Information Notice 1988-14, Potential Problems with Electrical Relays
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C.
20555
April 18, 1988
NRC INFORMATION NOTICE NO. 88-14:
POTENTIAL PROBLEMS WITH ELECTRICAL RELAYS
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose
This information notice is being provided to alert recipients to potential
problems involving HFA, PVD 218, PVD 21D, and HGA relays manufactured by
General Electric Company (GE), as described below. Although some of these
problems are several years old, they are included because utilities are still
identifying problems discovered while implementing advice issued by GE in the
early 1980s. The specific problem with the HFA relays concerns mechanical
binding in the relay caused by incorrect location of a stop tab that is welded
to the armature. The problems with the PVD 21B, PVD 21D, and HGA concern their
seismic capability. It is expected that licensees 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
a. HFA Relays
In June 1986, Duane Arnold Energy Center reported that HFA relays were not
resetting. GE determined, after investigation, that mechanical binding in
the relays prevented the normally closed contacts from making contact when
the relays were de-energized. This was caused by the incorrect location
of a stop tab that is welded to the armature. The incorrect location, com- bined with possible movement of the magnetic assembly, causes the armature
binding. In July 1986, TVA experienced similar problems.
On July 21, 1986, the GE Meter and Control Business Division (MCBD),
Malvern, Pennsylvania, issued a 10 CFR Part 21 report to the NRC. On
November 14, 1986, MCBD issued Service Advice Letter (SAL) 188.1, which
- .instructed recipients to test the relay to identify and correct improper
operation. The SAL stated that MCBD could not determine when the stop
tab problem had begun, but that relays manufactured between January 1983 and October 1986 were suspect. Date codes were provided that could be
IN 88-14 April 18, 1988 used to identify potentially affected relays.
However, on June 5, 1987, Pilgrim implemented SAL 188.1 and identified several improperly operating
relays which were manufactured outside the suspected date codes.
In view of this, all HFA relays may be suspect.
Additionally, the NRC
recently issued NRC Bulletin 88-03, "Inadequate Latch Engagement in HFA
Type Latching Relays Manufactured by General Electric (GE) Company,"
March 10, 1988, regarding problems from inadequate latch engagement.
b. PVD 21B and PVD 21D Relays (see Attachment 1)
In 1977, GE listed the seismic capability of the normally open contacts of
the PVD 21B and PYD 21D differential relays as 6g zero period acceleration
(ZPA) with the relay energized and the contacts closed. The tripping of
each of these relays in response to differential over current is by a "low
set" voltage unit, device 87L, and a "high set" current unit, device 87H.
Device 87L is an instantaneous voltage unit that has its coil connected
across the dc terminals of a full wave rectifier device. Device 87L has
two sets of normally open contacts, one of which is connected in parallel
with the contacts of the seal-in unit.
Device 87H is an instantaneous
overcurrent unit, with its coil connected in series with thyrite discs;
it has a single set of normally open contacts.
Originally, GE published data which implied that the seismic capability
of 6g ZPA applied equally to both 87H and 87L functions.
In 1983, GE
revised the seismic capabilities as follows:
the capability of the 87L
function remained at 6g ZPA, and the capability of the 87H function was
reduced to 2g ZPA.
GE stated that the 87H set of normally open contacts
is generally wired in parallel with both the open 87L contacts and the
open 87L seal-in contacts when the PVD relay is used to trip a circuit
breaker.
GE stated that the 87H function of the PVD is less sensitive
than the 87L function (it requires more operating signal).
As a result, opening the normally open 87H contacts for a time greater than 2 milli- seconds as a consequence of a seismic event between 2g and 6g ZPA should
not interfere with tripping the circuit breaker because the parallel 87L
contact would remain closed up to 6g ZPA. In view of the 2g ZPA seismic
capability of the 87H contact, GE recommended the application be checked
if the 87H contacts are used separately for any functions other than
tripping.
c. HGA Relays (see Attachment 1)
During a re-evaluation of qualification data for relays used in nuclear
Class IE systems, MCBD determined that the seismic data for HGA 11 and
HGA 111 relays published in MIL No. RS77-3, dated March 25, 1977, were
in error. The incorrect data were revised in MIL No. 82-12, dated
July 26, 1982. Specifically, MIL No. RS77-3 listed the seismic capa- bility of the normally closed contacts of ac-rated HGA 11 or HGA III
IN 88-14 April 18, 1988 relays at 1.Og ZPA when the relays were in the de-energized state. The
dc-rated relays were listed at 1.5g ZPA for the same condition. The re- vised seismic capability of the normally closed contacts of both ac and
dc HGA 11 and HGA 111 relays in the de-energized state is less than 0.5g
ZPA.
GE has conducted studies to determine design changes that could improve
the seismic capability of thie normally closed contacts when the relay is
de-energized. Additionally, a separate study considered the seismic capa- bility of alternate IGA relay models as a means for improving the seismic
capability of normally closed contacts with the relay de-energized. At
this time, GE has no plans for development of an HGA relay with improved
seismic capability.
On the basis of the above information, GE recommends that Class lE cir- cuits using normally closed contacts of HGA 11 and HGA 111 relays, with
the relay de-energized, be evaluated for the effect on the entire circuit
of an HGA 11 or HGA 111 contact opening long~r than 2 milliseconds.
On June 24, 1987, Duane Arnold reported to the NRC (1) that, based on the
revised data, HGA 11 relays providing critical functions in the core spray, low pressure coolant injection, high pressure coolant injection, and
-
reactor core isolation cooling systems at Duane Arnold have indeterminate
qualification, and (2) that the relays were being replaced.
Discussion:
a. HFA Relays
For HFA relays, in addition to SAL 188.1, GE issued the following SALs:
(1) SAL 139.2, dated April 28, 1976.
This SAL superseded SAL 139.1, dated September 5, 1973.
(2) SAL 152.1, dated April 28, 1976.
(3) SAL 152.2, dated November 3, 1980.
(4) SAL 152.2A, dated March 12, 1982.
(5) SAL 169.1, dated May ?8, 1982.
b. PYD 21 Relays
For PVD 21 relays, GE issued SAL 174.1 dated April 11, 1983.
This SAL
provided clarification of the seismic capability of the 87H and 87L
contacts.
.r
IN 88-14 April 18, 1988 *
Most plants using PVD and HGA style relays are subject to the verification of
seismic adequacy of mechanical and electrical equipment under Unresolved Safety
Issue (USI)
A-46 (as outlined in Generic Letter 87-02). However, PVD and HGA
style relays have also been found in newer plants that are not subject to
Generic Letter 87-02 (e.g., Susquehanna Unit 2 LER 86-024-000).
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
K. R. Naidu, NRR
(301) 492-0980
Attachments:
1. General Electric Letter to NRC
dated February 24, 1983
2. List of Recently Issued NRC Information Notices
Attachment 1
GENERAL
- ELECTRIC
OENERAL ELECTRIC COMPANY. IN GRAT VALLEY PARKWAY, MALVERN PA 135513 o
"MO
(115) 251-7T00
' POWER SYSTEMS
MANAGEMENT
BUIINESS
DEPARTMENT
February 24, 1983
Mr. Richard DeYoung
Director of Office of Inspection and Enforcement
United States Nuclear Regulatory Coumission
Washington, D.C. 20555
Dear Hr. DeYoung:
Attached is a copy of a letter relating to PVD21B and PYD 21D relays and
a copy of a letter relating to HGAlI and HGAlIl relays addressed to customers
we have knowledge of who may be applying these devices In nuclear
Installations.
It is our understanding that this fulfills our obligation to the Nuclear
Regulatory Cowission.
Yours truly, V Wa'nt
L. L. Hankoff
Manager-Engineering
LLM/gs
Attachment
cc: E. J. Flerko
T. R. Macon
M. J. Kirray
V. Thomas
Malvern-1203 Malvern-1205 Halvern-1206 NRC
-694039409 830224 PDR PT21 EMVGENE
83-758-000
.PYD21B and PYD21D SEISMIC CAPABILITY
During a re-evaluation of qualification data for relays used In nuclear IE
systems, some seismic data for PVD 21 relays published in MIL No. RS77-3, March 25, 1977 were found to be in error.
The incorrect data were
subsequently revised In part In MIL No. 82-12, dated July 26, 1982.
The
correct data for these relays are 6 9 ZPA for the 87L function and 2 9 ZPA for
the 87H function.
The normally open contacts of the PVD218 and PVD21D relays were listed In MIL
No. RS77-3 as having a 6 g ZPA capability when these contacts were closed with
the relay in the operate oode. During the period Decezber 19. 1980 through
April 27, 1981, a few Huclear Certification documents were Issued with a
revised value of 4 g ZPA. Certifications issued after April 27, 1981 through
January 17, 1983 listed the seismic Capability at 2 g U A. For-each of the
above cases, the seismic capability was implied to apply equally to the 87H
and 87L functions, the two tripping modes of the relay.
The seismic ceuability of the 87L function was correct at 6 9 VPA.
The
seismic capability of the 87H function should have been listed as 2 g ZPA.
The 87H normally open contact is generally applied in parallel with the
normally open 87L contact and normally open 87L seal-in contact when the PVD
relay is used to trip a circuit breaker.
The 87H function of the PYD is less
sensitive than the 87L function, (requires more operating signal), therefore
opening of the normally open 87H contact for a time greater than two
milliseconds as a consequence of a seismic event between 2 and 6 g ZPA, should
not interfere with tripping the circuit breaker because the parallel 67L
contact would remain closed up to 6 g ZPA.
If the 87H contact is used separately for any functions other than trip~ing, the application should be checked in view of the 2 g ZPA seismic capab iity of
the 87H contact.
HGAll and HGAlI SEISMIC CAPABILITY - NORMALLY CLOSED
CONTACT
S
During a re-e nluat10n-'ofqualfffeatfon data'for relays used In nuclear lE
systems, some seismic data for HGAlI and HGAlil relays published in NIL
No. RS77-3, March 25, 1977 were found to be in error. The incorrect data were
subsequently revised in NIL No. 82-12, dated July 26, 1982.
The normally closed contacts of AC rated HGAll or HGAltl rt;ays were listed in
NIL No. RS77-3 as having a 1 9 ZPA seismic capability when the relays were In
the de-energized state. TheDC rated relays were listed as having 1.5 9 ZPA
capability for the same condition.. A value of 0.3 9 ZPA should have been
listed for the normally closed contacts of both relays in the deenergized
state.
HGAlIl relays were recently re-tested for seismic capability and the values
obtained for normally closed contacts with the relay de-energ1ied were less
than the 0.5 g ZPA low limit of the test equipment..
Studies are underway to determine If there are design changes which could
increase the seismic capability of the normally closed contacts when the relay
is de-energized.
In addition, a separate study will consider the seismic
capabilities of alternate models of HGA relays as a means for Improving
seismic capability, of normally closed contacts with the relay de-energized.
Based on the preceding Information, It is reconnended that Class 1E circuits
using HGAtl or HGAlIl normally closed contacts with the relay de-energized be
evaluated for effect on the entire circuit of an HGAll or HGAlIl contact
opening exceeding two milliseconds duration.
Attachment 2
April 18, 1988 LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issuance
Issued to
88-13
88-12
88-11
88-10
87-44, Supp. 1
88-09
88-08
Water Hammer and Possible
Piping Damage Caused by
Misapplication of Kerotest
Packless Metal Diaphragm
Globe Valves
Overgreasing of Electric
Motor Bearings
Potential Loss of Motor
Control Center and/or
Switchboard Function Due
to Faulty Tie Bolts
Materials Licensees: Lack
of Management Controls Over
Licensed Programs
Thimble Tube Thinning in
Westinghouse Reactors
Reduced Reliability of
Steam-Driven Auxiliary
Feedwater Pumps Caused
by Instability of Woodward
PG-PL Governors
Chemical Reactions with
Radioactive Waste
Solidification Agents
4/18/88
4/12/88
-4/7/88
3/28/88
3/28/88
3/18/88
3/14/88
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All holders of OLs
or CPs for nuclear
power reactors.
All NRC licensees
authorized to use
byproduct material.
All holders of OLs
or CPs for nuclear
power reactors that
employ a Westinghouse
NSSS.
All holders of OLs
or CPs for nuclear
power reactors.
All NRC licensees
generating or pro- cessing low level
radioactive waste.
0
Operating License
CP = Construction Permit
1.
IN 88-14 April 18, 1988 Most plants using PVD and HGA style relays are subject to the verification of
seismic adequacy of mechanical and electrical equipment under Unresolved Safety
Issue (USI) A-46 (as outlined in Generic Letter 87-02).
However, PVD and HGA
style relays have also been found in newer plants that are not subject to
Generic Letter 87-02 (e.g., Susquehanna Unit 2 LER 86-024-000).
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact 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 Contact:
K. R. Naidu, NRR
(301) 492-0980
c Letter to NRC
r 24, 1983 f Issued NRC Information Notices
Attachments:
1. General
dated
2. List of
Electric
Februar3 Recentl3
- SEE PREVIOUS CONCURRENCES
- OGCB:DOEA:NRR*VIB:DRIS:NRR
BMann
KNaidu
02/23/88
02/23/88
- C/OGCB:DOEA:NRR
CHBerlinger
0
88 U/11/88
- SC/VIB:DRIS:NRR*A/BC/VIB:DRIS:NRR
EBaker
JStone
02/24/88
02/24/88
- D/DRIS:NRR
JGPartlow
03/15/88 PPMB:ARM
TechEd
03/11/88
IN 88-XX
April xx, 1988 Most plants using PYD and HGA style relays are subject to the verification of
seismic adequacy of mechanical and electrical equipment under Unresolved Safety
Issue (USI) A-46 (as outlined in Generic Letter 87-02). However, PVD and HGA
style relays have also been found in newer plants that are not subject to
Generic Letter 87-02 (e.g., Susquehanna Unit 2 LER 86-024-000).
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact 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 Contact:
K. R. Naidu, NRR
(301) 492-0980
Attachment:
List of Recently Issued NRC Information Notices
- SEE PREVIOUS CONCURRENCES
- OGCB:DOEA:NRR*VIB:DRIS:NRR
BMann
KNaidu
02/23/88
02/23/88 D/DOEA:NRR
- C/OGCB:DOEA:NRR
CERossi
CHBerlinger
04/ /88
03/11/88
- SC/VIB:DRIS:NRR*A/BC/VIB:DRIS:NRR
EBaker
JStone
02/24/88
02/24/88
- D/DRIS:NRR
JGPartlow
03/15/88 PPMB:ARM
TechEd
03/11/88
IN 88-XX
March xx, 1988 HGA style relays are subject to the
ical and electrical equipment under
outlined in Generic Letter 87-02).
been found in newer plants that are
Susquehanna Unit 2 LER 86-024-000).
verification of seismic adequacy of mechan- Unresolved Safety Issue (USI) A-46 (as
However, PVD and HGA style relays have also
not subject to Generic Letter 87-02 (e.g.,
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact 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 Contact:
K. R. Naldu, NRR
(301) 492-9659 Attachment:
List of Recently Issued NRC Information Notices
- SEE PREVIOUS CONCURRENCES
- OGCB:DOEA:NRR*VIB:DRIS:NRR
BMann
KNaidu
02/23/88
02/23/88 D/DOEA:NRR
- C/OGCB:OWEA:NR
CERossi
CHBerlinger
Partlow
03/
/88
03/11/88
03//S /88
- SC/VIB:DRIS:NRR*A/BC/VIB:DRIS NRR PPMB:ARM
EBaker
JStone
TechEd
02/24/88
02/24/88
03/11/88
K>
IN 88-XX
March xx, 1988 HGA style relays are subject to the
ical and electrical equipment under
outlined in Generic Letter 87-02).
been found in newer plants that are
Susquehanna Unit 2 LER 86-024-000).
verification of seismic adequacy of mechan- Unresolved Safety Issue (USI) A-46 (as
However, PYD and HGA style relays have also
not subject to Generic Letter 87-02 (e.g.,
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact 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 Contact:
K. R. Naidu, NRR
(301) 492-9659 Attachment:
List of Recently Issued NRC Information Notices
- SEE PREVIOUS CONCURRENCES
- OGCB:DOEA:NRR*VIB:DRIS:NRR
BMann
KNaidu
02/23/88
02/23/88 D/DOEA:NRR
CERossi
02/ /88
- SC/VIB:DRIS:NRR*A/BC/VIB:DRIS:NRR
EBaker
JStone
02/24/88
02/24/88
0h5 JA/4/8
- C/OGCB:DOEA:NRR
CHBerlinger
02/29/88 PPMB:ARM
TechEd i
o0/11/88
IN 88-XX
February xx, 1988 HGA style relays are subject to the verification of seismic adequacy of mechan- ical and electrical equipment under Unresolved Safety Issue (USI) A-46 (as
outlined in Generic Letter 87-02). However, PVD and HGA style relays have also
been found in newer plants which are not subject to Generic Letter 87-02, (e.g., Susquehanna Unit 2 LER 86-024-000).
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact 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 Contact:
K. R. Naidu, NRR
(301) 492-9659 Attachment:
List of Recently Issued NRC Information Notices
- SEE PREVIOUS CONCURRENCES
- OGCB:DOEA:NRV
X
RIS:NRR SC/VIB:DRIS:NRR
BMann 93K.
KNaidu
EBaker
02/23/88
02/23/88
02/24/88 D/DOEA:NRR
C/O
C
D:0
CERossi
CHBerlinger
02/ /88
02/19/88
- A/BC/VI tDRIS:NRR PPMB:ARM
JStone %
TechEd
02/24/88
02/ /88
IN 88-XX
February xx, 1988 HGA style relays are subject to the verification of seismic adequacy of mechan- ical and electrical equipment under Unresolved Safety Issue ((USI) A-46 (as
outlined in Generic Letter 87-02). However, PVD and HGA style relays have also
been found in newer plants which are not subject to Generic Letter 87-02, (e.g., Susquehanna Unit 2 LER 86-024-000).
No specific action or written response is required by thisA. ion Ratien_4n*t4ee.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
office.
Issue.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact:
K. R. Naidu, NRR
(301) 492-9659 Attachment:
List of Recently Issued NRC Information Notices
OGCB:DOEA:NRR
BMann SjIi
02/19/88 VIB: ~%
NRR SC
RIS:NRR
KNai l
EBak
02/30288 D2/*48 D/DOEA:NRR
CERossi
02/
/88 A/BC/VIB:DRIS:NRR
JStone
02@4 /88
9,.6p-'
6-1,.
C/OGCB:DOEA:NRR
CHBerlinger
02/
/88 PPMB:ARM
TechEd
02/ /88