Part 21 Report - 1996-742
ACCESSION #: 9609170010
Public Service
Electric and Gas
Company
E.C.Simpson Public Service Electric P. O. Box 236, 609-339-1700
and Gas Company Hancocks Bridge,
NJ 08038
Senior Vice President -
Nuclear Engineering LR-N96274
SEP 06 1956
United States Nuclear Regulatory Commission
Document Control Desk
Washington, DC 20555
Gentlemen:
10 CFR 21 NOTIFICATION, NUS SUMMATOR AND ISOLATOR MODULES
SALEM GENERATING STATION UNITS 1 AND 2
FACILITY OPERATING LICENSE NO. DPR-70 AND DPR-75
DOCKET NOS. 50-272 AND 50-311
Pursuant to the notification requirements of 10 CFR 21.21(d)(3)(ii),
Public Service Electric and Gas Company (PSE&G) is providing the attached
written notification on the identification of a defect in NUS summator
and isolator logic modules. PSE&G identified this deviation on June 25,
1996 and made initial notification to the NRC Operations Center as
required by 10 CFR 21.21(d)(3)(i) on August 8, 1996.
Should you have any questions, please contact us.
Sincerely,
Attachment (1)
Document Control Desk -2- SEP 06 1996
LR-N96274
C Mr. H. J. Miller, Administrator - Region I
U. S. Nuclear Regulatory Commission
475 Allendale Road
King of Prussia, PA 19406
Mr. L. Olshan, Licensing Project Manager Salem
U. S. Nuclear Regulatory Commission
One White Flint North
11555 Rockville Pike
Mail Stop 14E21
Rockville, MD 20852
Mr. C. Marschall (X24)
USNRC Senior Resident Inspector
Mr. K. Tosch, Manager IV
Bureau of Nuclear Engineering
33 Arctic Parkway
CN 415
Trenton, NJ 08625
NUS
P.O. Box 50736
Idaho Falls, ID 83405
10 CFR 21 Notification
NUS Summator and Isolator Modules
I. NAME AND ADDRESS OF THE INDIVIDUAL(S) INFORMING
THE COMMISSION.
NAME:
E. C. Simpson
Senior Vice President - Nuclear Engineering
ADDRESS:
Public Service Electric and Gas Company P.O. Box 236
Hancock's Bridge, NJ 08038
II. IDENTIFICATION OF THE FACILITY, ACTIVITY OR COMPONENT WHICH
FAILS TO COMPLY OR CONTAINS A DEFECT.
The facility is the Salem Generating Station, Units 1 and
2. The basic components are Reactor Control and Protection
System signal isolator and signal summator modules:
Isolator module Model No. OCA801
Summator module Model No. MTH801
III. IDENTIFICATION OF THE FIRM SUPPLYING THE BASIC COMPONENT
WHICH FAILS TO COMPLY OR CONTAINS A DEFECT.
The modules were manufactured by:
NUS
P.O. Box 50736
Idaho Falls, ID 83405
IV. NATURE OF THE DEFECT OR FAILURE TO COMPLY AND THE SAFETY
HAZARD WHICH IS CREATED OR COULD BE CREATED.
NUS Model OCA801 signal isolator modules and Model MTH801
Signal Summator Modules are being installed as replacements for
modules in the Hagan 7100 Reactor Control and Protection System
to provide improved reliability. During bench testing, an
electrical connection with no solder was observed on a
replacement summator module. The replacement summator and
isolator modules for Salem Unit 2
Attachment 1 -2-
were then inspected. Of 220 modules inspected, fifteen were
found to have solder workmanship deficiencies (i.e., joints
with no solder or with insufficient or cold solder). Some of
the defective connections were covered by heat shrink
insulation.
The isolator modules function to provide electrical separation
between the Reactor Protection System (Class 1E) and the
Process Control System (non-Class 1E) portions of the Reactor
Control and Protection (RCP) instrument loops. The summator
modules are used to algebraically combine analog signals,
either adding or subtracting inputs in combination with module
gain and bias.
The reactor protection system is designed to assure that the
system can perform its required functions in the event of a
design basis earthquake. The missing and defective solder
joints could affect the modules' ability to function during a
design basis earthquake. It is not practical to determine the
exact failure modes introduced by these defects for each plant
application. However, due to the interchangeability of the
modules, the defects could result in a loss of redundancy
sufficient to constitute a major degradation of essential
safety related equipment.
V. THE DATE ON WHICH THE INFORMATION OF SUCH DEFECT OR
FAILURE TO COMPLY WAS OBTAINED.
The information was obtained on June 25, 1996.
VI. IN THE CASE OF A BASIC COMPONENT WHICH CONTAINS A DEFECT OR
FAILS TO COMPLY, IDENTIFY THE NUMBER AND LOCATION OF ALL SUCH
COMPONENTS IN USE AT OR SUPPLIED FOR PSE&G FACILITIES SUBJECT
TO THE REGULATIONS OF 10 CFR 21.
219 replacement modules are being installed or kept as spares
for Salem Unit 2. The replacement modules for Salem Unit 1
have been returned to the vendor.
Attachment 1 -3-
VII. THE CORRECTIVE ACTION WHICH HAS BEEN, IS BEING, OR WILL BE
TAKEN; THE NAME OF THE RESPONSIBLE INDIVIDUAL OR ORGANIZATION;
AND THE LENGTH OF TIME THAT HAS BEEN OR WILL BE TAKEN TO
COMPLETE THE ACTION.
The replacement modules including spares for Salem Unit 2 have
been inspected by the vendor and repaired. The replacement
modules for Salem Unit 1 have been returned to the vendor for
inspection and repair.
PSE&G requested the vendor to perform a root cause analysis of
the deficiencies. NUS provided a report of their evaluation to
PSE&G on September 3, 1996. NUS concluded that the soldering
workmanship deficiencies were due primarily to failure to
perform self-verification by assembly personnel and inadequate
supervisory monitoring of module assembly. NUS stated that
they had taken action to prevent recurrence and had
communicated the results of their inspection to affected
personnel.
VIII. ANY ADVICE RELATED TO THE DEFECT OR FAILURE TO COMPLY THAT
HAS
BEEN, IS BEING, OR WILL BE GIVEN TO PURCHASERS OR LICENSEES.
None.
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