RBG-30090, Responds to Generic Ltr 88-14, Instrument Air Supply Sys Problems Affecting Safety-Related Equipment. Startup Testing Ensured That air-operated Components Failed as Designed on Loss of Instrument Air

Responds to Generic Ltr 88-14, Instrument Air Supply Sys Problems Affecting Safety-Related Equipment. Startup Testing Ensured That air-operated Components Failed as Designed on Loss of Instrument Air

ML20235J326
Person / Time
Site:	River Bend
Issue date:	02/16/1989
From:	Booker J GULF STATES UTILITIES CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-14, RBG-30090, NUDOCS 8902240244
Download: ML20235J326 (5)

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.. u GULF STATES UTILITIES COMPANY RNER BIND STMION POST OrFICE 80X 220 ST FRANOSVILLE, LOutSIANA 70775 AREA CODE 504 636-6094 346 8651 February 16, 1989 RBG- 30090 File Nos. G9.5, G9.33.4

.U. S. Nuclear Regulatory Commission

Document Control Desk

Washington, D. C. 20555 Gentlemen:

-River Bend Station - Unit 1 Docket No. 50-458 NRC Generic Letter 88-14 This- letter provides. Gulf States . Utilities Company's (GSU) initial response to Generic Letter 88-14, " Instrument Air Supply System Problems.

- Affecting Safety-Related Equipment".

On August 22, 1988, Gulf States Utilities received the subject Generic Letter which requested that each licensee / applicant review NUREG-1275,

. Volume 2, and perform a design and operations verification of the instrument air system.

As a result, GSU reviewed NUREG-1275, Volume 2 " Operating Experience Feedback. Report - Air Systems Problems", and performed a self-initiated Safety' System Functional Inspection (SSFI) on the River Bend Station instrument air system (IAS). The SSFI was conducted from November 17 to December 21,- 1988, and formed the basis for the above' requested verifications. This was an integrated ' team effort consisting of a team leader.and three experienced personnel from United Energy . Services Corporation, and ten personnel. from Gulf States' Utilities' Quality Assurance (QA) department and Independent Safety Engineering Group (ISEG).

The SSFI generated a. number of concerns which are summarized in the attachment to this letter. The resolution of those concerns is proceeding. Several modifications to programs and plant systems have been proposed to alleviate some of these concerns. These include

. revisions to the instrument air system operating procedure and design drawings, improved air quality testing, installation of additional air filtration at specific components, increased preventive maintenance on air filters,'and changing the' failure positions of some air operated  ;

components. A test program is being developed to verify instrument air '

system performance. .This testing will be completed during GSU's upcoming refueling outage. All of these concerns have been evaluated and it has been determined that the current instrument air system is god adequate for continued safe operation.

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8902240244 890216 PDR ADOCK 05000458 P PDC P

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This response is intended to satisfy the 180 day response time prescribed in the generic letter. Since activities such as filter installation, testing of instrument air accumulators, and component failure position adjustment shall occur during River Bend's upcoming refueling outage scheduled to start March 15, 1989, River Bend will submit a follow-up response by July 15, 1989, to update progress in addressing these items. When the SSFI concerns are resolved and corrective actions are complete, a final response to Generic Letter 88-14 will be submitted.

If you have any questions or require additional information, please contact Mr. L. L. Dietrich of my staff at (409) 839-3011.

Sincerely,

2. Mn J. E. Booker Manager-River Bend Oversight River Bend Nuclear Group WJS/lp Attachment cc: U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 4 Senior Resident Inspector P. O. Box 1051 St. Francisville, LA 70775 l

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1 i UNITED STATES OF AMERICA

-NUCLEAR REGULATORY COMMISSION STATE OF LOUISIANA )

PARISH OF WEST FELICIANA )

Docket No. 50-458 In the Matter of )-

GULF STATES UTILITIES COMPANY )

(River Bend Station - Unit 1)

AFFIDAVIT

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J.- E. Booker, being- duly sworn, states that he is Manager-River Bend . Oversight for Gulf States Utilities Company; that he is authorized on the part of said company to sign and file with the Nuclear Regulatory Commission the documents attached hereto; that he has read all of the statements contained in such documents attached thereto and made a part thereof; and that all such statement. made and matters set forth therein are true and correct to the best of his knowledge, information and belief,

d. E M h.E. Booker Subscribed and sworn to before me, a Notary Public in and for the State and Parish above named, this l/f day of do//to tLug ,.19 [7 . My Commission expires with Life. I 8

(h& A A/uAof 6 tary Public in and for N'

West Feliciana Parish, Louisiana

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I ATTACl#fENT 1

The Safety System Functional ' Inspection (SSFI) was structured to address the various areas of interest cited in the Generic Letter 88-14.

Specifically, the following items were addressed:

-1) Instrument air- quality requirements contained in the USAR, vendor i

specifications, etc.; adequacy of air quality testing; i system / component. air filtration (design vs. as-built); and instrument air system (IAS) moisture control and monitoring

2) Preventive maintenance on safety-related components and associated air filters

3) Calibration of IAS regulators and instruments

4) Periodic testing of IAS relief valves

5) Adequacy of post-maintenance and post-modification testing of IAS components

6) Emergency procedure actions affected by loss of instrument air-

7) Adequacy of IAS system operating procedure, including field walkdowns of system valve line-ups

8) Adequacy of training of licensed personnel on modifications to the instrument air' system j

9) Timeliness of close-out of IAS modification packages, and the effects of close-out on training, procedures, and drawings for instrument air

10) Start-up testing on IAS (failure positions of individual components) vs. pressure drop testing (per the generic letter)

11) Adequacy of safety-related component failure positions on loss of air

12) Adequacy of IAS accumulator sizing calculations.

The following is an overall evaluation of the quality of the instrument (

air system rt River Bend Station:

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l a) Proper instrument air quality is provided by a system which includes i air compressors which produce clean, oil-free compressed air; air  !

dryers which reduce moisture content to a dew point of below -40~F; and i 1-micron dryer afterfilters which limit the introduction of particles j into the instrument air system. Instrument air supplied to  ;

safety-related equipment complies with the requirements of ANSI l MC11.1-1976 (ISA-S7.3), Quality Standard for Instrument Air, with  !

regard to dewpoint, oil content and freedom from all corrosive 6 contaminants and hazardous gases (flammable and toxic).

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/ g ,A b) Most components that utilize instrument air are provided with some type of air filtration. This includes safety-related components that are required to operate during normal and abnormal conditions, and were supplied. with integral filters. During installation filters were added for other components' which were supplied without filters. For safety-related components without adequate filtration, filters which meet component vendor requirements for maximum allowable particulate size will be installed. This program will begin during the next refueling outage (RF2) and will be completed by April 1, 1990.

- c) Air quality is verified periodically by sampling for humidity, oil content, corrosive contaminants, and hazardous gases (flammable and toxic). Initial sampling for particulate will be completed during RF2.

and will occur during each refueling outage thereafter.

d) Preventive maintenance procedures are being reviewed to determine if

-additional periodic servicing of instrument air filter / regulators >

-should be provided. ,

I e) Start-up testing ensured that air-operated components failed as  ;

designed on loss of instrument air. Additional IAS accumulator testing will be performed as required during RF2. Component failure positions will be re-evaluated and modified as necessary during the outage.

Field walkdowns and verification of accumulator sizing calculations will be included in RF-2 activities.

f) It was noted that periodic leak testing of safety related air accumulators is not performed to maintain assurance that the airtight integrity of these subsystems has not degraded during the operating life of the plant. As a result of this concern, it was determined that the design of the auxiliary building HVAC system allows the standby gas treatment filter to operate following a LOCA even if no air is 1 available to the dampers because these dampers fail opcn on loss of l IAS. j l

g) Various A0Ds in the control building HVAC system fail closed on loss of l air. Safety related air accumulators are provided to hold A0Ds open post-DBA, but there is no provision for replenishing air to the air accumulators to meet the system design basis of 30 day post DBA operation. It was determined that air accumulators were sized to provide sufficient volume to maintain control building environment to allow operator action to occur. Accumulators are sized for about 2 days of operation, after which action taken can be either to manually open and block appropriate dampers or recharge the accumulators.

Design modifications are being developed to the control building IAS to provide a backup supply of air to the accumulators. In addition, a testing plan for these accumulators is being developed for implementation during RF2.

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- h). Various A0Ds in the fuel building HVAC system fail closed on a loss of air.- Safety related air accumulators are provided to hold their A0Ds open post-DBA, but there is no provision for replenishing air to the air accumulators to meet the system @ sign basis of 30 day post DBA opera ti on . . It was determined that during a DBA with loss of offsite power the radiation levels are low enough in the fuel building to allow accessability, and by calculation the accumulators are sized to provide from 2 to 7 days of air._ GSU is currently preparing a modification to change the failure position for these A0Ds to make them fail-safe on loss of IAS -This activity will be completed during RF-2 i) Depletion of the. standby gas treatment (GTS)/IAS accumulators renders the charcoal filter decay heat removal loop inoperable following a DBA. j The amount of air flow required for GTS decay heat removal has been i determined. An evaluation is being performed to discern if the i backdraft through the backdraft damper. on an idle GTS train will i provide adequate decay heat removal. Additional information on this j concern will be provided in GSU's follow-up response j) The adequacy of the calculation to verify the capacities of safety I related accumulators is being assessed. This will be accomplished by walkdown of the system to identify all air users for the accumulator tanks and will be completed during RF2. The results of this walkdown will be used as input to revise. the above referenced calculation.

Additional information on this concern will be provided in GSU's follow-up response.

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