At approximately 1400
CST on 12/16/16, during the performance of VEF-38A Lead Penetration Room Ventilation System (PRVS) Exhaust Fan Monthly Test, flow was found to be at 2000
SCFM with an operability limit of 1620 to 1980
SCFM. VEF-38A was declared inoperable. Unit 1 entered Technical Specification Limiting Condition for Operation (LCO) 3.7.11 Condition C for both trains of PRVS inoperable. With VEF-38A aligned as the lead fan and capable of auto-start, the operable standby fan (VEF-38B) would not have started.
During the time that VEF-38A was inoperable and capable of auto-starting, the Unit 1 PRVS was in a condition that could have prevented the control of the release of radioactive material.
At 1546 CST on 12/16/16, Unit 1 rendered VEF-38A incapable of auto starting by placing its hand switch in PULL-TO-LOCK. Unit 1 Entered LCO 3.7.11 condition A for one PRVS train inoperable and Exited LCO 3.7.11 Condition C.
This is a notification per 10 CFR 50.72(b)(3)(v) for a condition that could have prevented the control of the release of radioactive material.
The licensee has notified the NRC Resident Inspector.
- * * UPDATE ON 2/7/17 AT 1528 EST FROM BUCHANON DICKSON TO DONG PARK * * *
EN 52441 was initiated on December 16, 2016, when the VEF-38A fan flow was found to be in excess of the procedurally defined operability limit during the monthly lead penetration room ventilation system test.
The revision of the procedure in use at the time had inadvertently included acceptance criterion for fan air flow in the monthly supplements. The monthly tests demonstrate the flow paths for the two trains are functional and open, but they are not performed in the designed Engineered Safeguards (ES) configuration. The monthly tests do not secure the normal supply and exhaust ventilation within the penetration room boundaries; therefore, flow may be outside limits required during the ES configuration. The 18 month surveillance, which measures the flowrate of the system while in the ES configuration, was completed in April 2016. The surveillance verified the system's operability. The systems have not been modified or altered since this surveillance; therefore the measured flowrate remains the same.
The procedure has been revised subsequent to this event to remove the flowrate as an 'acceptance criterion' for the monthly test.
Because the VEF-38A flow did not result in fan inoperability, both fan trains remained operable; therefore, ANO-1 did not lose a safety function to control a radioactive release. Based on that, conclusion EN 52441 is being retracted.
The licensee will notify the NRC Resident Inspector. Notified R4DO (Warnick).
