United States Nuclear Regulatory Commission - Protecting People and the Environment

Instrument Air Supply System Problems Affecting Safety-Related Equipment (Generic Letter No. 88-14)


                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                           WASHINGTON, D.C. 20555

                               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. 

8808120294 

                                    -2-

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 
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