Part 21 Report - 1996-703

 
 
ACCESSION #:  9609040049
                       LICENSEE EVENT REPORT (LER)

FACILITY NAME:   Virgil C. Summer Nuclear Station          PAGE: 1 OF 5

DOCKET NUMBER:  05000395

TITLE:  ITT Barton Model 763 Pressure Transmitter Strain Gage
        Failures

EVENT DATE:  07/30/96   LER #:  96-07-00    REPORT DATE:  08/29/96

OTHER FACILITIES INVOLVED:                          DOCKET NO:  05000

OPERATING MODE:  1   POWER LEVEL:  75

THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR
SECTION:
OTHER

LICENSEE CONTACT FOR THIS LER:
NAME:  George A. Lippard, III               TELEPHONE:  (803) 345-4810

COMPONENT FAILURE DESCRIPTION:
CAUSE:  B   SYSTEM:  AB   COMPONENT:       MANUFACTURER:  B080
REPORTABLE NPRDS:  Y

SUPPLEMENTAL REPORT EXPECTED:  YES  EXPECTED SUBMISSION DATE: 10/18/96

ABSTRACT:

This report is being made pursuant to 10 CFR Part 21.

On June 5, 1996, engineering review of plant incident reports identified
the third failure of M Barton Model 763 pressure transmitters at V. C.
Summer Nuclear Station within a one week period.  In each case.  a strain
gage lead was broken at its terminal pin.

Model 763 transmitters are used at V. C. Summer Nuclear Station to
provide protection signals based an pressurizer pressure; specifically.
reactor trip on high pressurizer pressure or reactor trip and safety
injection on low pressurizer pressure.  The transmitters exhibiting the
described defect were all from existing VCSNS stock and were received in
the same shipment.  Each transmitter was calibrated, and installed as
IPT00457-RC where two filled after being in service for a short period of
tim, and one failed prior to return to service.  A Model 763 pressure
transmitter, of a different purchase, was calibrated and installed as
IPT00457-RC. V. C. Summer Nuclear Station ensured that the associated
application was restored to operable status.  Reliability of pressurizer
pressure transmitters is verified by weekly monitoring and channel
checks.

ITT Barton has not established a root cause for what appears to be a
repetitive failure of the Model 763 pressure transmitters.  Barton is in
the process of evaluating the defective V. C. Summer Mode 763
transmitters for failure analysis.

END OF ABSTRACT

TEXT                                                          PAGE 2 OF 5

PLANT IDENTIFICATION:

Westinghouse - Pressurized Water Reactor

EQUIPMENT IDENTIFICATION

Pressure transmitters used in the protection scheme circuits for
Pressurizer High Pressure Reactor Trip or Pressurizer Low Pressure
Reactor Trip and Safety Injection.

EIIS Code AB

IDENTIFICATION OF EVENT:

Potential failure of protection circuitry for Reactor Trip and Safety
Injection.

DISCOVERY DATE:

July 30, 1996 - Virgil C. Summer Nuclear Station, upon review of failures
which occurred through June 5, 1996, determined that the failure
mechanism presented a substantial safety hazard and should be reported in
accordance with 10CFR Part 21.

REPORT DATE:

August 29, 1996

This report was generated by Non-Conformance Notice 5481.

COMMONS PRIOR TO THE EVENT

MODE 1 75% Reactor Power

TEXT                                                          PAGE 3 OF 5

DESCRIPTION OF EVENT

On July 30, 1996, Virgil. C. Summer Nuclear Station determined that a
substantial safety hazard, reportable pursuant to 10 CFR Part 21, existed
relative to the potential failure of transmitters used for pressure
projection in the Engineered Safeguards and Reactor Trip circuitry.  The
devices are ITT Barton Model 763 pressure transmitters.

The Model 763 transmitters are used for providing High Pressurizer
Pressure Reactor Trip, Low Pressurizer Pressure Reactor Trip and Low
Pressurizer Pressure Safety Injection.

On June 5, 1996, a Model 763 pressure transmitter was installed at the
IPT00457-RC location and fail high prior to being placed in service,
Non-Conformance Notice 5481 was generated for evaluation of the failure.
Engineering review of plant incident reports identified this as the third
failure of a transmitter installed at this location within i one week
period.  The two previous failures of Model 763 pressure transmitters at
this location failed after being in service for a short period of time
(2-5 days).  Each of the transmitters installed at the IPT00457-RC
location were obtained by the same purchase order and received at VCSNS
in the same shipment.

CAUSE OF EVENT:

In each case, a strain gage lead was broken loose at its terminal pin.
This condition appears to be an inherent defect in manufacturing/repair
based on ITT Barton Failure Analysis Report PA 960701 and the number of
similar failures occurring in a short period of time.

ANALYSIS OF EVENT:

The defect could cause a loss of safety function to the extent that there
is a major reduction in the degree of protection provided to the public
health and safety.  The pressurizer pressure transmitters
(IPT00455(6)(7)-RC) provide the following protection signals:

1.   Reactor Trip on high pressurizer pressure.

2.   Reactor Trip on low pressurizer pressure.

3.   Safety Injection on low pressurizer pressure.

TEXT                                                          PAGE 4 OF 5

ANALYSIS OF EVENT: (continued)

The VCSNS FSAR takes credit for the low pressurizer pressure protection
signals to mitigate the consequences of a Large Break LOCA.  A
transmitter installed at IPT 00455 (6)(7)-RC which fails high would not
provide the low pressure protection signal.  The protection circuitry is
based on 2 out of 3 input logic, so the failure of one transmitter would
not, in and of itself, prevent the proper protection function.  However,
this failure condition coincident with an additional transmitter failure
would affect the automatic activation of safety injection should a large
break LOCA occur.  This could result in potential offsite exposure
exceeding 10 CFR 100.11 limits.

V. C. Summer Engineering, personnel have discussed this situation with
ITT Barton.  The failed transmitters were shipped and received together.
The preliminary consensus is, that a manufacturing process error
potentially contributed to the defect and this condition is an isolated
occurrence limited to the lot of transmitters from which those shipped to
VCSNS was supplied.

V. C. Summer Engineering personnel also performed a review of M Barton
760 model series transmitter failures using the NPRDS data base.  NPRDS
indicated that most failures were either age related or unknown. There
were no strain gage figures identified; thus this review was inconclusive
as to industry experience with the problems noted for V. C. Summer.

Other licensees with ITT Barton Model 763 pressure transmitters should
review the history for their particular applications and determine if
broken/loose strain gages have attributed to any failures which may lave
occurred at their plants.

IMMEDIATE CORRECTIVE ACTIONS:

A Model 763 pressure transmitter, independent of existing VCSNS warehouse
stock, was procured and installed at the IPT00457-RC location.

V. C. Summer Station ensured that the associated applications were
restored to operable status upon identification, replacement and testing
of the respective Model 763 pressure transmitters.  As the Model 763
currently totalled is from an unrelated stock and is performing
satisfactorily, continued operation does not present an adverse impact on
safety.

TEXT                                                          PAGE 5 OF 5

ADDITIONAL CORRECTIVE ACTIONS:

Long term corrective actions are under evaluation and will be coordinated
with the vendor.  SCE&G expects to obtain the vendor's analysis results
and be able to submit a final report by October 18, 1996.

PRIOR OCCURRENCES:

None

ATTACHMENT TO 9609040049                                      PAGE 1 OF 2

                  SOUTH CAROLINA ELECTRIC & GAS COMPANY
                    Virgil C. Summer Nuclear Station
                              P. O. Box 88
                         Jenkinsville, SC 29065
                          FAX # (803) 345-4356

                Nuclear Licensing & Operating Experience

To:

Company:

Telecopy No.:

From:

Telephone No.:

Number of Sheets Including Transmittal Sheet:

Special Instructions:

Confirmation:

Distribution:

ATTACHMENT TO 9609040049                                      PAGE 2 OF 2

SCE&G/NL/SG

SCE&G
A SCANA COMPANY

South Carolina Electric & Gas Company                  Gary J. Taylor
P.O. Box 88                                            Vice President
Jenkinsville, SC 29065                                 Nuclear Operations
(803) 345-4344

                                        August 29, 1996
                                        RC-96-0222

Document Control Desk
U. S. Nuclear Regulatory Commission
Washington, DC 20555

Gentlemen:

Subject:  VIRGIL C. SUMMER NUCLEAR STATION
          DOCKET NO. 50/395
          OPERATING LICENSE NO. NPF-12
          LICENSEE EVENT REPORT (LER 960007)

Attached is Licensee Event Report No. 96-007 for the Virgil C. Summer
Nuclear Station.  This report is submitted pursuant to the requirements
of 10CFR Part 21.

Should you have questions, please call Mr. Jim Turkett at (803) 345-4047.

                                     Very truly yours,

JWT/GJT/nkk
Attachment

c.   J. L. Skolds                            K. R. Jackson
     W. F. Conway                            D. L. Abstance
     R. R. Mahan (w/o attachment)            NPRDS Coordinator
     R. J. White                             NRC Resident Inspector
     S. D. Ebneter                           J. B. Knotts Jr.
     A. R. Johnson                           INPO Records Center
     S. R. Hunt                              Marsh & McLennan
     S. F. Fipps                             NSRC
     A. R. Koon                              RTS (LER 960007)
     G. E. Williams                          Files (818.07, 818-18)
     T. L. Matlosz                           DMS (RC-96-0222)

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