United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 80-06: Engineered Safety Feature (ESF) Reset Controls

                                                            SSINS: 6820 
                                                            Accession No.: 

                               UNITED STATES 
                           WASHINGTON, D.C. 20555 
                              March 13, 1980  

                                                     IE Bulletin No. 80-06 


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 

IE Bulletin No. 80-06                                       March 13, 1980 
                                                            Page 2 of 3 

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 

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. 

Actions To Be Taken By Licensees: 

For all PWR and BWR facilities with operating licenses: 

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 

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. 

IE Bulletin No. 80-06                                       March 13, 1980 
                                                            Page 3 of 3 

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 (ROO72); clearance expires 7-31-80. Approval was 
given under a blanket clearance specifically for identified generic 
Page Last Reviewed/Updated Friday, May 22, 2015