ENS 54760: Difference between revisions

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{{ENS notification
{{ENS notification
| event number = 54760
| event number = 54760
| facility = Paragon Energy Solutions
| facility =  
| Organization = Paragon Energy Solutions
| Organization = Paragon Energy Solutions
| license number =  
| license number =  
Line 10: Line 10:
| utype =  
| utype =  
| cfr = 10 CFR 21.21(d)(3)(i)
| cfr = 10 CFR 21.21(d)(3)(i)
| emergency class = Non Emergency  
| emergency class = Non Emergency
| notification date = 06/30/2020 17:41
| notification date = 06/30/2020 17:41
| notification by = Tracy Bolt
| notification by = Tracy Bolt
| NRC officer = Brian Lin
| NRC officer = Brian Lin
| event date = 06/01/2020 00:00 CDT
| event date = 06/01/2020 00:00 CDT
| last update date = 06/30/2020
| last update date = 07/21/2020
| title = Part 21 - Failure of Size 1 and 2 Freedom Series Auxiliary Contacts
| title =  
| event text = The following is a summary of information received from Paragon Energy Solutions:
| event text = EN Revision Imported Date : 7/22/2020
DUKE Harris Nuclear Plant (HNP) has identified instances where Size 1 and 2 Eaton Freedom Series starters have failed to function as expected in assemblies that were originally supplied by NLI. The auxiliary contacts have degraded prematurely and have failed to change state when the starter was energized which has affected indication and other controlling actions within the circuit.
PART 21 - FAILURE OF SIZE 1 AND 2 FREEDOM SERIES AUXILIARY CONTACTS
The premature degradation of the auxiliary contacts with the old model NLI special coil, part number: 057018-COIL-1/2, has occurred on size 1 and 2 contactors that were continuously energized with significant run time after approximately 3 to 5 years of service time. HNP has provided information to manage the known degradation. The auxiliary contacts should be replaced at an increased frequency until new auxiliary contacts are installed along with the new design NLI special coil, part number: 057018-COIL-1/2-M.
The following is a summary of information received from Paragon Energy Solutions:
The nature of the defect is the pre-mature aging of the component within the auxiliary contact mechanism that is adjacent to the operating coil. The starter coil is potentially being subjected to voltages of a nature that elevates the temperature within the starter adjacent to the auxiliary contacts.
DUKE Harris Nuclear Plant (HNP) has identified instances where Size 1 and 2 Eaton Freedom Series starters have failed to function as expected in assemblies that were originally supplied by NLI. The auxiliary contacts have degraded prematurely and have failed to change state when the starter was energized which has affected indication and other controlling actions within the circuit.
It is recommended that the starters and coils be replaced in the applications where the units are being operated in a continuous duty application. It is also recommended that the control transformer be replaced with a true 4:1 ratio transformer. Paragon/NLI has developed a true 4:1 ratio transformer that will provide additional mitigation of this potential over-voltage condition. Replacing the transformer with a true 4:1 ratio reduces the control voltage that is being applied to the control circuit in a manner that will not prevent the unit from providing a sufficient voltage during a degraded voltage condition, and also will not subject the components to a voltage above the ratings when the supply voltage is operated above the nominal 480 VAC bus voltage.
The premature degradation of the auxiliary contacts with the old model NLI special coil, part number: 057018-COIL-1/2, has occurred on size 1 and 2 contactors that were continuously energized with significant run time after approximately 3 to 5 years of service time. HNP has provided information to manage the known degradation. The auxiliary contacts should be replaced at an increased frequency until new auxiliary contacts are installed along with the new design NLI special coil, part number: 057018-COIL-1/2-M.
The nature of the defect is the pre-mature aging of the component within the auxiliary contact mechanism that is adjacent to the operating coil. The starter coil is potentially being subjected to voltages of a nature that elevates the temperature within the starter adjacent to the auxiliary contacts.
It is recommended that the starters and coils be replaced in the applications where the units are being operated in a continuous duty application. It is also recommended that the control transformer be replaced with a true 4:1 ratio transformer. Paragon/NLI has developed a true 4:1 ratio transformer that will provide additional mitigation of this potential over-voltage condition. Replacing the transformer with a true 4:1 ratio reduces the control voltage that is being applied to the control circuit in a manner that will not prevent the unit from providing a sufficient voltage during a degraded voltage condition, and also will not subject the components to a voltage above the ratings when the supply voltage is operated above the nominal 480 VAC bus voltage.
Paragon has no other recommendations as the accelerated aging of the components and the expected life based on the additional heat the units have been subjected to is unknown.
Paragon has no other recommendations as the accelerated aging of the components and the expected life based on the additional heat the units have been subjected to is unknown.
Affected plants:
Affected plants:
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River Bend
River Bend
Beaver Valley
Beaver Valley
Should you have any questions regarding this matter, please contact:  
Should you have any questions regarding this matter, please contact:
Tracy Bolt
Tracy Bolt
Chief Nuclear Officer
Chief Nuclear Officer
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817-284-0077
817-284-0077
tbolt@paragones.com
tbolt@paragones.com
| URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2020/20200701en.html#en54760
* * * UPDATE ON 7/21/20 AT 1241 EDT FROM TRACY BOLT TO ANDREW WAUGH * * *
The following is the summary of an email received from Paragon Energy Solutions:
The root cause of the degraded component is due to the increased voltage and the overall temperature of the starter coil at the elevated voltage. This elevated voltage and temperature has degraded the mechanism of the auxiliary contact operator to a point to which it has become separated from the parent component.
Paragon/NLI has developed a new version of the special coil (part number: 057018-COIL-1/2-M) that operates at a lower temperature than the original special coil that is currently in use at HNP. When the new version of the special coil is subjected to the same voltages, the temperature is lower.
The affected plants have been revised to:
Sharon Harris
Oconee
Turkey Point
Columbia
North Anna
Notified R1DO (Carfang), R2DO (Miller), R4DO (Drake), and Part 21 Reactors Group (email).
| URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2020/20200722en.html#en54760
}}
}}


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Latest revision as of 12:30, 15 January 2021

ENS 54760 +/-
Where
Paragon Energy Solutions
Fort Worth, Texas (NRC Region 4)
Organization: Paragon Energy Solutions
Reporting
10 CFR 21.21(d)(3)(i), Failure to Comply or Defect
Time - Person (Reporting Time:+708.68 h29.528 days <br />4.218 weeks <br />0.971 months <br />)
Opened: Tracy Bolt
17:41 Jun 30, 2020
NRC Officer: Brian Lin
Last Updated: Jul 21, 2020
54760 - NRC Website