SAFETY STUDIES TO MEASURE EXOTHERMIC REACTIONS OF SPENT PLUTONIUM CONTAMINATION CHEMICALS USING WET AND DRY DECONTAMINATION METHODS
The Plutonium Finishing Plant (PFP) at the Hanford site in Eastern Washington is currently being decommissioned by Fluor Hanford. Chemicals being considered for decontamination of gloveboxes in PFP include cerium (IV) nitrate in a nitric acid solution, and proprietary commercial solutions that include acids and sequestering agents. Aggressive chemicals are commonly used to remove transuranic contaminants from process equipment to allow disposal of the equipment as low level waste. Fluor's decontamination procedure involves application of chemical solutions as a spray on the contaminated surfaces, followed by a wipe-down with rags. Alternatively, a process of applying oxidizing Ce IV ions contained in a gel matrix and vacuuming a dry gel material is being evaluated. These processes effectively transfer the transuranic materials to rags or a gel matrix which is then packaged as TRU waste and disposed. Fluor is investigating plutonium decontamination chemicals as a result of concerns regarding the safety of chemical procedures following a fire at Rocky Flats in 2003. The fire at Rocky Flats occurred in a glovebox that had been treated with cerium nitrate, which is one of the decontamination chemicals that Fluor Hanford has proposed to use. Although the investigation of the fire was not conclusive as to cause, the reviewers noted that rags were found in the glovebox, suggesting that the combination of rags and chemicals may have contributed to the fire. Because of this underlying uncertainty, Fluor began an investigation into the potential for fire when using the chemicals and materials using wet disposition and dry disposition of the waste generated in the decontamination process and the storage conditions to which the waste drum would be exposed. The focus of this work has been to develop a disposal strategy that will provide a chemically stable waste form at expected Hanford waste storage temperatures. Hanford waste storage conditions are such that there is added heat to the containers from ambient conditions during storage especially during the summer months. Treatability tests under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) were used to assess the use of certain chemicals and wipes (wet method) and chemical-gel matrices (dry method) during the decontamination process. Chemicals being considered for decontamination of gloveboxes at PFP include cerium (IV) nitrate in a nitric acid solution, and proprietary commercial decontamination agents such as RadPro? , Glygel? and ASPIGEL 100?. As part of the treatability study, Fluor and the Pacific Northwest National Laboratory (PNNL) personnel have evaluated the potential for self-heating and exothermic reactions in the residual decontamination materials. From these wet and dry method treatability studies, certain limiting conditions have been defined that will aid in assuring safe operations and waste packaging during the decommissioning and waste disposition process.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 889089
- Report Number(s):
- PNNL-SA-46965; 830403000; TRN: US0604370
- Resource Relation:
- Conference: The 10th International Conference on Environmental Remediation and Radioactive Waste Management September 4-8, 2005, Scottish Exhibition & Conference Centre, Glasgow, Scotland ,
- Country of Publication:
- United States
- Language:
- English
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