Remediation of Hanford's N-Reactor Liquid Effluent Waste Disposal Sites


R. B. Sitsler, D. K. DeMers


Hanford's N-Reactor operated from 1963 to 1987 generating approximately 9 x107 m3 of radioactive and hazardous liquid effluent as a result of reactor operations. Two liquid waste disposal sites, essentially large trenches designed to filter contaminants from the water as it percolates through the soil column, were established to dispose of the effluent. The discharges to the sites included cooling water from the reactor primary, spent fuel storage, and periphery systems, along with miscellaneous drainage from reactor support facilities. Today, both sites are classified as Treatment Storage and Disposal Facilities under the Resource Conservation and Recovery Act of 1976, which makes them priority sites for remediation. The two sites cover approximately 4,100 m2 and 9,300 m2, respectively. Remediation of the sites requires removing a combined total of approximately 2.6 x108 kg of contaminated soil and debris. Principal radionuclides contained in the soil/debris are 60Co, 137Cs, 239Pu, and 90Sr. Remediation of these waste sites requires demolishing concrete structures and excavating, hauling, and disposing of contaminated soils in work areas containing high levels of contamination and whole body dose rates in excess of 1 mSv h-1. The work presents unique radiological control challenges, which are highlighted in the paper. Through innovative approaches to dose reduction and contamination control, Hanford's Environmental Restoration Contractor has met the challenge, completing the first phase on schedule and with a total project exposure below the originally estimated 0.08-0.1 person-Sv.


This abstract was presented at the 35th Annual Midyear Meeting, "Decommissioning and Environmental Restoration", Controlling Dose I Session, 2/17/2002 - 2/20/2002, held in Orlando, FL.

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