ENS 52480
ENS Event | |
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21:04 Nov 10, 2016 | |
Title | Part 21 - Failure of Power Supplies to Meet Voltage Stability Specifications |
Event Description | This notification is a 10 CFR 21.21(a)(2) interim report for power supply model N-2ARPS-A6. Two instrument power supplies for the 'B' Residual Heat Removal (RHR) system were being bench tested prior to installation when it was discovered that they failed to meet Vendor Technical Manual specifications for voltage stability for varying loads. The deviation was a voltage drop of approximately 300mV. This did not meet the specification of less than 150mV when varying current from 5 amps (full load) to 2.5 amps. A second replacement power supply exhibited a similar 300 mV drop.
James A. FitzPatrick (JAF) reviewed the work order instructions to determine if there was a deviation from the recommendations in the Foxboro technical manual F180-0309 Spec 200 Multinest Power Supply 2ARPS Series calibration. Since as-found voltage readings were within the required tolerance of the RHR instrument loops, the power supplies appear to have been capable to perform their intended function. However, this evaluation did not troubleshoot why the power supplies failed to meet the calibration requirements. The power supplies were sent to a repair vendor. The input from this vendor is expected to allow JAF to complete the evaluation per 10 CFR 21.21(a)(1) by March 21, 2017, and a notification for failure to comply or defect per 10 CFR 21.21(d)(3)(i) is expected by March 24, 2017, if necessary. This notification is being submitted as an interim report per 10 CFR 21.21(a)(2)." The licensee notified the NRC Resident Inspector.
The licensee is retracting this report based on the following: The testing vendor Argo Turboserve Corp provided input to this condition in Non Conformance Report NC161. Engineering reviewed NC161 and discussed this condition with the vendor. The power supplies showed an initial drift following a 100 hour0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> burn-in but continued operation was stable. Therefore, even though the initial voltage drift did not meet the power supply's calibration requirement in F180-0309, it would not be expected to drift significantly further. Engineering concluded that this condition will have a negligible impact on system components. Readings were steady and within the tolerance of the RHR instrument specification. Based on all current information, the component will function over its mission time of 100 days.Based on these results, a notification for failure to comply or defect per 10 CFR 21.21(d)(3)(i) is not required and the interim report per 10 CFR 21.21(a)(2) may be retracted." The licensee informed the NRC Resident Inspector. Notified R1DO (Bickett) and Part 21 Group via email. |
Where | |
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Fitzpatrick New York (NRC Region 1) | |
Reporting | |
10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component | |
Time - Person (Reporting Time:+1465.68 h61.07 days <br />8.724 weeks <br />2.008 months <br />) | |
Opened: | Mark Hawes 22:45 Jan 10, 2017 |
NRC Officer: | Donald Norwood |
Last Updated: | Jan 10, 2017 |
52480 - NRC Website
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Unit 1 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (67 %) |
After | Power Operation (67 %) |
WEEKMONTHYEARENS 574372024-09-26T22:01:00026 September 2024 22:01:00
[Table view]10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part 21 - Defective Thermal Overload Relay Discovered During Testing ENS 524802016-11-10T21:04:00010 November 2016 21:04:00 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component Part 21 - Failure of Power Supplies to Meet Voltage Stability Specifications 2024-09-26T22:01:00 | |