ML15348A292
| ML15348A292 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 12/07/2015 |
| From: | Dairyland Power Cooperative |
| To: | Office of Nuclear Material Safety and Safeguards |
| Marlayna Vaaler, 301-415-3178 | |
| Shared Package | |
| ML15348A285 | List: |
| References | |
| Download: ML15348A292 (22) | |
Text
La Crosse Boiling Water Reactor License Termination Plan Presentation to NRC Staff December 7, 2015
Topics for Discussion
Site Overview
Current Status of LACBWR Restoration Project
Project Milestones
Characterization Summary and Survey Unit Classification
Groundwater
Radionuclides of Concern
End State Description
Demonstrating Compliance with Radiological Criteria
Final Status Surveys and Source Term Surveys
Supplement to Environmental Report
Q & A
Site Overview
BWR (50MWe)
AEC demonstration reactor
Owned by Dairyland Power Cooperative (DPC)
Operated from 1967 to 1987
Licensed site shared with operational fossil plant
Decommissioning to Date
LACBWR staff performed limited dismantlement work between 1996 and 2004
In 2005, efforts shifted to RPV and Class B/C waste removal that was successfully completed in 2007
EnergySolutions (ES) performed the removal and disposal of the RPV and B/C waste at the Barnwell disposal facility
Fuel transfer to dry storage commenced in 2008 and was completed September 19, 2012
Additional dismantlement work completed in 2012 - 2014 including removal of fuel racks and completion of main turbine generator component removal
General Project Milestones
Q1/2016 Submit LTP to NRC
Q2/2016 License Transfer from DPC to LaCrosseSolutions
Q2/2016 Mobilization Complete
Q3/2016 Stack Demolition Complete
Q3/2017 LTP Approval by NRC
Q3/2017 Component Removal Complete
Q4/2017 Building Demolition Complete
Q4/2018 Transportation and Disposal Complete
Q4/2018 Site Remediation Complete
Q4/2018 Final Radiation Surveys Complete
Q1/2019 Site Restoration Complete
Q1/2019 Submit Remaining FRS Reports to NRC
Q1/2019 Submit License Transfer from LaCrosseSolutions to DPC
Q1/2020 License Transfer to DPC Approved by NRC
Q1/2020 LACBWR License Termination Approval by NRC
Characterization Summary
Historical Site Assessment performed in August 1999
October of 2005, DPC performed limited characterization of LSE prior to placing in SAFSTOR condition
October 2014 through August 2015, more detailed characterization of entire 165.3 acre licensed site for LTP development and accelerated decommissioning
Non-Impacted and Impacted Land Areas
Surface/subsurface soil, asphalt, concrete and coal ash samples
Angle coring (GeoProbe) beneath Turbine Building (drains)
Gamma scans using 2x2 NaI detector
87 of 163.5 acres deemed Non-Impacted (G-3 land and across highway)
Non-Impacted Structures
Structures associated with G-3 Coal Plant verified as Non-Impacted
Based on alpha/beta-gamma proportional detector scan/static measurements biased toward roofs, entryways, travel paths, low points, etc.
Gamma spectroscopy of roof material and other bulk materials
G-3 High Pressure Service Water and LACBWR Water Well buried Piping also designated as non-impacted based on operating history
Impacted Structures
Obtained basic radiological data on all above-grade structures
Obtained concrete core samples from basement floors/walls
Continuing characterization
Soils under/adjacent to structures, soils under concrete or asphalt, underlying concrete in RB after liner removal, currently inaccessible structure surfaces, interiors of buried pipe
Survey Unit Classifications
Groundwater Evaluation
Preparation of Hydrogeological Conceptual Site Model (Haley &
Aldrich)
Preparation of Hydrogeological Investigation Report for the La Crosse Boiling Water Reactor (Haley & Aldrich)
Groundwater is encountered 20 BGL and is in direct communication with the Mississippi River
On-going monitoring well sample collection and analysis Very low concentrations of plant-derived radionuclide's identified in groundwater near Turbine Building
Groundwater Evaluation
Radionuclides of Concern
NUREG/CR-3474, NUREG/CR-4289, WINCO-1191 reviewed
Eliminated noble gases, theoretical neutron activation products with an abundance less than 0.01% total activity and radionuclides with half-lives less than two years
An initial suite of 22 radionuclides produced for use in characterization
Based on radionuclide mixture from characterization cores and applying dose modeling results, the insignificant contributors were eliminated (those representing aggregate dose less than10% of the 25 mrem/yr criteria)
Remaining ROCs and mixtures and percent of total activity :
Cs-137 / 97.6%
Co-60 / 1.4%
Sr-90 / 1.0%
Dose Modeling Objectives NUREG-1757, Volume 2, Revision 1, Appendix I, Section 1.2.3 states that, generally, the licensees dose modeling should have one of the following objectives:
Develop DCGLs commensurate with demonstrating compliance with the dose-based release criterion, and then demonstrate through FSS that residual radioactivity concentrations at the site are equal to or below the DCGLs.
Assess dose associated with actual concentrations of residual radioactivity distributed across the site to determine whether the concentrations will result in a dose that is not equal to or below the regulatory dose criterion.
Surface and Sub-Surface Soil Buried Piping Backfilled Basements/Structures Groundwater FSS STS
End State Structures
End State Basement Structure
Below Ground Basements/Structures to Remain in End State Basement/Structure Material remaining Floor and Wall Surface Area (m2)
Floor Elevation (feet AMSL)
Reactor Building Concrete 511.54 612 Waste Treatment Building Concrete 101.90 630 Waste Gas Tank Vault Concrete 460.04 621 Remaining Structures Piping and Ventilation Tunnels Concrete 177.07 629 Reactor/Generator Plant Concrete 359.59 629 Chimney Slab Concrete 117.86 635 Turbine Sump Concrete 5.64 618 Turbine Pit Concrete 7.09 618
Basement Fill Model
Dose from residual radioactivity remaining in backfilled Basements calculated using the Basement Fill Model (BFM)
End State Basements demolished to three feet below grade and physically altered to a condition where it is implausible that future land use would include excavating fill material and occupying backfilled Basements
BFM conceptual model differs from Zion:
basements are small
generally above water table
insufficient volume below water table to support a well installed directly into basement
source term modeled as a layer of sub-surface soil contamination with no credit for structure resistance to flow
Average Member of Critical Group (AMCG) at LACBWR is the Industrial Worker
Basement Fill Model
The BFM conceptual model includes two source term geometries
the In situ geometry where the concrete remains in the as-left configuration at the time of license termination (including Drilling Spoils scenario) and
the Excavation geometry where the concrete is excavated and brought to the surface.
BFM Industrial Use Exposure Pathways
Direct exposure to external radiation in as-left End State geometry
Inhalation of airborne radioactivity in as-left End State geometry
Ingestion of concrete or fill material in as-left End State geometry
Ingestion of water from onsite well
Direct exposure, inhalation dose and ingestion dose from contaminated drilling spoils brought to the surface during installation of the onsite well that contacts basement concrete floor
Direct exposure, inhalation dose and ingestion dose from concrete that is brought to the surface by excavation The agricultural and gardening pathways are not applicable to industrial land use. The meat, grain and vegetable ingestion pathways are therefore not included
Source Term Surveys
ISOCS Instrumentation used for Basements
Determines total inventory with depth in concrete
Allows remote access; minimizes hands on scan/static surveys or sampling (coring)
Nominal FOV of (10-30 m2)
STS Survey Units
BFM not sensitive to activity levels and size of elevated areas
Each footprint (area) broken into survey units based on access, physical configuration and contamination potential Performed on Basement Surfaces (No Embedded Piping or Penetrations at LACBWR)
Source Term Surveys
Areal Coverage
Estimated mean activity and standard deviation derived from characterization and/or remediation data
Graded approach similar to MARSSIM but based on expected fraction of allowable hypothetical total inventory level for each basement rather than expected fraction of a DCGL
Data Quality Objectives (increase sample size if necessary based on statistical design)
Locations randomly chosen
Data Assessment
Perform Sign Test at Type I error of 5%
If the Sign Test passes then the STS results are acceptable and the mean value is used for source term in the BFM compliance calculation
If the Sign test fails then additional remediation will be performed and the STS is re-designed and performed again
Final Status Surveys
Planning, designing, implementing and evaluating the FSS done in accordance with MARSSIM
Survey Packages developed for each Survey Unit
Turnover, Isolation and Control Measures
Data Quality Objectives
Instrument Sensitivity
Survey Methods: scan/static measurements, volumetric sampling of soil and buried piping
Data Assessment including application of Statistical Tests
Quality Assurance
Reporting (FSS Survey Unit Release Records/Final Reports)
Performed on impacted Open Land Areas (surface/subsurface soil/roadways) and Buried Piping that remain at time of License Termination; Above grade remaining buildings and misc.
structures (duct banks) will undergo Unconditional Release Survey with Default DCGLs
Supplement to Environmental Report
Review of generic and site-specific environmental impacts
Evaluation followed approach outlined in NUREG-0586
All environmental impacts considered to be Small
Questions?