ML18018B650

Forwards Addl Info Re Essential Svcs Chilled Water Sys,In Response to NRC 840411 Request

ML18018B650
Person / Time
Site:	Harris
Issue date:	05/15/1984
From:	ZIMMERMAN S R CAROLINA POWER & LIGHT CO.
To:	DENTON H R Office of Nuclear Reactor Regulation
References
NLS-84-198, NUDOCS 8405250055
Download: ML18018B650 (11)

Text

DOCKET¹'5000400 NOTES: ')'REGULATIOIFORMATION

'DISTRISUTIOI+INEM (RIOS)ACCESSION NBR:8405250055)

.DOC UPDATES 84/05/15 NOTARIZED!" NO" FACIL:50-400 Shearon Harris Nuc,lear Power P.lanti;Unit) li Carol'ina AUTH~NAME~AUTHOR AFFILIATION ZIMMERMANiS

~R~'ar ol ina Power 8 Light Co.RKC IP~NAME REGIP'IENT'FFILIATION DKNTONiH~RE'ffice of Nuclear Reactor Regulation~

Director

SUBJECT:

Forwards addi~info, re essentia,l aves chilled water sysiin response to NRC 840411,request; DISTRIBUTION CODE,: B001S COPIES RECEIVEDGLTR f ENCLI SIZES (I 5 TITLE: Licensing Submittal i PSAR/FSAR Amdts L Re)lated Cor respondence RECIPIENT ID COPE/NAME NRR/DL/AOLI NRR LB3 LA',INTE/NAL s ELD/HDS1>>IE/DEPER/EPB 36 IE/DQASI P/QAB21.NRR/DK'/CEBt 11 NRR/DK'/EQB 13 NRR/DE'/MEB 18 NRR/DK/SAB

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Dear Nr.Denton:

Carolina Power&Light Company hereby submits additional information on the Shearon Harris Nuclear Power Plant Essential Services Chilled Water System.This information is submitted in response to the NRC request for additional information dated April 11, 1984.If you have any additional questions on this subject, please contact our staff.Youxs very truly, JHE/ccc (9945JHE)Attachment S.R Zi erman ger Nuclear Licensing Section cct Hr.BE C.Buckley (NRC)Hr.G.F.Maxwell (NRC-SHNPP)

Hr.J.P.O'Reilly (NRC-RII)Nr.N.Wagner (NRC-ASB)Hr Travis Payne (KUDZU)Hr Daniel F.Read (CHANGE/ELP)

Chapel Hill Public Library Wake County Public Library Hr.Wells Eddleman Dr.Phyllis Lotchin Hr.John D.Runkle Dr.Richard D.Wilson Hr.G.0.Bright (ASLB)Dx.J.H.Carpenter (ASLB)Hr.J.L.Kelley (ASLB)84052$005g'BPPgg FOR ADOCX OSaoaooo PDR 411 Fayettevilte Street o P.O.Box 1551 I Raleigh, N.C.27602 Oo T i'YP'>1 II', l-fl RESPONSE TO REQUEST FOR ADDITIONAL INF019fATION

-SHEARON HARRIS, UNIT 1 1.How are the water chillers seismically qualified to assure operability during an earthquake' A.Water chillers will be seismically qualified to assure operability by combination of analysis and test based on seismic acceleration input.The seismic qualification reports have not yet been received.These reports, when received, will be reviewed to assure that the chillers are seismically qualified.

2.Does the seismic qualification include the control panels attached to the chiller unit?These panels may contain numerous control relays which may not be permitted to"chatter" during an earthquake.

A.The chiller units, including attached panels, will be seismically qualified as a unit by combination of test and analysis to remain functional during and after a seismic event.Panel mounted control relays are energized during the seismic testing to assure that relay"chatter" will not impair chiller unit operability prior to, during and following an SSE.The seismic qualification reports have not yet been received.These reports, when received will be reviewed to assure that the chiller control panels are seismically qualified.

3.What are the limitations concerning restart of operating compressors following a loss of off-site power during an earthquake?

A.Following are the limitations concerning restart of operating compressors following a loss of off-site power during an earthquake.

a.Control power availability (constant power available from UPS).b.Water chiller control timer for stopping (116 sec.).c.Availability of power to oil pump (15 sec.block on D.G.sequence).

d.Water chiller control timer for starting (30 sec.).e.Availability of power to compressor (45 sec.block on D.G.sequence).

Total worst case time delay of compressor restart is on the order of 146 sec.4.Is the restart delay time acceptable?

A.Due to the relatively short duration, the restart delay time is considered acceptable.

5.Is the restart control circuitry control grade?A.All essential service chiller restart control circuitry is safety grade (i.e., Class 1E).(9945JHE/ccc)

~0'g tg III g~s I t II How is the compressor restart programmed into the diesel-generator loading sequence?Essential services water chiller loads are sequenced onto the diesel-generator as follows: a.."Start signal only" is energized in block//1 (t~10 sec.).b.Power available to chiller oil pump in block//2 (t~15 sec.).c.Chiller compressor is energized in block/f8 (t-45 sec.).After 45 seconds the chiller compressor start circuit will be energized provided all protective devices are aligned in the start position and the oil pressure is 30 psig.If the compressor breaker does not close in load block 8 (45 seconds)it will close automatically at any time after load block 8 after satisfying all protective interlocks.

Is the control panel and associated components environmentally qualified' CP6L is awaiting receipt of vendors'ualification reports.These reports when received will be reviewed to assure that the control panel and associated components are environmentally qualified.

How essential are the chillers?How long can the plant operate without them?The essential services water chillers are required for normal and post-accident plant operation.

The system has been designed to perform its safety function following a SSE while satisfying the single failure criterion.

Consequently one chiller train is always available.

In light of this no evaluation has been performed of the hypothetical condition of continued plant operation coupled with total loss of the essential services chilled water system.The SHNPP design includes certain non-safety-related HVAC systems in addition to the ESCWS.If the entire essential services chilled water system were to become unavailable, plant HVAC could be realigned to provide once-thru cooling.The availability, and effectiveness of optional sources of cooling depends on various factors including initiating events, ambient air conditions, availability of off-site power, qualification margin and so forth.What are the materials of construction of the chiller package?Have the materials been qualified for low-temperature operation during a seismic event?The materials of construction of the chillers are shown on the following enclosed drawings.1364-7702R5,-7703R5,-7704R4,-7705R4, 11946R3, 11947R3,-19166R4, 19167R4,-19174R4,-19175R4,-40075R3,-43351R3,-51098R1,-51099R1 (9945JHE/ccc)

>manufacturer materials selections are based on experience and the appropriate service conditions (e.g., low temperature (32'F operation)).

As previously stated the chiller units will be environmentally and seismically qualified thereby assuring their continued availability.

10.AH-12 (switchgear room)contains two coils, one on subsystem A and the other one on B.Is either centrifugal fan in AH-12 in close proximity of the two coils such as a fan failure will rupture both coils?A.Fan manufacturer calculation demonstrates that the fan housing will retain any internally generated missiles.Consequently coil failure due to internal missiles is not considered since the area does not include any other potential missile sources.Xf a simultaneous leak should occur in both chiller systems, how will it be isolated without damage to the chiller pumps?How much recovery time is available?

A, As previously stated, the ESCWS is designed in accordance with the single failure criterion and the appropriate guidance for moderate energy piping systems (i.e., FSAR Section 3').Accordingly, simultaneous failure has neither been postulated nor evaluated.

Refer to answer 8 for discussion of single failure philosophy.

12.The chilled water supply to AH-14 (non-essential equipment room)comes from both systems A and B through isolation valves.What signal isolates these valves in both chiller systems?'A.The isolation valves fail closed on loss of AC power.They also close on receipt of SIA signal.13'hat provision is made to isolate AH-12 and AH-13 from System A and B chilled water (no isolation valves shown in Figure 9.2.8-1)?A.AH-12 and AH-13 chilled water system"A" and"B" are not interconnected.

Therefore no isolation valves are required.14.Will a fire, or act of sabotage, in the vicinity of chiller A and its associated area coolers (AH-19 SA and SB supplied by chilled water A and B), which are physically close, wipe out all essential chilled water?What would be the consequences?

A.The loss, of both essential chilled water systems due to a fire in the area of chiller A is not considered plausible due to: a.the moderate combustible loading (88,000 BTU/SF)for the zone, b.early warning ionization detectors are provided throughout the area, c.thermal actuated multicycle sprinklers are provided throughout almost the entire zone and d.hose stations, portable fire extinguishers and manual alarm stations are provided in and adjacent to the area.(9945JHE/ccc)

Therefore, sufficient protection exists to ensure that a fire in this area will not disable both trains of chilled water.The physical security provided to the area in which the ESWS chillers are located is described in the SHNPP Security Plan.The protection provided to this system and to other systems in the plan have been found to be accepted by the NRC'staff.Each essential service chiller can be monitored in the control room or at its'ocal control panel.All monitoring instrumentation and controls are safety grade, physically and electrically independent.

The instrumentation, as described in PSAR Section 9.2.8.5, Table 9.2.8-2 and Figure 7.3'-16, Sheets 1-18, provides a full range of monitoring and indication thereby assuring that each essential services chiller train is operating correctly.

Should'problems develop, the instrumentation will alert the plant operators and operating procedures will detail required corrective actions.Por these reasons, simultaneous loss of both trains of essential services chilled water has never been assessed.15.Is AH-19 typically a single unit with system A and B chiller coils or are there two separate AH units'l A.AH-19 (1A-SA)and AH-19 (1B-SB)are two separate units.16'hat other forms of room cooling is provided in areas served by the ESP equipment cooling fan coolers?A.The essential services chilled water system consists of two (redundant) and independent trains.Additionally, non-safety-related HVAC systems are available.

If the entire essential services chilled water system were to become unavailable, plant HVAC could be realigned to provide once-thru cooling.The availability and effectiveness of"optional" sources of cooling depend upon various factors including initiating events, ambient air conditions, availability of off-site power, qualification margin and so forth.(9945JHE/ccc)

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