05000282/LER-2022-001, Fuel Assemblies Incorrectly Placed in Spent Fuel Pool
| ML22290A172 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/17/2022 |
| From: | Domingos C Northern States Power Company, Minnesota, Xcel Energy |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-Pl-22-042 LER 2022-001-00 | |
| Download: ML22290A172 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2822022001R00 - NRC Website | |
text
Xcel Energy*
1717 Wakonade Drive Welch, MN 55089 L-Pl-22-042 10 CFR 50.73 October 17, 2022 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Docket Nos. 50-282 and 50-306 Renewed Facility Operating License Nos. DPR-42 and DPR-60 Prairie Island Nuclear Generating Plant Licensee Event Report 2022-001-00 Pursuant to 10 CFR 50.73(a)(2)(i)(B), Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM"), hereby submits Prairie Island Nuclear Generating Plant (PINGP) Licensee Event Report (LER) 50-282/2022-001-00.
Summary of Commitments new commitments and no revisions to existing commitments.
Christoph r P. Domingos Site Vice President, Monticello and Prairie Island Nuclear Generating Plants Northern States Power Company - Minnesota Enclosure cc:
Administrator, Region 111, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC State of Minnesota
ENCLOSURE1 PRAIRIE ISLAND NUCLEAR GENERATING PLANT LICENSEE EVENT REPORT 50-282/2022-001-00 3 pages follow
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 08/31/2023 (08-2020)
- 3. Page Prairie Island Nuclear Generating Plant, Unit 1 05000
- - 282 1 OF 3
- 4. Title Fuel Assemblies incorrectly placed in Spent Fuel Pool
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Month Day Year Year Sequential Revision Month Day Year Facility Name Docket Number Number No.
Prairie Island, Unit 2 05000
- - 306 08 15 2022 22 -
001 -
00 10 17 2022 Facility Name Docket Number 05000
- 9. Operating Mode 1
- 10. Power Level 1
100
)
On August 17, 2022, with both Unit 1 and Unit 2 of the Prairie Island Nuclear Generating Plant (PINGP) operating in Mode 1 at 100 percent power, it was discovered that 38 fuel assemblies had been placed in an incorrect location of the Spent Fuel Pool (SFP) during the move of fuel assemblies which commenced at 12:30 on August 15, 2022 and was completed on August 16, 2022. The location of 29 of these 38 fuel assemblies did not comply with Technical Specification Design Feature 4.3.1.1, resulting in Technical Specification 3.7.17 Action Statement A being entered on August 17, 2022, at 10:53. The cause of this condition was a procedural step that wasn't followed resulting in an incorrect date being entered in the software configuration tool. This incorrect date caused the software configuration tool to calculate longer fuel assembly cooling times resulting in mis-categorization of the fuel assemblies.
Following discovery, the correct date in the software configuration tool was used to ensure the non-complying fuel assemblies were moved to the correct locations to restore compliance and Technical Specification LCO 3. 7.17 Action Statement A was exited on August 19, 2022, at 10:32.
This event is being reported pursuant to 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by technical specifications.
EVENT DESCRIPTION
On August 17, 2022, with both Unit 1 and Unit 2 of the Prairie Island Nuclear Generating Plant (PINGP) operating in Mode 1 at 100 percent power, it was discovered that 38 fuel assemblies had been placed in an incorrect location of the Spent Fuel Pool (SFP). The location of 29 of the 38 fuel assemblies did not comply with Technical Specification Design Feature 4.3.1.1 resulting in Technical Specification 3.7.17 Action Statement A being entered on August 17, 2022, at 10:53.
On August 4, 2022 Fuel Transfer Logs were generated using the software configuration tool in preparation for upcoming fuel assembly moves in anticipation of a core offload scheduled to occur during an upcoming refueling outage on Unit 1.
The generation of the Fuel Transfer Logs unknowingly carried over a planning date of June 1, 2029 which had been previously used for a scoping study of future SFP configurations. This incorrect planning date resulted in the software configuration tool calculating longer fuel assembly cooling times and mis-categorizing 38 fuel assemblies such that they were assigned a less reactive category than they should have been. The fuel assemblies were classified as Fuel Category 6 when they should have been classified as Fuel Category 4 or 5.
On August 15, 2022, the move of fuel assemblies commenced at 12:30 using the Fuel Transfer Logs that were generated on August 4, 2022 with the incorrect planning date. The fuel assembly moves were completed on August 16, 2022.
On August 17, 2022, during preparations for the move of new fuel assemblies from the new fuel pit to the SFP, new Fuel Transfer Logs were generated in software configuration tool using a correct planning date. This process resulted in receipt of multiple warnings which alerted engineering of the configuration errors. Investigation into the warnings identified the incorrect planning date that had been previously used.
These fuel assembly configuration errors resulted in non-shutdown Technical Specification 3.7.17 Action Statement A being entered on August 17, 2022, at 10:53.
This event is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by technical specifications.
Human Performance The Reactor Engineer did not use the guidance contained within the work instructions for the SFP fuel assembly verification when entering the planning date in the software configuration tool.
CAUSE OF THE EVENT
The cause of this condition was a procedural step that was not followed resulting in an incorrect planning date being allowed to remain in the software configuration tool. Contributing to this was the lack of adequate guidance for verification of critical parameters within the associated surveillance procedure that would ensure SFP configuration would conform to Technical Specification Design Feature 4.3.1.1.
ASSESSMENT OF SAFETY CONSEQUENCES
There were no safety consequences related to this condition.
The SFP criticality analysis evaluates accident conditions in the SFP including the mis-load of multiple fresh fuel assemblies. Calculations show that the amount of soluble boron concentration in the SFP required to offset the highest reactivity increase caused by accident conditions would be 2030 ppm. The boron concentration was measured once during the time the fuel assemblies were not compliant with Technical Specification Design Feature 4.3.1.1. This measurement was 2873 ppm, which was taken on August 17, 2022 at 12:25. The boron requirements for keff remained met even with the 29 fuel assemblies loaded in the incorrect location. Therefore, the SFP never entered an unanalyzed condition and did not exceed any safety limits.
This event does not represent a safety system functional failure for Unit 1 or Unit 2. There were no radiological, environmental, or industrial impacts associated with this event. The health and safety of the public and site personnel were not impacted during this event.
CORRECTIVE ACTIONS
The planning date was corrected in the software configuration tool and action was taken to move the 29 non-complying fuel assemblies to acceptable locations. This action restored compliance with Technical Specification Design Feature 4.3.1.1 and allowed Technical Specification 3.7.17 Action Statement A to be exited on August 19, 2022, at 10:32.
To enhance procedural guidance, procedure changes will be made to the relevant procedures to require explicit verification of critical parameters including the planning date, discharge date, burnup, and enrichment.
PREVIOUS SIMILAR EVENTS
No previous similar events have occurred at PINGP in the prior 3 years.
ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) CODES Not applicable to this report, as this is not against an equipment/ component issue. Page 3
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