Freestone Environmental Services

Water Resources

Regulatory Support to Closure of the Hanford Site’s Radioactive Waste Storage Tanks

Category: Regulatory Support | Client: U.S. Department of Energy

At the U.S. Department of Energy’s (DOE) Hanford Site in Washington State, Freestone supports the various federal contractors who are engaged in the largest waste management and environmental cleanup effort in the nation’s history.  CH2M Hill Hanford Group, Inc. sought Freestone’s assistance with the regulatory process for closure of a vast, radioactive tank waste storage infrastructure.

The technical challenges of tank closure are formidable. The single-shell tanks system is comprised of 149 tanks, most with 500,000- to 1-million-gallon capacities that contain mixed radioactive and dangerous chemical waste, a legacy of plutonium production for the Manhattan Project and Cold War U.S. nuclear weapons arsenal.  These 149 single-shell tanks are operated as 12 underground tank farms which have vast networks of piping and ancillary equipment, and are grouped into 7 waste management areas for regulatory purposes.

The tanks are well past their design life, and several have leaked waste to the soil and groundwater. Closure of the tanks follows retrieval of the waste from the tanks and transfer to safer, double-shell tanks for storage prior to treatment and disposal. The process of waste retrieval, treatment (including vitrification), closure of tanks and ancillary equipment, cleanup of contaminated soil and groundwater, and ultimate disposal of treated waste in approved facilities and a geologic isolation repository will take decades to complete, and is unprecedented in technical complexity and scale.  There are 53 Million gallons of radioactive and dangerous waste stored in the single-shell and more competent double-shell tank systems that will be transferred to the Waste Treatment Plant (WTP) for vitrification.  53 million gallons of waste is equivalent to a football field covered 150 feet high. The WTP is under construction and will cost about $11 Billion to complete. Operations of the WTP are estimated to take 28 years to convert the tank sludges and liquids to a stable glass form, ready for ultimate disposition in a geologically isolated repository.

Closure of the tank waste management areas is conducted under the mantle of a Tri-Party Agreement between the U.S. Department of Energy, U.S. Environmental Protection Agency and Washington State Department of Ecology. Together these agencies guide cleanup and closure of the Hanford Site and establish milestones for achieving progress.  Closure planning involves numerous regulatory requirements and Department of Energy orders, with the primary drivers being DOE Order 435.1 with authority from the Atomic Energy Act, and implementation of RCRA through Washington’s Dangerous Waste requirements and a Site Permit. In addition, there are interrelated requirements under NEPA, SEPA, and CERCLA.  

A three-tiered system for closure was established including:

  • A Framework Plan - for overall Single-Shell Tank System Closure
  • Waste Management Area (WMA) Closure Action Plans - which comprise a single regulatory unit each with component groupings of tanks, ancillary equipment, contaminated soil and groundwater
  • Component Closure Activity Plans - for individual facilities or groupings of tanks, ancillary equipment, or contaminated media within a waste management area.

In addition to assisting our client with closure strategy development, Freestone performed the following closure related work:

  • Preparation of Closure Action Plans for WMAs C and S-SX, and a draft plan for WMA U.  To prepare these plans, Freestone coordinated information and data input from numerous Hanford contractor personnel engaged in a multitude of activities that contribute to closure including, residual waste sample characterization, characterization of contaminated soil, groundwater monitoring, engineering plans for grout stabilization of emptied tanks, and post-closure performance assessment modeling and risk assessment.  The documents addressed compliance with Tri-Party Agreement milestones, and requirements for RCRA and dangerous waste, LDR, NEPA, SEPA, retrieval verification, groundwater monitoring, and risk assessment.
  • Remote video system measurement of Tank Residual Waste Volumes during and after retrieval efforts, including development of procedures, training and qualification of CH2M Hill staff to perform future measurements

And numerous supporting documents and activities including:

  • Integration Studies for conduct of component closures within WMAs
  • Ancillary Equipment Characterization Approach
  • Residual Tank Waste Volume Classification Analysis Model
  • Component Closure Activity Plans technical review
  • Grab Sampling and Analysis Plan For Residual Waste Liquids In The C-200 Series Tanks
  • Sampling and Analysis Plan For Residual Waste Solids In The C-200 Series Tanks
  • Sampling and Analysis Plan For Single-Shell Tanks Component Closure
  • Liquid And Solids Grab Sampling And Analysis Plan For Tank 241-C-106 Component Closure Action
  • Tank 241-C-106 Component Closure Action Data Quality Objectives

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