Newswise — Since the dawn of the nuclear era 75 years ago, when the world’s first nuclear chain reaction ignited at the University of Chicago, the U.S. Department of Energy’s (DOE) Argonne National Laboratory has built up a legacy developing nuclear power for peaceful purposes. For evidence, look no further than today’s commercial nuclear reactors, which evolved from Argonne reactors’ designs and experiments to now suppling nearly 20% of U.S. electricity.
That legacy comes full circle through Argonne’s Decontamination and Decommissioning (D&D) Program, which has led the way in decommissioning nuclear facilities at the lab and around the world for over 40 years.
“Argonne was one of the first sites that decommissioned a significant number of facilities beginning in 1977. We helped the DOE and the industry get their legs under themselves on the decommissioning process.”
“Argonne was one of the first sites that decommissioned a significant number of facilities beginning in 1977. We helped the DOE and the industry get their legs under themselves on the decommissioning process,” said Larry Boing, an Argonne decommissioning subject matter expert with over 38 years of experience.
Along with several small-scale projects, Argonne’s D&D team has led the decommissioning of nine large-scale facilities at Argonne, including the Experimental Boiling Water Reactor (EBWR), an early prototype of reactors used for power generation, and Argonne’s Chicago Pile 5 (CP-5), a research reactor that provided neutrons, tiny particles that exist within atoms, for experiments for over 20 years.
Today, Boing and his team have broadened their original scope and have grown into providing expert technical support, knowledge management and other training to national and international groups looking to do their own decommissioning projects.
As a spin-off of this work, Argonne organizes and directs a team of decommissioning experts who, over the last 20 years, have trained over 2,400 people from 65 countries on the proper steps for decommissioning, from safe shutdown, licensing issues, project management to waste management and environmental assessments, up to and including conducting final site radiation surveys.
Most recently, Argonne has expanded to the international arena, including the International Atomic Energy Agency (IAEA), the central intergovernmental forum for co-operation in nuclear science. The laboratory has also engaged regions in Asia, North America and Europe.
“The importance of the training we provide cannot be overstated, especially when you consider our aging nuclear workforce, the slow and gradual decline in the number of people graduating with nuclear engineering or health physics degrees and the shortage of college programs that specifically address decommissioning,” Boing said.
“By managing and sharing this information, we’re protecting the knowledge and lessons learned for generations to come. We’re also helping build confidence and trust among the public and other key stakeholders by showing them that these facilities can be maintained safely and effectively throughout their entire life cycle.”
According to Boing, the process for safely decommissioning a facility generally proceeds in four key steps. These same steps apply for all different kinds of facilities, including research reactors, which are non-power reactors that typically provide neutrons for research purposes; commercial reactors, which are used to generate electricity; and gloveboxes, which supply transparent containment units in which hazardous materials are handled.
First is shutting down the site and removing operational waste. The second is to develop a decommissioning plan, including a schedule and budget, and get it approved and licensed by the U.S. Nuclear Regulatory Commission. The next step is to execute the plan in a strategic manner, then lastly, to assess the thoroughness of the process in accordance with the preapproved plan.
Many different considerations go into developing a decommissioning plan, including the amount and types of materials and waste that are on the site and the other contractors or specialists involved. The plan must also consider the procedures for removing and disposing materials on the site, which could require the licensee to provide workers with specialized training or deploy shielding or other equipment, such as remote or semi-remote systems.
“Depending on the risk level of the site, the process for regulatory approval could take months or several years to be fully completed, and thereafter allow the decommissioning work to start. It can take a couple years or even up to 10 years depending on the type of site you’re working on,” Boing said.
Once plans are approved, the licensee and contractors can begin working that plan – removing equipment in a pre-mediated process, moving towards the ‘hotter’ or more radioactive pieces, Boing said. When removing waste, workers must make sure that it is classified correctly and put into the correct configuration to be handled appropriately for shipping and ultimately disposal at a licensed off-site waste facility.
Finally, to assess whether a site has met agreed-upon standards for cleanup, contractors often rely on benchmarking tools like RESRAD. RESRAD, which refers to RESidual RADioactive materials, is a suite of software tools developed by the Environmental Science Division of Argonne National Laboratory. It has been used to derive cleanup criteria for hundreds of sites including the CP-5 reactor and other Argonne facilities.
Today RESRAD is widely used in more than 100 countries to evaluate radioactively contaminated sites and establish cleanup criteria. The tool calculates radiological dose and risk to humans, plants and animals through multiple pathways including direct exposure, inhalation of particulates and radon, and ingestion of plant foods, meat, milk, aquatic foods, water and soil.
“Without RESRAD it would be much harder to prove scientifically that a site is clean,” said researcher Charley Yu, the Argonne lead for the RESRAD program. “Other codes can calculate dose, but RESRAD is specifically developed to derive cleanup criteria for radiologically contaminated sites.”
Throughout the process, project management, waste management and stakeholder engagement are three key areas that the licensee must manage well to be successful, Boing said.
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.
The U.S. Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit the Office of Science website