ML22277A422
| ML22277A422 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 08/16/2022 |
| From: | Marlayna Vaaler Doell Reactor Decommissioning Branch |
| To: | Steven Roberts, Van Noordennen G Energy Solutions |
| Doell M, 415-3178 | |
| Shared Package | |
| ML22277A350 | List: |
| References | |
| Download: ML22277A422 (1) | |
Text
From: Doell, Marlayna To: Gerard P. Van Noordennen-ext; Sarah Roberts
Subject:
Additional Question for ES about WTB Sample Judgmental 16 Date: Tuesday, August 16, 2022 2:20:00 PM Attachments: Responses to NRC Questions from June 7 - Final.pdf FSS Plan 101C IIII WTB Analysis 01052018.xlsx Hi again!
So we have been scratching our heads a little this week about judgmental sample 16 from the original FSS data for the WTB, and how (whether?) the side walls of this (and other?) excavation survey units were included in the 100% coverage scans, as well as the handling of elevated areas per the LTP in general. Some of this may be based on a misunderstanding, but the main concern is that the data suggests the surveys may not be including the side walls in the scans of the excavations.
And importantly we have evidence that there was an elevated area in the side wall of WTB per sample 16. Accordingly, if you could take a look at the below as we prepare for an additional call next week I would appreciate it:
In the final responses to the NRC questions from June 7, in response to Question 3 the licensee provided a spreadsheet (attached) with the original samples that were taken for the WTB survey unit, collected 9/12/17 - 9/14/2017. Sample number L1-010-101-FJ-GS-C16-SB shows a concentration of 154 pCi/g of Cs-137. This sample is shown in the associated figure as being outside the boundary of the survey unit to the west. It is also outside the boundary of the part of the survey unit that was later remediated (which is shown in the dotted line). In the call on Friday, the licensee said that sample 16 was taken from the sidewall of the excavation on the west side.
- 1. If the spreadsheet is accurate and sample 16 was 154 pCi/g of Cs-137, please explain if the sample area was investigated per Section 5.6.4.6 of the LTP, which states that any samples above the Operational DCGL (17.39 Cs-137) would be investigated. (The Base Case DCGL for Cs-137 is 48.3 pCi/g.) If the sample area was not investigated please provide (1) information as to why not; (2) a bounding analysis for the potential area and volume of soil that could bound the elevated area near sample 16; and (3) an assessment of the potential dose contribution of this elevated area.
- 2. Please provide an analysis of why the licensee believes an elevated area was located on the WTB sidewall. The response to Question 11 discusses a general lack of oversight of the contractor performing the excavation of the WTB. Please indicate if additional contamination could have spread to the side walls during the excavation activities.
- 3. The licensee indicated that they could not locate the original gamma spec reports. Please indicate whether these can be identified with some additional effort or if they are no longer available. Please also indicate if the licensee is in possession of the original sample 16 and if so whether it could be recounted.
- 4. The license provided a map of the scan lanes for the original FSS in Figure 1 and for the remediated portion of the WTB in Figure 3. They also provided a photo showing that the scan lanes marked E and N showing a view facing east. The NRCs interpretation of this data is
that the area to the west that contained the sample with 154 pCi/g of Cs-137 appears not to have been scanned, either in the original or post-remediation scans for the WTB. Note that MARSSIM states that Class 1 survey units should receive a 100% scan, and unless an argument is presented that classifies the sidewalls differently, they would also be expected to receive 100% coverage. The survey classification of an excavation should consider whether the entire excavated area, including the floor and the sidewalls, has the same contamination potential.
In this case, the side walls are considered part of the same Class 1 survey unit and should have received a scan. Note that the release record states that soil scanning was performed on 100% of the total surface area in the survey unit even though the scans in Figure 3 provided only cover the remediated area. Please indicate whether the side walls of the excavation, especially to the west received a scan. Please provide additional information to support that acceptable levels of contamination remain in the portions of the survey unit that were not scanned (including the side walls).
- 5. Please clarify the extent to which the side walls were scanned for the other excavation survey units. If the sidewalls were not scanned as part of the 100% scan of the excavation, please provide a technical basis for why.
I am hopeful there is an easy answer to all of these but wanted to add them to the open item list while there is still an opportunity. Let me know if next week still works for a call and I can work to get something on the calendar. Much appreciated as always and please give a shout if you need anything in the meantime!
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Decommissioning Project Manager U.S. Nuclear Regulatory Commission NMSS/DUWP/RDB Phone: 301.415.3178 Mobile: 440.668.7399 Home: 605.348.2334 E-mail: marlayna.doell@nrc.gov Office Location: Fulltime Telework from Rapid City, South Dakota!
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