ML22278A029

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Enclosure Request for Confirmatory Information Enclosure Related to the Review of the Class 1 Survey Units
ML22278A029
Person / Time
Site: La Crosse  File:Dairyland Power Cooperative icon.png
Issue date: 10/12/2022
From: Marlayna Vaaler Doell
Reactor Decommissioning Branch
To: Sauger J
EnergySolutions
M. Doell, NMSS/DUWP 301-415-3178
Shared Package
ML22278A027 List:
References
CAC 000083, EPID L-2019-LIT-0000
Download: ML22278A029 (2)


Text

La Crosse Boiling Water Reactor (LACBWR) - Request for Confirmatory Information Related to the Remaining LACBWR Class 1 Survey Units

1. The LACBWR License Termination Plan (LTP) requirement is to ensure 100 percent scan survey coverage of Class 1 impacted areas and that the sample results meet the statistical test for unrestricted release To meet the scan and survey requirements of the LACBWR LTP, the NRC staff needs to understand the RPGPA, CDR, and TDS B survey unit boundary overlap and how the CDR final status survey (FSS) results were or were not impacted by subsequent activities in the adjacent RPGPA and TDS B survey areas.

The staff understands that CDR was backfilled up to a certain elevation in 2017, but needs to confirm controls were in place after the backfill of CDR to prevent recontamination prior to more backfill being put in that area to bring it to final grade when the final survey of the L1-10-101 and L1-10-102 survey units was conducted.

For the part of the CDR that was not overlapped by other survey unit boundaries, the staff seeks confirmation to ensure the survey unit remained clean during the surrounding remediation and FSS activities.

RCI: Please confirm that during the remediation of the survey units adjacent to CDR, EnergySolutions (ES) followed all their isolation and control procedures until backfill and continued to meet MARSSIM requirements for survey and sampling procedures.

RCI: Please confirm that the statistical test for L1-SUB-CDR and the number of systematic samples required for the statistical test are still valid given that several of the samples were invalidated due to them being in L1-SUB-TDS A and L1-SUB-TDS B after the original survey unit was divided.

2. Requirement is to investigate elevated areas per the approved LACBWR LTP 2a. The staff needs to be able to evaluate the investigation and background radiation assumptions in CDR, and provide a basis for why there were several areas (28 if the median is assumed for background radiation) not investigated that should have been, but that this failure to investigate elevated areas does not negate the FSS result.

The licensees CDR scan results demonstrate that investigations should have been performed in multiple areas of the survey unit but were not conducted due to incorrect instrument alarm set points. ES stated that if the instruments had appropriately accounted for background radiation, 28 investigations would still need to be performed, but the method for estimating background is not a standard method.

The high background rate could be due to the shine from the reactor building, but there is no justification for statements about the level of shine present during the CDR FSS.

RCI: Please confirm if the reactor building shine was contributing to the background radiation levels in the CDR survey unit at the time of FSS scan.

2b. In the RPGPA, the survey unit did not receive FSS before it was backfilled due to water intrusion. This led to the RPGPA needing GeoProbe samples be taken to fulfill FSS

requirements. During these activities an elevated area was identified and labeled as sample B04; ES did an analysis to try to narrow down the size of the elevated area and demonstrate compliance with the LTP and the unrestricted release criteria.

RCI: Please confirm that none of the maximum activity readings were from the bottom stratum of the GeoProbe samples in the RPGPA.

2c. In order to support the statement that the WTB judgmental sample 16 Cs-137 result is a typo, an additional discussion or analysis of why the MDA of the scan instruments, or the prior FSS scan readings, support the indication that the result is a typo and not an actual elevated area of the survey unit would be beneficial. Absent that, an updated record that removes the erroneous sample result would improve documentation for this survey unit.

RCI: Please confirm that an updated spreadsheet for the WTB sample results with an N/A or something similar for sample 16 instead of the typo result will be submitted.