Part 21 Report - 1997-011
ACCESSION #: 9701150043
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ITT Barton
ITT Industries 900 S. Turnbull Canyon Rd.
AUTOMOTIVE P.O. Box 1882
DEFENSE & ELECTRONICS City of Industry, CA 91749-1882
FLUID TECHNOLOGY Tel: (818)961-2547
Fax: (918) 333-7241
January 10, 1997
Westinghouse Energy Center
4350 Northern Pike
Monroeville, Penn. 15146-2886
Attention: Mr. Ray Kelchner
Manager Quality Assurance
Subject: 10CFR21 Notification on Model 753 Gage Pressure Electronic
Transmitters.
Dear Mr. Kelchner;
ITT Barton supplies Model 753 Gage Pressure Electronic Transmitters to
the commercial nuclear power industry for use in safety related
applications through Westinghouse Nuclear Energy. The attached POTENTIAL
10 CFR PART 21 NOTIFICATION is ITT Barton's official notification that a
situation has been discovered that ITT Barton believes may represent a
substantial safety hazard in some of these instruments that we have
manufactured.
ITT Barton sells the Model 753 through Westinghouse, however, the
utilities identified as being involved in our failure analysis efforts
are being notified directly regarding this concern. Those utilities are;
South Carolina Electric & Gas (V.C. Summer Nuclear Plant)
Duquesne Light (Beaver Valley Nuclear Plant)
Pacific Gas & Electric (Diablo Canyon Nuclear Plant)
Regarding any additional information and status of this notification,
please do not hesitate to contact the undersigned.
Regards;
Ted Holdredge
Quality Manager
ITT Industries
ITT Barton
phone: (818) 961-2547
fax (818) 937-0418
(doc. NRC2)
Check us out on Industry Net at http://www.industry.net/itt.barton
cc:
U.S. Nuclear Regulatory Commission
South Carolina Electric & Gas, (V,C, /Summer Nuclear Plant)
Duquesne Light, (Beaver Valley Nuclear Plant)
Pacific Gas & Electric, (Diablo Canyon Nuclear Plant)
D. Evarts, General Manager, ITT Barton
R. Krechmery, Director of Engineering, ITT Barton
A. Lussier, Director of Operations, ITT Barton
M. Larson, ITT Barton Nuclear & Government Product Engineering
J. Incontri, ITT Barton, Director of Marketing
S. Noji, ITT Barton Consumer Affairs
POTENTIAL 10 CFR PART 21 NOTIFICATION
(January 10, 1997)
ITT Barton supplies Model 753 Gage Pressure Electronic Transmitters to
the commercial nuclear power industry for use in safety related
applications through Westinghouse Nuclear Energy. A situation has been
discovered that ITT Barton believes may represent a substantial safety
hazard in some of these instruments that we have manufactured. This
situation involves sulfur induced corrosion of the #40 AWG copper strain
gage lead wires and the beryllium copper link clip. Until recently, ITT
Barton was not able to ascertain the source of the sulfur contamination
and believed that the limited occurrences of this problem originated
outside the factory.
There was an incident involving sulfur induced corrosion of strain gage
lead wires circa 1983 where a number of Model 753 transmitters were
returned from the Diablo Canyon Nuclear Plant. Because the source of the
sulfur contamination could not be uncovered and because only Diablo
Canyon reported the incident, it was believed to be an out of factory
related situation.
In 1994, two Model 753 transmitters were returned from the V. C. Summer
Nuclear Plant for failure analysis because of excessive drift concerns.
These units had been repaired previously and had failed again after only
about nine months where the units had been in storage. This failure
analysis, much like the 1983 investigation, identified the failure to be
caused by sulfur induced corrosion and could not uncover the source of
the sulfur contamination. The units were repaired and returned to the
customer where, after some storage time, The units failed again (third
time) for the same reason.
In 1996, another Model 753 transmitter was returned from the Beaver
Valley Nuclear Plant for excessive drift concerns. This instrument was
found to have suffered a failure as a result of sulfur induced corrosion
of the beryllium copper link clip between the bourdon tube and the strain
gage beam. When two more Model 753 transmitters were returned by a non-
power customer after less than one year of out of factory life for drift
concerns, which were identified to be caused by sulfur induced corrosion
of the strain gage lead wires, ITT Barton initiated another investigation
into the problem in order to ascertain the source of the sulfur causing
the corrosion in the Model 753 transmitters.
A test was devised to expose copper and copper alloy items to components
removed from the transmitters actually subject to the corrosion concerns
in an accelerated corrosion environment. This test demonstrated that the
corrosion could be recreated. This testing uncovered that the cork
gasket used with the bourdon tube transducer housing caused corrosion of
copper and copper alloy parts. In addition, interviews with instrument
assembly personnel uncovered a situation which indicated that some link
adjust assemblies used in the Model 753 transmitter may have been
contaminated with Dow Corning Molykote (molybdenum disulfide).
Corrective actions implemented in the factory included removal of all the
gaskets of concern, substitution of a gasket made from a more stable
material, assembly procedure upgrades, operator training, and cleaning of
all existing fink adjust assemblies.
Page 1 of 3
The existence of the sulfur induced corrosion can be seen in an operating
instrument in the form of abnormal drift (i.e., drift in excess of
normally experienced drift for the particular unit monitored over a
period of at least days for steady state conditions). The direction of
the strain gage lead wire corrosion drift can be high or low depending on
the corrosion rate applicable to the compression or tension strain gage
leads. Link clip drift direction is always negative. The electrical
lead corrosion drift is caused by the increase in resistance of the
circuit as the corrosion reduces the diameter of the lead wires while the
link clip corrosion drift is caused by material stretching as the link
clip thickness is reduced. There is no difference between a safety
related and a non safety related Model 753 with respect to this corrosion
concern. This concern is limited to the Model 753 transmitter because of
the usage of the sulfur contaminated components.
ITT Barton recommends that the transducer housing gasket be replaced in
all Model 7533 transmitters at the first convergent opportunity with the
new gasket (ITT Barton P/N 0590-1244C). ITT Barton also recommends that
lead wire attachment to the top of the strain gage beam, the link clip
and the grip ring at the bourdon tube bearing be inspected for evidence
of sulfur induced corrosion when the gasket is replaced. All instruments
showing any visual evidence of the sulfur induced corrosion should be
returned to the factory for repair (strain gage assembly replacement
required which invalidates the existing temperature compensation). The
sulfur induced corrosion of copper and copper alloy components appears as
a heavy/fuzzy black substance on exposed surfaces (not under the wire
insulation and not a thin coating/darkening of the material which is
normal). The strain gage lead wires corrode at the short portion of the
exposed copper conductors where they leave the solder pool on the strain
gage beam just before the wire insulation resumes. This location is
embedded in a clear silicone material which can be inspected using
magnification (8X minimum recommended along with good lighting).
It is the opinion of ITT Barton that only instruments manufactured or
subjected to repair activities involving replacement of the housing
gasket since 1992 are highly suspect of this sulfur induced corrosion
concern. Furthermore, it is the opinion of ITT Barton that the
instrument can be considered free of the concern following replacement of
the gasket and performance of the visual inspection without finding
evidence of the corrosion. ITT Barton formed these opinions based on the
following facts:
o There has been no reported sulfur induced corrosion concerns
since 19833 until units built in 1992 have shown evidence of
the problem.
o Significant instrument performance degradation generally occurs
within a short period of time (less than one year).
o Corrosion of the strain gage lead wires is not limited to a
single wire. All four conductors showed evidence of the
corrosion product buildup in all the failures inspected.
If you have any questions please contact Theodore Holdredge, Quality
Assurance Manager, at (818) 961-2547 Ext. 363.
Page 2 of 3
Figure "Model 753 Transducer Assembly" omitted.
GENERAL INFORMATION or OTHER EVENT NUMBER: 31570
LICENSEE: ITT INDUSTRIES NOTIFICATION DATE: 01/10/97
CITY: CITY OF INDUSTR REGION: 4 NOTIFICATION TIME: 16:07 [ET]
COUNTY: STATE: CA EVENT DATE: 01/10/97
LICENSE#: AGREEMENT: AGREEMENT: Y EVENT TIME: 16:07[PST]
DOCKET: LAST UPDATE DATE: 01/10/97
NOTIFICATIONS
VERN HODGE RDO
NRC NOTIFIED BY: TED HOLDREDGE
HQ OPS OFFICER: JOHN MacKINNON
EMERGENCY CLASS: NOT APPLICABLE
10 CFR SECTION:
CDEG 21.21(c)(3)(i) DEFECTS/NONCOMPLIANCE
EVENT TEXT
A SITUATION HAS BEEN DISCOVERED (IN THE BARTON MODEL 753 GAGE
PRESSURE
ELECTRONIC TRANSMITTERS) THAT ITT BARTON BELIEVES MAY REPRESENT A
SUBSTANTIAL HAZARD IN SOME OF THESE INSTRUMENTS THAT ITT HAS
MANUFACTURED. THIS HAZARD IS SULFUR INDUCED CORROSION OF THE #40
AWG
COPPER STRAIN GAGE LEAD WIRES AND THE BERYLLIUM COPPER LINK CLIP.
ITT INDUSTRIES (ITT BARTON) LOCATED AT 900 S. TURNBULL CANYON RD., P.O
BOS 1882, CITY OF INDUSTRY, CA. NOTIFIED WESTINGHOUSE ENERGY CENTER
LOCATED AT 4350 NORTHERN PIKE, MONROVILLE, PA. OF THIS POTENTIAL 10
CFR
PART 21 NOTIFICATION ON 01/10/97.
ITT BARTON SUPPLIES MODEL 753 GAGE PRESSURE ELECTRONIC TRANSMITTERS
TO
THE COMMERCIAL NUCLEAR POWER INDUSTRY FOR USE IN SAFETY RELATED
APPLICATIONS THROUGH WESTINGHOUSE NUCLEAR ENERGY. A SITUATION HAS
BEEN
DISCOVERED THAT ITT BARTON BELIEVES MAY REPRESENT A SUBSTANTIAL
SAFETY
HAZARD IN SOME OF THESE INSTRUMENTS THAT THEY HAVE MANUFACTURED.
THIS
SITUATION INVOLVES SULFUR INDUCED CORROSION OF THE #40 AWG COPPER
STRAIN
GAGE LEAD WIRES AND THE BERYLLIUM COPPER LINK CLIP. UNTIL RECENTLY,
ITT
BARTON WAS NOT ABLE TO ASCERTAIN THE SOURCE OF THE SULFUR
CONTAMINATION
AND BELIEVED THAT THE LIMITED OCCURRENCES OF THIS PROBLEM
ORIGINATED
OUTSIDE THE FACTORY. ITT BARTON UNCOVERED THAT THE CORK GASKET
USED WITH
THE BOURDON TUBE TRANSDUCER HOUSING CAUSED CORROSION OF COPPER
AND COPPER
ALLOY PARTS. IN ADDITION, INTERVIEWS WITH INSTRUMENT ASSEMBLY
PERSONNEL
UNCOVERED A SITUATION WHICH INDICATED THAT SOME LINK ADJUST
ASSEMBLIES
USED IN THE MODEL 753 TRANSMITTER MAY HAVE BEEN CONTAMINATED WITH
DOW
CORNING MOLYKOTE (MOLYBDENUM DISULFIDE). CORRECTIVE ACTIONS
IMPLEMENTED
IN THE FACTORY INCLUDED REMOVAL OF ALL GASKETS OF CONCERN,
SUBSTITUTION
OF A GASKET MADE FROM A MORE STABLE MATERIAL, ASSEMBLY PROCEDURE
UPGRADES, OPERATOR
(Continued on next page)
LICENSEE: ITT INDUSTRIES PAGE 3 2 OF EVENT NUMBER; 31570
TRAINING, AND CLEANING OF ALL EXISTING LINK ADJUST ASSEMBLIES.
THE EXISTENCE OF THE SULFUR INDUCED CORROSION CAN BE SEEN IN AN
OPERATING
INSTRUMENT IN THE FORM OF ABNORMAL DRIFT(i.e., DRIFT IN EXCESS OF
NORMALLY EXPERIENCED DRIFT FOR THE PARTICULAR UNIT MONITORED OVER
A
PERIOD OF AT LEAST DAYS FOR STEADY STATE CONDITIONS). TH DIRECTION OF
THE STRAIN GAGE LEAD WIRE CORROSION DRIFT CAN BE HIGH OR LOW
DEPENDING ON
THE CORROSION RATE APPLICABLE TO THE COMPRESSION OR TENSION STRAIN
GAGE
LEADS. LINK CLIP DRIFT DIRECTION IS ALWAYS NEGATIVE. THE ELECTRICAL
LEAD CORROSION DRIFT IS CAUSED BY THE INCREASE IN RESISTANCE OF THE
CIRCUIT AS THE CORROSION REDUCES THE DIAMETER OF THE LEAD WIRES
WHILE THE
LINK CLIP CORROSION DRIFT IS CAUSED BY MATERIAL STRETCHING AS THE
LINK
CLIP THICKNESS IS REDUCED. THERE IN NO DIFFERENCE BETWEEN A SAFETY
RELATED AND A NON SAFETY RELATED MODEL 753 WITH RESPECT TO THIS
CORROSION
CONCERN. THIS CONCERN IS LIMITED TO THE MODEL 753 TRANSMITTER
BECAUSE OF
THE USAGE OF THE SULFUR CONTAMINATED COMPONENTS.
NUCLEAR POWER PLANTS OF CONCERN ARE: 1) SOUTH CAROLINA ELECTRIC &
GAS
(V.C. SUMMER ), 2) DUQUESNE LIGHT (BEAVER VALLEY), AND PACIFIC GAS &
ELECTRIC (DIABLO CANYON).
*** END OF DOCUMENT ***
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