ML20043F296

Special Rept SR-1-90-006-00:on 900509,discovered That Tech Spec Temp Limit for Main Steam Penetration Area Exceeded for Greater than 8 H.Caused by Inadequate Operating Procedure for Safeguards Bldg Ventilation Sys.Pipe Supports Insulated

ML20043F296
Person / Time
Site:	Comanche Peak
Issue date:	06/08/1990
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
SR-1-90-006-00, SR-1-90-6, TXX-90205, NUDOCS 9006140346
Download: ML20043F296 (4)

Text

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momemame MM Log # TXX-90205

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~ ~ File # 10250 903.llN C C 903.11B nlELECTRIC 909 4 Ref. # 10CFR50.36(c)(5)

Dld,T, r,, a,,,, June 8, 1990 Mr. R. D. Martin, Region IV U. S. Nuclear Regulatory Commission 611 Ryan Plaza, Suite 1000 Arlington, Texas 76011

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NO. 50 445 ELEVATED TEMPERATURES IN SAFEGUARDS BUILDING NORMAL ARCAS SPECIAL REPORT NO. SR 1-90 006 00 Gentlemen:

Enclosed is a 30 day special report submitted in accordance with CPSES Unit 1 Technical Specification 3.7.10 " Plant Systems - Area Temperature Monitoring."

Sincerely,

/ '

f William J. C4 ill, Jr.

JRW/daj Enclosure c - Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Resident Inspectors, CPSES (3) 1 DATE. ,

L 9006140346 900608 enn w oCu osooo44s FDC [78l l 400 North Ohre Street LB $1 Dallas Tnas 73201

1 Enclosure to TXX-90205 ,

Special Report SR 90-006 Elevated Temperatures in Safeguards Ba8 Wag Normal Areas 1.0 REPORT REQUIREMENT l

'Ihis Special Report is being submitted in accordance with Comanche Peak i i

Steam Electric Station Unit 1 Technical Specification 3/4.7.10, AREA TEMPERATURE MONITORING. Specification 3.7.10 requires that with one or more areas exceeding the specifled temperature limits for normal cond!Uons for more than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, a Special Report be submitted to the I Nuclear Regulatory Commission, pursuant to Specification 6.9.2, providing a record of the cumulative time and the amount by which the temperature in the affected areas exceeded the limits and an analysis to demonstrate the ,

continued operability of the affected equipment.  ;

l 2.0 SVENT DESCRIPTION l

On May 9,1990, during performance of the Power Ascension Heating l it was Ventilating discovered that and the Air Technical Conditioning (HVAC) Temperature Specification temperature limit Survey, for the main steam penetration area was exceeded for greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. For purposes of compliance with Technical Specification 3/4.7.10, these rooms

, are considered normal areas as specified in Technical Specification Table  ;

I 3.7 3. The temperature limit for normal conditions was observed to be in l

excess of 104*F for a total of 58 hours6.712963e-4 days <br />0.0161 hours <br />9.589947e-5 weeks <br />2.2069e-5 months <br />, and the temperature reached a l

maximum of 119'F at the hottest measured locations within the affected rooms. .

The purpose of the Power Ascension HVAC Temperature Survey is to obtain temperature data at various power levels through Power Ascension. The data is evaluated by engineering to determine if design changes are requised to maintain indoor area temperatures below the values listed in the applicable design calculations. The test procedure requires immediate notiflcation of Operations Supervisory personnel if observed temperatures exceed or may exceed those listed in Technical Specification Table 3.7 3.

During test performance on May 9,1990, no additional areas were '

identified with temperatures in excess of the temperature limps of Technical Specification Table 3.7-3.

At the time the overtemperature condition was observed, only one set of 50 percent capacity main steam and feedwater area supp and exhaust fans was in operation. Operations personnel were informed o the overtemperature condition and initiated additional ventilation by starting the second set of '

supply and exhaust fans. Operation with both sets of fans was only partially effective at reducing area temperatures: an unrelated reactor shutdown initiated on Ma affected areas. y 9 contributed to the reduction in temperature in the

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Enclosure to TXX 90205 Performance of the Operations Shiftly Routine Tests procedure ensures that the sun'e111ance requirements of Technical Specification 3/4.7.10 are satisfled. The sun'elllance points consist of those areas listed on Technical Specification Table 3.7-3, except the normal areas which are sun'ellied by monitoring building area exhaust temperatures displayed in the Control Room. Upon notification by Performance and Test personnel of the overtemperature condition existing in the main steam and feedwater penetration are- +he Operations Department added that area to the list of surveillance 1 :catio ' to be surveyed locally by an Ativhry Operator during performanet of the Alftly test.

An analysis w c9,)erformed to determine the effects of the elevated temperature on the operability of the safety-related equipment in the affected areas. The maximum temperature obsen'ed is less than the maximum temperature limits for abnormal conditions specified in Technical ,

Specificadon Table 3.7-3. It is concluded that the elevated temperatures had no impact on the operability of equipment requiring environmental qualification in the affected area.

Analysis also determined the effects of the elevated temperature on the qualified life of the equipment located in the affected area. Since there is no record of temperatures in the area prior to May 9,1990, it has been conservatively as tumed that the temperature in the area may have been 119 degrees F from 3,'20/90 (entry into Mode 3) till 5/11/90, a total of 53 days, ne room temper,tture for the main steam and feedwater penetration area is a function of outsIde ambient air temperature, and meteorological history l data supports the conservatism of the assumed temperature.  ;

Analysis using thi s assumption results in an equivalent expended life of one year at 104 degrees F for the most limiting material in the affected area, and reduces the first replacement interval by one year. 'Ihe most limiting qualified life of a part or component in these rooms is 4 years from fuel load.

The change in the first replacement interval does not result in any replacement activity prior to the first refueling outage.

3.0 CAUSE OF THE EVENT Root Cause l

The Main Steam and Feedwater Area HVAC System design calculations used to determine required system capacity do not normally consider the effects of thermal contributions from uninsulated valve bodies and pipe supports, small steam leaks, or convective heat transfer from the feedwater penetration area to the main steam penetration area.

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. Enc'losure to TXX-90205  !

3 Contributing Facton ne system operating procedure for the Safeguards Bul! ding Ventilation System did not cleary specify when both sets of 50 pervent capacity supply and exhaust fans are required to operate. He procedure implied that only one set of supply and exhaust fans is necessary for normal operation and that additional fans may be required if area temperatures are high. He design configuration for normal operations requires that both sets of supply and exhaust fans be in operation.

4.0 CORRECTIVE ACTIONS Cause: Less than adequate design Corrective Action: Various pipe supports, valve bodies, etc. In the main steam and feedwater penetration areas have been insulated to reduce heat gains into the affectec. rooms and resultant loads on the HVAC system.

Continuing engineering evaluation is being conducted to determine additional actions to be taken to control temperatures in the affected areas.

The Power Ascension HVAC Temperature Survey will continue to be performed at additional power plateaus to provide data for engo.:ering analysis, for the evaluation of the effectiveness of design modifications, and '

4 for verification of the representativeness of surveillance points in this and other areas to verify design.

Contributing Factor: Procedure ambiguity Corrective Action: The system operating procedure for the Safeguards Building Ventilation System has been revised to more clearly identify when both sets of supply and exhaust fans should be in operation.

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