Tank Waste Storage Project

Protecting Groundwater

The primary focus of the project will be the safe retrieval and storage of wastes in the twenty-eight (28) double shelled tanks (DSTs) and one hundred and forty-nine (149) single shelled tanks (SSTs). Specifically, for DSTs, the project will include: operations, upgrades, permitting, safety, characterization, systems inspections, and waste volume projections. The project, for SSTs, will cover: operations, interim stabilization, leak detection, characterization, system inspections, safety, and groundwater issues. See the groundwater brochure for more information about groundwater cleanup.

Jeff Lyon is the Tank Waste Storage Project manager.

Project Mission

Safe storage, management, and retrieval of all tank wastes to complement the treatment and disposal of tank wastes. Supports a systematic approach to the closure of the tank system and the safe treatment of any remaining materials.

The TWS Project regulates how tank waste is treated and stored, ensures that the Department of Energy maintains the DSTs, prevents harmful releases to the environment, and conducts safe operations, governs the closure of SSTs, and governs the retrieval of waste from the SSTs and its transfer to the DSTs.

The Tank Waste Storage (TWS) Project oversees management of highly radioactive waste in 177 underground storage tanks at the Hanford Site. The tanks range from 50,000 to more than one million gallons in capacity. Most of the tanks (149) are single shell tanks (SSTs) that are well beyond their planned life expectancy of 20 years.

Out of these 149 SSTs, 67 have been declared known or assumed leakers that have released more than one million gallons of waste to the soil and groundwater. The released waste is now moving toward the Columbia River.

To provide safer storage for tank wastes, 28 double shell tanks (DSTs) were built. More than three million gallons of liquid waste has been moved from the SSTs into the DSTs. To date, there have been no leaks to the environment from the DSTs.

Eventually, the tank waste will be transferred to the Waste Treatment Plant (WTP) for vitrification and immobilization.

Terms to Know

Single Shell Tank (SST): waste storage tank built with only one wall

Double Shell Tank (DST): waste storage tank built with two walls

Vitrification: process by which tank waste is turned into glass