116-N-1 Crib and Trench Backfill

Department of Energy / Washington Closure Hanford LLC
Hanford Nuclear Site, Richland, Washington

The 116-N-1 treatment, storage, and disposal unit was the primary liquid waste disposal facility for the N Reactor at the Hanford Site and operated from 1963 to 1985. The “crib” was part of the 116-N-1 unit and it received radiologically contaminated water from multiple reactor facilities on the Hanford Site. The contaminated water contained radioactive reactor byproducts, limited quantities of corrosive liquids, and chemicals from the laboratories on site. The crib was approximately 360 feet long by 125 feet wide and had a total of ten pipelines that discharged into it. The walls of the crib were composed of a sloped soil and gravel embankment and the bottom of the crib was lined with 2-foot to 3-foot diameter boulders. DelHur was contracted to perform backfill, grading, and fence installation in the process of remediating this contaminated site. The project included the hauling and placement of approximately 230,000 bank cubic meters of fill material in the crib and trench area. This project was performed utilizing ALARA radiation safety methods to minimize radiation exposure to the workers and the environment and to ensure there was no spreading of the contamination outside of the work zones.