United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 83-63: Potential Failures of Westinghouse Electric Corporation Type SA-1 Differential Relays

                                                            SSINS No.: 6835 
                                                            IN 83-63 

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C. 20555

                             September 26, 1983

Information Notice No. 83-63:   POTENTIAL FAILURES OF WESTINGHOUSE 
                                   ELECTRIC CORPORATION TYPE SA-1 
                                   DIFFERENTIAL RELAYS 

Addressees: 

All holders of a nuclear power reactor operating license (OL) or 
construction permit (CP). 

Purpose: 

This information notice is provided as notification of a potentially 
significant problem pertaining to random trip output of Westinghouse 
Electric Corporation type SA-1 differential relays. Addressees are expected 
to review the information for applicability to their facilities. No specific 
action or response is required at this time. 

Description of Circumstances: 

On April 13, 1983, Westinghouse Electric Corporation, Bala Cynwyd, 
Pennsylvania, notified Brown-Bovery Electric, Inc. of a potential deficiency
in Westinghouse SA-1 differential relays. These relays are used on 
safety-related systems and designed to sense a fault within the differential
circuit to protect either a transformer, generator, switchgear, or 
distribution system bus. A differential relay trip output will open the 
circuit breakers to isolate the differential circuit when a fault occurs. 
However, a random differential relay trip output will trip the breakers of 
the differential circuit without the presence of a fault, thereby isolating 
a transformer, generator, switchgear, or system bus unnecessarily. 

The Westinghouse Electric Corporation Relay and Instrument Division in Coral
Springs, Florida, evaluated some field reports of random SA-1 relay tripping
and tested 18 field relay silicon-controlled rectifiers (SCRs) and more than
150 inhouse inventory relay SCRs, concluding that certain SCRs in the relay 
trip output circuits can cause the random trip output. 

Only some SCRs manufactured by S. T. SEMICON for Westinghouse Electric 
Corporation relays since January 10, 1980, have been found to cause the 
random trip output. The tendency to provide a random trip is dependent upon 
the history of ambient temperature, voltage, and time. The higher any of 
these parameters, the more likely an S. T. SEMICON SCR will provide a random
trip. 



8308300345 
.

                                                      IN 83-63 
                                                       September 26, 1983 
                                                       Page 2 of 3 

Westinghouse-Recommended Corrective Action: 

Following the Westinghouse Electric Corporation investigation, the 
Westinghouse Relay-Instrument Division's Engineering and QA Departments 
notified the customers listed on Attachment 1 by individual correspondence 
and advised them of the following: 

1.   A Raytheon SCR (TAG Semiconductors Ltd, type TAG9N600DUX FTS3905-1) has
     been chosen as a replacement for the S. T. SEMICON device, in 
     production and for replacement in relays in the field. The W style 
     number for this device is S/N 184A614HO5. 

2.   To prevent recurrence of this type of problem Westinghouse receiving 
     inspection is continuing its 100% electrical parameter test. In 
     addition, on a sample basis, a "burn-in" of SCRs from every received 
     lot is accomplished. 

3.   Testing indicates that SCRs may be replaced without affecting the 
     calibration of the relay. 

The Westinghouse Electric Corporation Relay and Instrument Division also 
asked its customers to take the following corrective action on the relays 
listed on Attachment 1. 

1.   Determine if the relay contains an S. T. SEMICON SCR (identified by a 
     [s] logo and CR127). If it does, it should be replaced by the SCR 
     described in item 1 above. A Westinghouse SCR (identified by a W logo 
     and 2N1850 printed on the barrel) or a SYNTRON (identified by a FMC 
     logo and 184A614 on the barrel) does not have to be replaced. 

2.   SCR replacement should be accomplished by an electronics technician 
     taking special care in the following areas: 

     a.   Tag the wires when disassembling to ensure correct reconnection to
          the new SCR. 

     b.   Do not stress the anode and cathode leads of the SCR when 
          reconnecting the wires. 

     c.   Do not overheat the SCR leads when resoldering. Heat sinks applied
          to the SCR terminals during resoldering will help to ensure that 
          overheating does not occur. 

3.   Verify correct replacement by following the "Adjustments and 
     Maintenance" and "Electrical Checkpoints" section of I.L. 41-348-11 
     "Type SA-1 Generator Differential Relay for Class 1E Applications." 

As stated previously, Westinghouse Electric Corporation notified all its 
SA-1 relay customers listed in Attachment 1, however, most of these 
customers are not the end-users. Therefore, it is suggested that licensees 
review the relay serial numbers on Attachment 1 and compare them with the 
serial numbers on SA-1 relays in their nuclear facilities to determine if 
corrective action is required. 
.

                                                      IN 83-63 
                                                       September 26, 1983 
                                                       Page 3 of 3 

If you have any questions regarding this matter, please contact the Regional
Administrator of the appropriate NRC Regional Office, or this office. 


                                   Edward L. Jordan, Director 
                                   Division of Emergency Preparedness 
                                     and Engineering Response 
                                   Office of Inspection and Enforcement 

Technical Contact:  W. Laudan, IE
                    (301) 492-9759

Attachments:
1.   List of Customers
2.   List of Recently Issued IE Information Notices
.

                                                      Attachment 1 
                                                      IN 33-63 
                                                      September 26, 1983 
                                                      Page 1 of 2 

                                        WESTINGHOUSE G.O.
SA-1 RELAY CUSTOMER           SERIAL NO.     NO. & ITEM     CUSTOMER ORDER
                                                            NO. 

Beloit Power Systems          5256A          RK43470-NI-9   01507
Beloit, WI                    5257A          RK43470-NI-9   01507
                              5258A          RK43470-NI-9   01107
                              5259A          RK43470-NI-9   10507 
                              5486           RK43330-NI-25  01401
                              5487           RK43330-NI-25  01401 
                              7437           RK44202-NI-3   32476 
                              7438           RK44202-NI-3   32476 
                              7439           RK44202-NI-3   32476 
                              7440           RK44202-NI-3   32476 
                              7441           RK44202-NI-3   32476 
                              7442           RK44202-NI-3   32476 
                              7443           RK44202-NI-3   32476 
                              7444           RK442O2-NI-3   32476 
                              7455           RK44202-NI-3   33858

Brown-Bovery Electric, Inc.   4772           PH68-333-NI-H1 J96608-53566
Chalfont, PA                  5768A          PH69899-NI-D   J5253i-53170 
                              6912           PH61036-NI-C   J57018-51128 
                              7808           PH61316-NI-I   J66315-51128 

Brown-Bovery Electric, Inc.   4310           TL70147-NI-36  5-30852
Tulsa, OK                     5074           TL69994-NI-36  5-41094
                              5254           TL71248-NI-37  5-10342 
                              5255           TL71248-NI-37  5-10342 
                              6864           TL72584-NI-36  5-41633 
                              7434           TL70147-NI-36B 5-30852 
                              7435           TL71248-NI-36X 5-20342A 
                              7436           TL71248-NI-36X 5-10342A 
                              7607           TL71249-NI-36  5-10343

Cooper Energy Services        7802           CB64416-NI-1   370941511
Mt. Vernon, OH                7803           CB64416-NI-1   370941511
                              7804           CB64416-NI-1   370941511 
                              7805           CB64416-NI-1   370941511 
                              7806           CB64416-NI-1   370941511 
                              7897           CB64416-NI-1   37094-1511 

Cooper Energy Services        5767           CB63404-NI-1   3609J8150
Mt. Vernon, OH                8060           CB64596-NI-1   360941935
                              8061           CB64596-NI-1   360941935

Duke Power Company            5778A          CHI1784-NI-1   F3527-82
McGuire Nuclear Station
Cornelius, NC
.

                                                      Attachment 1 
                                                      IN 83-63 
                                                      September 26, 1983 
                                                      Page 2 of 2 

WESTINGHOUSE G.O.
SA-1 RELAY CUSTOMER           SERIAL NO.     NO. & ITEM     CUSTOMER ORDER
                                                            NO.

Siemens Allis, Inc.           4713           MK20280-NI-P   WAH378586V
Raleigh, NC                   4714           MK20280-NI-D   WAH378586V
                              5007           MK20280-NI-J1  WAH378586V

Systems Control Corp.         5766A          AP42372-NI-1   74178-8
Iron Mountain, MI             5769A          AP42372-NI-1   74178-8

Washington Public Power       6996           NA-40038-Y1    01YN085
Supply System                 6997           NA-40038-Y1    01YN085
Portland, OR                  6903           NA-40038-Y1    01YN086 
                              6904           NA-40038-Y1    01YN086

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