GO2-21-093, Core Plate Wedge Installation Report Required by License Condition 2.C.(36)
| ML21235A454 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 08/23/2021 |
| From: | Javorik A Energy Northwest |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GO2-21-093 | |
| Download: ML21235A454 (3) | |
Text
Alex L. Javorik Columbia Generating Station P.O. Box 968, 964P Richland, WA 99352-0968 Ph. 509.377.8555 l F. 509.377.2354 aljavorik@energy-northwest.com 10 CFR 50.71(a)
GO2-21-093 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
Subject:
COLUMBIA GENERATING STATION, DOCKET NO. 50-397 CORE PLATE WEDGE INSTALLATION REPORT REQUIRED BY LICENSE CONDITION 2.C.(36)
Dear Sir or Madam:
In accordance with License Condition 2.C.(36) of Columbia Generating Station's (Columbia) renewed operating license (No. NPF-21) Energy Northwest has installed core plate wedges (CPW) around the periphery of the core plate within the shroud to prevent lateral motion of Columbia's core plate. Consistent with the License Condition, the following summary of the results of the installation including the corrective actions taken during the installation are being provided to the U.S. Nuclear Regulatory Commission for information only.
Energy Northwest Design Equivalent Change (EC) Package 17537, "Install Core Plate Wedges," provides a description of the design, configuration changes (affected documents), and installation and testing requirements of the CPWs. Work Order 02146986 was used to measure and install eight CPWs per the EC requirements. GE Hitachi (GEH) Nuclear Energy installed the CPWs under the direction of Energy Northwest's Engineering Department during Refueling Outage 25. The installation was completed satisfactorily. During the preparation for the installation of the CPWs, several issues were encountered. These are discussed below. The rim hold-down bolts were not inspected during the outage.
Prior to installation of the CPWs, GEH used two specialized tools to measure the locations where the CPWs were to be installed. The first measurement tool failed during initial placement (Condition Report [CR] 419805). Additionally, during the measurement activity, an "L" pick became wedged between two fuel bundles and an intermediate range monitor (CR 419825). The "L" pick was retrieved, and the tool was repaired allowing the measurements to be successfully taken at all eight locations. The second measurement tool (HEX tool) would not seat properly and after receiving replacement parts and modifying the tool, the GEH team was able to measure four out of the eight locations. The GEH field team provided the measurements to GEH Engineering. Based
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August 23, 2021 ENERGY
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GO2-21-093 Page 2 of 3 on the data from the four measured locations, GEH Engineering was able to provide machining dimensions for the four locations that could not be measured.
During installation of machined CPW SN-0007, it was noted that the wedge was loose (CR 420259). A second gap measurement was performed, and a spare wedge was then machined to the correct size and installed.
Three CPWs were installed with minor gaps between the top of the core support and the wedge. Field Deviation Disposition Request (FDDR) 006N6458 was developed to determine the acceptability of the observed gaps. All gaps were within the tolerances allowed under the FDDR.
As left inspections were performed on all eight (8) CPWs to verify proper fit and installation. The installation of the CPWs was determined to be acceptable.
Condition Reports x CR 419805, FME-Lost Dial Indicator Face, Bezel, and Scale Plate During the measurement for core plate wedge at 32 degrees an "L" pick was being used to position the hex measurement tool when the "L" pick went under the bezel and the cover and pulled it off the dial indicator. The parts were located in the water gap. A recovery plan was developed, and the parts were successfully retrieved.
The cause was determined to be a loss of situational awareness of the L pick to the hex tool and proper tool use. A Project standdown was held by the Plant General Manager with GEH supervision, GEH crews and members of Construction and Project Management (CPM). In addition to the standdown, the Site Vice President also briefed GEH supervision and CPM Project Management prior to recommencement of work.
x CR 419825, FME - Refuel Floor - Broken L Pick GEH During the hex measurement an "L" pick became wedged between two bundles (47-52 and 49-52) and IRM B 48-53 about 6" down from the bottom of the top guide. The "L" pick ~1/8" diameter stainless steel rod approximately by 12" long was then broken off the small pole adapter at the welded connection. All work was stopped. Actions for this CR were moved to CR 419805. The "L" pick was retrieved, and all tooling was removed from the vessel.
x CR 420259, Core Plate Wedge Size Incorrect During installation of the machined core plate wedge (SN-0007) for the Azimuth location 302, it was noted that the wedge was loose during the installation
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GO2-21-093 Page 3 of 3 process. The team kept hand tightening the bolt, but the wedge would not seat. It was concluded that the core plate wedge gap measurement must have been incorrect.
The gap measurement at the azimuth 302 location was reperformed. The first gap measurement was performed on May 17th. The dial indicator reading was 0.163 (gap of 1.773"). The second measurement was performed on May 21st was 0.427 (gap of 2.037"). A spare CPW body was machined using the updated measurements and installed satisfactorily.
No new commitments are being made in this letter. If there are any questions or additional information required, please contact Mr. R. M. Garcia, Licensing Supervisor, at 509-377-8463.
I declare under penalty of perjury that the foregoing is true and correct.
Executed this ______ day of ____________, 2021.
Respectfully, Alex. Javorik Vice President Engineering Projects cc: NRC RIV Regional Administrator NRC Project Manager NRC Senior Resident Inspector CD Sonoda - BPA EFSECutc.wa.gov - EFSEC E Fordham - WDOH R Brice - WDOH L Albin - WDOH
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