Part 21 Report - 1995-154
95150
ACCESSION #: 9507030139
VIRGINIA ELECTRIC AND POWER COMPANY
RICHMOND, VIRGINIA 23261
June 27, 1995
U. S. Nuclear Regulatory Commission Serial No. 95-318
Attention: Document Control Desk NL&P/DAS
Washington, D.C. 20555 Docket Nos. 50-280
50-281
License Nos. DPR-32
DPR-37
Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY
SURRY POWER STATION UNITS 1 AND 2
NOTIFICATION OF DEFECT IN ACCORDANCE WITH 10 CFR 21
Virginia Electric and Power Company (Virginia Power) has identified
several incidents of instrument drift in excess of specified limits for
the Rosemount pressure transmitter Model 1154SH9. In accordance with 10
CFR 21.21, the following information is provided as written notification
of an existing defect.
1. Name and address of the individual or individuals informing the
Commission.
Mr. R. F. Saunders
Vice President - Nuclear Operations
Virginia Electric and Power Company
5000 Dominion Boulevard
Glen Allen, Virginia 23060
2. Identification of the facility, the activity, or the basic
component supplied for such facility or such activity within
the United States which fails to comply or contains a defect.
Surry Power Station Units 1 and 2
Rosemount Pressure Transmitter Model 1154SH9
3. Identification of the firm constructing the facility or
supplying the basic component which fails to comply or contains
a defect.
Rosemount Aerospace Inc.
1256 Trapp Road
Eagan, MN 55121
Attn: Mr. K. Ewald
Business Unit Manager
4. Nature of the defect or failure to comply and the safety hazard
which is created or could be created by such defect or failure
to comply.
In February 1995, Virginia Power initiated a root cause
evaluation (RCE) to determine the cause of calibration
discrepancies identified with the pressurizer pressure
protection transmitters. During this evaluation, three spare
Model 1154SH9 transmitters were tested in an oven to determine
if they were affected by temperature variations. As a result
of this testing and readings taken in the process racks,
Virginia Power concluded that some Rosemount Model 1154SH9
pressure transmitters were exhibiting instrument drift greater
than specification. This drift was due to changes in
containment ambient temperature between calibration during
shutdown and normal operations. Affected transmitters
exhibited a zero shift in the negative direction of between 6
and 15 psig. This shift was greater than the 5.8 psig shift
expected for such temperature variation as specified in
Rosemount Product Data Sheet PDS 2631/4631 Rev 8/93 and the
Part 21 letters from Rosemount to Virginia Power on May 27,
1993 and August 31, 1993. Although this instrument drift was
not safety significant for Surry, it was a causal factor in an
incident in which Unit 2 pressurizer pressure channels had been
set outside of Technical Specification limits. Accordingly, it
was determined that given the variability observed in
instrument drift and the multiple examples of occurrence, this
condition could have the potential to be safety significant in
other similar safety-related applications at other facilities
dependent on plant specific setpoint margins. Specific
applicability with respect to safety systems or licensee
facilities is not known.
5. The date on which the information of such defect or failure to
comply was obtained.
April 26, 1995
6. In the case of a basic component which contains a defect or
fails to comply, the number and location of all such components
in use at, supplied for, or being supplied for one or more
facilities or activities subject to the regulation in this
part.
There are twelve Model 1154SH9 pressure transmitters at Surry:
three installed in Unit 1 for pressurizer pressure, three
installed in Unit 2 for pressurizer pressure, and six spares.
Only the three Unit 2 pressurizer pressure transmitters and one
spare have exhibited excessive instrument drift and are
therefore affected by this notification. There are seven Model
1154SH9 pressure transmitters at North Anna: three installed in
Unit 1 for pressurizer pressure, three installed in Unit 2 for
pressurizer pressure and one spare. Excessive instrument drift
has not been observed in the transmitters presently installed.
(One previous Unit 2 transmitter, which had exhibited excessive
shift, was replaced earlier with a spare.)
7. The corrective action which has been, is being, or will be
taken; the name of the individual or organization responsible
for the action; and the length of time that has been or will be
taken to complete the action.
As stated above, Virginia Power performed an RCE which resulted
in the identification of the excessive instrument drift
concern, the variability of the degree of drift between
individual transmitters, and the individual transmitter
applicability (i.e. not all Model 1154SH9 transmitters exhibit
excessive drift). Individual instrument channels identified as
subject to the excessive drift phenomena were evaluated to
ensure continued operability by establishing that the
individual transmitter drift was within overall channel
setpoint margins.
The NRC was advised of our preliminary findings in a meeting
with Region II on April 24, 1995. Copies of our RCE were
provided to the resident inspectors. The industry was notified
of our RCE findings in an INPO Network entry made on June 15,
1995, which addressed various calibration errors identified
with the pressurizer pressure protection transmitters.
We will continue to work with the manufacturer and intend to
ship one of the transmitters exhibiting excessive drift for
future investigations of the condition we have observed.
8. Any advice related to the defect or failure to comply about the
facility, activity or basic component that has been, is being
or will be given to purchasers or licensees.
Virginia Power advises other licensees to be alert to
differences in pressure indication between individual Model
1154SH9 transmitters as well as between functional groupings of
Model 1154SH9 transmitters and other related but non-Model
1154SH9 pressure indications. Either circumstance might
indicate the presence of excessive shift. Furthermore for
temperature sensitive applications, consideration should be
given in the interim to temperature testing Model 1154SH9
transmitters prior to use to determine actual temperature
related shifts.
Should you have any questions or require additional information, please
contact Mr. M. L. Bowling, Manager Nuclear Licensing and Programs, at
(804) 273-2699.
Very truly yours,
R. F. Saunders
Vice President - Nuclear Operations
cc: U. S. Nuclear Regulatory Commission
Region II
101 Marietta Street, N. W.
Suite 2900
Atlanta, Georgia 30323
Mr. M. W. Branch
NRC Senior Resident Inspector
Surry Power Station
Mr. R. D. McWhorter
NRC Senior Resident Inspector
North Anna Power Station
Mr. K. Ewald
Business Unit Manager
Rosemount Aerospace Inc.
1256 Trapp Road
Eagan, Minnesota 55121
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