NRC Generic Letter 88-14, Instrument Air Supply System Problems Affecting Safety-Related Equipment

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August 8, 1988

TO ALL HOLDERS OF OPERATING LICENSES OR CONSTRUCTION PERMITS FOR NUCLEAR POWER REACTORS

SUBJECT: INSTRUMENT AIR SUPPLY SYSTEM PROBLEMS AFFECTING SAFETY-RELATED EQUIPMENT (GENERIC LETTER 88-14)

The NRC has been studying the problems associated with instrument air systems for a number of years. The results of these studies, including concerns relating to adverse effects on safety-related equipment caused by instrument air system failures, were most recently identified in NRC Information Notice 87-28, Supplement 1, dated December 28, 1987. This information notice transmitted to all licensees and applicants a report that addresses these concerns, NUREG-1275, Volume 2 "Operating Experience Feedback Report-Air Systems Problems." This report indicates that the performance of the air-operated safety-related components may not be in accordance with their intended safety function because of inadequacies in the design, installation, and maintenance of the instrument air system. The report also indicates that anticipated transient and system recovery procedures are frequently inadequate and that operators are not well trained for coping with loss of instrument air conditions.

The purpose of this generic letter is to request that each licensee/

applicant review NUREG-1275, Volume 2, and perform a design and operations verification of the instrument air system.

This verification should include:

1. Verification by test that actual instrument air quality is consistent with the manufacturer's recommendations for individual components served.

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.

3. Verification 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 design-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.

In addition to the above, each licensee/applicant should provide a discussion of their program for maintaining proper instrument air quality.

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The NRC staff requires each licensee/applicant to provide a response to the staff within 180 days that confirms that verification as described above has been performed. The staff recognizes that some instrument air system testing as indicated in Item 3 above may have potentially adverse consequences on plant power operation, and therefore, such testing should be performed at a refueling or other scheduled outage in order to avoid adverse system interactions. If instrument air system testing cannot be completed within 180 days, it may be deferred until the next scheduled outage. However, the licensee/applicant should indicate in its response those tests which have been completed and those which will be completed at a subsequent outage.

In accordance with the provisions of 10 CFR 50.54(f), the response should consist of a submittal signed under oath or affirmation which indicates that the above actions have been completed or that the licensee's plan/schedule has been provided. The submittal should also identify any components that cannot accomplish their intended safety function, and state the corrective action taken or to be taken. When all requirements of this generic letter have been implemented, a written notification should be provided stating that all actions are complete, Each licensee/applicant should retain the documentation assembled for this verification for future audit by the staff. This documentation should be maintained for a minimum of two years from the date of the licensee's/applicant's submittal.

This request is covered by the Office of Management and Budget Clearance Number 3150-0011, which expires December 31, 1989. Comments on burden and duplication may be directed to the Office of Management and Budget, Reports Management, Room 3208, New Executive Office Building, Washington, D.C. 20503.

Any questions regarding this letter should be directed to William LeFave, U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Washington, D.C. 20555, (301) 492-0862.

Sincerely,

Frank J. Miraglia, Jr. Associate Director for Projects Office of Nuclear Reactor Regulation