Depending on the size and complexity of a decommissioning project, the transportation and disposal of radioactive waste will have an oversized impact on planning, schedule, and budget. The scope of decommissioning a site contaminated with radioactive material begins and ends with the proper and safe packaging of waste and subsequent transportation from the site to the final disposal location. Once all of the waste is gone from the site, the compliance exercise can be completed and the site released from controls (i.e., the radioactive materials license is terminated and the site is decommissioned).
Having managed multiple decommissioning projects, including both open-land areas and structures, I have learned that the number one lesson is to plan work “in reverse,” that is, from the end point of off-site disposal of all waste streams generated during decommissioning, to the beginning of deconstruction and decontamination efforts—specifically to avoid delays in schedule, rework, and unplanned costs.
Planning should start with the identification of waste streams, followed by the identification of corresponding disposal options. The waste acceptance criteria and packaging requirements for receiving the waste at identified disposal facilities can then be considered and used to plan deconstruction and decontamination of the site.
Planning for transportation of the packaged waste streams is next and results in the planning of on-site resources (rail spur, truck haul routes, cranes, and other equipment for loading, storage areas, facilities for waste, etc.) and off-site resources, including the limitations of the transporter and processing/disposal facility for the receipt of waste. Planning in reverse will help prevent potential bottlenecks in work flow resulting from waste accumulating on the site because it is not in the appropriate form, size, and/or package for transportation and off-site disposal.
Waste classification and disposal The planning of a decommissioning project is captured, reviewed, and approved within the overarching decommissioning plan (DP). The Nuclear Regulatory Commission’s NUREG-1757, Consolidated Decommissioning Guidance, Volume 1, Decommissioning Process for Materials Licensees, provides guidance on appropriate content for the DP and includes a prescribed section on waste. The NUREG guidance provided is for solid, liquid, and mixed radioactive waste. For solid waste, the following information is recommended for inclusion in the DP and subsequently in the project work plans:
A summary of the types of solid radioactive waste that are expected to be generated during decommissioning operations, including, but not limited to, soil, structural and component metal, concrete, activated components, contaminated piping, wood, and plastic.
A summary of the estimated volume, in cubic feet, of each solid radioactive waste type summarized in the above bullet point.
A summary of the radionuclides (including the estimated activity of each radionuclide) in each estimated solid radioactive waste type summarized under bullet No. 1.
A summary of the volumes of Class A, B, C, and greater-than-Class C solid radioactive waste that will be generated by decommissioning operations.
A description of how and where each of the solid radioactive wastes summarized under bullet No. 1 will be stored on-site prior to shipment for disposal.
A description of how each of the solid radioactive wastes summarized under the bullet No. 1 will be treated and packaged to meet disposal-site acceptance criteria prior to shipment for disposal.
If appropriate, a description of how the licensee intends to manage volumetrically contaminated material.
A description of how the licensee will prevent contaminated soil or other loose solid radioactive waste from being redispersed after exhumation and collection.
The name and location of the disposal facility that the licensee intends to use for each solid radioactive waste type summarized under bullet No. 1.
Similar information is required for liquid waste streams. And for mixed waste, in addition to the information requested above, the following should be included in the DP:
A discussion of the requirements of all other regulatory agencies having jurisdiction over the mixed waste.
A demonstration that the licensee possesses the appropriate permits from the Environmental Protection Agency and/or state to generate, store, and/or treat the mixed wastes.
A key step in decommissioning planning, specifically for anticipating transportation and disposal requirements, is characterization of all waste streams. The first step is an extensive review and analysis of all existing site data. In addition to the obvious waste characterization sample and analyses data, there are other sources of historical data that may help appropriate planning.
Survey data can be used to identify potential waste. Process data may shed light on potential mixed waste streams (e.g., where hazardous constituents were routinely used). Groundwater monitoring data is a good source for identifying both potential soil and water waste. Effluent discharge data can identify other potential contamination pathways. Historical data and walk-downs of the site may identify asbestos-bearing materials from old construction and a litany of other historically used hazardous constituents, such as lead-based paints. The overall review of existing data will identify data needs, and appropriate characterization surveys, sample, and analysis can be designed and implemented to fill in data gaps.
Waste packaging and transportation
Once all the potential waste streams are compiled and appropriate disposal facilities for each have been identified, planning on how each waste stream is to be packaged for transportation from the site to the disposal facility can begin. Package requirements should consider all of the following factors:
Disposal facility receiving requirements
Transportation method (truck, railcar, boxcar, gondola car, etc.) requirements
On-site storage requirements
Loading for shipment off-site requirements
Waste stream-driven requirements (e.g., acids and bases)
Criticality safety requirements
Time (i.e., shelf-life requirements)
Equipment for loading packages
Lessons learned and good practices
Experience is the best teacher! After 40 years in the nuclear services business, the last 20-plus years managing decommissioning efforts, many missteps have occurred and lessons have been learned. Here are some missteps to avoid by proper planning of transportation and disposal.
1. Don’t create an unexpected waste stream. This can easily happen during decontamination and/or deconstruction when waste streams are comingled unintentionally or unknowingly. The costliest of these is when a hazardous waste stream is mixed with a rad-only waste stream, driving the cost of transportation and disposal up by a factor of two or more, sometimes as high as a factor of 10.
2. Don’t package waste in bags or other containers with a shelf life shorter than the wait time to be shipped off-site. Repackaging costs and lost schedule will result.
3. Understand completely the waste acceptance criteria for the disposal facility being used. Nothing hurts more than shipments rejected at the disposal site. Surcharges for acceptance and/or the cost to ship back to the site can quickly break the project budget.
4. Understanding the waste acceptance criteria can lead to efficiencies and cost savings. For example, when using large containers such as gondola cars, physical types of waste with the same classification can be mixed (e.g., soil and construction debris). Creative loading can maximize the weight of each container, whereas poor planning can minimize the weight and result in additional shipments.
5. On-site blending to meet the radionuclide concentration limits of the waste acceptance criteria may be allowed with prior approval by the regulator(s). The savings can be significant for large volumes of waste blended to meet a lower-cost waste classification. On-site blending plans can be developed to ensure each package is maximized and other conditions of the shipment can be addressed during the process. For example, meeting the moisture content requirements by adding a drying agent to your waste (often the case for excavated soils) can be accomplished during the same process.
6. Designing a package specific to the waste shipment campaign can add value to the project. Having the right package can save time (schedule) and budget. Allowing lead time for the construction and delivery of custom packages and of off-the-shelf packages is critical to keeping the overall project on schedule.
7. Engineering the space and equipment needed for a successful shipping campaign is critical to both schedule and budget. Rail spurs, loading docks, truck routes including turnarounds, survey areas, lift areas, and package closure areas may all be critical elements of a cost-effective and efficient campaign.
8. Scheduling trucks, trains, cars, packages, and other elements needed for shipping is critical. Often, train routes and access are limiting and should be considered immediately if train transportation is part of the plan.
9. Weather can impact all aspects of the packaging, loading, and shipping of waste.
10. The availability of qualified waste certifiers and an experienced waste manager cannot be underestimated.
11. It is critical to coordinate waste shipping with the overall site decommissioning schedule to avoid bottlenecks. The critical steps and schedule may be driven by the availability of space on site for the temporary storage of waste, both before and after on-site packaging.
All these factors may be considered and incorporated into the DP, work plans, and procedures, and still unforeseen circumstances will likely arise during the project. Building contingency into your schedule, as well as into all the processes involved in transportation and disposal, is a necessary and important element of a successful decommissioning project. Now that you have all your waste streams identified and a good plan for packaging and transportation off-site, you can begin planning how to decontaminate and deconstruct your site. Good luck!
Andy Lombardo is executive vice president of Nuclear Services for PermaFix Environmental Services.