Construction of the 242-A Evaporator started in 1974 and operations began in 1977. From 1977 through the late 1980s, the 242-A Evaporator missions included supporting defense-related production of nuclear weapons material, protecting the environment by concentrating and transferring liquid waste from single-shell tanks into double-shell tanks, and managing double-shell tank space by reducing the volume of waste. The original design life of the 242-A Evaporator was 10 years. The facility has undergone several life extension upgrades.
The current and future mission of the 242-A Evaporator is to support environmental restoration and remediation of the tank farms by optimizing the 200 Area double-shell tank waste volumes. The 242-A Evaporator is maintained and upgraded as necessary to support this mission.
The 242-A Evaporator is designed to reduce the volume of the stored liquid waste in the tank farms. The process uses a conventional, forced-circulation, vacuum evaporation system operating at low pressure (approximately 60 torr) and low temperature (approximately 122°F) to concentrate radioactive waste solutions.
The primary interface with the 242-A Evaporator is the tank farms, which transfers waste (feed) to the 242-A Evaporator for concentration and then receives the concentrated product (slurry).
Since it began operating in 1977, the Evaporator has reduced the total volume of waste in Hanford's tanks by 85 million gallons, helping avoid the high cost of building new waste storage tanks.