United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 85-03: Supplement 1, Motor-operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings

                                                  OMB No.: 3150-0011
                                                  NRCB 85-03, Supplement 1

                                  UNITED STATES
                          NUCLEAR REGULATORY COMMISSION
                      OFFICE OF NUCLEAR REACTOR REGULATION
                             WASHINGTON, D.C.  20555

                                 April 27, 1988


NRC BULLETIN NO. 85-03, SUPPLEMENT 1:  MOTOR-OPERATED VALVE COMMON MODE 
                                       FAILURES DURING PLANT TRANSIENTS 
                                       DUE TO IMPROPER SWITCH SETTINGS


Addressees:

All holders of operating licenses or construction permits for boiling water 
reactors (BWRs).

Purpose:

The purpose of this supplement to NRC Bulletin 85-03 (B 85-03), 
"Motor-Operated Valve Common Mode Failures During Plant Transients Due to 
Improper Switch Settings," is to clarify (1) which valves are to be included 
and (2) the meaning of the phrase ". . . inadvertent equipment operations 
(such as inadvertent valve closures or openings) . . ." as used in the 
bulletin.

Background:

B 85-03, which was issued on November 15, 1985, was prompted by the June 9, 
1985 event at the Davis-Besse plant in which the inability to reopen two 
valves that had inadvertently been closed led to a loss of both trains of the 
auxiliary feedwater system.

Discussion:

Review of the responses to B 85-03 from BWR facilities, including those from 
the owners group, has indicated that there is a misunderstanding in regard to 
the related issues of (1) which valves are to be included and (2) the meaning 
of the phrase ". . . inadvertent equipment operations (such as inadvertent 
valve closures or openings) . . ." as used in the bulletin.

The first misunderstanding pertains to which valves are addressed by the 
bulletin.  As written, the action portion of B 85-03 applies to motor-operated 
valves in selected systems that ". . . are required to be tested for 
operational readiness in accordance with 10 CFR 50.55a(g) . . ."  At the time 
the bulletin was issued, the staff believed that the inservice testing 
programs required by 10 CFR 50.55a(g) were applicable to most, if not all, of 
the safety-related valves in the selected systems.  However, recent 
conversations with the owners group and several licensees have indicated that 
a number of valves in these systems are normally kept in their safety 
positions and are not covered by the 



8804210018
.                                                  NRCB 85-03, Supplement 1
                                                  April 27, 1988
                                                  Page 2 of 4


inservice testing program.  However, if the proper precautions are not taken, 
these valves which are normally properly positioned could be mispositioned, 
either before or during the initial phases of an event.  This would render the 
safety system inoperable unless the valves could be repositioned to the proper 
position.  Therefore, the heading of the action section of B 85-03 has been 
revised to include all safety-related valves in the selected systems.

The meaning of the phrase ". . . inadvertent equipment operation (such as in-
advertent valve closures or openings) . . ." used in action item a of the 
bulletin can also be misunderstood.  This phrase stems from the desire to 
address the salient feature of the Davis-Besse event -- namely, the inability 
to reposition either of two redundant valves that had been mispositioned 
earlier in the event.  Although it was not the intent of the bulletin to 
expand the design-basis events for plants, it was intended to ensure the high 
reliability of individual safety systems.  To this end, and given the chain of 
events associated with the Davis-Besse event, the staff felt that the only way 
to ensure this high reliability was to verify the ability of all valves to 
recover from mispositioning.  Therefore, action item a of B 85-03 has been 
revised to clearly indicate that each motor-operated valve must be able to 
recover from an inadvertent mispositioning.

This revision to B 85-03 may expand the number of valves addressed by some 
licensees.  In addition, some of these licensees may have already completed 
their scheduled activities to comply with the bulletin.  Therefore, the time 
limits for completing all the activities (action item e) have been modified to 
allow additional time for those licensees who have already completed their 
planned activities.

Actions for All BWR Holders of Operating Licenses or Construction Permits:

For safety-related motor-operated valves in the high pressure coolant 
injection/ core spray and reactor core isolation cooling systems not included 
in the actions planned or completed in response to the original bulletin, 
develop and implement a program to ensure that valve operator switches are 
selected, set, and maintained properly.  This should include the following: 

a.   Review and document the design basis for the operation of each valve.  
     This documentation should include the maximum differential pressure 
     expected during both opening and closing of the valve for both normal and 
     abnormal events to the extent that the events are included in the 
     existing, approved design basis (i.e., the design basis documented in 
     pertinent licensee submittals such as FSAR analyses and fully approved 
     operating and emergency procedures, etc.).  In addition, when determining 
     the maximum differential pressure for valves that can be inadvertently 
     mispositioned,(1) the fact that the valve must be able to recover from 
     such mispositioning should be included.

                                   

(1)  Any motor-operated valve that is not blocked from inadvertent operation 
     from either the control room, the motor control center, or the valve 
     itself should be considered capable of being mispositioned.
.                                                  NRCB 85-03, Supplement 1
                                                  April 27, 1988
                                                  Page 3 of 4


b.   Perform action item b of the original bulletin for any additional valves 
     identified above.  

     The intent is to provide assurance that a program exists for selecting 
     and setting valve operator switches to ensure a high reliability of 
     safety system valves.  If changing the switch settings is not sufficient 
     to ensure the capability for repositioning a particular mispositioned 
     valve, a justification for continued operation should be provided in the 
     bulletin response if the licensee does not elect to implement additional 
     actions, such as administrative or procedural controls or equipment 
     modifications, to minimize the likelihood of valve malfunction. 
     
c.   Perform action item c of the original bulletin for any additional valves 
     identified above.  

d.   Perform action item d of the original bulletin for any additional valves 
     identified above.  

e.   Within 30 days of receipt of this supplement, submit a written report to 
     the NRC that, for any additional valves:  (1) provides the revised 
     results of item a, above and (2) contains a schedule for completion of 
     items b through d, above.  

     1.   No changes from the schedule for complying with the original 
          bulletin are anticipated for plants with an OL that, as of the date 
          of this supplement, had not yet begun the refueling outage during 
          which the activities in the original bulletin were scheduled to be 
          accomplished.

     2.   Plants with an OL that, as of the date of this supplement, have com-
          pleted their planned activities in response to the original bulletin 
          have until the completion of their next refueling outage to complete 
          any additional activities resulting from this supplement.  The final 
          report covering the activities already completed in response to the 
          original bulletin shall be submitted in accordance with the original 
          schedule.  

     3.   No changes from the schedule for complying with the original 
          bulletin are anticipated for plants with a CP. 

f.   Revise the report requested by the original bulletin to include any addi-
     tional valves.  This revised report shall be submitted to the NRC within 
     60 days of completion of the program for the additional valves.  
     
Additional Related Generic Communications:

B 85-03 identified a number of related generic communications.  Since its 
issuance on November 15, 1985, the following additional related information 
notices have been issued:

a.   Information Notice No. 86-29, "Effects of Changing Valve Motor-Operator 
     Switch Settings," was issued on April 25, 1986.

.                                                  NRCB 85-03, Supplement 1
                                                  April 27, 1988
                                                  Page 4 of 4


b.   Information Notice No. 86-93, "IEB 85-03 Evaluation of Motor-Operators 
     Identifies Improper Torque Switch Settings," was issued on November 3, 
     1986.

c.   Information Notice No. 87-01, "RHR Valve Misalignment Causes Degradation 
     of ECCS in PWRS," was issued on January 6, 1987.

The written reports requested above shall be addressed to the U. S. Nuclear 
Regulatory Commission, ATTN:  Document Control Desk, Washington, D.C.  20555, 
under oath or affirmation under the provisions of Section 182a, Atomic Energy 
Act of 1954, as amended.  In addition, a copy shall be submitted to the appro-
priate Regional Administrator. 

This request for information was approved by the Office of Management and 
Budget under clearance number 3150-0011.  Comments on burden and duplication 
should be directed to the Office of Management and Budget, Reports Management, 
Room 3208, New Executive Office Building, Washington, D.C.  20503.

Although no specific request or requirement is intended, the time required to 
complete each action item above would be helpful to the NRC in evaluating the 
cost of this bulletin.

If you have any questions about this matter, please contact the technical 
contact listed below or the appropriate NRR project manager.




                                   Charles E. Rossi, Director
                                   Division of Operational Events Assessment
                                   Office of Nuclear Reactor Regulation


Technical Contact:  Richard J. Kiessel, NRR
                    (301) 492-1154


Attachment:  List of Recently Issued NRC Bulletins
Page Last Reviewed/Updated Tuesday, July 23, 2013