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Nuclear Disposal Area West Valley
Project Information
- Project Location:
- West Valley, NY
- Approx Contract:
- $4,000,000
- Status:
- Completed
- Structure Type:
- Government
References
- Client:
- West Valley Environmental Service
Scope Of Work
West Valley is a complex radioactive waste site with long-lasting nuclear waste mainly from atomic weapons and power production and some other generators. The site known as the Nuclear Disposal Area (NDA) has buried waste consisting of high-level, “low-level” transuranic and mixed (radioactive and hazardous) wastes. Burial of radioactive waste in 20-30 foot deep trenches began in the early 1960s and continued until 1974 when water filled up the trenches, burst through the trench. Another 190,000 cubic feet were disposed there from 1982 to 1986 as part of the early West Valley Demonstration Project.
To prevent the infiltration of groundwater and surface water into the NDA, Pangea was contracted to construct an 850-foot underground soil-bentonite slurry wall on two upgradient sides of the NDA and install a 410,000 ft2 geomembrane cap over the NDA. Prior to the start of construction activities, Pangea prepared the NDA and established construction boundaries with appropriate postings and barriers for the NDA project.
The construction of the groundwater barrier wall included construction of a working platform and slurry mixing pad; preparation, placement and cleaning of slurry; excavation of the slurry trench; stockpiling; sand and sediment removal from the slurry trench bottom; cobble and boulder removal; supplying, hauling, blending and placing all backfill materials; temporary and permanent treatment of the top of the slurry wall; disposal of excess slurry and quality control testing.
The construction of the geomembrane cover included installation of a Geotextile cushion for protection of the geomembrane. Pangea also fabricated and installed an XR-5 geomembrane cap and Jersey barriers.
Pangea also installed upgrades to the storm water drainage system in the vicinity of the NDA. The installation of the stormwater draining system included excavation of trenches and installation of new catch basin, storm draining pipes and related structures, including backfilling to the grade. Pangea provided all as-built dimensions and invert pipe elevations.
In addition, Pangea performed relevant ancillary work such as monitoring well abandonment and installation, soil testing, civil land surveys, clearing and grubbing, management of surface water and erosion controls, equipment decontamination, and waste characterization and transportation, and site restoration.
