ML24149A160
| ML24149A160 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 05/24/2024 |
| From: | Knott R Paragon Energy Solutions |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| Download: ML24149A160 (1) | |
Text
Paragon Energy Solutions 7410 Pebble Drive
- Fort Worth, Texas
- 76118 817-284-0077
- Fax 817-590-0484 Date: 05/24/2024 To:
Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555 10CFR Part 21 Initial Notification: P21-05242024-IN, Rev. 0
Subject:
Defect with Emergency Diesel Generator Voltage Regulator Part Number NLI-3S7950GR751A1 Paragon has identified a defect in the subject voltage regulator supplied as identified below.
Plant Client PO#
Project Number Serial #
QTY AEP DC Cook 01600229 351030025 NLI-3S7950GR751A1-1007 1
Pursuant to 10CFR Part 21 § 21.21(d)(3)(i) Paragon is providing initial notification of a defect associated with the Emergency Diesel Generator Voltage Regulator as noted in the table above. The voltage regulator was refurbished under the customer purchase order noted above. Part of the refurbishment involved complete replacement of the units wiring, physical inspection and testing of the unit to Paragon approved acceptance testing instructions. The refurbished unit was supplied to the customer in December 2023. Prior to installation (March 2024), the unit successfully passed bench testing at the plant. During post installation testing, the emergency diesel generator was started, and the output voltage pegged high and was not controllable. DC Cook subsequently removed the voltage regulator and documented the non-conformance. DC Cook troubleshooting determined the unit was mis-wired. The unit was returned to Paragon, and inspection confirmed the plants diagnosis. The identified mis-wire affects the system circuitry by placing silicon controlled rectifier 5CD in a reverse biased position. The reversed biased rectifier blocks the flow of current which creates an open circuit condition. This open circuit condition causes the output voltage to max out and does not allow the output voltage to be adjusted. This condition, if left uncorrected could contribute to a substantial safety hazard and is reportable in accordance with 10CFR Part 21.
Date of Discovery: May 9th, 2024 Reportability Determined: May 23rd, 2024 Paragon has entered this condition in our corrective action program, and we have custody of the effected unit. The extent of condition is limited to this unit supplied to DC Cook. Paragon has determined there is no action necessary for DC Cook at this time.
Sincerely, Richard Knott Vice President Quality Assurance, Paragon Energy Solutions.