05000440/LER-2021-001, Division 3 Eog Inoperability Resulting in an Operation or Condition Prohibited by Technical Specifications
| ML21209A105 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 06/27/2021 |
| From: | Penfield R Energy Harbor Nuclear Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-21-200 LER 2021-001-00 | |
| Download: ML21209A105 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4402021001R00 - NRC Website | |
text
menergy
harbor Rod L. Penfield Site Vice President, Perry Nuclear June 27, 2021 L-21-200 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Perry Nuclear Power Plant Docket No. 50-440, License No. NPF-58 Licensee Event Report Submittal Energy Harbor Nuclear Corp Perry Nuclear Power Plant 10 Center Road Perry, Ohio 44081 440-280-5382 724-462-0816 (cell) 10 CFR 50.73(a)(2)(i)(B)
Enclosed is Licensee Event Report (LER) 2021-001, "Division 3 EOG lnoperability Resulting in an Operation or Condition Prohibited by Technical Specifications." There are no regulatory commitments contained in this submittal.
If there are any questions or if additional information is required, please contact Mr. Glendon Burnham, Manager - Regulatory Compliance, at (440) 280-7538.
Sincerely, Rod L. Penfield
Enclosure:
LER 2021-001 cc:
NRG Project Manager NRG Resident Inspector NRG Region Ill Regional Administrator
Enclosure L-21-200 LER 2021-001
Abstract
On June 1, 2021, with the Perry Nuclear Power Plant operating at 100 percent power an operation or condition prohibited by Technical Specifications occurred. During the monthly Division 3 Diesel Generator (DG) run on June 1, 2021, erratic output voltage was noted for approximately 45 seconds after start. At the time operations had reasonable expectation of operability and requested a Follow-up Operability Determination (FOD). Results from the Division 3 DG FOD could not support continued Operability of the Division 3 DG. The Division 3 DG was declared inoperable and unavailable on June 3, 2021 at 18:15.
The most plausible cause for the erratic output voltage falling below the allowable band during startup is an internal infant component mortality failure of the voltage regulator. The component will be sent for failure analysis.
On June 1, 2021 at 10:15, when erratic output voltage was first noted for the Division 3 Diesel Generator, entry into TS 3.8.1 Condition B and the accompanying actions did not occur. Surveillance requirement 3.8.1.1 was not performed as required within one hour and subsequent action TS 3.8.1 Condition F was also not met to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Since completion times were not met for TS 3.8.1 Condition F, this issue is reportable under 50.73(a)(2)(i)(B) as an operation or condition prohibited by the plant's technical specifications.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
EVENT DESCRIPTION
YEAR 2021 SEQUENTIAL NUMBER 001
- - I REV NO.
00 During the monthly Division 3 Diesel Generator (DG) [EK] run on June 1, 2021, erratic output voltage was noted for approximately 45 seconds after start. Operations had reasonable expectation of operability and requested a Follow-up Operability Determination (FOO).
Results from the Division 3 DG FOO could not support continued Operability of the Division 3 DG. The Division 3 DG was declared inoperable and unavailable on June 3, 2021 at 18:15. On June 4, 2021 the new voltage regulator [RG] was replaced and was tested satisfactory and the DG returned to operable status at 21 :25.
A review of the Division 3 DG maintenance history revealed that the voltage regulator was replaced and passed the Post Maintenance Test (PMT) on May 15, 2021. No other failures of the Division 3 DG or the voltage regulator could be found during the previous three years.
On June 1, 2021 at 10: 15, when erratic output voltage was first noted for the Division 3 Diesel Generator, entry into TS 3.8.1 Condition B and the accompanying actions did not occur. Surveillance requirement 3.8.1.1 was not performed as required within one hour and subsequent action TS 3.8.1 Condition F was also not met to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Since completion times were not met for TS 3.8.1 Condition F, this issue is reportable under 50.73(a)(2)(i)(B) as an operation or condition prohibited by the plant's technical specifications.
CAUSE
The most plausible cause for the erratic output voltage falling below the allowable band during startup is an internal infant component mortality failure of the voltage regulator. The component will be sent for failure analysis.
EVENT ANALYSIS
A Probabilistic Risk Assessment (PRA) evaluation was performed for the June 3, 2021 Division 3 Diesel Generator voltage regulator lnoperability event. Fire and other external hazards were qualitatively addressed to be of low risk. The analysis of this event results in delta CDF and delta LERF values that are below the acceptable thresholds of 1.0E-06/yr and 1.0E-07/yr, as discussed in Regulatory Guide 1.17 4. The risk of this event is therefore considered to be of very low safety significance in accordance with the Regulatory Guidance.
CORRECTIVE ACTIONS
Completed Actions On June 4, 2021 the voltage regulator was replaced and was tested satisfactory.
Scheduled Actions A corrective action was created to send the defective voltage regulator for failure analysis testing. Further corrective action will be taken based on the results.
PREVIOUS SIMILAR EVENTS
No failures of the Division 3 DG or the voltage regulator could be found during the previous 3 years.
COMMITMENTS
None