United States Nuclear Regulatory Commission - Protecting People and the Environment

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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                                                            October 19, 1988
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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, November 12, 2013