Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
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
