Information Notice No. 88-83: Inadequate Testing of Relay Contacts in Safety-Related Logic Systems
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
October 19, 1988
Information Notice No. 88-83: INADEQUATE TESTING OF RELAY CONTACTS
IN SAFETY-RELATED LOGIC SYSTEMS
Addressees:
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose:
This information notice is being provided to alert addressees to potential
problems resulting from inadequate testing of relay contacts in safety-related
logic systems. It is expected that recipients will review the 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 inspection of the reactor core isolation cooling (RCIC) and high
pressure coolant injection (HPCI) systems reliability program at the Duane
Arnold Energy Center (DAEC), NRC inspectors discovered apparent deficiencies
with the logic system functional test procedures for both systems. Specifi-
cally, during the first phase of the functional test, the test procedures
called for either the isolation or the blocking of relay contacts while the
operation of the actuation relay was tested. These contacts were then either
bypassed or jumpered when the second phase of the test was performed. Thus,
the relay contacts were not being tested. This is significant in that failure
of these relay contacts could result in the inoperability of the RCIC or HPCI
systems.
Discussion:
The DAEC Technical Specifications define a logic system functional test as "a
test of all relays and contacts of a logic circuit to ensure all components
are operable per design intent. Where practicable, action will go to
completion; i.e., pumps will be started and valves operated." Although the
DAEC Technical Specifications clearly define a Logic System Functional Test as
"a test of all relays and contacts . . ." (emphasis added), the licensee
apparently inter-preted "all relays and contacts" to not include relay
contacts. Enforcement
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. IN 88-83
October 19, 1988
Page 2 of 2
action was taken since the failure to test the initiation isolation relay
contacts had resulted in a violation of the Technical Specifications. Al-
though the preceding discussion concerns the RCIC and HPCI system logic,
inadequate logic system functional testing may exist in other safety-related
systems.
As a result of NRC concerns regarding this matter, the licensee initiated an
augmented testing program to ensure that safety-related circuit components and
contacts are verified to be operable per design intent. The specific
objective of the program is to ensure that the test procedures demonstrate
full logic system performance from the sensor to the actuated device within
the design intent of the systems safety function.
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: R. Lasky, NRR
(301) 492-0772
Attachment: List of Recently Issued NRC Information Notices
. Attachment
IN 88-83
October 19, 1988
Page 1 of 1
LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
_____________________________________________________________________________
Information Date of
Notice No._____Subject_______________________Issuance_______Issued to________
88-82 Torus Shells with Corrosion 10/14/88 All holders of OLs
and Degraded Coatings in or CPs for BWRs.
BWR Containments
88-81 Failure of Amp Window 10/7/88 All holders of OLs
Indent Kynar Splices or CPs for nuclear
and Thomas and Betts power, test, and
Nylon Wire Caps During research reactors.
Environmental Quali-
fication Testing
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
_____________________________________________________________________________
OL = Operating License
CP = Construction Permit
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021