05000333/LER-2016-005
| James A. Fitzpatrick Nuclear Power Plant | |
| Event date: | 9-19-2016 |
|---|---|
| Report date: | 11-17-2016 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3332016005R00 - NRC Website | |
| James A. Fitzpatrick Nuclear Power Plant | |
| Event date: | 9-19-2016 |
|---|---|
| Report date: | 11-17-2016 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3332016005R00 - NRC Website | |
comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
James A. FitzPatrick Nuclear Power Plant 05000 — 333
3. LER NUMBER
— 005 — 00 2016
Background
The James A. FitzPatrick Nuclear Power Plant (JAF) Control Room Air Conditioning (AC) System [EllS identifier: VI] and the Control Room Emergency Ventilation Air Supply (CREVAS) System [VI] (a mode of the Control Room AC) provides a protected environment from which occupants can control the plant during normal conditions and following an uncontrolled release of radioactivity, hazardous chemicals, or smoke.
The Control Room AC System and CREVAS System consists of two redundant subsystems that provide recirculated control room air. A single subsystem is sufficient to maintain a suitable control room environment for a sustained occupancy of 20 persons. Each subsystem consists of air handling units, recirculation exhaust fans, air handling unit fans, ductwork, dampers, and associated Instrumentation and controls; and, each CREVAS subsystem consists of a series of filters, a control room emergency air supply fan, valves or dampers, doors, barriers and instrumentation.
The recirculation / exhaust fans consist of two full capacity fans for the Control Room. The intake air supply is mixed with air from one of the recirculation / exhaust fans before it is recirculated back to the room. One Control Room exhaust fan runs at all times to support the normal or emergency mode while the other fan is on standby. Normally these exhaust fans are swapped manually. An automatic start function occurs only if the running exhaust fan stops.
This Licensee Event Report (LER) addresses the ability to start one of the Control Room recirculation / exhaust fans (70FN-4A).
Event Description
On September 19, 2016, JAF was at 54 percent power when the Control Room Ventilation recirculation / exhaust fan lineup was being changed to place 70FN-4A inservice when it did not start as expected. A second attempt to start the fan was successful when gentle pressure was applied to assist the linkage between the damper (70MOD-108A) and motor actuator (70MOD-108A(OP)). This damper is located on the outlet to 70FN-4A.
To maintain the operability of 70FN-4A, it was placed in service as the lead fan with 70FN-4B in standby. In addition, a manual Operator compensatory action was developed to have an Operator dispatched to assist the damper linkage in the event that an exhaust fan does not start. This compensatory action requires a short transit from the Control Room to the Control Room Ventilation Equipment room.
Event Analysis
The switch in the Control Room begins the sequence to start the fan (70FN-4A) by opening its associated damper (70MOD-108A). The circuit logic starts the fan after a time delay so the damper has time to open; but, it only starts the fan if there is a permissive signal that the damper has fully opened. The open permissive signal originates from a position switch integral / internal to the damper actuator (70MOD-108A(OP)) itself.
When gentle pressure was applied to assist the damper linkage during the event, it caused the actuator to complete its motion and close the contact for the permissive signal and initiate the fan start.
Prior to this event, on August 16, 2016, 70FN-4A did not start during post maintenance testing. In addition, the time delay start logic relay (70-62-1CRVA04) was found out-of-tolerance and damper position indication in the Control Room was dual. Indication in the Control Room for damper position comes from position switches 70PNS-108A1 and 70PNS-108A2. However, these position switches are for indication only and they do not comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
James A. FitzPatrick Nuclear Power Plant 05000 — 333
3. LER NUMBER
— 005 — 00 2016 provide the permissive signal. The corrective actions were to make a minor adjustment to the damper linkage, lubricate and clean moving parts, and re-calibrate 70-62-1CRVA04. The damper was tested and 70FN-4A started successfully with appropriate Control Room damper position indication. The damper actuator 70MOD- 108A(OP) was not replaced at that time.
After the event on September 19, 2016, the damper actuator 70MOD-108A(OP) was replaced.
Troubleshooting identified that the old damper actuator was slow / degraded compared to the new damper actuator. If 70MOD-108A(OP) were slow or did not fully actuate the internal position switch then 70FN-4A would not receive a permissive signal to start.
The inconsistent and degrading damper actuator performance began to affect system operability on August 16, 2016. This deficiency prevented the reliability of one of two redundant subsystems of the Technical Specification (TS) 3.7.4 Control Room AC System and TS 3.7.3 CREVAS system. If one CREVAS subsystem is inoperable then Required Action A.1 of TS 3.7.3 requires that it be restored within 7 days. If the completion time of Condition A were not met then Required Action C.1 requires that the plant be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and subsequently be in Mode 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. Similarly, if one Control Room AC System is inoperable then Required Action A.1 of TS 3.7.4 requires that it be restored within 30 days. If the completion time of Condition A were not met then Required Action C.1 requires that the plant be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and subsequently be in Mode 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. In both cases, the allowed out-of-service time was exceeded. This is a condition prohibited by Technical Specifications; reportable under 10 CFR 50.73(a)(2)(i)(B).
Cause
Degraded damper actuator 70MOD-108A(OP) affected the ability of the Control Room Ventilation recirculation / exhaust fan 70FN-4A to start reliably.
Similar Events There were no other identical failures of 70MOD-108A(OP) historically. However, similar ventilation damper actuator problems have occurred on other components.
April 8, 2005: The relay room exhaust isolation damper 70MOD-102A did not reach full open before the time delay relay timed out. A new damper actuator was installed. (CR-JAF-2005-01396) June 7, 2007: The Control Room air handling unit 70AHU-3A starts but the damper 70MOD-106A did not appear to be opening. This was caused by the damper actuator and was corrected when it was replaced. (CR- [[::JAF-2007-02124|JAF-2007-02124]]) August 5, 2011: The control room supply fan 70AHU-3A discharge damper 70MOD-106A will not open on initiation of fan start. This was caused by inadequate damper and damper linkage lubrication which increased the resistance to proper damper actuator performance. (CR-JAF-2011-04043)
FAILED COMPONENT IDENTIFICATION:
Manufacturer: Honeywell Inc Manufacturer Model Number: M8185D1006 NPRDS Manufacturer Code: H260 NPRDS Component Code: VALVOP FitzPatrick Component ID: 70MOD-108A(OP) comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
James A. FitzPatrick Nuclear Power Plant 05000 — 333
3. LER NUMBER
— 005 2016 — 00
Corrective Actions
Completed Actions
- 70MOD-108A(OP) replaced and tested.
Future Actions
- Evaluate changes to the preventative maintenance activities for 70MOD-108A(OP).
- Evaluate the need to replace similar damper actuators.
Safety Significance
There was no actual radiological or nuclear safety consequence during this event.
The condition where 70FN-4A would not reliably start existed between August and September 2016. During this time, the "B" Control Room exhaust fan remained available to perform the required safety function. This deficiency affected the redundant "A" Control Room exhaust fan to start reliably; either, manually or automatically in response to a failure of the "B" exhaust fan.
If the "A" Control Room exhaust fan was needed, and did not start, a plant Operator could manually correct the deficiency by traveling to the damper actuator location and locally assisting the damper linkage. When the deficiency was identified in September 2016, this manual Operator action was evaluated and accepted as a compensatory measure. Based on the calculated accumulated doses which could be received in these areas for the various design basis accidents combined with the relatively short period of time needed to perform this compensatory action, the increase in dose that could be incurred during the performance of this compensatory action would be negligible when compared to the dose that would be received by maintaining continuous occupancy in the Control Room.
References
- Condition Report: CR-JAF-2016-03593, September 19, 2016
- Condition Report: CR-JAF-2016-03116, August 16, 2016