Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
GL80025 SSINS No. 6820
Accession No.:
8002280639
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
March 13, 1980
IE Bulletin No. 80-06
ENGINEERED SAFETY FEATURE (ESF) RESET CONTROLS
Description of Circumstances:
On November 7, 1979, Virginia Electric and Power Company (VEPCO) reported
that following initiation of Safety Injection (SI) at North Anna Power
Station Unit 1, the use of the SI Reset pushbuttons alone resulted in
certain ventilation dampers changing position from their safety or emergency
mode to their normal mode. Further investigation by VEPCO and the
architect-engineer resulted in discovery of circuitry which similarly
affected components actuated by a Containment Depressurization Actuation
(CDA, activated on Hi-Hi Containment Pressure). The circuits in question
are listed below:
Component/System Problem
Outside/Inside Recirculation Spray Pump motors will not start after
Pump Motors actuation if CDA Reset is depressed
prior to starting timer running
out (approx. 3 minutes)
Pressurized Control Room Dampers will open on SI Reset
Ventilation Isolation Dampers
Safeguards Area Filter Dampers Dampers reposition to bypass
filters when CDA Reset is depressed
Containment Recirculation Cooler Fans will restart when CDA Reset
Fans is depressed
Service Water Supply and Discharge If service water is being used as
Valves to Containment the cooling medium prior to CDA
actuation, valves will reopen
upon depressing CDA reset
Service Water Radiation Monitoring Pumps will not start after Sample
Pumps actuation if CDA reset is depressed
prior to motor starting timers
running out
Main Condenser Air Ejector Exhaust After receiving a high radiation
Isolation Valves to the Containment monitor alarm on the air ejector
exhaust, SI actuation would shut
these valves and depressing SI Reset
would reopen them
Review of circuitry for ventilation dampers, motors, and valves reported by
.
VEPCO resulted in discovery of similar designs in ESF-actuated components at
Surry Unit 1 and Beaver Valley; where it has been found that certain
equipment would return to its normal mode following the reset of an ESF
signal; thus, protective actions of the affected systems could be
compromised once the associated actuation signal is reset. These two plants
had Stone and Webster Engineering Corporation for the architect-engineer as
did the North Anna Units.
The Stone and Webster Engineering Corporation and VEPCO are preparing design
changes to preclude safety-related equipment from moving out of its
emergency mode upon reset of an Engineered Safety Features Actuation Signal
(ESFAS). This corrective action has been found acceptable by the NRC, in
that, upon reset of ESFAS, all affected equipment remains in its emergency
mode.
The NRC has performed reviews of selected areas of ESFAS reset action on PWR
facilities and, in some cases, this review was limited to examination of
logic diagrams and procedures. It has been determined that logic diagrams
may not adequately reflect as-built conditions; therefore, the requested
review of drawings must be done at the schematic/elementary diagram level.
There have been several communications to licensees from the NRC on ESF
reset actions. For example, some of these communications have been in the
form of Generic Letters issued in November, 1978 and October, 1979 on
containment venting and purging during normal operation. Inspection and
Enforcement Bulletins Nos. 79-05, 05A, 05B, 06A, 06B and 08 that addressed
the events at TMI-2 and NUREG-0578, TMI-2 Lessons Learned Task Force Status
Report and Short-Term Recommendations. However, each of these
communications has addressed only a limited area of the ESF's. We are
requesting that the reviews undertaken for this Bulletin address all of the
ESF's.
Action To Be Taken By Licensees:
1. Review the drawings for all systems serving safety-related functions
at the schematic level to determine whether or not upon the reset of
an ESF actuation signal, all associated safety-related equipment
remains in its emergency mode.
2. Verify the actual installed instrumentation and controls at the
facility are consistent with the schematics reviewed in Item 1 above
by conducting a test to demonstrate that all equipment remains in its
emergency mode upon removal of the actuating signal and/or manual
resetting of the various isolating or actuation signals. Provide a
schedule for the performance of the testing in your response to this
Bulletin.
3. If any safety-related equipment does not remain in its emergency mode
upon reset of an ESF signal at your facility, describe proposed system
modification, design change, or other corrective action planned to
resolve the problem.
4. Report in writing within 90 days, the results of your review and
include a list of all devices which respond as discussed in item 3
above, actions taken or planned to assure adequate equipment control,
and a schedule for implementation of corrective action. This
.
information is requested under the provisions of 10 CFR 50.54(f).
Accordingly, you are requested to provide within the time period
specified above, written statements of the above information, signed
under oath or affirmation. Reports shall be submitted to the Director
of the appropriate NRC Regional Office and a copy shall be forwarded
to the NRC Office of Inspection and Enforcement, Division of Reactor
Operations Inspection, Washington, D.C. 20555.
For all power reactor facilities with a construction permit, this Bulletin
is for information only and no written response is required.
Approved by GAO, B180225 (R0072); clearance expires 7-31-80. Approval was
given under a blanket clearance specifically for identified generic
problems.
