ML20245K906

Significant Deficiency Repts L2-89-08,38,43 & 45-48 Re Safe Shutdown Analysis.Corrective Actions Completed & Significant Deficiencies Considered Resolved

ML20245K906
Person / Time
Site:	Limerick
Issue date:	06/30/1989
From:	Kowalski S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CCN-89-11025, L2-89-08, L2-89-38, L2-89-43, L2-89-45, L2-89-46, L2-89-47, L2-89-48, L2-89-8, NUDOCS 8907050296
Download: ML20245K906 (7)

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PHILADELPHIA ELECTRIC COMPANY

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2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101

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(zis) s41-4som S. J. KOWALSKI VIC E-P R ESID E N T nucLean enormaamens US Nuclear Regulatory Corrmission' 10CFR50.55(e)

Attn: Document Control Center Washington, DC 20555 June.30, 1989

. Docket No.: 50-353 CCN-89-11025

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SUBJECT:

Limerick Generating Station,. Unit 2 i

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Significant Deficiency Report Safe Shutdown Analysis Deficiencies l

(L2-89-08, 38, 43, 45, 46, 47, and 48)

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REFERENCES:

(1) Telecon of June 2, 1989 from H. D. Honan (PECo) i to H. Williams (NRC)

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(2) Telecon of June 7, 1989 from M. Miller (PECo) to H.

I WI11Iams (NRC)

(3) Telecon of June 22, 1989 from M. Miller (PECo) to T. Kenny (NRC)

(4) Letter from S. J. Kowalski (PECo) to NRC entitled

" Supplemental Significant DefIclency Report, Safe Shutdown Analysis" dated May 31, 1989 1

(SDR-L2-88-07, SDR-L2-89-03, 04, 05, 06, 17, and j

SDR 249-2)

.l Gentlemen:

By telephone conference calls of June 2, 7, and 22, 1989, Phila-delphia Electric Company (PECo) reported six deficiencies with the Limerick i

Unit 2 safe shutdown analysis under 10CFR50.55(e). These deficiencies were l

Identified during the Limerick Safe Shutdown Analysis Improvement. Program discussed in Reference 4.

Our assessment and corrective actions for these.

deficiencies are discussed in the enclosed final significant deficiency

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report. The corrective actions were completed by Unit 211 censing. PECo considers these significant deficiencies resolved.

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PDC l

If you have any further questions at this time, please contact us.

MAM/ct/06068900 Enclosure cc:

W. T. Russell, USNRC, Administrator, Region I T. J. Kenny, USNRC, LGS Senior Resident Inspector R. J. Clark, USNRC, LGS Project Manager I

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l bec: S.:J. Kowalski G. M. Leitch L. B. Pyrih R. J. Lees l

G. A. Hunger, Jr.

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C. J. McDerTrott 1

E. J. Bradley W. J. Boyer, Jr.

A. S. MacAinsh M. S. lyer J. F. O'Rourke H. D. Honan G. J. Reid P. J. Duca j

i M. A. Miller l

N. Floravante DAC (NG-8) 1

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Enclosure j

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Limerick Generating Station, Unit 2

.Significant Deficiency Report i

Safe; Shutdown Analysis Deficiencies i

Description of Deficiencies In the June 2, 1989 telecon, PECo reported four safe shutdown l

CSSD) analysis deficiencies.

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I 1.

The first reportable condition was that a fire in certain--

j plant areas could result-In the spurious opening of high/ low pressure. Interface valves. - Spurious ~ opening of the residual-heat removal (RHR) shutdown cooling' suction valves (HV51-2F008 l

and F009) could result in possible overpressurization of the q

-low pressure piping. Also, spurious opening of three valves a

in series in the reactor water' cleanup (RWCU) system blowdown line (HV44-2F031, -2F033, and -2F034 or'-2F035) could result'in loss of reactor vessel inventory beyond makeup capabilities of

.j the RCIC.

2.

The second reportable condition was that in the event'of a fire in the auxillary equipment room infiltration of. smoke Into the rerrote shutdown panel (RSP) room through HVAC ducts connecting the two rooms had not been prevented.from occurring.

3.

The third reportable condition concerned the start of the RHR Pump A on Reactor Level I by either a valid process parameter or a spurious signal before transfer of control to the RSP in conjunction with fire-caused damage on the minimtm flow bypass isolation valve (HV51-2F007A) circuits.

In this scenario,.the pump could run without the minimtm flow bypass isolation valve open, causing ptrnp operation at zero flow to the point where pump damage may occur.

4.

The fourth reportable condition involved a fire in certain plant areas where the reactor core Isolation coo 1Ing (RCIC) or high pressure coolant-Injection (HPCI) systems would be utilized for safe shutdown.

In -responding to a lack of quall-fication of the barometric condenser subsystems, it was'de-termined that the environmental condition resulting from the--

postulated failure of the RCIC or-HPCI barometric condenser subsystems would not adversely impact operability of the'RCIC or HPCI systems. However, this conclusion: asstmed inmediate initiation of the single unit cooler, which is not available in post-fire conditions, in each of the RCIC'or HPCI compartments.

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By the telecon of June 7, 1989, PECo reported an additional SSD analysis deficiency. This reportable condition was that a fire in cer-tain plant areas could result in the loss of communication systems which would be utilized to support safe shutdown activities.

In a design basis fire, communication may be needed between the control room, the rerrote shutdown panel room, and the Operational Support Center, but may be un-available.

By telecon of June 22, 1989, PECo reported an additional SSD deficiency.

As part of the Safe Shutdown Analysis Improvement Program, a ventilation study was performed. The results of this study confirmed that portable fans would be required to maintain acceptable temperatures In the control room, auxiliary equipment room, and remote shutdown panel room to support operator actions and/or equipment operability. Except for the improvement program discovery, the installation of the portable fans would not have been ccmpleted as outilned in the Fire Protection Evaluation Report (FPER).

Safety Imp 1IcatIons 1.

The spurious opening of the high/ low pressure interface valves could ultimately lead to a lack of a viable means of achieving-safe shutdown due to a loss of reactor inventory that may exceed the makeup capability of RCIC for both the RHR valves and the RWCU valves.

2.

With a fire in the Auxiliary Equipment R,xm, smoke may travel through ventflatton ducts in this room to the RSP room. The possible infiltration of smoke into the RSP room could hinder operator access to the room thereby preventing safe shutdown.

3.

The deadheading of the RHR Pump A under design basis fire cond!-

tions could result in failure and unavailability of this pump which would be the only RHR pump available, thereby preventing safe shutdown.

4.

The inmediate non-availability of the room coolers and the postu-lated failure of the HPCI and RCIC barometric condenser subsystems may lead to envirortnental conditions which would adversely impact RCIC or HPCI operability, thereby preventing safe shutdown.

5.

The loss of communications between the control room, the remote shutdown panel room, and the Operational Support Center will hinder operator response, delaying initiation of safe shutdown systems and possibly preventing safe shutdown.

6.

As a result of a design basis fire, the potential existed that the ventilation system for the control room, auxiliary equipment room and remote shutdown panel room would be rendered inoperable. The resulting increasing temperatures in these three areas potentially could (a) render safe shutdown equipment inoperable and/or (b) chal-lenge the habitability of these areas in wh!ch operator actions would have to be performed. Either of these two conditions would impact the ability to achieve a safe shutdown condition.

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.s Corrective Actions i

1.

Spurious operation (opening) of the outboard RHR shutdown cooling suction valve (HV51-2F008) which would result.In overpressurization of-the low pressure piping has been prevented by instituting a procedure which requires an operator to de-energize and lock open the breaker 'for the valve. prior. to reactor pressure exceeding 75 psig.

This action insures that the valve wi11 remain in the closed position whenever reactor pressure is above 75psig.

An isolation switch has been installed in the power cable for one of l

the three in series valves (HV44-2F031).

This switch is. Installed I

outside of the fire area in which the three. In-series valves are l

located. This modification' prevents valve HV44-2F031 from opening during a fire thus limiting the reactor blowdown rate to a maximum of 110 gpm due to flow orifices'F044-20001A and.F044-20001B. The operation of the switch is contro11ed by. plant. procedures. Operators

'i will open this switch when RPV pressure is greater than 75 psig j

thus preventing spurious valve operation.

The switch will normally j

be opened during operation so that the potential flow rate past this -

valve due to the fire damage is limited to 110gpm.. The flow rate is well within the capability.of the RCIC, HPCI, and' RH1 pumps and will not impact the ability to safely shutdown the plant.'

2.

To minimize stroke inflitration into the RSP room in the event of a fire in the Auxiliary Equipment Room, we have implemented a rrodl-

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fication to maximize the airtightness.of the RSP room.. e have W

Installed Q-listed smoke dampers at the' exhaust and supply duct openings in the RSP room and reduced the exhaust direct. opening to 12 In. x 8 in.

These dampers are the secmd in series (behind a fire damper) and would prevent that stroke which seeps past the fire damper from entering the RSP. A member of the fire brigade w!11 manually isolate the newly-installed damper from inside the RSP following verification of a fire in the auxillary equipment room.

In addition, we have also Installed gaskets around the, door and caulked fire penetration seals to further minimize smoke inleakage to the RSP.

3.

The potential zero-flow operation of RHR Pump A has been resolved by changing the minirrtm flow bypass isolation valve from normally closed to normally open. With the valve normally open, it would take two fire-caused spurious signals (one to spuriously' Initiate RHR purrp operation and one to spuriously close HV51-2F007A) for the RHR deadheading situation to occur. The assumption of two spurious-signals is beyond current regulatory Interpretation. This corrective action' required no plant trodifications (i.e., no wiring changes) but only paper work changes.

4.

The Limerick Fire Protection Evaluation Report (FPER) did not evaluate the barometric condenser subsystems In the' event of a fire in the original safe shutdown analysis. Because of. environmental concerns, the possibility of losing the HPCI/RCIC barometric condenser subsystems as a result of a fire and the effects of this-loss on the L_________-_-_-

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safe shutdown capability was evaluated. This evaluation showed that the operability of the HPCI and RCIC systems would be unaffected by increased temperature in the HPCI/RCIC room compartments but that increased humidity in these compartments in post-fire condi-tions could affect operability of these systems. The necessary corrective actions have been completed to make the HPCI and RCIC systems noisture-proof and, as such, compensate for a possible loss of their barometric subsystems due to a fire.

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Communications between the control room, renote shutdown panel room, and Operational Support Center (OSC) (control points) will be accom-plished by the use of additional radio equipment.

Portable radio equipment has been installed in the RSP room and the OSC to allow communications between these control points and_ from these points to other plant areas. Monitoring equipment has been installed on the existing radio trunk lines (allowing communications from the control l

room) to detect fire or water damage and automatically separate the trunk lines from the communication lines to the radio repeaters.

Thus, in case of radio console fire damage, survival of the radio repeaters will be ensured allowing use of hand-held radios.

Battery backup cabinets (72-hour) have been installed on the two redundant repeaters containing the radio channels used by the control room.

This ensures continued operation of the repeaters in a loss of offsite power and diesels.

6.

Portable fans (and support equipment) have been located within the l

Plant in order to ensure adequate ventilation in the control rocm, auxillary equipment room, and remote shutdowr 9anel room to achieve safe shutdown. Additionally, information has,een provided to the operational staff regarding (a) when the fans are required to be in place and operational, (b) installation location, and (c) their con-figuration in order to provide adequate ventilation for all three areas. The number of fans required, and their size, location, and configuration, as well as when they are required to be in place and operational, have been based on the ventilation study performed as part of the improvement program mentioned previously.

Action to Prevent Recurrence The above deficiencies were identified through the Limerick Safe Shutdown Analysis improvement Program. This program was initiated in response to concerns about the Limerick safe shutdown (SSD) analysis raised as a result of previously identified deficiencies and to lessons learned from a Peach Bottom SSD reanalysis. The program determined the root cause of the pre-vlously-Identified deficiencies and specified corrective actions for these deficiencies and additional deficiencies identified through the course of the program.

By identifying and addressing SSD analysis defici-encies through a detailed program, the improvement program provides confi-dence that future inadequacies will be prevented and helps to ensure that regulatory compliance is maintained.

MAM/ct/06068901