ML20215N876

Forwards Responses to NRC Request for Addl Info Re 860515 App R Exemption Requests

ML20215N876
Person / Time
Site:	Hatch
Issue date:	10/31/1986
From:	Gucwa L GEORGIA POWER CO.
To:	Muller D Office of Nuclear Reactor Regulation
References
SL-1483, TAC-61626, TAC-61627, NUDOCS 8611100017
Download: ML20215N876 (16)

Text

• Georgia Fow:r Company 333 Piedmont Avenue Atlanta, Georgia 30308 Telephone 404 526-6526 Maihng Address:

Post Office Box 4545 Atlanta. Georgia 30302 Georgia Power

• "

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lanage Nuclear Safety and Licensing 0851C October 31, 1986 Director of Nuclear Reactor Regulation Attention: Mr. D. Muller, Project Director BWR Project Directorate No. 2 Division of Boiling Water Reactor Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 NRC DOCKETS 50-321, 50-366 OPERATING LICENSES DPR-57, NPF-5 EDWIN I. HATCH NUCLEAR PLANT UNITS 1 AND 2 REQUESTS FOR ADDITIONAL I'iORMATION:

APPENDIX R EXEMPTION RcQUESTS Gentlemen:

Enclosed please find Georgia Power Company's responses to the NRC's informal request for additional information relative to our May 16, 1986, Appendix R Exemption Requests, i

If you have questions in this regard, please contact this office at any time.

Sincerely, f&m L. T. Gucwa JDH/lc Enclosure c

c: Georgia Power Company U.S. Nuclear Regulatory Commission Dr. J. N. Grace, Regional Administrator Mr. t . P. O'Reilly Mr. J. T. Beckhan, Jr. Mr. P. Holmes-Ray, Senior Resident fir. H. C. Nix, Jr. Inspector-Hatch GO-NORMS L

8611100017 861031 OF PDR ADOCK 05000321 P PDR t

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ENCLOSURE NRC DOCKETS 50-321, 50-366 OPERATING LICENSES DPR-57, NPF-5 l

EDWIN I. HATCH NUCLEAR PLANT UNITS 1 AND 2

. REQUESTS FOR ADDITIONAL INFORMATION:

--' APPG DIX R EXEMPTION REQUESTS NRC Request No. 1:

(Reference Section 1.2 of GPC's May 16, 1986, Appendix R Exemption Requests.)

Provide a diagram showing the rerouting of pathway 2 circuits that now pass through the diesel generator switchgear rooms'1E and 1F. If any of these lines are still shown to pass through sections of 1E and 1F having substantial fuel loads, then automatic suppression will be required. ,

Response:'

There is no proposed additional circuit rerouting of any safe shutdown circuits which currently pass through switchgear rooms 1E or 1F. .

Safe shutdown circuits, which are routed through switchgear rooms 1E and 1F and are required in the event of a fire, will be protected with a 1-hour rated fire barrier system which is now complete and in place.

The addition of automatic suppression in rooms 1E and 1F is not desirable, since numerous 4160-Volt switchgear banks located in these rooms would require protection from water spray due to the suppression system.

l We maintain that the 1-hour rated fire barrier, couplad with the area-wide fire detection systems. -the CO2 hose reels, and the portable fire

.-extinguishers located in these rooms, affords adequate protection and meets the intent of the rule.

i b

0851C i' E-1 10/31/86

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ENCLOSURE 4 REQUESTS FOR ADDITIONAL INFORMATION:

@ APPENDIX R EXEMPTION REQUESTS 4

it NRC Request No. 2:

(Reference Section 1.3 of GPC's May .16, 1986, Appendix R Exemption Requests.)

I How is the control room lighting switched onto the station battery and

the emergency diesel generators? If operator. action is required,-

describe the steps and show that the necessary emergency lighting will be available for the actions.

How long will' the station batteries power the lights (and other required loads) without the emergency diesels?

jg Provide an analysis showing that a single fire event cannot sever both offsite and emergency power to the control room.  ;

i i Response:

?

' Normal control room lighting is assumed to be' lost following a loss-of-offsite power (LOSP) and is not considered available for any fire event.

4 l The control room emergency lighting consists of two divisions, per' unit, of de-powered incandescent fixtures. Each division is designed to independently supply adequate emergency lighting in each unit's respective side of the control room. The control room emergency lighting i is automatically switched on when the normal ac lighting power is lost.

J The emergency lighting is powered from the station batteries off . a 125-Vol t-dc bus.. After the emergency diesel generators. start, the  :

-station battery chargers can be re-energized to maintain - the required

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125-Yolt-dc loads. The operator rJst use local switches on the Control 4

i Building 130-ft elevation to re-energize the chargers.

The station batteries have the capability to power the control room l emergency. lights and other required loads ' without the emergency diesels

for a minimum of 120 minutes.

The evaluation for control room lighting did not consider the routing of the normal ac power circuits to the lights, since offsite power cannot be '

assumed to be_always available. The circuits required to supply power to the emergency lights were evaluated. This evaluation determined that the circuits for Division I and Division II power to the emergency lights were separated, and that a single fire occurring outside of the control complex (fire area 0024) would not disable both divisions of emergency lighting.

For a fire occurring within the control complex (fire area 0024), the alternate shutdown panels will be used to shut down the plant.

1 0851C E-2 10/31/86

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ENCLOSURE RE0 VESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS l

NRC Request No. 3:

(Reference Section 1.4.1.1.5 of GPC's May 16, 1986, Appendix R Exemption  ;

Requests.)

Why are the Unit 1 torus water temperature instruments not completely fire protected with a 1-hour barrier? How are the Unit 2 instruments protected?

Response

Circuit routing for the Unit 2 torus water temperature instruments is such that, for a fire occurring anywhere within the torus room (fire areas 2203 and 2205), at least one instrument will always be available.

For Unit 1, we reevaluated instrument location and circuit routing and concluded that the same situation exists as for Unit 2. Thus, protection of these instruments is not required by Appendix R. However, since some of the torus water temperature instruments are located within the torus

- room water curtain zone, to not wrap these instruments still re' presents a deviation to our previous commitment to wrap all safe shutdown-related circuits located within the water curtain zones. (Reference GPC's June 14, 1985, submittal . ) This deviation is justified on the basis that a redundant instrument will always be available.

0851C E-3 10/31/86

ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS NRC Request No. 4:

(Reference Section 1.5.1.1.3 of GPC's May 16, 1986, Appendix R Exemption Requests.)

The description of the routing of the HPCI cables in the Unit 2 Reactor Building is inadequate. Provide a more specific description of the

-location of the cables on the various elevation levels, and where credit is taken for vertical separation, describe the composition of intervening floors and combustibles.

Describe the procedures relative to securing the HPCI system to be followed in the event of a fire and/or alarm in the Turbine Building east cableway. Provide details as to steps taken following 1) initial alam signals, 2) sprinkler activation, and 3) fire brigade arrival. Include the maximum time required to secure HPCI.

, Response:

I. Description of Cable Routings in the Reactor Building A. HPCI Inboard Steam Isolation Yalve

1. Control Cable from the Main Control Room (MCR) to the Motor Control Center (MCC)

This cable is routed in a conduit, which enters the Reactor Building south fire area on el 130 ft, through the south portion of the west wall. Upon entering the Reactor Building, the conduit runs southward along the west wall, penetrates the ceiling (el 164 ft floor slab), and enters the Reactor Building heating, ventilation, and air-conditioning (HVAC) room. The conduit located at el 130 ft will be protected with a 3-hour fire protective barrier.

Once the conduit enters the HVAC room (also part of the Reactor Building south fire area), it is routed to the MCC where the starter for the valve is housed.

2. Control and Power Cables from the MCC to the Valve These cables are routed in conduit from the MCC, which is located in the HVAC room on el 164 ft in the Reactor Building, through the floor and enter the north fire area of the Reactor Building where the conduits are then routed to an electrical penetration.

0851C E-4 10/31/86

ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS Response to NRC Request No. 4 (continued):

3. Power Cable for the MCC

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This cable is routed in a cable tray, which enters the Reactor Building north fire area on el 130 ft, through the north portion of the west wall. Upon entering the Reactor Building, the cable is routed in trays which turn upward through the ceiling (el 164 ft floor slab) and enters the Reactor Building HVAC room (Reactor Building south ' fire area) where the cable is then routed into a channel which enters the MCC.

B. High Pressure Coolant Injection (HPCI) Outboard Steam Isolation Valve

1. Control Cable from the MCR to the MCC This cable is routed in a cable tray, which enters the Reactor Building south fire area on el 130 ft, through the south portion of the west wall. Upon entering the Reactor Building, the cable is routed in cable trays, which run in an eastward direction, to the MCC where the starter for the valve is housed. The MCC is located on the east portion of the south wall on el 130 ft.

2. Control Cable from the MCC to the Valve These cables are routed in a combination of conduit and cable tray from the MCC located on the east portion of the south wall (el 130 ft) to the valve which is located in the pipe penetration room on the east side of . the Reactor Building (el 130 ft south of the Reactor Building's center line).

3. Power Cable for the MCC This cable is routed in a channel, which enters the Reactor Building south fire area on el 130 ft, through the south portion of the west wall. Upon entering the Reactor Building, the channel . connects to a tray which routes the cable to the MCC located on the east portion of the south wall (el 130 ft).

0851C E-5 10/31/86

ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

, APPENDIX R EXEMPTION REQUESTS

Response to NRC Request No. 4 (continued):

C. HPCI Trip Solenoid Valve Control Cable (to Energize the Valve) from the MCR to the Valve This cable is routed in a cable tray, which enters the Reactor

Building south fire area on el 130 ft, through the south portion i of 'the west wall. Upon entering the Reactor Building, the cable

' is routed in cable trays, which run in an eastward direction, to near the east portion of the south wall on el 130 ft where the cable enters another. tray which runs downward through the floor into the torus room (Reactor Building south fire area, el 87 ft). From the torus room, the esble is routed in conduit through the east portion of the south wall into the HPCI room where the cable is routed in cable tray and conduit to the valve.

II. Description of Cable Separation As may be confirmed from the descriptions of cable routings, the cables for two of the means by which the HPCI system can be isolated are separated by either a 3-hour fire rated barrier, the Reactor Building north and south fire areas, or- the non-rated floor slab (el 164 ft). The floor slab is constructed of reinforced concrete, ranging in thickness from 2 to 4 ft, poured onto 41/2-in.-deep metal decking and is supported t,y structural. steel beams and columns. This floor should prevent.the spread of ire from the HVAC room, which has a fire loading of 82,688. BTU /ft{, to the Reactgr Building el 130 ft, which has - a. fire loading of 83,485 BTU /ftz.

The BTU loading is largely comprised of cable insulation with a lesser percentage of Class A plastics and other miscellaneous combustibles. Our conclusion is that at least one circuit will always be available for any fire which occurs in the Reactor Building. ,

The procedure for securing HPCI, should the system fail to trip as required following the filling of the reactor vessel, is the same regardless of the reason for failure. All necessary controls. are located in the MCR on the same panel. The - following note is provided in the Emergency Operating Procedure to assist the operator in the event that the auto-trip function fails during a fire:

0851C E-6 10/31/86

ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS Response to NRC Request No. 4 (continued):

FIRE 1 IF FIRE IN CONTAMINATED AREA, NOTIFY HEALTH PHYSICS TO RESPOND TO FIRE SCENE IF HPCI IS REQUIRED TO BE TRIPPED THEN ONE OF ' THE FOLLOWING MEAMS OF SECURING HPCI WILL REMAIN AVAILABLE:

HPCI REMOTE TRIP ON PANEL 2H11-P601.

CLOSE HFCI STEAM SUPPLY ISOLATION VALVES 2E41-F002 OR 2E41-F003 AT PANEL 2Hil-P601.

HPCI procedures ' allow the system to be run in the manual or automatic mode. If the operator is manually controlling the system, the problem will not occur. If the system were running unattended, the operator would note the presence of a reactor vessel high level and manually shut down the system. The maximum time required to secure HPCI would be about 60 seconds. With HPCI operating at normal flow, the minimum time for the water level to reach the steam lines from the HPCI auto-trip level would be approximately 2 1/2 mirutes, based upon a test conducted on the Hatch 2 MCR

. simulator.

0851C E-7 10/31/86.

ENCLOSURE I REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS l

NRC Request No. 5:

(Reference Section 1.6 of GPC's May 16, 1986, Appendit: R Exemption

, Requests.)

Provide an analysis which shows that the cable tray supports will be able to withstand the complete combustion of the fuel load which is in close proximity to the cable trays. Provide a cross .section of the cable tray supports and describe other dimensions. Supports should be wrapped for.

at least 18 inches to prevent heat conduction to the cables.

Response

All supports are wrapped for at least the minimum "18-in." rule per the TSI qualified and tested configuration. Some ' supports are not wrapped beyond the 18-in. criteria. The supports are located in areas covered by automatic sprinkler systems. Our justification for this deviation is l based upon the fact that the supports 'will reach a certain maximum temperature at which time the suppression system will actuate and limit further temperature rise. This position is based upon an evaluation of the reduction in the yield strength of steel with increasing temperature and the maximum actuation temperature of the sprinkler heads. A more detailed calculation is being prepared to confirm this evaluation. This esiculation will consider one or more of the worst-case areas in question based upon the quantity of exposed cables located near the supports, the size of the supports, and the yield strength 'of steel at elevated temperatures. Data relative to- free-burning cable which is located in trays will be based upon the FMRC/EPRI test reports (EFRI NP-1881 ) .

Temperature profiles above the burning cable trays will be determined by correlating the test configurations with our worst-case configurations.

This analysis is expected to require approximately 3 weeks to complete, and an additional 2 weeks will be needed for verification.

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0851C E-8 10/31/86

1 ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS NRC Request No. 6:

(Reference Section 3.1 of GPC's May 16, 1986, Appendix .R Exemption Requests.)

The staff does not agree with the lack of compensatory measures for the schedular exemption related to the installation of new circuit breakers and fuses to ensure . coordinated circuits. The staff proposes that the licensee provide a procedure when in the event of an alarm signal in an area containing an affected circuit, an operator is dispatched to the affected circuit breaker locations to open the breakers upon verification of the existence of a fire.

Response

The circuit breaker and fuse coordination study for Plant Hatch identified several areas in which coordination could be improved. The results of the study indicated the need for 12 specific plant design changes. Six of these changes have now been completed. This exemption request involves the remaining six changes. However, the completed changes have corrected all of the most significant problems revealed by the study. Implementation of the remaining six changes will improve coordination only slightly. By- November 30, 1986, all Appendix R associated circuits will meet the minimum coordination interval requirements of IEEE 242-1975, Chapter 7, and IEEE 241-1983, page 378.

The low-voltage ac power circuit breakers supplying Appendix R-designated loads are coordinated and selective with downstream molded-case circuit breakers located in the MCCs and distribution panels. The degree of selectivity meets the requirements described in. IEEE 242-1975, Chapter 7.

The design changes remaining to be completed after November 30, 1986, will improve coordination for low-voltage control and power circuits.

The coordination and selectivity of these circuits are basically good when taking credit for the fault limiting -ability of the branch circuit cable. When considering an Appendix R-type fire in which we might lose part of the cable impedance, the possibility exists for the molded-case circuit breakers connected in series to simultaneously trip. This would be considered a loss of selectivity. However, we do not believe that selectivity would be lost, because the cable insulation exposed to a fire is likely to degrade over a period of time and the resulting fault would be far below the value of a bolted fault considered for the study.

0851C E-9 10/31/86

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l ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

, APPENDIX R EXEMPTION REQUESTS Response to NRC Request No. 6 (continued):

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, With the remaining six design changes, we are attempting to achieve  ;

coordination and selectivity on Appendix R low-voltage power and control circuits without taking credit for cable impedance lowering the fault

. current and eliminating the chance that an Appendix R-type fire might cause an overtrip and the temporary loss of a panel.

In reference to establishing a procedure designed to control affected circuits as a compensatory measure, GPC will establish a procedure to '

cover'the following areas until the target changes are complete:

In the unlikely event that a fire occurs in associated circuit faulting which results in the loss of a lead center, the procedure will detail how to reestablish power to the affected- Appendix R components. This procedure will direct that existing plant procedures. (34AB-0PS series) for the loss of de busses, loss of instrument busses, loss of vital ac busses, and loss of essential ac

- distribution busses be implemented to reestablish power to the  ;

Appendix R components powered by the tripped panel.

• We strongly believe that it would be detrimental to plant safety to require or even suggest load stripping prior to an actual probleir ,

especially as a. compensatory measure for a problem which we consider to -

be minor.

i 0851C E-10 10/31/86

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ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS NRC Request No. 7:

(Reference Section 3.2 of GPC's May 16, 1986, Appendix R Exemption Requests.)

Can the control power for RHR pump Ell-C002D be manually transferred to the swing diesel? If not, provide a procedure for manually controlling the pump. If yes, verify that the transfer can be completed in an acceptable timeframe. Al so , provide a procedure for ma, Aally trans-ferring control power from the swing diesel.

Response

Control power cannot be transferred manually; however, the pump breaker can be operated manually without control power. A procedure will be established relative to manually starting the pump at the breaker until the modification is complete. Since this problem affects only cold shutdown equipment, there is adequate time to take this action.

0851C E-11 10/31/86

ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS NRC Request No. 8:

(Reference Sections 1.7.1.2 and 1.7.1.7 of GPC's May 16, 1986, Appendix R Exemption Requests.)

The staff does not agree that 30 minutes is adequate time to allow operators to start the RCIC room coolers should the control room circuits be damaged by a fire.

Response

A reanalysis of the RCIC room temperature rise without coolers has been performed. The RCIC room coolers need not be started 'for a minimum of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after the RCIC system has been started. This provides ample' time for operators to complete the necessary actions.

0851C E-12 10/31/86

ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS NRC Request No. 9:

(Reference Sections 1. 7.1. 3 , 1.7.1.4, 1.7.1.8 and .1.7.1.9 of GPC's May 16,1986, Appendix R Exemption Requests.)

The staff feels that an operator should be immediately dispatched to the Diesel Generator Building upon control room evacuation and dedicated to the purpose of operating the diesel generators during remote shutdown.

Rest.onse:

Our procedures for remote shutdown require that -an operator be immediately dispatched to the Diesel Generator Building to ensure proper operation of the equipment upon a LOSP which occurs during remote shutdown.

L 0851C E-13 10/31/86

ENCLOSURE REQUESTS FOR ADDITIONAL INFORMATION:

APPENDIX R EXEMPTION REQUESTS NRC Request No.10:

(Reference Sections 1.7.1.5 and 1.7.1.10 of GPC's May 16, 1986, Appendix R Exemption Requests.)

The staff's position is that if the C-T shorting blocks mentioned in the exemption request are installed, then there is no need for the exemption or deviation in this case.

Response

, Since we are proceeding with the installation of the shorting blocks, the exemption requests described in Sections 1.7.1.5 and 1.7.1.10 of our May 16,1986, letter are hereby withdrawn.

0851C E-14 10/31/86

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