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
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
October 7, 1988
Information Notice No. 88-81: FAILURE OF AMP WINDOW INDENT KYNAR SPLICES
AND THOMAS AND BETTS NYLON WIRE CAPS DURING
ENVIRONMENTAL QUALIFICATION TESTING
Addressees:
All holders of operating licenses or construction permits for nuclear power,
test, and research reactors.
Purpose:
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.
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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.
Discussion:
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.
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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
configuration.
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
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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.
Stratification
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.
Circuitry
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
reactors.
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
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