LOW TEMPERATURE EXOTHERMIC REACTION OF REILLEX^TM HPQ IN NITRIC ACID

ABSTRACT

Despite reports of the relative inertness of Reillex^TM HPQ to chemical and radiolytic degradation, thermal stability studies in nitric acid solutions identified a low temperature exothermic reaction using the Reactive System Screening Tool (RSST). Comparative data for Reillex^TM HPQ and Ionac^TM A-641 both show runaway behavior in nitric acid above 130˚C, but only Reillex^TM HPQ had a low temperature exotherm that initiated at about 69˚C. While this exotherm is small in magnitude, gaseous products were identified, leading to concerns of pressurization within the ion exchange column. This work identifies and characterizes the low temperature exothermic reaction of Reillex^TM HPQ in nitric acid, identifies ethylbenzene pendant groups as the origin of this reaction, and proposes a chemical pretreatment to eliminate it.

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