ML17304B043

Responds to Generic Ltr 88-14, Instrument Air Supply Sys Problems Affecting Safety-Related Equipment. Lesson Plans Revised to Sensitize Personnel on Vulnerability of safety-related Equipment to Common Mode Failures

ML17304B043
Person / Time
Site:	Palo Verde
Issue date:	02/20/1989
From:	Karner D ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
161-01697-DBK-J, 161-1697-DBK-J, GL-88-14, NUDOCS 8903020424
Download: ML17304B043 (16)

Text

g~~TED Dl~Bt'Tl ON DEMONS~ON SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR:8903020424 DOC.DATE: 89/02/20 NOTARIZED:

YES DOCKET FACIL:STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 STN-50-529 Palo Verde Nuclear Station, Unit 2,.Arizona Publi 05000529 STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTH.NAME AUTHOR AFFILIATION KARNER,D.B.

Arizona Nuclear Power Project (formerly Arizona Public Serv RECIP.NAME RECIPIENT AFFILIATION R Document Control Branch (Document Control Desk)

SUBJECT:

Responds to Generic Ltr 88-14,"Instrument Air Supply Sys I Problems Affecting Safety-Related Equipment." DISTRIBUTION CODE: A048D COPIES RECEIVED:LTR ENCL SIZE: TITLE: OR/Licensing Submittal:

Equipment Quali cation 5 NOTES:Standardized plant.Standardized plant.Standardized plant.05000528 j 05000529 05000530)1 RECIPIENT ID CODE/NAME PD5 LA CHAN,T DAVIS,M.J.

COPIES LTTR ENCL 1 0 1 1 1 1 RECIPIENT ID CODE/NAME PD5 PD DAVIS,M COPIES LTTR ENCL 1 0 1 1 INTERNAL':

ACRS NRR/DEST/ADE 8H NRR/DEST/SGB 8D OGC/HDS1 RES/DSIR/EIB 6 6 ARM/DAF/LFMB 1 0 NRR/DEST/MEB 9H 1 1 QQ$-ABSTRACT 1 1 REG FILE 01 1 1 1 0'1 1 1 1 1 EXTERNAL: LPDR NSIC NOTES: 1 1 1 1 1 1 NRC PDR 1 1 R I NOTE'IO ALL"RIDS" BECIPIENIS:

PLEASE HELP US'IO REZGCE HASTE!CGNI'ACT'THE DOCUMENT CON'HKL DESK, BOOM Pl-37 (EXT.20079)TO ZZJMINATE YOUR NAME FRY DISTEHBUTIGN LISTS FOR DOCUMENl'S YOU DClN'T NEEDf TOTAL NUMBER OF COPIES REQUIRED: LTTR 23 ENCL 19 41 Arizona Nuclear Power Project P.o.SOX 52034~PHOENIX.ARIZONA 85072-2034 161-01697-DBK/JMQ February 20, 1989 Docket Nos.STN 50-528/529/530 Document Control Desk U.S.Nuclear Regulatory Commission Mail Station Pl-137 Washington, D.C.20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)Units 1, 2 and'Generic Letter 88-14,"Instrument Air Supply System Problems Affecting Safety-Related Equipment" File: 89-010-026;~

89-056-026

Reference:

Letter from NRC to All Holders of Construction Permits for Nuclear Power Reactors Dated'ugust 8, 1988;~

Subject:

Generic Letter 88-14.The referenced letter requested a review of NUREG-1275, Volume 2 and a design and operations verification of the instrument air system.In order to accomplish this task a list of safety related components, that rely on instrument air was produced.The total number of components identified was 144 for each unit.Attachments 1 and 2 provide the PVNGS response to Generic Letter 88-14.If you have any questions, please contact Mr.A.C.Rogers of my staff.Very truly yours, D.B.Karner Executive Vice President DBK/JMQ/vlb Attachments cc: A.C.Gehr T.J.Polich T.L.Chan M.J.Davis J.B.Martin (a11 w/a)8903020424 890220 PDR ADOCK 05000528 PDC Qi J P' STATE OF ARIZONA))ss.COUNTY OF MARICOPA)', Donald B.Karner, represent that I,am Executive Vice President of Arizona Nuclear Power Project, that the foregoing document has been signed by me on behalf of Arizona Public Service Company with full authority to do so, that I have read such document and know its contents, and that to the best of my knowledge and belief, the statements made therein are true.Donald B.Karner Sworn to before me this~~day of~1989.My Commission Expires: My Commhs!Gn Exnire"!n~r.~gy Notar r s>>C c=

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ATTACHMENT 1'RESPONSE TO VERIFICATION ACTIONS OF GENERIC'LETTER 88-14~ACTION 1 Verification by test that actua1 instrument air quality is consistent with the manufacturer's recommendations for individual components served.APS RESPONSE The major suppliers of the affected components were contacted'nd although the vendors did not commit to any specific document in writing, the PVNGS test procedures for air quality were developed using, ISA-S7.3, 1975-"Quality Standard for Instrument Air" for guidance.Because all three Units at Palo Verde are of standard design the test results and design changes for the Units are expected to be similar.Therefore, the air quality test results from Unit 2 will determine the design modifications for all 3 units.In order to perform this verification by test, equipment was procured to test air quality and test connections were installed in Unit 2.An air quality test is currently being conducted on Unit 2.Preliminary results after 4 days are as follows: The dew point is approximately

-10'F at 120 PSIG.The measured dew point is greater than the design value.Compensatory measures are currently in place to open low point drains on the air distribution piping on a periodic basis to prevent moisture accumulation.

The particulates are predominatly less than 3 micron in.size, however there are particulates in the 3 to 5 micron size and no significant quantity of particulates greater than 10 microns.Hydrocarbons are less than 1 ppm.The air quality data will be ,taken for approximately one month in order to obtain adequate test data.After sufficient data is collected, it will be evaluated to determine what improvements or modifications may be required to ensure maintaining the instrument air quality.The test data will also be used to adjust the frequency of.preventative maintenance tasks as noted in Attachment 2.A supplemental letter will be provided by April 28, 1989 indicating if any improvements or modifications will be made and providing the schedule for completion.

1672K/0059K 4l~P~'

ACTION 2 Verification that maintenance practices, emergency procedures and training are adequate to ensure that safety-related equipment, will function as intended on loss of instrument air.APS RESPONSE Maintenance Practices Preventati've maintenance tasks were reviewed and are provided in Attachment 2"Program for Maintaining Instrument Air Quality".Emer enc Procedures APS has reviewed the abnormal operating procedure for loss of instrument air and is.making enhancements to the existing procedure to further address the following recommendations from Significant Operating Experience Report (SOER)88-01"Instrument Air System Failures:" The revision of this procedure is currently in the review and approval process.It is expected that the procedure will be revised by June 30, 1989.*indications of loss of instrument air, such as alarms, automatic actions, functions.

lost.*identification of critical components operated by instrument air and the position in which they fail.*expected system, and plant responses to a loss of instrument air and the consequences of these responses.

• actions to take if critical components do not fail in the intended position.*manual actions the operator should be expected to take to respond to a loss of instrument air event.*restoration actions to be taken after instrument air is regained., T~raintn The Operations staff is trained on the abnormal operating procedure for loss of instrument air.The training consists of a walk through and discussion of the procedure in the simulator.

At the present time the simulator is not modeled to illustrate loss of instrument air.The malfunction scenarios for the Basi'c Simulator and Requalification Courses will be developed in conjunction with the simulation certification under 10CFR55.Lesson plans have been, revised to sensitize plant operations and maintenance ,personnel on the vulnerability of safety, related equipment to common mode failures that could result from air degradation.

<~i~e II,'

ACTION 3 Verificati'on that the design of the entire instrument air system including air or other pneumatic accumulators is in accordance with its intended function, including verification by test that air-operated safety-related components will perform as expected in accordance with all'esign-basis events, including a loss of the normal instrument air system.This design verification should include an analysis of current air operated component failure positions to verify that they are correct for assuring required safety functions.

Verification of Instrument Air S stem Desi n Verification of the design of the instrument air system will'be performed in conjunction with our Design Basis Review Program.Since the instrument air system is classified as non-safety related but interfaces with safety related systems, it will be reviewed immediately after the safety related systems.'Due to,the large scope of the program, the review is expected to be completed during the first quarter of 1991.Veri'ficati'on of Pneumatic Accumulator Desi n Verification of the design of the pneumatic accumulators was done as a result.of SOER 88-01.APS utilizes three safety related air or gas reservoir systems.They are the Main Steam Isolation Valve/Feedwater Isolation Valve air accumulators, atmospheric dump valve nitrogen gas accumulators, and the Diesel Generator air start accumulators.

The accumulator capaci'ties were reviewed for these valves and found to be adequate.The accumulator pressures are continuously monitored with an in-place"low accumulator pressure" type alarm which causes an audible and visual alarm to annunciate in the respective unit's Main Control Room.The Emergency Diesel Generator Starting Air Flasks and the Atmospheric Dump Valves have installed local pressure indicators.

These pressure indicators are monitored periodically by auxiliary operators.

Verification b Test Verification by test was accomplished.through the preoperational testing program and surveillance tests.Out of the 144 safety related valves and dampers which rely on instrument air, 135 were tested by the preoperational testing program and nine were tested by surveillance tests.The tests verified the failure positi'on of the equipment.by isolating the air supply and/or air signal then noting the positions the valve/damper assumed.Anal sis of Failure Positions The failure modes of the 144 valves and dampers were analyzed, to ensure that they failed in a position of least risk to reactor safety.The preoperational tests results for the failure mode of the 135 valves and dampers for Unit 1 were pulled and compared to the analyzed failure modes.

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All the components tested satisfactorily except that a discrepancy was found on one damper.The individual who performed the test on that, damper determined the test to be , acceptable,however,.he documented'n incorrect failure position.A retest of the damper has been performed verifying it does fail in the proper position.The nine components.tested by the Unit 1 surveillance tests ,have been verified'hat their failure positions from the surveillance test was the same as the analyzed failure positions.

Due to the standardization in design and the same preoperational and surveillance test program applied to all three units, it may be assumed that this verification applies to all three units.

Ik 4l~)IN~~a L' ATTACHMENT 2'ROGRAM FOR'MAINTAINING AIR UALITY The program for maintaining air quality will, primarily be a function of a periodic test of air quality and the preventative maintenance program.The air'uality test-procedure shall be performed in each unit on a ,periodic basis to be determined from.the results of the initial air quality test as described in ACTION 1 of Attachment 1.The procedure will be effective in<<-all three units after completion of the design modifications described in ACTION 1.This procedure will measure such parameters as total air flow, humi'dity/dew point, particulates and contaminants including hydrocarbons and water vapor.A review of the existing, preventative maintenance tasks was performed which include the following:

Inspect, clean or repl'ace air compressor inlet filter;performed'nnually.

Remove and'eplace instrument air prefilters; performed semi-annually.

Remove and replace instrument air after filters;performed, annually.'Replace dessicant; performed annually.The frequency of these.tasks may.change dependent on, the results of the analysis of the air quality test.In addition to.these tasks being performed on a regularly scheduled basis, supplemental tasks such as disassembly of drain traps including inspection and cleaning of the internals are al'so performed on the prefilter, moisture separator and receiver on a quarterly basis along with a multitude of other tasks performed on related instruments, relays, motors, bearings, vibration monitoring equipment and,similar equipment.

In addition,,preventative maintenance tasks are currently scheduled to be written by March 31, 1989 to change the filters.inside the air regulators supplying safety related valves and components.

This work is scheduled'o be implemented every two years.The frequency of this, work may change depending on the air quality test analysis.

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