SSINS No.:  6835 
                                                            IN 85-27 

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                    OFFICE OF INSPECTION AND ENFORCEMENT 
                            WASHINGTON, DC 20555 

                               April 3, 1985 

Information Notice No. 85-27:  NOTIFICATIONS TO THE NRC OPERATIONS center
                                  AND REPORTING EVENTS IN LICENSEE EVENT 
                                  REPORTS 

Addressees: 

All nuclear power reactor facilities holding an operating license (OL) or a 
construction permit (CP). 

Purpose: 

This notice is provided to clarify the requirement for licensees to report 
to the Headquarters Operations Center an event or condition that results in 
or could result in multiple failures in safety systems. This guidance is 
also applicable to the requirement for licensees to report events as 
Licensee Event Reports (LERs). It is expected that recipients will review 
the information for applicability to their facilities and take appropriate 
action. No specific action or response is required by this notice. 

Description of Circumstances: 

This issue has arisen as a result of a recent event at a nuclear power plant
during which multiple failures occurred in the scram system, but the 
licensee did not consider it necessary to report the failures to the 
Headquarters Operations Center. 

The event occurred while performing single control rod scram time testing. 
One of the control rods scheduled for testing failed to scram when the scram
pilot solenoid valve stuck in the energized position. Subsequent testing of 
the remaining rods revealed that 3 additional rods would not scram and that 
11 control rods exhibited initial hesitation. The unit was operating at 
power when the problems occurred. 

Discussion: 

The paragraph of 10 CFR 50.72 that requires reporting of all multiple fail-
ures and some single failures is paragraph 50.72(b)(2)(iii), which requires 
the licensee to notify the NRC Operations Center as soon as practical and in
all cases within 4 hours of the occurrence of:  



8504010039  
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                                                           IN 85-27  
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          Any event or condition that alone could have prevented the 
          fulfillment of the safety function of structures or systems that 
          are needed to: 

          (a)  Shut down the reactor and maintain it in a safe shutdown 
               condition, 
          (b)  Remove residual heat, 
          (c)  Control the release of radioactive material, or 
          (d)  Mitigate the consequences of an accident. 

10 CFR 50.73(a)(2)(v) also contains words identical to the preceding 
excerpt. Multiple failures of redundant components required to perform any 
of the above safety functions are reportable. A single failure in a 
component required to perform any of the above safety functions is 
reportable when there is sufficient reason to expect that the failure 
mechanism is one that could occur in a redundant component. 

Multiple failures of redundant components of a safety system are sufficient 
reason to expect that the failure mechanism, even though not known, could 
prevent the fulfillment of the safety function. While the failure of a 
single rod to scram may not cause a reasonable doubt that other rods would 
fail to scram, the failure of multiple rods to scram causes a reasonable 
doubt that other rods could be affected and, thus, this is an event or 
condition that could prevent the fulfillment of the safety function (i.e., 
the RPS scram) needed to shut down the reactor. 

A single failure in a safety system is reportable when it is determined that
the failure mechanism could reasonably be expected to occur in a redundant 
component or components of a safety system such that the fulfillment of the 
safety function would be prevented. The preamble to the Federal Register 
Notices that published the 10 CFR 50.72 and 10 CFR 50.73 rules provide as an
example: 

          ... if a pump fails because of improper lubrication, there is a 
          reasonable expectation that the functionally redundant pump, which
          was also improperly lubricated, would have also failed before it 
          completed its safety function, then the failure is reportable and 
          the potential failure of the functionally redundant pump must be 
          reported. 

Such a single failure is reportable to the NRC Operations Center as soon as 
practical and in all cases within 4 hours of determining that the failure 
mechanism could reasonably be expected to occur in a redundant component or 
components of a safety system. Similarly such a single failure is reportable
in a Licensee Event Report within 30 days of determining that the failure 
mechanism could reasonably be expected to occur in a redundant component or 
components of a safety system. 
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                                                           IN 85-27 
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No written response to this information notice is required. If you need 
additional information about this matter, please contact the Regional 
Administrator of the appropriate NRC regional office or the technical 
contacts listed below. 



                                   Edward L. Jordan, Director 
                                   Division of Emergency Preparedness 
                                     and Engineering Response 
                                   Office of Inspection and Enforcement 

Technical Contacts:  10 CFR 50.72 
                     E. W. Weiss, IE 
                     (301) 492-9005 

                     10 CFR 50.73 
                     F. J. Hebdon, AEOD 
                     (301) 492-4480 

Attachment:  List of Recently Issued IE Information Notices