ML17328A510

LER 90-009-00:on 900921,potential Loss of Control Room HVAC Noted During Postulated Fire W/O Conpensatory Action.W/ 901019 Ltr

ML17328A510
Person / Time
Site:	Cook
Issue date:	10/19/1990
From:	Blind A, Brewer S INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-009-02, LER-90-9-2, NUDOCS 9010290037
Download: ML17328A510 (9)

Text

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9010290037 DOC.DATE: 90/10/19 NOTARIZED: NO DOCKET FACIL:50-316 Donald C. Cook Nuclear Power Plant, Unit, 2; Indiana & 05000316 AUTH. NAME AUTHOR AFFILIATION BREWER,S.J. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele BLIND,A.A. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 90-009-00:on 900921,potential loss of control rroom NVAC during postulated fire w/o conpensatory action.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR I ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

'RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-1 LA 1 1 PD3-1 PD 1 1 COLBURN,T. 1 1 INTERNAL: ACNW 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DS P 2 2

-NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E 1 1 ~NRR/J3~% PLB8 D 1 1 1 NRR/DST/SRXB 8E 1 1 G~LM FILE 01 02 1 1 RES/DSIR/EIB 1 1 RGN3 1 1 EXTERNAL EG&G BRYCE i J ~ H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHYgG A 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALI "RIDS'ECIPIENTS:

PLEASE HELP US TO REDUCE O'AS1'E! CONTACT THE DOCUMENT CONTROL DESK, ROOiiI Pl-37 (EXT. 2N79) TO ELlihllNATEYOUR NAiXIE FROiv! DISTRIBUTION LISTS I'OR DOCUi~!ENTS YOU DOiN'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 30 ENCL 30

Indiana Michigan Power Company Cook Nuclear Plant PO. Box 458 Bridgman. Ml 49106 616 465 5901 INDIANA MICHIGAN POMfFR October 19, 1990 United States Nuclear Regulatory Commission Document Control Desk Rockville, Maryland 20852 Operating Licenses DPR-75 Docket No. 50-316 Document Control Manager:

In accordance with the criteria established by 10 CFR 50.73 entitled Licensee Event Re orting S stem, the following report is being submitted:

90-009-00 Sincerely, A.A. Blind Plant Manager AAB:clj Attachment cc: D.H. Williams, Jr.

A.B. Davis, Region III M.P. Alexich P.A. Barrett J.E. Borggren R.F. Kroeger B. Walters Ft. Wayne NRC Resident Inspector T. Colburn NRC J.G. Keppler M.R. Padgett

'..'.. G. Charnoff, Fsct.

Dottie Sherman, ANI Library D. Hahn INPO S.J. Brewer/B.P. Lauzau B.A. Svensson ~ E2-Z I))

NRC FORM 366 (64)9)

LICENSEE EVENT REPORT ILER)

U.S. NUCLEAR REGULATORY COMMISSION t APPROVED OMB NO. 31504))04 EXPIRES! 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION AEOUESTt 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON. DC 20555, AND TO THE PAPERWORK. REDUCTION PROJECT (31500104). OFFICE OF MANAGEMENTAND BUDGET,WASHINGTON,OC20503.

FACILITYNAME (1) DOCKET NUMBER l2) PA E D. C. Cook Nuclear Plant, Unit 2 o 5 o o o 31 610F06 Potential Loss of Control Room HVAC during Postulated Fire,'ithout Com ensator Action, due to Pversi ht in A endix R Loss of HVAC Stu d EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (SI MONTH OAY YEAR YEAR IMI SEQUENTIAL :pyc REvstoN MONTH OAY YEAR FACILITYNAMES DOCKET NUMBERISI NUMBER NUMbER D. C. Cook, Unit 1 o so o o3 0 9 2 1 9 0 9 0 0 0 9 0 0 1 0 1 9 9 0 0 5 0 0 0 THIS REPOAT IS SUBMITTED PURSUANT T 0 THE REQUIREMENTS OF 10 CFR g: /Cnrclt onr or motr of tnr followinp) (1'll OPERATING MODE (0) 5 20. 402 (b) 20.405(c) 60.73( ~ )(2Hivl 73.7)(II)

POWER 20.405( ~ ) ll Ii)) 50.36(c))11 60.73NH2)(r) 7(L71(cl LEVEL (10) p p p 20.405 (e IllI(i)I 50.36(c)(2) 50.73(e)(2) (v)l) OTHER /SPrctfy tn Abtttrct priow rnd In Trrt. HRC Pofm 20.405(e ) (1)(ill) 60.73( ~ ) (2)(i) 60,73(el(2)(riii)IA) 36'SA/

20.405(e)(1)(iv) 50.73( ~ l(2)(e) 50,73(e I (2)(v ii)) I 8 I 20A05( ~ l(1) (v) 50.73( ~ l(2)(iii) 50.73( ~ ) l2) I e I LICENSEE CONTACT FOR THIS LER (12I NAME TELEPHONE NUMBER S. J. Brewer, Nuclear Safety and Licensing AREA CODE Section Manager 614 223 -2 020 COMPLETE ONE LINE FOR EACH COMPONENT FAILVAE DESCRIBED IN THIS REPORT (13I go MANUFAC qY' MANUFAC. EPOATABLE CAUSE SYSTEM COMPONENT TO NPRDS <nt 9 CAUSE SYSTEM COMPONENT TURER TVRER TO NPADS SUPPLEMENTAL REPORT EXPECTED l14) MONTH DAY YEAR EXPECTED SUBMISSION DATE (16)

YES /lf yrt, complrtr EXPECTED SIISMISSIOH DATE/ NO ABSTRACT ILimlt to /400 tprcrb Ir.. rpproeimrtrly fifNrn elnplr lprcr typrwnttrn linm/ (16)

On Se~xz 21, 1990 during an investigation concexning the need for Control Room Heating, Ventilation ard Air-Corditioning (HVAC) Systen for safe shutdown of either unit, it Fire Zones 44N/44S, 51/52 or 69 could cause a loss of both primary and was determined that a single fire in redundant HVAC Systems for both control rocans which is not currently covered by Plant procedures.

IacnaHately upon determination that the problem existed, fire watches were posted for the aff~ areas. 'Ihe long-tenn corrective action is to institute procedures to cope with fire-irduced loss of normal control rocan HVAC. lhe primary cause of the condition was an oversight in the HVAC Systems evaluated. for the Appendix R loss of HVAC study.

Without in-place procedures and training, the exact course of events for the postulated fire cannot be deten()ined. However, actions are taken to mitigate a rise in control rocan temperature following if reasonable operator a fire, the control room(s) would not require evacuation due to habitability or equipment operability concerns for a nun)ber of hours.

Based on this, we believe this cordition does not represent a significant hazard to the health ard safety of the public.

NAC Form 366 (669)

NRC F 0 RM 366A U.S. NUCLEAR REGULATORY COMMISSION (64)9) APPROVED OMB NO. 31504)104 EXPIRES: 4/30/92 LICENSEE EVENT REPORT ILER) ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 603) HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P.530), U.S. NUCLEAR REGULATOR> COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3(504)104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON. 00 20503.

FACILITYNAME (ll DOCKET NUMBER (2)

I.ER NUMBER (6) PAGE (3)

D. C. Cook, Unit 2 YEAR BIO SSOUENTIAL NUMSSR REVISION NUM SR TEXT ///mors 4/rsso/s rsr/Ir/rsd, oss sddrr/oos//VRC Form 3r/SAB/(17) 0 5 0 0 0 3 9 0 009 00 02 OF 06 Conditions Prior to Occurrence Unit 1 in Node 1 at 100 percent Rated 'Ihermal Power.

Unit 2 in Mode 5 (Cold Shutdown) .

Descri ion of Event During an investigation concerning the need for control room Heating, Ventilation and Air-Conditioning (HVAC) System (EIIS/VI) for safe shutdown of either unit, it was determined that a single fire in either fire zone 44N/44S, 51/52 or 69 could cause a loss of both primary and redundant HVAC Systems for both control rooms. Calculations performed during the evaluation of the need for control room cooling following an Appendix R fire revealed that control room temperatures would increase to unacceptably high values within several hours unless the operator takes simple actions to mitigate the ten(perature rise. Even without operator action to restore cooling, the Plant'could have achieved Hot Standby before control room temperature increase became a co~.

The control rooms at. Cook Nuclear Plant are each provided with a control room ventilation system that includes two air-conditioning systen(s, each of which is capable of providing 100% of the capacity. Lhe two air-conditioning systems for each unit share a common r~ed airconditioning air distribution (duct) system. Each system includes a liquid chiller, air handling unit, circulating water pump, water piping, duct heaters, humidifier, mUang valves, duckwork, Ch((pers, and auto(matic controls.

In order to determine whether a fire posed a cc(mmon failure mode for the control room ventilation systems, the cable routings (EIIS/VI~) for the power and control cables associated with the air handling unit were determined. 'lhe cables associated with the remainder of the contxol roc(m ventilation system were not evaluated. 'Ihe reason for not including cables associated with chiller operation is that as long as an air handler ventilation fan (EZIS/VI-FAN) is running, the control room can be maintained below 120 degrees F by manually diverting essential service water (ESW) directly through the water coils of an air handling unit.

Present Plant procedures provide the control switch positions and manual valve operations necessary to establish this mode of control room cooling in the event that both chiller packages fail while the air handling units are functional.

'Lhe initial investigation of electrical cable routings associated with the control room air handling units reviewed the routing of: 1) the poorer cable for the ventilation fan motor between its motor control center (MCC) and the air handling unit'.; and 2) control cables associated with the air handling unit. A review of these cable routes determined that electrical NRC Form 366A (64)9)

NRC'FORM 366A V.S. NUCLEAR REGULATORY COIAMISSION APPROVED 0MB NO. 31504)104 (64)9)

E XP IR ES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT ILER) INFORMATION COLLECTION REQUEST.'0D HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (PJ)30), V.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104), OFFICE OF MANAGEMENTANO BUDGET, WASHINGTON. DC 20503.

FACILITYNAME (11 DOCKET NUMBER (2I LER NUMBER (6) PAGE I3)

YEAR SEQUENTIAL IIEVISION oXa NUMBESI NUMBEII D. C. Cook, Unit 2 0 5 0 0 0 3 I 9 0 009 00 03 oF 0 TEXT /llmort s/Mst is tsar/rtd, rrst tddr)r)rrMIAIRC Form 3664'4/ Ill) cables for the redundant air handling units for both control roams were located in Fire Zones 6M, 44N, 52 and 69.

Since Fire Zone 6M is cornl(an to both Units 1 and 2, the HVAC cable routing in adjacent fire zones was not needed for further analysis. In FZ's 44N/44S and 51/52, the cabling for all four of the HVAC units is within 20 feet of each other; and in FZ 69 the cabling for three of the four HVAC units is within 20 feet of each other. In addition, in FZ s 51/52 and 69, same of the Unit 1, Train A and B cables are routed in the same tray. Due to this lack of separation between these cables, even the low fixed combustible loadings for these areas could nat prevent a postulated fire from resulting in a loss of scane of the cables. In FZ 6M, it was deternuned that at least one HVAC unit fram Unit 1 and Unit 2 would survive. Iherefore, Fire Zone 6M was removed fram the unacceI<able list.

Fire Protection systems are provided in FZ's 44N/44S, 51/52 and 69. An ionization detection system is provided in each of these fire zones in the areas where the HVAC cables are routed. Khese detection systems would provide early warning fire detection in the Unit 1 Control Roam. Upon notification, the control room operators would initiate manual fire fighting activities. %he fire brigade would utilize the available manual fire fighting ectuipment to control and/or extinguish the fire. Ihe fire brigade's activities would assist the autcanatic fire suppression systems provided in FZ's 44N/44S, and 51/52.

Ihe sprinkler systems in FZ's 44N and 44S are located beneath the auctions caused by cable trays, corduits, piping, etc. Lhese sprinkler systems would control and/or extinguish a floor-based fire, but would not be able to control or extinguish a fire in the cable trays above. 'Xhese fire detection and suppression systems would be able to mitigate the extent of the fire's damage, but may not be able to prevent damage to all of the HVAC cables located in these fire zones.

Assuming a loss of ventilation to the control roams, an evaluation was needed to examine control roam temperature response. %he initial evaluation of loss of control roam cooling condition concluded that control room temperature would reach 120 degrees F in two hours, 135 degrees F in ten hours and 175 degrees F at the end of the 72-hour period evaluated. 'Ibis evaluation assumed normal control roam electrical heat gains without a count loss of off-site power. Upon discovery that a design basis fire could render the control roam cooling systems inoperable, the condition was reported to the NRC under 10 CFR 50.72 Section (b) (ii) (C), "In a condition not covered by the Plant's operating and emergency procedures," on Septen8m 21/ 1990 ~ Huis det(Q~ination was made because Plant procedures do not provide guidance for restoring control room cooling following the postulated scenario. Additionally, a roving fire watch was established in the fire areas of concern as an interim compensatory mea.~e.

NRC Form 366A (64)9)

NRC'FORM 366A US. NUCLEAR REGULATORY COIAMISSION APPROVED OM 8 NO. 3)500104 (686)

E XP I R ES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REOUESTI 500 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P4)30), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PRO/ECT (31504104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503, FACILITYNAME (I) DOCKET NUMBER (2I LER NUMBER (6) PAGE (3) gg. SSOVSNTIAL a' R 6 V IS I 0N D. C. Cook, Unit 2 NVMSSII . cS NUMSSR 0 5 0 0 0 3 ]. 6 9 0 009 0 0. 0<oF0 6 TEXT /I/mori spiceis rtr/o/rtd, osi tdditr'or>>/NRC Form 366A'4/ (17)

Further control roam tett(perature evaluations were performed to deternune whether operator actions that could reasonably be expected to be taken would mitigate the control room tengperature rise.

One of the potential operator actions that would have had a significant effect on reducing the control roam heat-up rate would be to shut off normal control r(xm lighting.and rely on emergency lighting. 'Ihis action, ccimbined with propping open the control roam doors leading to the turbine building, is expE~d to delay the time to reach 120 degrees F to 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> and reduces the maximum control roam tengperature to 133t9 degrees F. It is noted that loss of normal control room lighting. would occur if the Plant ~mrienced a loss of off site power concurrent with the fire.

'Iherefore, a loss of off site power scenario is less severe with respect to fire-induced loss of control roce cooling.

A poll of operators revealed that most operators would try to mitigate the control room heat-up by propping open both the control roc'oors leading to the turbine building and the door leading to the auxiliary building and using portable fans to force air to circulate thrmxjh the control roam.

It is reasonable to expect that power will be available for povering portable electric fans during an Appendix R fire scenario when offmite pcarer is available. A control room temperature evaluation assuaung normal control room lighting and a 4000 cfm portable fan flow rate would delay the time to reaching 120 degrees F to ten hours and would aunimize the maximum control room temperature to 132.2 degrees F.

An almost infinite number of response models could have been evaluated.

Without in-place proccxhu.-es and training, the exact course of events for the postulated fire cannot be deternuned.

Cause of Event

'Ihe primary cause of the condition was an oversight in the HVAC Systems evaluated for the Appendix R loss of HVAC study. 'Ihe study did not include an evaluation of the susceptibility for loss of control room HVAC systems due to fire or analyze the resulting control room

. temperature increase for such a scenario. 'Ihe control roam HVAC Systems were omitted from the study due to the lack of high heat genexating equipmnt in the control roam, and because our station blackout study indicated that control room ten)perature would only increase to approximately 104 degrees F after four hours. In addition, every safety-related HVAC System normally considered to be required for safe shutdown should have either been evaluated for the effect of loss of HVAC, or should have been documented to have been protected from fire. 'Ihe control roam was a system identified with no evaluation performed; NRC Form 366A (64)S)

NRC'FORM 366A US. NUCLEAR REGULATORY COIAMISSION (649) APPROVED OMB NO. 3(500(04 EXPIRES: d/30/92 LICENSEE EVENT REPORT ILER) ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50A) HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (F430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150410S), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME 11) DOCKE'T NUMBER (2)

LER NUMBER I6) PAGE (3)

YEAR SEQUENTIAL AEVISION D. C. Cook, Unit 2 NVMBEII NVMSEA o 5 o o o 316 9 0 009 0 0 0 5 oF06 1 ExT In'ars srrsss ls rsordrsd, uss sddr(rbrrsr ivRc Form 366sr'sl I )7)

Anal is of Event 10 CFR 50.73 Section (a) {2) {ii)(C) requires that conditions resulting in the Nuclear Pcarer Plant being in a condition not: covered by the Plant's operating and emergency procedures to be reported. Our investigation of control roam HUE revealed that certain fires have the ability to 'he disable the Control Rc)am Ventilation System for both control roan)s. It has been demonstrated that control roam cooling is needed to maintain control roam operability/habitability following such a fixe and that operator actions may be r~ed to mitigate control roam'heat-up. Since the actions required to restore control roam cooling capability have nat been incorporated into Plant reportable per 10 CFR 50.73 Section (a) (2) (ii) (C);

pries, the condition described is An almost infinite number of response models cauld have been evaluated.

With in-place p~ures and training, the exact course of events for the postulated taken fire cannot be determined. However, to mitigate a rise in control roam tetnperature following a design if operator actions are basis fire, the control roam(s) would not require evacuation due to habitability or equipment operability concexm for a number of hours. We believe that this would have allawed the Plant to proceed to cold shutdcm conditions while additional control room ventilation restoration actions are taken to ensure that long-term contxol roam temperatures are limited to acceptable values. Based on this, we believe this condition does not represent a significant hazard to the health and safety of the public.

Corrective Actions Immediately upon detmx6nation of the problem, fire watches were posted for the affect~ area. %he roving fire watch will continue to be posted in the areas of concern until: 1) Plant procedures are revised to incorporate actions for restoration of control roam cooling capability in the event of fire-induced loss of this capability; 2) the necessary repair equipment is made available and MCC poorer supplies called for in the restoration. procedure have been cammitted for Apperdix R use; and

3) cognizant personnel are made aware of the actions required to mitigate the loss of control roam cooling during a fire. 'Ihe long-term corrective action is to institute procedures to cope with fire-induced loss of normal Control Roam HVAC. 'Ihe procedure will provide detailed steps necessary to te(nporarily repowex the fans in case of fire-,induced failure. 'Ihe procedural changes will be coupled with: 1) assuring that MCC's are available and controlled; ard 2) assuring that wiring necessary to make the temporary ~es is dedicated and conveniently available. In addition to the above actions, additional documentation changes are

%he wall between the control roam machine roams (HVAC equipment rooms) is NRC Farm 366A (649)

NRC FOAM 366A" US, NUCLEAR REGULATORY COMMISSION APPROVEO OMB NOi 3(500104 (649) EXPIRES: O/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT ILER) INFORMATION COLLECTION REQUEST: SOS) HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION., AND REPORTS MANAGEMENT BRANCH IP430). U.S. NUCLEAR REGULATORY COMMISSION WASHINGTON, OC 20555 AND TO THE PAPERWORK REDUCTION PROJECT (315041(M). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, OC 20503.

FACILITY NAME (I) DOCKET NUMBER (2) LFR NUMBER (6) PAGE (3)

SEQUENTIAL +EYISION YEAR NUMB( A NVMSS II D. C. Cook, Unit. 2 o s o o o 316 9 0 009 00 06 OF 0 6 TEXT /I/ rrroro J/roco /s ror/rr/rod, oso oddrteno/ NRC Form 3//SAS / (17) currently maintained as a three-hour barrier. The following documents need to be revised to reflect the need for this barrier to remain intact follmring a fire in either machine r(xm:

Fire Protection Program Manual Safe Shutdown Capability Assessment Fire Hazard Analysis Safe Shutdown System Analysis We are also considering protecting or rerouting the HVAC cables of concern as a long-term corrective action.

At the time the loss of HVAC evaluation was performed, there were no formal proc(xIures requiring documented information for such evaluations.

Since this evaluation was performed, we have reorganized. New procedures developed after the reorganization include r~ements to document information such as the safe shutdown equipment list for Appenlhc R. It is unlikely that a similar situation would recur. Iherefore, preventative actions have already been taken and no further actions are required.

Failed nent Identified Not Applicable Previous Similar Events 050-315/90-6 050-315/90-8 050-315/90-10 050-315/88-14 NRC Form 366A (SJ)9)