United States Nuclear Regulatory Commission - Protecting People and the Environment

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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