously evaluated in the FSAR. No new performance requirements or alignments are being imposed on the CVCS or RMWS such that any design criteria will be exceeded. The recommended chemistry guidelines will continue to be adhered to, precluding the creation of an adverse chemical environment which may prematurely affect component performance. This dilution flow path, although administrative 1y precluded in Modes 5b and 6, was previously considered for Modes 3, 4, 5 and 6 in Chapter 15 of the FSAR.

The classification of the boron dilution event continues to be an ANS condition II incident, one of moderate frequency. Other boron dilution flow paths will continue to be precluded by the technical specifications.

2. The consequences of an accident previously evaluated in the FSAR are not increased due to this chemical addition procedure. The results presented in the FSAR for the Modes 3, 4, and Sa dilution events remain valid. Boron

dilution as a result of chemical addition in Modes 5b and 6 will not create j more severe dose consequences.

3. This chemical addition procedure does not create the possibility of an accident which is different than any already evaluated in the FSAR. Boron dilution configurations in Modes 5b and 6 have been previously considered and evaluated in the FSAR. The conclusion was to keep the flow paths i

isolated so that no dilution flow was possible. In order to support the l chemical addition procedure, an alternative approach, which utilized specific analyses that are bounding for the injection path configuration, ,

was used. The results indicate that the required operator action time is available given the expected dilution flow rates. Therefore, the Modes 5b and 6 boron dilution analyses meet the Plant Vogtle licensing basis acceptance criteria for this event. Other boron dilution flow paths will  ;

continue to be precluded by the technical specifications. i

4. The margin of safety in the plant licensing basis for boron dilution is l- defined as operator action time between the high flux at shutdown alarm and loss of shutdown margin (criticality). The high flux at shutdown alarm setpoint defined in Technical Specification Table 4.3-1, Note 9, is 2.3

ENCLOSURE 2 10 CFR 50.92 EVALUATION (CONTINVEQl .

times background. For Mode 5b, the operator action acceptance criteria as defined in SRP Section 15.4.6 is fifteen minutes and for Mode 6, SRP Section i 15.4.6 defines the acceptance criteria as thirty minutes. The analysis criteria is designed to provide sufficient time for the operator to mitigate the event and prevent the complete loss of shutdown margin. Prevention of the_ loss of shutdown margin ensures that all ANS Condition 11 criteria are met. Therefore, the margin of safety is not reduced. l Conclusion ,

Based upon the preceding analysis, it has been dctermined that the proposed change to the technical specifications does not involve a significant increase in the probability or consequences of an accident previously evaluated, create the possibility of a new or different kind of accident from any accident previously evaluated or involve a significant reduction in a margin of safety.

Therefore, it is concluded that the proposed change meets the requirements of 10 CFR 50.92 (c) and does not involve a significant hazards consideration.

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