United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #:  9502210142

     ITT                                          ITT Barton

                                                  ITT Fluid Technology
                                                  Corporation

February 15, 1995

U. S. Nuclear Regulatory Commission
Washington, DC 20555

ATTN:          Director, Office of Nuclear Material and Safeguards

Subject:       Final Report of Potential Defect (Model 288A & 289A Switch
               Chatter)

References:    Interim Report of Potential Defect dated January 20, 1995

ITT Barton is a supplier of basic components to the Nuclear Power
Industry.  The specific components being reported are Model 288A and 289A
Differential Pressure Indicating Switches.  These indicating switches
were qualified for safety related applications per ITT Barton Engineering
Reports R3-288A-1, dated May 1980, and R3-288A-13, dated September 1996
(seismic testing included five OBE's and one SSE at 6 G's and 12 G's
respectively).

ITT Barton has completed testing at Wyle Laboratories in Norco, CA which
has confirmed that these products may demonstrate switch contact chatter
not identified during previous nuclear qualification efforts associated
with these devices.  Attachment A presents the now known switch
performance characteristics for various seismic loadings which will allow
the instrument users to evaluate their specific installations for safety
implications.  The cause of this situation is attributed to use of test
equipment with insufficient sensitivity to detect the existence of
chatter.  ITT Barton has reviewed all other test reports where switch
chatter testing methodology could potentially be a concern and has found
that the test methodologies implemented clearly meet the industry
standards for contact chatter monitoring sensitivity (i.e., 2
milliseconds).

Attachment B is a list of Customers who have Purchased Model 288A and/or
Model 289A Indicating Switches within the past 10 years.  We are now
notifying each of these customer of this concern.

If there are any questions regarding this notification, please contact
Jerry Anderson at (818) 961-2547.


Charles L. Perry
General Manager

Attachments A and B


             900 South Turnbull Canyon Road, P.O. Box 1882, 
                     City of Industry, CA 91749-1882
                            (illegible print)


                                                             Attachment A

                          10CFR21 NOTIFICATION
                           (February 15, 1995)

ITT Barton is a supplier of basic components used in safety related
applications in Nuclear Power Plants.  ITT Barton has supplied Model 288A
and 289A Differential Pressure Indicating Switches to Nuclear Power
Plants with Certification to IEEE-323/344 Qualifications which indicate
there is no switch contact chatter during seismic loadings of up to 12
G's as long as the monitored differential pressure is at least 10% of
full scale away from the switch setpoint when the seismic event occurs. 
In recently performed unrelated testing, potential concerns regarding
contact chatter were identified which resulted in performance of
additional testing on qualified configurations of these Products.

Switch contact chatter sensitivity testing has been performed on IEEE-323
& IEEE-344 qualified versions of ITT Barton Model 288A and 289A
Differential Pressure Indicating Switches at Wyle Laboratories in Norco,
California during the first week of 1995.  This testing has again
verified that these Products are capable of surviving earthquake loadings
up to 12 G's with no degradation in structural or pressure boundary
integrity and no degradation in functionality with regard to pointer
accuracy, switch setpoint change and switch deadband.  However, this
testing has also verified the recently identified concern that the
contacts in the high and low switches may chatter when subjected to
elevated seismic loadings.

The occurrence of chatter and the contact opening duration has been
determined to be dependent on the switch operating forces, the switch
setpoint with respect to the monitored process condition (i.e, actual
differential pressure condition) at the time of the event, and the
acceleration level of the earthquake.  Switch performance characteristics
in the form of contact chatter duration for various G-level loadings are
presented in the following table as a function of the distance (% of full
scale) of the monitored differential pressure from the switch setpoint at
the time of the seismic event occurrence.  This data conservatively
considers instrument configurations and switches most sensitive to
chatter.

               MODEL 288A & 289A SWITCH CHATTER DURATION'S

     G                        DP WITH RESPECT TO SETPOINT
   LEVEL  >/= 10% FS     >/= 15% FS     >/= 20% FS     >/= 25% FS

     4      None           None           None           None
     6    






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