LAS VEGAS - Workers recently completed construction of a mixed low-level waste (MLLW) disposal cell at the Nevada National Security Site (NNSS) to support environmental cleanup in Nevada and across the U.S.
The EM Nevada Program worked closely with the National Nuclear Security Administration Nevada Field Office and the State of Nevada throughout a two-year process to obtain a modified Resource Conservation and Recovery Act (RCRA) permit for the project. The state-issued permit sets forth conditions for the disposal of low-level radioactive waste containing hazardous constituents at NNSS.
The RCRA-regulated permit process included several engineering design reviews, a 2,085-page permit application, and a - all of which was coordinated with the Nevada Division of Environmental Protection (NDEP), the state agency responsible for overseeing RCRA-related activities and issuing permits.
NDEP provided comments that were addressed in the permit application, which saved time and taxpayer dollars, and enhanced the quality of the permit application. NDEP signed the permit in July 2017 after extensive review and a formal public engagement process that resulted in no comments or appeals.
Before sunrise on Aug. 21, 2017, a Consolidated Group of Tribes and Organizations representative blessed the land to reaffirm the group’s cultural connection to it before the groundbreaking.
“Providing access for this important event reinforces DOE’s longstanding commitment of working closely with 16 culturally-affiliated tribes with ties to the NNSS," EM Nevada Program Manager Rob Boehlecke said.
The 20-foot-deep cell was constructed with a double liner. The primary, upper layer captures and moves any precipitation collected into a sump where it is pumped into a tank. The lower, secondary layer serves as a leak detection system by collecting any water that penetrates the primary liner. Water in the tank from both liners is regularly sampled. To ensure the liners are not compromised by the heavy weight of disposal operations, an engineered layer of soil was placed over the liners.
The cell has a capacity of 37,000 cubic meters. NNSS will need to apply to renew the permit in 2020 and every five years thereafter. As with all radioactive waste disposed at the NNSS, MLLW must meet the requirements of the, which includes satisfying U.S. Environmental Protection Agency land disposal restrictions and prohibiting waste containing free liquids.
“Ensuring compliance with the NNSS Waste Acceptance Criteria contributes to the safe operation and long-term performance of the disposal facility for the protection of workers, the public, and environment," Boehlecke said.
To monitor MLLW cell performance, water collected in the tank is analyzed for hazardous and radioactive constituents. Historically, the results of water samples collected from the tank of the existing MLLW cell indicate that any constituents identified comply with regulatory limits.
A groundwater monitoring system comprised of three wells is positioned along the perimeter of the Area 5 Radioactive Waste Management Complex. The wells are sampled twice a year and no radioactive or hazardous contaminants from waste disposal operations have been detected by routine analysis. Results of sampling are published annually. An additional well down-gradient from the new cell will be installed within four years.
DOE requires additional monitoring to ensure buried waste is not creating a risk to NNSS workers, the public, or the environment. These activities include monitoring direct radiation, air, soil gas, and biota. With so many cleanup programs depending on the availability of NNSS disposal, including onsite remediation activities, the EM Nevada Program is committed to carrying out its mission to the highest level of safety, integrity, transparency, and regulatory compliance.
Source: U.S. Dept. of Energy, Office of Environmental Management
