United States Nuclear Regulatory Commission - Protecting People and the Environment

IEB 80-23 Failures of Solenoid Valves Manufactured by Valcor Engineering Corporation (Generic Letter 80-97)


                                UNITED STATES
                                  REGION II
                     101 MARIETTA ST., N.W., SUITE 3100
                           ATLANTA, GEORGIA 30303

                              November 14, 1980

Duke Power Company
ATTN:     W. O. Parker, Jr.
          Vice President, Steam Production
P. O. Box 2178
Charlotte, NC  28242


Enclosed is IE Bulletin No. 80-23 which requires action by you with regard 
to your nuclear power facility.

In order to assist the NRC in evaluating the value/impact of each bulletin 
on licensees, it would be helpful if you would provide us an estimate of the 
manpower expended in conduct of the review and preparation of the report(s) 
required by the bulletin.  Please estimate separately the manpower 
associated with corrective actions necessary following identifaction of 
problems through the bulletin.  

Should you have any questions regarding this bulletin or the actions 
required by you, please contact this office.


                                   James P. O'Reilly

1.   IE Bulletin No. 80-23
2.   List of Recently Issued IE Bulletins

cc w/encl:
J. T. Moore, Project Manager

                                                           SSINS NO.:  6820 
                                                           Accession No. : 
                                 UNITED STATES             IEB 80-23 
                         NUCLEAR REGULATORY COMMISSION 
                            WASHINGTON, D.C.  20555 

                        ENGINEERING CORPORATION 


Valcor Engineering Corporation (Valcor) has submitted 10 CFR 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 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 


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 
Casare 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 Pwr Dist.    43472               V70900-21-3           19
Stone and Webster         L000 #43            V70900-21-3            8
Copes Vulcan              911,553             V70900-21-1            4
                                                           TOTAL   610 

                                                          IEB 80-23 
                                                          November 14, 1980 
                                                          Page 2 of 4 

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.  


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 I2R 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: 


                                                          IEB 80-23 
                                                          November 14, 1980 
                                                          Page 3 of 4 

     (a)  Daily for solenoid valves operated in a normally energized mode; 

     (b)  Weekly for solenoid valves operated in a normally deenergized 

     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 382-1982 and IE Bulletin No. 79-01B 
     and supplements thereto. 

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 Resident and Regional Reactor Inspection, Office of Inspection 
and Enforcement, United States Nuclear Regulatory Commission, Washington, 
D.C.  20555. 

                                                          IEB 80-23 
                                                          November 14, 1980 
                                                          Page 4 of 4 

Approved by GAO, B180225(R0072); clearance expires November 30, 1980. 
Approval was given under a blanket clearance specifically for identified 
generic problems.  

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