Use of a Treatability Study to Investigate the Potential for Self-Heating and Exothermic Reactions in Decontamination Materials at the Plutonium Finishing Plant.

Ewalt, J. R. ; Hopkins, A. M. ; Scheele, R. D. ; Scott, P. A. ; Trent, D. S. ; Minette, M. J. ; Simiele, C. J. ; Romine, L. D.

Technical Information Center Oak Ridge Tennessee

关键词: Decontamination;    Heating;    Cerium nitrates;    Exothermic reactions;    Alpah-bearing wastes;   

RP-ID  :  DE2005837633

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Cerium Nitrate has been proposed for use in the decontamination of plutonium contaminated equipment at the Plutonium Finishing Plant (PFP) located on the Hanford Nuclear Reservation in eastern Washington. A Treatability Study was conducted to determine the validity of this decontamination technology in terms of meeting its performance goals and to understand the risks associated with the use of Cerium Nitrate under the conditions found at the PFP. Fluor Hanford is beginning the decommissioning of the PFP at the Hanford site. Aggressive chemicals are commonly used to remove transuranic contaminants from process equipment to allow disposal as low level waste. 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, degreasers, and sequestering agents. Fluor's decontamination procedure involves application of the chemicals, followed by a wipe-down of the contaminated surfaces with rags. This process effectively transfers the decontamination liquids containing the transuranic materials to the rags, which can then be readily packaged for disposal as TRU waste. As part of a treatability study, Fluor Hanford and the Pacific Northwest National Laboratory (PNNL) have evaluated the potential for self-heating and exothermic reactions in the residual decontamination materials and the waste packages. Laboratory analyses and thermal-hydraulic modeling reveal a significant self-heating risk for cerium nitrate solutions when used with cotton rags. Exothermic reactions that release significant heat and off-gas have been discovered for cerium nitrate at higher temperatures. From these studies, limiting conditions have been defined to assure safe operations and waste packaging.