Instrument Air Supply System Problems Affecting Safety-Related Equipment (Generic Letter No. 88-14)
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D.C. 20555
August 8, 1988
TO ALL HOLDERS OF OPERATING LICENSES OR CONSTRUCTION PERMITS FOR NUCLEAR
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
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.
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.
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.
Frank J. Miraglia, Jr.
Associate Director for Projects
Office of Nuclear Reactor Regulation
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