ML11214A196
| ML11214A196 | |
| Person / Time | |
|---|---|
| Site: | West Valley Demonstration Project, P00M-032 |
| Issue date: | 02/27/2011 |
| From: | Chamberlain J West Valley Environmental Services |
| To: | NRC/FSME |
| References | |
| Download: ML11214A196 (18) | |
Text
West Valley y Demonstration Project j
West Valley Environmental Services Design and Installation of a Permeable Treatment Wall to Mitigate Expansion of Strontium Strontium--90 Contaminated Groundwater John Chamberlain Sr Technical Advisor WMS 2011, Feb 27 - Mar 3 11138_1
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Project Partners WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_2
Site Background
~3,330-acre New York State-owned site located ~35 miles south of Buffalo Si off only Site l commercial i l used d ((spent)) nuclear l ffuell reprocessing i facility to operate (1966-72) in the United States DOE assumed control off developed d l d portion ti of site (~160 acres) in 1982 to solidify the high-level high level waste generated from reprocessing and decommission facilities used Site is a small plateau with streams on th three sides id
Reference:
WMS 2010 Paper 10409 WVDP premises (~160 acres) marked by white line WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_3
Strontium-90 Groundwater Plume Groundwater containing Sr-90 identified in northeast (NE) section of site (1993)
Relatively permeable glacial sediment 4-30 feet-thick overlies very low permeability clay till G
Groundwater d t iin northern th portion ti off site it moves NE and surfaces in ditches or N as seeps at edge of plateau Investigation indicated that Sr-90 Sr 90 came from process line leak(s) during reprocessing (1966-72)
Two actions taken to slow plume expansion Pump and treat wells installed at one location (< 30 feet apart) in 1995 Pilot PTW (~ 30 feet wide) in 1999
Reference:
WMS 2010 Paper 10409 WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_4
Plume Mitigation Approach Selected 2006-07 Plan to address site decommissioning in stages (phases) was developed p Placement of full-scale Clay (till)
PTW was proposed to control plumes leading edge while decommissioning progresses 2008 2009 2008-2009 Characterization of leading edge of plume confirmed viabilityy of a full-scale PTW WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_5
Design Relied on Data from Pilot PTW Pilot PTW installed 1999 Performance was limited Zeolite used removed Sr-90 Limited groundwater flow through; most groundwater bypassed pilot PTW Evaluation completed 2002 identified key factors Pilot PTW installation Scale:
S l sizei relative l i to plume l important Depth: assure PTW is keyed into clay Trench walls: must be permeable Zeolite: chemical composition and physical strength must resist compaction Pilot PTW monitoring wells WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_6
Projecting PTW Longevity Analyte Units Mean Goal: Control Calcium µg/L 166,820 expansion p of leading g Potassium µg/L 3 028 3,028 edge of plume for up to 20 years Magnesium µg/L 26,203 Sodium µg/L 184,733 Sr-90 removal dependent on Strontium-88 µg/L 327 Zeolite cation exchange capacity Groundwater cation content Sr-90 concentration in groundwater Volume of groundwater that passes through PTW thickness is only factor that can be adjusted to enhance longevity WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_7
Testing Addresses Uncertainties Zeolite Lab testing (2 zeolites)
- Column tests for cation exchange capacity (over a year)
- Standardized synthetic water with Sr-88 (University at Buffalo, UB)
- Actual site groundwater with Sr-90 (WVDP)
- Field testing
- Checked for possible breakdown due to shipping, equipment handling, handling installation Columns in UB lab
- Selected material from Bear River Mine in Preston, ID
- Higher clinoptilolite content
- No measurable clay content
- No observed breakdown due to shipping, equipment handling, installation Pre-shipment testing WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_8
Addressing Uncertainties (cont)
Trencher Focused on use of one one-pass pass trencher to minimize "smearing" smearing on trench walls
- Surveyed suppliers and found one with trencher capable of installing PTW
- Conducted three trencher tests over a year to check:
- Trencher assembly and general operation
- Zeolite handling and placement
- Soil management
- Decontamination Trencher WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_9
Initial Trencher Test Trench Box Cutting Teeth Trencher T
Trenching hi Test Trench Trenching WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_10
Trencher Findings and Adjustments Stone slinger and bag cutter for zeolite loading Conveyor y for f excavated soil System to add water to zeolite Developed system to add water to zeolite in the trench box to counteract groundwater pressure in the trench Tested and adopted use of stone slinger to feed zeolite to the trencher Developed lifting bar for zeolite bags and bag cutters to place on stone slingers Developed conveyor to directly collect excavated soil and place it in an above-ground containment structure WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_11
PTW Installation Area WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_12
Final Design Aerial View 39 bborings i
placed to Cross confirm Section depth p to till WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_13
InstallationOct 17 - Nov 18, 2010 Soil Structure PTW Platform Soil Access Road Structure October 17 November 6 WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_14
Installation (cont)
November 1. 2010 WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_15
Addressed Field Conditions Internal belts in conveyer Soil containment replaced and strengthened reinforced to ensure after cobble-sized cobble sized stones containment of wetter wetter-were encountered than-expected soil Resolved Resolved Conveyor rebuilt and containment re-enforced in parallel; 12 days WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_16
Installation (cont)
November 5 November 5 November 18 November 21 WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_17
PTW - February 6, 2011 Nov 30 Trenching equipment off site Dec 27 Completed installation of 66 monitoring wells Jan 27 Initial sampling 860 long, 19-30 deep, 39 wide round 2,377 tons of zeolite installed completed ~ 45 trencher hours of operation WMS 2011, Feb 27 - Mar 3 Design and Installation of PTW to Mitigate Sr-90 Contaminated Groundwater 11138_18