Bulletin 80-23: Failures of Solenoid Valves Manufactured by Valcor Engineering Corporation
SSINS No.: 6820
Accession No.:
8008220257
IEB 80-23
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
November 14, 1980
IE Bulletin No. 80-23: FAILURES OF SOLENOID VALVES MANUFACTURED BY VALCOR
ENGINEERING CORPORATION
Introduction:
Valcor Engineering Corporation (Valcor) has submitted 10 CFR Part 21 Reports
addressing failures of Valcor solenoid valves used at nuclear power
facilities. These failures have occurred at nuclear facilities owned by Duke
Power Company and Omaha Public Power District, and are purportedly limited
to solenoid valves having part numbers (P/N's) V70900-21-1 and V70900-21-3.
The information presented in this bulletin is intended to shed light on the
defective solenoid valves so that appropriate actions can be taken to
circumvent the degradation of any safety-related system using such solenoid
valves.
DISCUSSION:
The specific Valcor solenoid valves addressed herein were purportedly
designed as Class IE components. However, in light of the reported failures,
it appears that neither the design nor the qualification tests were adequate
for Class IE service. Valcor has attributed the failures to a latent defect
in the magnet wire. Valcor believes that this defect manifests itself when
the solenoid valves are continuously energized at elevated temperatures by
an incompatibility between the magnet wire's polyvinyl varnish coating and
the wire's polyimide insulation which causes a dielectric breakdown leading
to turn-to-turn shorts within the coil.
Valcor states that the above incompatibility is limited to solenoid valves
having P/N's V70900-21-1 and V70900-21-3, and that all customers affected by
the aforementioned defect have been notified. A listing of Valcor customers
so notified and valves purchased follows.
CUSTOMER P.O. NO. VALVE P/N QTY
Anchor- Darling P-827 V70900-21-1,-3 24
Anchor-Darling N663 V70900-21-1 6
Cesare Bonetti (Italy) 1535/79 V70900-21-3 10
Duke Power Company E95188-11 V70900-21-3 100
Duke (Mill Power) C-97733 V70900-21-1,-3 335
Duke Power Company E97822-11 V70900-21-3 70
Ralph Hiller HA-187-0 V70900-21-3 14
Mill Power E52462-73 V70900-21-1,-3 20
Omaha Public Power Dist. 43472 V70900-21-3 19
Stone and Webster LOOO #43 V70900-21-3 8
Copes Vulcan 911,553 V70900-21-1 4
TOTAL 610
.
IEB 80-23
November 14, 1980
Pages 2 of 3
Valcor's corrective actions include making arrangements for replacing
existing coils with a newly designed coil using a 997 silicone varnish
coating instead of the polyvinyl varnish. Sample coils of the new design are
scheduled to undergo qualification tests. We do not know the particulars of
these tests, but Valcor has scheduled the first phase of these tests for
completion by November 15, 1980, and has identified the second phase as an
on-going aging test.
Fort Calhoun has replaced twelve of its original solenoid valves with Valcor
type V70900-21-3 valves, ten of which are located inside containment and two
outside. This substitution was made because the original solenoid valves did
not meet the requirements of IE Bulletin No. 79-01. However, subsequent to
the replacement, Fort Calhoun has experienced five failures of these Valcor
solenoid valves. Each failure involved a solenoid valve located inside
containment and designed for operation in the normally energized mode. These
two factors (i.e., continuously energized mode of operation and a somewhat
elevated temperature inside containment) tend to support Valcor's contention
regarding the failure mechanism.
ACTIONS TO BE TAKEN BY LICENSEES:
1. Determine whether Valcor solenoid valves having P/N's V70900-21-1 or -3
are used to perform any safety-related function at your facility. If
so, identify the safety-related systems using these solenoid valves,
the total number of such solenoid valves used, and evaluate
acceptability of continued operation with potentially defective
solenoid valves. A report of the results of the evaluation of continued
operation shall be submitted within ten (10) days of the date of this
bulletin and should include factors such as (a) operator's ability to
promptly identify a failing or failed solenoid valve, (b) effect of
solenoid valve failures on safety-related systems and subsequent
operator actions required, and (c) possible degradation of the power
supply serving a failed solenoid valve and the effects on other
components served by said power supply. If no such solenoid valves are
used, you need only submit a negative declaration to this effect within
thirty (30) days of the date of this bulletin and you need not respond
to the remaining items.
2. Licensees of operating plants using the aforementioned solenoid valves
in safety-related applications shall periodically test the coils for
potential turn-to-turn shorts in a manner that will not violate any LCO
or cause any undesirable transient. The tests should account for coil
resistance changes due to temperature effects attributed to the
environment and to I2 R losses in the coil to provide accurate
indications of changes in resistance due to turn-to-turn shorts.
These tests are to be initiated within ten (10) days of the date of
this bulletin. The following schedule is recommended until the units
are replaced with qualified units:
(a) Daily for solenoid valves operated in a norally energized mode;
(b) Weekly for solenoid valves operated in a normally deenergized
mode.
.
IEB 80-23
November 14, 1980
Pages 3 of 3
Whenever the tests indicate that ten percent or more of the coil turns
have been shorted, said solenoid valve, or its coil, shall be replaced
with a new unit.
3. Licensees of operating plants shall submit a report within forty-five
(45) days of the date of this bulletin describing their longer term
corrective action plan and the date by which the corrective actions
will be implemented. As a minimum, the longer term corrective measures
should include the replacement of the coils with fully qualified coils.
New solenoid valve assemblies (i.e., a repaired unit with a replacement
coil or a completely new unit) shall be demonstrated to be qualified
for its safety-related application per the applicable requirements of
IEEE 323-1974, IEEE 344-1975, IEEE 382-1972 and IE Bulletin No. 79-01B
and supplements thereto.
ACTIONS TO BE TAKEN BY HOLDERS OF CONSTRUCTION PERMITS:
1. Determine whether Valcor solenoid valves having P/N's V70900-21-1 or -3
are to be used to perform safety-related functions at your facility. If
so, a report addressing this matter shall be submitted by the earlier
of the two following dates: (a) within ninety (90) days of the date of
this bulletin; (b) two weeks prior to the date by which you expect to
receive an operating License.
The above report should indicate your plans to replace said valves
prior to commencing operation, if this is the case. Otherwise, if you
propose to commence operation prior to replacing said valves, the
report should indicate the safety-related systems where such valves are
to be used, and should include an evaluation of the acceptability of
operating with potentially defective valves. This evaluation should
address factors such as your proposed test plan, operator's ability to
promptly identify a failing or failed valve, effect of solenoid valve
failure on safety-related systems and subsequent operator actions
required, and the preventive measures you plan to implement to
circumvent the effects of failures of these valves.
If no such valves are to be used in your facility, submit a negative
declaration to this effect within forty-five (45) days of the date of
this bulletin but prior to the date by which you expect to receive an
operating license.
The above requested reports shall be submitted to the director of the
appropriate NRC region within time stipulated for each item in the this
bulletin. A copy of each report shall be forwarded to the Director, Division
of Reactor Operations Inspection, Office of Inspection and Enforcement,
United States Nuclear Regulatory Commission, Washington, D. C. 20555.
Approved by GAO, B180225(ROO72); clearance expires November 30, 1980.
Approval was given under a blanket clearance specifically for identified
generic problems.
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