Project Decom14 December 2016
Joe Smetanka, managing director of the Hematite Decommissioning Project for Westinghouse Electric Company, discusses the project, the challenges it posed and how the company worked to address them.
Westinghouse Electric Company recently completed the first decommissioning of a nuclear fuel facility in the US at the former Hematite Nuclear Fuel Fabrication Facility in Jefferson County, Missouri, US.
Named Hematite for the abundance of hematite mineral in the local area and its proximity to the more than 150-year-old Hematite community, the site had hosted nuclear fuel-related research and manufacturing operations from 1956 to 2001.
The site has a long history within the nuclear community. From 1956-74, Hematite operations were focused on uranium fuel research and production of research reactor fuels for the US Navy and US Army, as well as rocket fuel destined for the US National Aeronautics and Space Administration. From 1974-2001, work at Hematite switched to focus on manufacturing fuel pellets from low-enriched uranium (LEU), and eventually, fuel assemblies for commercial operations. Hematite was also used to recover uranium compounds from scrap.
Westinghouse became site owner as part of the company’s acquisition of Asea Brown Boveri Ltd. in 2000 and consolidated Hematite’s fuel fabrication operations to Westinghouse’s Columbia Fuel Fabrication Facility in Columbia, South Carolina, US.
Now known as the Hematite Decommissioning Project, Westinghouse, backed by more than 30 years of global experience in decommissioning and waste management of government facilities, had a mission to complete site cleanup, decommissioning and remediation in order to meet the site’s decommissioning license requirements. Central to Westinghouse’s mission was completing the work in a safe, socially responsible and environmentally sound manner. As part of its mission, Westinghouse:
- Developed a detailed decommissioning plan for the US Nuclear Regulatory Commission (NRC);
- Developed a record of decision for the Missouri Department of Natural Resources (DNR);
- Derived radioactive contaminant level criteria based on US NRC-established criteria;
- Conducted investigations for environmental and radiological characterization;
- Performed chemical and radiological confirmation sampling and environmental field characterisation activities related to site, soil and groundwater characterization;
- Decontaminated, dismantled and removed equipment and buildings;
- Excavated waste burial pits and removed contaminated soil; ¦ Shipped impacted soil and material for offsite treatment and disposal; and
- Established a plan to continue groundwater monitoring.
Westinghouse worked with two regulatory agencies throughout the project duration: the US NRC for radioactive contamination and the Missouri DNR for chemical contamination, including volatile organics. These regulatory agencies determine the requirements for satisfactory decontamination and ultimately whether these requirements are met.
Following the consolidation of Hematite’s fuel fabrication capacity to Westinghouse’s Columbia site, the company submitted a request to the US NRC in 2001 to change the scope of authorised activities to decommissioning activities. The US NRC is the authority regulating radioactive contamination above and below ground, including air and water. Additionally, Westinghouse submitted a ‘Record of Decision for Operable Unit 1’ to the Missouri DNR, which is the regulatory authority over chemical contamination underground. The record of decision formalises the selected remedy for chemical remediation of a site.
Westinghouse’s goal was to reduce radioactivity and chemical contamination to levels that permitted the license to be terminated in accordance with the governing Code of Federal Regulations and to release the site for unrestricted use. The US NRC accepted the decommissioning plan for technical review in 2009 and approved the plan in October 2011. The Missouri DNR reviewed and concurred with the record of decision in 2009, allowing the first phase of chemical remediation to begin.
Planning for the Hematite Decommissioning Project included consideration of all site work, including full radiological site remediation above and below ground, and a timeline for completing the work. The timeline needed to consider completing the related regulatory review and approval processes of both the US NRC and the Missouri DNR.
Since the site contained buildings, buried waste, soil contaminated with radioactive material as well as soil and groundwater contaminated with chemicals, an important determining factor for scheduling and successfully performing the work was defining the contamination levels for cleanup of the soil, buildings and equipment based upon the regulatory criteria. Once the cleanup criteria were established and understood, processes had to be defined to achieve the ultimate end-state of the site. This included where the contaminated materials would be disposed, in accordance with federal and state regulations.
Identifying human resources with the proper expertise and skill sets in the areas of health physics, criticality and the environment, was an essential step to successfully planning and completing the work. Arranging key contracts with waste disposal and prime contractors with the necessary capabilities to perform the physical work onsite was also crucial.
Implementation: challenges and successes
In December 2010, Westinghouse received approval from the US NRC to dismantle the roofs and walls of ten buildings on the site that were used for the production and storage of nuclear fuel.
Decontamination, dismantling and removal – equipment and buildings
Of the site’s ten buildings, four were used for storage of special nuclear material; the other six were production buildings. The challenge associated with safely dismantling these buildings was ensuring that contamination wasn’t released into the environment and allowed to become airborne. To solve this concern, a fixative coating was applied to all interior building surfaces prior to demolition and all contaminated equipment was removed and packaged separately as waste. Water spray was used to control dust generation during demolition activities and portable dust monitors were placed around the perimeter of the work area to ensure that airborne contamination was not spread.
Radiological and chemical air monitoring stations were also established in appropriate locations throughout the work site.
The surface water created by the water spray for dust control was monitored and sampled regularly to verify that the contamination control measures were working. In addition, routine radiological surveys of the site were performed to ensure the safety of the workers, the public and the environment.
Representatives from the Missouri DNR and US NRC routinely inspected the extensive work activities. In all, at that first stage of the physical project work, Westinghouse dismantled 83,537 square feet of structures and shipped nearly eight million pounds of building debris offsite to licensed facilities.
After removing the site buildings, Westinghouse cleaned and once again sealed with an epoxy fixative the remaining concrete slabs and foundations to contain contaminants embedded in the concrete. The epoxied slabs also served as a barrier against surface water infiltration of the soil. They remained in place until the US NRC approved the decommissioning plan, allowing full remediation of the site to proceed in early 2012.
Underground environmental field characterisation
Once the US NRC approved the decommissioning plan and the Missouri DNR reviewed and concurred with the record of decision, environmental field characterisation work began.
A significant challenge in decommissioning sites with underground contamination is the investigative work that provides certainty that sufficient environmental field characterisation studies have been conducted. These studies include installing boreholes and performing soil analyses to assess the types and extent of the contaminants, which in turn defines the processes for removal and disposal. For radioactive contaminants, the criteria generally reflect levels of radiation and the contamination levels to which personnel will be exposed during soil excavation and processing. For chemical waste remediation, goals for the chemicals present are developed, providing the acceptable exposure limits for the workers and also establishing the criteria for excavation and disposal.
To facilitate radiological characterisation in large volumes of soil, Westinghouse installed a mobile assay system for soil analysis that was used in concert with other sampling and characterisation activities on the site. The mobile assay system was designed to detect trace amounts of radioactivity. The data generated was used to characterise the soil so that its ultimate destination could be determined.
Burial pit and other underground excavation
The burial pits were an area of concern for the US NRC and Westinghouse as onsite burial of waste without documentation was authorised by the regulations of the US NRC’s predecessor, the US Atomic Energy Agency, during the early years of the site’s operations. Burial documentation, which was required by subsequent regulation beginning in 1960, indicated that waste was typically buried in the northeastern portion of the site, in an area that was remote from the site’s buildings. Site records indicated there were 40 documented burial pits.
Both Westinghouse and the US NRC recognised the possibility existed for a volume of radioactive waste to have been buried without documentation between 1956 and 1960. Interviews with personnel who had been employed at the site during its operable years confirmed there was the possibility of 20-25 more burials of construction debris and general non-contaminated waste. Site characterisation confirmed that there was other buried waste near the burial pits area. The process utilised to remediate the area ensured that all waste was identified and removed for disposal.
Other areas of the site that required excavation included locations where underground piping existed such as storm water and sanitary piping.
Westinghouse reviewed national historic weather data of the area to anticipate weather conditions that were likely to occur during site decommissioning that might create an issue. A significant rain event was determined to be the most likely event that would impact remediation activities. Work plans were designed to accommodate a possible “25-year” rain event, which is a ten-day rain event totaling nine inches of rain in that period.
Westinghouse planned for the rain since flooding at this level could move storm water and cause cross-contamination from site areas not yet remediated to site areas that were either already remediated or that had never been contaminated. Planning for the rain event helped the response effort needed for the additional unexpected rain events that occurred during site remediation. On three occasions significant rain events caused flash flooding and, even with the initial preparations, productivity was impacted, causing significant delays in the overall project schedule. Site personnel who were assigned to remediation activities were diverted to excavated areas to assist in pumping the storm water out of excavations and processing the storm water for release. Once the storm water was removed from the excavations, the site staff sampled and tested the soil in the excavations to determine if it had been impacted by flooding.
Soil remediation and shipping
Following soil characterisation, contaminated soil above the acceptable criteria was removed for shipment to the disposal facility and soil that was found to be acceptable was stored for later use as backfill material.
There were 375 million pounds of soil and debris shipped offsite in 1350 railcars. Approximately 80% of the soil and debris requiring disposal was contaminated with low-level radioactivity and was shipped to US Ecology in Idaho, US, a qualified facility authorised for receiving such waste in compliance with US Resource and Recovery Act standards. The Resource and Recovery Act is a public law that creates the framework for the proper management of hazardous and non-hazardous solid waste. The remaining 20% of the soil and debris was contaminated with higher levels of radioactivity and shipped to qualified facilities in Texas and Utah.
Westinghouse decommissioning leaders on the site set up and held meetings with the US NRC and Missouri DNR, and conducted public meetings with the surrounding community members on a routine basis. The meetings were a vital means for the company to provide assurance of compliance with federal and state requirements, and for helping the surrounding community members understand the site’s activities. Westinghouse conducted a number of these public meetings onsite so that community members could see firsthand the types of activities that were happening and the precautions the company employed to protect community members, employees and the environment alike.
Current state and remaining work
Westinghouse completed most of the physical work to decontaminate Hematite in a little more than four years. During 2017, the company expects to complete final documentation demonstrating that Hematite meets the US NRC regulatory requirements for unrestricted use and to terminate the US NRC license. Also during 2017, Westinghouse expects to establish an agreement with the Missouri DNR for long-term groundwater monitoring. The agreement will include a method of demonstrating that chemical contaminants in both the soil and groundwater are within regulatory limits.
Westinghouse will retain ownership of Hematite until decisions for its future use are made. Regardless of future site use, Westinghouse expects to monitor groundwater for the next 20 to 25 years and has installed groundwater monitoring wells on the site to facilitate sampling. The number and location of the wells will change over time based on the results of analyses of those samples. Westinghouse will continue to communicate with the surrounding community to keep community members abreast of the chemical remedy for residual soils and long-term groundwater monitoring plans and sampling results.
Westinghouse will apply the lessons learned during the Hematite Decommissioning Project to benefit future decontamination, decommissioning and remediation projects as the company assists other nuclear facilities globally to complete the full nuclear lifecycle.