Red oil 412461 205306869 2008-04-13T11:09:50Z 60.242.154.34 Decapitalisation '''Red oil''' is defined as a substance of varying composition formed when an organic solution, typically [[tri-n-butyl phosphate]] (TBP, an agent used for extracting heavy metals in [[nuclear reprocessing]] plants) and its [[diluent]], comes in contact with concentrated [[nitric acid]] at a temperature above 120 °C. Red oil is relatively stable below 130 °C, but it can [[chemical decomposition|decompose]] [[explosion|explosively]] when its temperature is raised above 130 °C. Three red oil events have occurred in the United States: at the [[Hanford Site]] in [[1953]], and at the [[Savannah River Site]] (SRS) in [[1953]] and [[1975]]. A red oil explosion also occurred in [[1993]] at the [[Tomsk-7]] site at [[Seversk]], Russia. Generic types of equipment capable of producing red oil in the complex are categorized as [[evaporator]]s, acid concentrators, and [[denitrator]]s. The chemicals necessary to produce red oil are, at a minimum, TBP and nitric acid; other, contributory chemicals can include diluent ([[kerosene]]-like liquid used to dilute TBP) and/or aqueous phase metal [[nitrates]]. Controls for prevention or mitigation of a red oil explosion are generally categorized as controls for temperature, pressure, mass, and concentration. Maintaining a temperature of less than 130 °C is generally accepted as a means to prevent red oil explosions. Sufficient venting serves to keep pressure from destroying the process vessel, while also providing the means for [[evaporative cooling]] to keep red oil from reaching the [[thermal runaway|runaway temperature]]. Mass controls utilize [[decanter]]s or [[hydrocyclone]]s to remove organics from feedstreams entering process equipment capable of producing red oil. Limiting the total available TBP is another mass control that mitigates the consequence of a red oil explosion by limiting its maximum available explosive energy. Finally, concentration control can be utilized to keep the nitric acid below 10 M (moles/liter). A U.S. government study concluded that none of the controls should be used alone; rather, they should be used together to provide effective defense in depth for prevention of a red oil explosion. == External links == * [http://www.dnfsb.gov/pub_docs/dnfsb/tr_20031113.pdf Control of red oil explosions in defense nuclear facilities] ([[Portable Document Format|PDF]], 120KB). [[Defense Nuclear Facilities Safety Board]], 2003. [[Category: Radioactive waste]]