JAFP-91-0835, Special Rept:Relay Room CO2 Sys Declared Inoperable Due to Failed Surveillance Test.Caused by Slow Closure Time of Temp Control Damper 70MOD-103.Continuous Fire Watch Established & Design Basis Reconstitution Planned

Special Rept:Relay Room CO2 Sys Declared Inoperable Due to Failed Surveillance Test.Caused by Slow Closure Time of Temp Control Damper 70MOD-103.Continuous Fire Watch Established & Design Basis Reconstitution Planned

ML20086P082
Person / Time
Site:	FitzPatrick
Issue date:	12/19/1991
From:	Radford Converse POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
JAFP-91-0835, JAFP-91-835, NUDOCS 9112260193
Download: ML20086P082 (2)

Text

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James A.Mt:Patrkk Nuclear Pow:r Ptnt P.O. Box 41

• * : Lycoming, New York 13093 315 342-3MO

1. > NewYorkPower noe,0,o 3. Con ,,,,,

&December Authonty 19, 1991-nesioent uaneoer f

- JAFP 0835 United States Nuclear Regulatory Commission Document Control Desk Mail Station P1-337 Washington, DC 20555

SUBJECT:

DOCKET NO. 50-333. RELAY ROOM CO2 SYSTEM INOPERABILITX

Dear Sir:

The New York Power Authority (NYPA) submits the following special report to address inoperability of the Relay Room CO System for 2 more than 14 days.

The event requires that a 30-day special report be submitted in accordance with Technical Specification 3.12.C.2 and 6.9.B.2.

Summary of Event The Relay Room CO2 System was declared inoperable due to a failed surveillance _ test and remains administratively inoperable due to concerns with-design basis and acceptance criteria.

Description of the Event and Corrective Action During performance of a functional test of the relay room smoke

. and heat detectors on October 22, 1991, temperature control damper 70 MOD-103 was observed to close slower than anticipated.

The CO3 system is interlocked within the ventilation system to prevent CO2 _ dilution during and af ter discharge. The supply and exhaust fans stop, their associated discharge dampers close, and 70 MOD-103 closes. Based on the slow closure time of 70 MOD-103 (approximate]y 10 minutes vice its normal 15 second closure time), the damper and the CO system were declared inoperable and the appropriate LCO entered.2 A continuous fire watch was established and a backap CO 2 cart put in place, as required by Techn.' cal Specification Section 3.12.C.1.b. The CO, system is

still functional. It was c onsidered administratively inoperable based on possible dilution when 70 MOD-103 closed slowly.

Subsegaent engineering evaluation verified that.the damper was operating as designed and was therefore declared operable. The rs' son for the slow closure time was a flawed interlock design. CP 70 MOD-103 has an electro-hydraulic operator. A small pump and servo valve operate together to modulate the damper. The pump _

runs continuously and the servo valve receives a signal from the j g teaperature control circuitry. The interlock with the CO2 system 9112260193 911219 .,

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• l r United Statos Nuclear Regulatory Commission Deced>er 19, 1991 SUEJECT: DOCKET NO. 50-333, RELAY ROOM CO 2 JAFP 0835

SYSTEM INOPERABILITY Page only de-energized the pump, but the servo valve still operated based on' temperature. While performing the surveillance test that identified this problem, the HVAC system was in the purge mode-so the damper was full open. When the pump was deenergized on CO2 initiation, the servo valve remained full closed. The damper closed slowly due to hydraulic fluid leakage back through the pump. The interlocks do not affect the HVAC system under normal or accident (non-fire) conditions.

As a result of the engineering evaluation, it was determined that the slow closure of 70 MOD-103 would have an insignificant effect on CO2 concentration in the relay room. The exhaust fan discharge dampers are upstream of 70 MOD-103 and both close on CO 2 initiation. The position of the tamperature control damper is irrelevant. Several other issues were raised during the evaluation relative to the design basis of the CO2 system, so although the damper was declared operable, the CO2 system remains administratively inoperable. The issues raised involved lack of clear CO2 concentration requirements for the room, questionable

" operability" test adequacy, and possible over-pressurization of the relay room due to extended CO2 discharge times and the HVAC system configuration during discharge.

NYPA-plans to pursue a reconstitution of the design basis of the Relay Room CO2 System including all calculations, discharge times, NRC ccumitments, and final acceptance criteria. NYPA will also evaluate che need for the performance of a design performance 'rerifier Lion test to address design concentration requirements at the cpecified elevations within the relay room for the required soaA Lime as established during the design basis reconstitution.

NYPA plans to complete the design basis reconstitution and evaluation prior to start up following the 1992 Refuel Outage (currently planned for March 24, 1992). A followup report will be submitted upon completion of this evaluation.

If you have any questions concerning this matter, please contact R. Schimpf at (914)684-6461.

Verypruly-yours,

'I l'l MJ RADFORD J. CONVERSE RESIDENT MANAGER RJC:CMJ:nrb cc: NRC Resident Inspector Document Control Center NRC Region I WPO Recoras Manager American Nuclear Insurers Internal Distribution