ML18003B094

Forwards Addl Info Re SER Open Items on Instrument Air Sys,Internally Generated Missiles & Fire Protection,In Response to NRC 850321 Request & 850322 Meeting

ML18003B094
Person / Time
Site:	Harris
Issue date:	04/05/1985
From:	Zimmerman S CAROLINA POWER & LIGHT CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NLS-85-113, NUDOCS 8504120159
Download: ML18003B094 (46)

Text

REGULA Y INFORMATION DISTRIBUTIO SYSTEM (RIDS)

ACCESSION NBR: 8504120159 DOC DATEr 85/04/Q5 NOTARIZED! NO OOCKE>>T FACIL150 400 Shear on Har AUTH NAME, AUTHOR AFFIL'IAT'ION r

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is Nuclear Power Planti Unit ii Carolina 05000400 ZIMMERMANiS,R, Carolina Power & Light Ca<

RECIP ~ NAME. RECIPIENT- AFFIL'IATION DENTONiH,Re Office>> of Nuclear Reactor>> Regulationi Director>>

SUBJECT:

Forwards =addi info r e'ER open items oo. instrument: a)r>>

sos-iiqternally generated missiles & fire protectioniin response to NRC- 850321 request, & 850322'eeting.

DISTRIBUTION CODE'! 8001D COPIES RECEIYED:Lrt'R "ENCL- "

Licensing Submittal: PSAR/FSAR Amdts & Related Correspondence'OTES!

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CRK Carolina Power & Light Company SERIAL: NLS-85-113 APR 05 <)85 Mr. Harold R. Denton, Director Of fice of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT UNIT NO. 1 - DOCKET NO.50-000 RESPONSE TO AUXILIARYSYSTEMS BRANCH QUESTIONS

Dear Mr. Denton:

Carolina Power R Light Company hereby submits additional information for the Shearon Harris Nuclear Power Plant concerning Safety Evaluation Report Open Items on the Instrument Air System (Attachment B), Internally Generated Missiles, and Fire Protection (Attachment A). The attached information is submitted in response to an NRC request for additional information transmitted by letter dated March 21, 1985 and clarified in a meeting with your staff on March 22, 1985.

If you have any questions concerning this submittal or required additional information, please contact me.

Yours very truly, S. merman Manager Nuclear Licensing Section 3HE/pgp (1330DCM)

Attachments cc: Mr.,B. C. Buckley (NRC) Mr. Wells Eddleman Mr. G. F. Maxwell (NRC-SHNPP) Mr. 3ohn D. Runkle Dr. 3. Nelson Grace (NRC-RII) Dr. Richard D. Wilson Mr. Travis Payne (KUDZU) Mr. G. O. Bright (ASLB)

Mr. Daniel F. Read (CHANGE/ELP) Dr. 3. H. Carpenter (ASLB)

Wake County Public Library Mr. 3. L. Kelley (ASLB)

Mr. Norm Wagner (NRC-ASB)

S504>aoa59 Ssoeos PDR ADOCK 05000400 l E PDR 411 Fayettevilte Street o P. O. Box 1551 o Raleigh. N. C. 27602 goo <

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ATTACHMENT A 410.43 Internally Generated Missiles Affecting Essential Service Chilled Water System (ESCWS) In the response relating to the possible effect of missiles upon the ESCWS, you provided the following responses:

In paragraph "C", entitled "Gravitational Missiles,"

you postulated the failure of nonseismically designed components and had determined that both ESCWS trains would not be rendered inoperable. In paragraph "d",

entitled, "Secondary Missiles" you stated that secondary missiles would be confined" -so that a single missile will be incapable of negating redundant safety trains." You then concluded with the following for paragraph "d". "Based on the above analysis, the generation of secondary missiles cannnot disable the necessary functioning of the redundant trains of the ESCWS." We are concerned that those statements may conflict with our position re missiles from safety-related and nonsafety-related equipment which is:

1. Missiles from safety-related equipment may adversely affect single trains of systems with redundant trains of safety-related equipment as long as the system function is maintained.

2. Missiles from nonsafety-related equipment may not adversely affect single trains of safety-related systems with redundant trains.

Describe how this position has been properly applied in the cases noted above in paragraphs "c" and "d" or describe the means taken to prevent failure of any safety-related system function because of missile impact.

RESPONSE

The following position applies to our response relating to the possible effects of missiles upon the ESCWS:

1. Missiles from safety-related equipment may adversely affect single trains of systems with redundant trains of safety-related equipment as long as the system function is maintained.

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2. Missiles from nonsafety-related equipment may not adversely affect single trains of safety-related systems with redundant trains.

The following are revised paragraphs "c" and "d" of our October 25, 1984 submittal addressing this position.

c Gravitational Missiles - SHNPP is designed to ensure that failure of non-safety related, non-seismically designed equipment and/or structures will not adversly affect the operation of safety-related equipment. The ESCWS has been reviewed in its entirety in order to ensure its continued availability. Equipment, systems, components and/or structures in the vicinity of the ESCWS are either seismically designed to ensure their continued structural integrity post-SSE or the postulated failure of non-seismically designed components has been assumed and it was determined that either train of the ESCWS would not be rendered inoperable.

d. Secondary Missiles The effects of secondary missiles on safety-related systems including ESCWS, structures, and components is based on fragments generated from primary missiles. Our review has identified the existence of potential secondary missiles generated by primary missiles from high pressure systems and rotating machinery. In the event that secondary missiles are generated, we have determined that one of the following interactions would occur:

safety-related equipment would not be within the strike zone of the secondary missiles generated; or

2. the impact energy from secondary missiles on safety-related equipment is negligible and would not cause any significant damage; or

3. barriers and compartmentalization of safety-related equipment would confine secondary missiles to a finite area so that a single missile will be incapable of negating the necessary functioning of the ESCWS.

Based on the above analysis, the generation of secondary missiles cannot disable the necessary functioning of the ESCWS.

NRC QUESTION NO. 410.44 Internally Generated Missiles From Pumps You stated that the criterion used to ensure against damage of safety-related equipment by pump missiles is: "Any pumps which are intended for use only during cold shutdown shall not be considered a potential danger to the safety of the plant." This criterion was applied only for the steam generator wet lay-up recirculation pump in the RAB at elevation 261 ft.

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Section 3.5.1.1 Of the Standard Review Plan, "Internally Generated Missiles (Outside Containment)" " states that structures, systems and components (SSC) necessary to perform functions required for attaining and maintaining a safe shutdown condition " must be assured adequate protection from internally generated missiles.

Discuss how all SSC necessary to maintain shutdown are adequately protected from missiles from the steam generator lay-up recirculation pump.

RESPONSE

The following is a revised Criteria 5 of our previous submittal of October 25, 1984, which states that SSC necessary to maintain shutdown are adequately protected from missles from the pumps eliminated by this criteria.

5. Any pumps which are used only after cold shutdown and cannot damage any structures, systems, and components necessary to maintain shutdown shall not be considered a potential danger to the safety of the plant.

NRC UESTION NO; '410;45 It is our position that alternative shutdown is required for any fire which necessitates evacuation of the control room.

However, you have not considered alternative shutdown stating

" -one train necessary to achieve and maintain safe shutdown is provided and alternative shutdown is not necessary" in Section VI of Appendix 9.5B dated June 18, 1983. In the latest version of Table 9.5 B3 (February 24, 1984) we find the following for fire area 12-A-CR, el. 305'Control room):

"Equipment Exposed to a Common Fire" I

A review of the drawings associated with this fire area indicates that various electrical cabinets, conduit, duct and the control board could be exposed to a fire. However, the plant design allows for shutdown of the plant from the auxiliary control panel with controls which are electrically isolated from systems on elevation 305'.

In view of the foregoing, we request that you show how alternative or dedicated shutdown capability in accordance with the provisions of Sections C.5.b and C.5.c of Branch Technical Position CMEB 9.5-1, "Guidelines for Fire Protection for Nuclear Power Plants."

RESPONSE

CPSL has provided alternative and dedicated shutdown systems for a fire in various areas of the plant. The SSA will be updated to IBMD-WKDB02-OS4 Page 3 of 19

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reflect this information and deviation requests will be submitted for not providing fixed suppression systems in the rooms under consideration per 10 CFR 50 Appendix R Section III.G.3. The areas requiring these systems are as follows:

1). Fire Area 12-A-CRCl (SSA Area FCACRC) 2). Fire Area 12-A-CR (SSA Areas FCACRlf)

+3). Fire Area 1-A-SWGRB (SSA Area FAASGB)

• 4). Fire Area 1-A-CSRB (SSA Area FFACSB)

• 5). Fire Area 1-A-BAL (SSA Area FAABL5)

• 6). Fire Area 12-A-BAL (SSA Area FCABAL) 7). Fire Area 12-A-HVIR (SSA Area FCAHVI)

+A fire in these areas requires the use of the same dedicated-HVAC unit to cool the safety-related SA PIC room located on Elevation 286 and does not require evacuation of the Control Room.

NRC QUESTION NO. 410;46 Show that the following list of instrumentation is available in the event of a fire requiring alternative shutdown.

a) pressurizer pressure and level, b) reactor coolant hot leg temperature or exit core thermocoupl'es, and cold leg temperature c) steam generator pressure and level (wide range) d) source range flux monitor e) diagnostic instrumentation for shutdown systems (e.g., flow measurements) level indication for all tanks used

RESPONSE

The following instrumentation is available for Safe Shutdown in event of a fire requiring evacuation of the control room: This response supercedes CP&L's previous response to NRC Question 410.24.

DESCRIPTION TAG NO. LOCATION a) Pressurizer Pressure PT 0455.2 ACP Pressurizer Level LT 0459.2 ACP RCS Pressure W.R. PT 0402.2 ACP b) RCS Loop 1 Hot Leg Temp TI 0413.2 ACP RCS Loop 2 Hot Leg Temp TI 0423.2 ACP RCS Loop 1 Cold Leg Temp TI 0410.2 ACP RCS Loop 2 Cold Leg Temp TI 0420.2 ACP c) Steam Generator A Pressure PI 0474.2 ACP Steam Generator B Pressure PI 0485.2 ACP Steam Generator A W.R. Level LI 0477.2 ACP Steam Generator B W.R. Level LI 0487.2 ACP IBMD-WKDB02-OS4 Page 4 of 19

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d) Neutron Flux Monitor (NEW) ACP NI 60A2 e) Charging Flow FI 122.2 -ACP RHR HX Flow FI 605B2 ACP AFW Turb Pmp Diff Press PDI-2180.2 ACP AH< Turb Pmp Speed SI 2180.2 ACP Charging Pmp 1B-SB Status Lights ACP Charging Pmp 1C-SAB (SB Train)Status Lights ACP RHR Pump 1B-SB Status Lights ACP AFW Turb Stm Inlet VAS Status Lights ACP CCW Pmp 1B-SB Status Lights ACP CCW Pmp 1C-(SB) Status Lights ACP ESW Pmp 1B>>SB Status Lights ACP ESW Pmp lA-SA Status Lights ACP B.A. Transfer Pmp 1B-SB Status Lights ACP B.A. Transfer Pmp 1A-SA Status Lights ACP Note that actual flow measurements are not necessarily available for the following pumps: AFW, CCW, ESW. The turbine driven AFW pump, which is fully independent of the effects of a fire on EL 305'fter transfer (i.e., control room-FCACRM or control complex-FCACRC), and pump performance can be monitored by means of pump speed, pump steam inlet to discharge differential pressure, and steam generator level. The ESW pumps, CCW pump lA and 1C and boric acid transfer pump are fully independent of the effects of a fire on EL 305'fter transfer. Pump and valve status indications are sufficient for the monitoring of these pumps since failure of the equipment concurrent with the fire causing the control evacuation has not been postulated.

f) CST Level LI 9010 B2 ACP Boric Acid TK Level LI 161.2 ACP Tanks are listed only where control action may be necessary.

NRC QUESTION 410.47 In question 410.24, we asked that you verify the availability of instrumentation necessary for safe shutdown in the event of a fire requiring evacuation of the control room. If the answer you provided for 410.24 is partially or completely the response to question 410.46, we have the following comments: You stated that actual flow measurements are not necessarily available for AFW pump XI-SAB (turbine driven), for CCW pumps 1B and 1C, and for ESW pumps 1A and 1. However, Table 7.4.1-1, "Monitoring Instruments for Safe Shutdown," shows that instruments are available at the auxiliary control panel to monitor flow to each steam generator, to each component cooling water heat exchanger and to each service water header.

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Later, in the same paragraph, you state, "The ESW pumps, CCW pump lA and 1C and boric acid transfer pump are fully independent of the effects of a fire on EL. 305. This, in some respects, appears contradictory to the initial statement.

In reviewing the instrumentation required for alternate safe shutdown in the event of a fire, you should consider these comments and provide the required instrumentation as noted in question 410.46, above.

RESPONSE

There is indication on the ACP other than that required for a fire induced evacuation of the main control room. The ACP was installed to meet GDC 19 and has been modified for Appendix R alternate shutdown. Table 7.4.1-1 identified all instruments on the ACP, not just those required by Appendix R.

Safe Shutdown as defined in Table 7.4.1-1 is Hot Shutdown. This meets the intent of the Appendix R Criteria but is not Cold Shutdown. Several of the instruments at the ACP could potentially be rendered inoperative by a fire in fire area 12-A-CRC or 12-A-HV-IR. Our response to 410.46 represents the absolute minimum instrumentation that would be available. For a fire in the control room (12-A-CR) itself, all instrumentation located on the ACP would be operative.

Our statements concerning the AFW, ESW, CCW, and Boric Acid Pumps are not contradictory. Flow indication may be available at alternative shutdown, but it cannot be guaranteed. Indication is available to determine system operation via pump breaker status, temperature, pressure, etc., as discussed in CPSL's response to 410.46.

NRC QUESTION 410.48 In response to question 410.25, it is stated that sound powered telephones, portable radios and the normally installed PA and phone systems will be used for communication in the event of a fire requiring evacuation of the control room. Show that all of these systems are available in the event of a loss of off site power or that the systems remaining thereafter are capable of providing the necessary communication links between operators.

RESPONSE

COMMUNICATIONS CAPABILITIES FOR MAIN CONTROL ROOM AND AUXILIARY CONTROL ROOM

1. A telephone system is distributed throughout the, Harris Site.

The switching equipment is located in the Administration Building. Normal supply for this sytem is provided from the Administration Building transformer 1-4A7, but a back-up supply will be provided from Security MCC 1-4A9 once this is operational. An automatic transfer switch will provide this IBMD-WKDB02-OS4 Page 6 of 19

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transfer. The PABX is also provided with a back-up power source from a storage battery system which has a useful life of approximately one hour. A public address sytem is installed in all plant areas and is connected to the PABX system so that instructions can be issued from either the main control room or the auxiliary control room. The power for the PA system is provided by UPP l-l in the communications room which has a reliable backup source of power from the station battery.

2. An operations, maintenance, and security radio system is installed in the communications room on the RAB 305'levation.

This system consists of base station equipment, four channel repeaters, two base stations for communication to the Sheriff's Department, and control stations in the main control. room, auxiliary control room, waste process control room, central alarm station, and secondary alarm station. The power for this system is provided from the UPS system. That portion which is dedicated to security communications will be powered from the security UPS once it is operational. The signal distribution system consists of external antennas for communications off site and to outlying plant areas. Inside the power block a distributed antenna system has been installed to allow communications between control room areas and portable radios.

3. A sound-powered phone system has been installed in the power block of the Harris Plant. This system consists of multiple wiring circuits and jacks. This system does not require power.

Master panels are located in the main control room, auxiliary control room, and waste processing control room. Loss of the main control room will not affect the sound power system in the auxiliary control room.

In the event of a shutdown, loss of off site power, evacuation of control room, loss of security diesel generator, or loss of the UPS system, the sound power system will still be operational and allow communications between plant areas and control points.

The major communication equipment is located in a separate room on the 305'levation of the Reactor Auxiliary Building ad)acent to the Process Control Instrumentation room. This room is manned 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day for security purposes and is also equipped with ionization detectors for early detection of fire-related problems. A hose station is located within 100 feet of this room. This room is serviced by a heating ventilation and air conditioning System (Air Handler HH-97) which would be free from fire damage in the rooms which house the Process Instrumentation Cabinets, Auxiliary Relay Panels, and the Hain Control Room.

Based on the above, CPSL has concluded that communications would be available in the unlikely event of a fire causing evacuation of the main control room.

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NRC UESTION 410.49 Commit to provide technical specifications for surveillance requirements, and limiting conditions for operation of equipment required for alternative shutdown after a fire. Surveillance testing should include periodic initiation, and operation of equipment from the emergency control station, which the applicant selects to operate from, upon vacating the control room; surveillance testing should be conducted at least once every 18 months. Specify the systems or equipment to be tested, and the individual surveillance tests for that equipment or those systems.

CP&L RESPONSE In CP&L's July 16, 1984 submittal (410.32), CP&L committed to provide technical specifications for equipment and controls required for the postulated scenario of a fire requiring shutdown from outside the control room. CP&L's submittal of Draft Technical Specifications for SHNPP will be submitted to the NRC in April, 1985.

NRC UESTION NO."410.50 An electrical isolation deficiency has been identified in which fuses in transfer switches might have had to be replaced in order to maintain a hot shutdown condition. This deficiency is discussed in the attachment (Appendix A). Provide notification as to whether a similar problem exists in the transfer switches in the Shearon Harris Plant. If such a deficiency exists in the Shearon Harris Plant, you should further advise us as to how this deficiency will be corrected as discussed in Appendix A.

RESPONSE

An electrical isolation deficiency such as that described does not exist at the Shearon Harris Plant. 120VAC essential control circuits cables have been isolated with transfer switches and provided with redundant fuses in the motor control centers or transfer panels. This is also true for 125VDC control circuits except breaker control and the diesel generator control circuits.

As part of the Shearon Harris Plant design, only the positive leg of the control circuits identified above are switched at the Hain Control Board. The only negative legs in the 1fain Control Board are for the indicating light circuits of air operated and solenoid Operated Valves as shown on the attached figure. The grounding of a positive leg of an essential 125VDC circuit coincident with the grounding of one of the negative legs in another cable having the same DC common is considered unlikely in view of the following design features of the Shearon Harris Hain Control Board: a) Low combustible loading, b) Use of Fire retardant materials, c) Use of enclosed switch modules, d) Use of individual flex conduit enclosed panel wiring for each switch module. Based on the above, CP&L feels IBMD-WKDB02-OS4 Page 8 of 19

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it has demonstrated that non-grounded cable-to-cable DC shorts are improbable.

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NRC UESTION 410.51 Safety-related air handling units AH-12 and AH-13 utilize coolant from the Essential Services Chilled Water Systems (ESCWS). In each case both trains (A and B) of these air handling units are separated by less than 20 feet and, thus, both trains may be damaged in a single fire. Show, in the event of a fire damaging both redundant air handling trains of either unit, that both trains of the ESCWS are not damaged or destroyed.

CPSL RESPONSE Air handling units AH-12 and AH-13 are constructed of an exterior casing of 14 gauge carbon steel. The units are physically separated by a three-hour fire wall. The following is a description of the protection and combustible loading found in each fire zone.

Fire Zone 1-A-5-HVA (FAABL5-5-HVA) Early warning ionization detection is provided throughout the fire zone. A hose station, portable extinguisher and manual alarm station are provided in the fire zone. The combustible loading for the fire zone is 18,100 BTU/sq.ft.

Fire Zone 1-A-5-HVB (FAABL5-5-HVB) - Early warning ionization detection provided throughout the area. Hose stations, portable fire extinguishers, and manual alarm stations are provided in and adjacent to the zone. The combustible loading for the Fire Zone is 60,000 BTU/sq.ft.

The combustible loading described above does not exist within'the air handling units. The motors which power the fans are located on the outside of the units. The SA and SB cooling coils internal to the units are located approximately 45" from each other. The safety-related chilled water piping is fed from opposite sides of the unit and is constructed of sch. 40 carbon steel. The chilled water control valves to the air handling units are three-way valves; therefore, the function of the system is assured regardless of the valves position.

Due to the lack of combustibles within the unit, the low area combustible loading, the protection and detection provided and the materials of construction, CP&L does not consider this an area of concern.

NRC UESTION 410;52 Show that, in the event of a single fire damaging motor operated valves 3SW-B70SA-l, 3SW-B71SA-1, 3SW-B72SB-1, and 3SW-B73SB-1, cold shutdown can be achieved without any adverse effects. Drawing CAR-SH-SK-688S09 shows the location of these valves.

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RESPONSE

Valves 3SW-B70SA-1, 3SW-B71SA-1, 3SW-B72SB-1, and 3SW-B73SB-1 are back-up supply valves to the suction of the Auxiliary Feed Water Turbin~

Driven Pump 1X-SAB. Should a single fire damage these valves, the normal feed to the pumps (Condensate Storage Tank) would not be impaired. The Condensate Storage Tank is capable of supplying a source of water for the steam generators for up to 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />. CP&L's response to previous NRC Question 410.23 identified that auxiliary feed water is

.needed for two hours, twenty-five minutes. In the unlikely event auxiliary feed water is required in excess of sixteen (16) hours, sufficient time is available to provide make-up to the Condensate Storage Tank, or to position valves 3SW-B73SA-1 and 3SW-B75SA-1 to supply alternate iced from the service water system to Auxiliary Feed Water Pump 1ASA.

NRC QUESTION'410".53 Your response to Question 410.28 regarding associated circuits appears to be ambiguous, in part. In order to clarify your response, please provide the following information:

a~ With regard to associated circuits having a common power source, you stated that power feeder(s) from buses, power centers and motor control centers are provided with breakers or fuses to isolate fire-induced electrical shorts so as to prevent tripping of or damage to the power source.

Show that you have considered suitability of the interrupting devices in accordance with the criteria of Section II.b.2 of the letter forwarded to you on October 18, 1983 (also attached herein as appendix B pages 4 and 5).

RESPONSE

Section 8.3.1.1.2.11 of the Shearon Harris FSAR provides a description of the electric circuit protection system provided. All electrical equipment is designed and manufactured to applicable ANSI, NEMA, IEEE and other industry standards. A breaker coordination study will be been performed for the Shearon Harris Nuclear Plant and periodic testing shall be performed to demonstrate that the overall scheme remains within the design criteria for low and medium voltage switch gear. Molded case circuit breakers that supply penetrations will be tested as required by regulatory guides.

NRC QUESTION: 410.53

b. With regard to associated circuits for equipment whose spurious action would adversely affect shutdown capabilities, you state that control circuits of such equipment have been identified. Further, you state that cables for these control circuits have been evaluated to assure conformance with Section III.G of Appendix R. Provide information to the staff to assure conformance with Section III.G.2 of Appendix R.

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Cable itl above is a 125 VAC control or power cable for an "associated" piece of equipment. Cable 82 is a "Non-Essential" control or power cable. In order for a spurious actuation of the equipment powered by cable fI2 eo occur due to a cable to cable fault the following would have to occur: Conductor A in Cable //1 would have to be exposed thxough ehe cable outer jacket and its own insulation. Conductor C in Cable f!2 would have to be energized.

Conductor C would also have to be exposed as was conductor A.

Conductor A and C would then have to come into good electrical contact with each other. However, if eieher conductor A contacts conductor B or conductor D contacts conductor C then spurious aceuaeion could noe occur. In addition to the above, if either conductor A or C contacts the raceway prior to the above actions then spurious actuation cannot occur.

IBMD-WKDB02-OS4 Page 17 of 19

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, NRC QUESTION 410.54 We have a concern regarding the potential for multi-high impedance faults in AC power circuits which could result in the loss of power to safe shutdown equipment. Figure 1 contains a sketch of circuit designs which, could result in the loss of needed power to safe shutdown equipment. As can be seen in Figure 1, redundant divisions of safe shutdown cables are properly separated in accordance with Appendix R criteria. However, a fire in fire area A could result in loss of Division A safe shutdown equipment and cause damage to nonsafe shutdown cables associated with the Division B bus.

Further, the individual fault current resulting from the fire, damage in the nonsafe shutdown cables may not be enough to trip the individual breakers (B and B ), but the sum of the faults may be sufficient to trip the main breaker, B3. If this were to occur, the Division B bus and the corresponding redundant Division B safe shutdown would be lost. You must show that multi-high impedance faults in AC power circuits resulting from a single fire cannot result in the loss of function of any safety-related system as outlined above.

RESPONSE

Carolina Power and Light Company as a member of the Nuclear Utility Fire Protection Group (NUFPG) endorses the answer in regards to high impedance faults filed with the Commission on February 14, 1985, in response to Generic Letter 85-01. (letter to Harold R. Denton from J. Michael McGarry III). This response is reproduced below:

4. uestion 5.3.8 (hi h im cdance. faults)

The response to Question 5.3.9 states "To meet the separation criteria of Section III.G.2 and II.G.7 (sic) of Appendix R, high impedance faults should be considered for all associated circuits located in the fire area of concern." It is the Group's position that the response to Question 5.3.8 goes beyond the design review required by Appendix R. Appendix R,Section III.G.2, requires protection of associated non-safety circuits which could degrade or prevent operation of safe shutdown systems through failure caused by hot short, open circuits, or shorts to ground. The rule does not, however, expressly require consideration of multiple high impedance faults.

Although a high impedance fault might occur in a cable subjected to fire damage, current industry codes for fault current calculation preclude the possibility of supply breaker trip for any one such fault occurring in a branch circuit. Postulating multiple high impedance faults simultaneously in branch circuits goes beyond the bounds of conservative electrical distribution design. In such a scenario, each branch circuit cable (carrying a different load current), would have to fail along its length in such a manner as to result in a unique insulation resistance that will produce a leakage current to ground (or conductor to conductor) which added to the conductor load would result in a current just below the protective IBMD-WKDB02-OS4 Page 18 of 19

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device rating. Thus, an improbable combination of temporary leakage currents in different cables would have to occur at once to produc~

a high impedance of sufficient magnitude to be of concern. In our view an analysis of such an event would be neither beneficial nor necessary. CP&L will add a general note to the Post Fire Recovery procedures to alert plant personnel to clear non-essential loads from a tripped bus (in the unlikely event the bus feeder breaker trips) prior to reclosing the feeder breaker.

NRC'QUESTION NO. 410;55 In question 410.53 above, you have been asked to verify that cables which could result in spurious action as a result of a fire are separated in accordance with a specific portion of Section III.G of Appendix R. Show that spurious action cannot result from cable-to-cable and wire-to-wire faults of nongrounded two-wire DC power circuits.

RESPONSE

See response to NRC question number 410.53 (b).

IBMD-WKDB02-OS4 Page 19 of 19

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ATTACHMENTB

~CtC i Ol A4 Instrument Air Testing - Particulates - In a November 0, 1983 response, you agreed to test for particulates in the instrument air system using an acceptance criteria of three microns. In a subsequent response, on 6/21/80, you stated that sampling for particulates is to be used to verify proper filter operation since filters are to be utilized in front of safety-related air-operated valves to protect them from particulate matter in sizes in excess of those which permit continued valve operability. In this response, you stated the intent to use the three micron level as a goal rather than an acceptance criteria.

Describe the plan which will be used to determine particulate size acceptance criteria when testing air quality during operation. Also provide information regarding the periodicity selected for inspection of filters in front of valves.

RESPONSE

Component filters will be provided in the design to protect safety-related air operated valves as described in our response of June 21, 1980. Therefore, no absolute limits are required on particulates that enter or are contained in the instrument air system. The previous response stated that a filtration of particles greater than 3 microns in size would be used as a goal for air entering the system because this value could only be obtained if the air filtration was highly efficient. While 100% efficiency is a desirable goal, it is not required as an acceptance criteria based on the use of component filters and inspection/replacement of these filters as discussed below. In lieu of specific exceptence criteria, the operation of the filtration will be monitored and if the efficiency of the filtration for particles larger than 3 microns is less than 9596, then the operation of the filters will be investigated and corrective actions identified. The number and size of particles will also be monitored to determine if there is a significant increase in particle size/quantity for particles greater than 3 microns in size. If a substantial increase is identified, then the filtration will be investigated and corrective actions identified. These performance criteria will be modified as necessary based on operating experience with the instrument air system and compatibility with the actual air requirements for safety-related air operated valves.

With regard to the inspection of filters in front of valves, the filters will be replaced at least once every refueling outage. This surveillance interval will be modified if experience indicates that a more frequent change-out is required or a less frequent change-out if it can be tolerated.

N~C Instrument Air Testing - Dew Point and Oil Content - You committed to test for dew point and oil content in addition to particulate size at every refueling with an acceptance criteria of -20 degrees F for dew point and less than 1 ppm for hydrocarbons. Show that the dew point is (13340CH/pgp)

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RESPONSE

The dew point acceptance criteria will be in accordance with the recommendations of ANSI MC l l.l-l976. The testing of instrument air for dew point will be done at least annually. Furthermore, the surveillance interval may be shorter and will be modified as necessary by equipment performance.

The acceptance criteria for dew point will be -25 degrees F. The lowest

'istorical outside air temperature experienced at the site is -7 degrees F (this occurred in 3anuary 1985). Selection of an acceptance criteria of -25 degrees F satisfies section 0.0.1 of MCC l l.l-l976.

(13340CM/pgp)