Information Notice No. 88-81: Failure of AMP Window Indent KYNAR Splices and Thomas and Betts Nylon Wire Caps During Environmental Qualification Testing

                                  UNITED STATES
                          NUCLEAR REGULATORY COMMISSION
                             WASHINGTON, D.C.  20555

                                 October 7, 1988

                                   AND THOMAS AND BETTS NYLON WIRE CAPS DURING
                                   ENVIRONMENTAL QUALIFICATION TESTING


All holders of operating licenses or construction permits for nuclear power, 
test, and research reactors.   


This information notice is being provided to alert addressees to potential 
generic problems involving failures of AMP window indent KYNAR electrical butt
splices and Thomas and Betts nylon wire caps during environmental quali-
fication (EQ) testing of these components by Illinois Power Company at the 
Wyle Laboratories.  It is expected that recipients will review this 
information for applicability to their facilities and consider actions, as 
appropriate, to avoid similar problems.  However, suggestions contained in 
this information notice do not constitute NRC requirements; therefore, no 
specific action or written response is required.

Description of Circumstances:

During an August 17 through 21, 1987, site inspection at the Clinton Station, 
the Region III EQ inspection team determined that installed AMP window indent 
electrical butt splices with KYNAR (Polyvinylidene Fluoride) insulation and 
Thomas and Betts nylon-insulated wire caps were unqualified because of inade-
quate test documentation.  

AMP Window Indent KYNAR Splices:

After the NRC findings during the Clinton inspection, the licensee conducted 
two tests at Wyle Laboratories, to demonstrate that the AMP window indent 
KYNAR butt splices were qualifiable to 10 CFR 50.49 for postulated accident 
environments at the Clinton Station.  

During the first test, six specimens were irradiated to 2.2E8 R and thermally 
aged for a 40.6-year simulated life at 125�F ambient temperature.  The speci-
mens were then exposed to a simulated LOCA environment of elevated temperature
(400�F peak), pressure, steam, and demineralized water spray while contacting 
grounded metal surfaces.  During the LOCA portion of the test, five of the six
specimens (energized by 528-Vac, 132-Vac, and 132-Vdc circuits) shorted to 
ground, thereby failing the test.  

.                                                            IN 88-81
                                                            October 7, 1988
                                                            Page 2 of 3

In order to establish near-term qualification, the licensee then performed a 
second test on six samples irradiated to 2.2E8 R and aged to simulate 8 years 
at 125�F.  The samples were exposed to the same simulated LOCA environment.  
One of the six specimens failed during the first 6 minutes of the LOCA expo-
sure.  Two other specimens failed after 17 and 24 hours of testing, respec-
tively.  The licensee discontinued the test and concluded that the splices 
failed to perform under conditions tested.  All of the tested splices were 
nuclear-type PIDG, AMP Part Number 53550-1.

Subsequent to this test, the licensee identified 196 window indent KYNAR butt 
splices in valve actuators, solenoid valve leads, and in one junction box.  
These splices have since been replaced at the Clinton Station with qualified 
tape or Raychem splices.

Thomas and Betts Nylon Wire Caps:

Subsequent to the NRC findings during the Clinton inspection, the licensee 
conducted two tests at Wyle Laboratories to demonstrate that the nylon wire 
caps were qualifiable to postulated accident environments at the Clinton 
Station.  Models RB-4 and RC-6 were tested.  

During the first test, six specimens were irradiated to 1.1E7 R and thermally 
aged for an 8-year simulated life at 125�F ambient temperature and then 
exposed to the simulated plant high-energy-line-break (HELB) of 270�F peak 
temperature.  With an applied phase-to phase-voltage of 537 Vac, no failures 
were observed.

The licensee performed a second test in which 12 specimens were irradiated to 
1.1E7 R.  Six specimens were thermally aged to simulate 125�F for a 40-year 
life and six specimens were aged to simulate 150�F for an 8-year life.  The 
specimens were then exposed to a simulated HELB environment of 270�F peak 
temperature while mounted on a metal surface.  At the 22-hour-point of the 
test, five specimens were found shorted to ground.  The test was discontinued.

The licensee determined that the nylon caps were qualified for at least a 
9.9-year plant life on the basis of the success of the first test and the 
actual lower plant ambient temperature.  The nylon wire caps will be replaced 
at Clinton before the end of their qualified life.  


10 CFR 50.49 requires that electrical equipment important to safety be 
environmentally qualified for postulated accident conditions.  AMP 
Qualification Test Report 110-11004, REL 2-2-82, "AMP Insulated Terminals and 
Splices for Class 1E, Inside Containment Service in Nuclear Power Generating 
Stations*," was used as a basis for qualifying the Clinton splices.  This 
report covers testing of AMP window indent KYNAR splices suspended between 
terminal blocks in a configuration in which the splices did not touch each 
other or the metal enclosure.  

*AMP Report 110-11004, REL 2-2-82 is available in the NRC Public Document 
 Rooms as Accession Number 8809290403.
.                                                            IN 88-81
                                                            October 7, 1988
                                                            Page 3 of 3

The tested configuration differs from the installed configuration of the 
splices. At the Clinton Station, AMP window indent KYNAR splices were free to 
touch each other or the metal enclosure and had been used to extend leads in 
various 10 CFR 50.49-designated circuits inside and outside the containment.  
Subsequent testing by the licensee demonstrated failures in configurations in 
which the splices touched a grounded metal surface.  These qualification tests
highlight the need for the testing of equipment in its expected installation 

Nylon wire caps were found installed in 480V motor leads in 90 dual-voltage 
Limitorque actuators at the Clinton Station.  Limitorque test reports did not 
identify these wire caps as part of the qualification tests, and Limitorque 
did not control the installed configuration of wire caps in delivered 
equipment.  Insufficient evidence of testing was interpreted by the NRC as a 
lack of qualification of these wire caps.  Subsequent testing of these wire 
caps by the licensee demonstrated the shorter qualified life of 9.9 years.  
These tests highlight the need to identify all degradable components in 10 CFR
50.49-designated equipment and to verify that they have been properly 
environmentally tested.

Information Notice 86-104, "Unqualified Butt Splice Connectors Identified in 
Qualified Penetrations," describes short circuits experienced during LOCA 
testing of nylon-insulated AMP butt splices, as well as Thomas and Betts and 
Hollinsworth splices, used in the Dresden Nuclear Power Station.  This problem
and those described in this information notice illustrate that some butt 
splices are designed to maintain circuit continuity and may not provide 
adequate electrical insulation from nearby conductors.

No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact one of the techni-
cal contacts listed below or the Regional Administrator of the appropriate 
regional office.

                                   Charles E. Rossi, Director
                                   Division of Operational Events Assessment
                                   Office of Nuclear Reactor Regulation

Technical Contacts:  A. S. Gautam, RIII
                     (312) 790-5523

                     R. C. Wilson, NRR
                     (301) 492-0997

Attachment:  List of Recently Issued NRC Information Notices
.                                                            Attachment 
                                                            IN 88-81 
                                                            October 7, 1988 
                                                            Page 1 of 1

                             LIST OF RECENTLY ISSUED
                            NRC INFORMATION NOTICES 
Information                                  Date of 
Notice No._____Subject_______________________Issuance_______Issued to________

88-80          Unexpected Piping Movement    10/7/88        All holders of OLs
               Attributed to Thermal                        or CPs for PWRs. 

88-79          Misuse of Flashing Lights     l0/7/88        All holders of OLs
               for High Radiation Area                      or CPs for nuclear
               Controls                                     power reactors. 

88-69, Supp 1  Movable Contact Finger        9/29/88        All holders of OLs
               Binding in HFA Relays                        or CPs for nuclear
               Manufactured by General                      power reactors. 
               Electric (GE) 

88-78          Implementation of Revised     9/22/88        All holders of OLs
               NRC-Administered Requali-                    or CPs for nuclear
               fication Examinations                        power reactors. 

88-77          Inadvertent Reactor           9/22/88        All holders of OLs
               Vessel Overfill                              or CPs for BWRs. 

88-76          Recent Discovery of a         9/19/88        All holders of OLs
               Phenomenon not Previously                    or CPs for nuclear
               Considered in the Design                     power reactors. 
               of Secondary Containment 
               Pressure Control 

88-75          Disabling of Diesel           9/16/88        All holders of OLs
               Generator Output Circuit                     or CPs for nuclear
               Breakers by Anti-Pump                        power reactors. 

88-74          Potentially Inadequate        9/14/88        All holders of OLs
               Performance of ECCS in                       or CPs for W and 
               PWRs During Recirculation                    B&W-designed 
               Operation Following a LOCA                   nuclear power 

88-73          Direction-Dependent Leak      9/8/88         All holders of OLs
               Characteristics of                           or CPs for nuclear
               Containment Purge Valves                     power reactors. 
OL = Operating License
CP = Construction Permit 

Page Last Reviewed/Updated Thursday, August 20, 2020