Waste Isolation Pilot Plant Technical Assessment Team Report

Abstract

This report provides the results of the Waste Isolation Pilot Plant (WIPP) technical assessment led by the Savannah River National Laboratory and conducted by a team of experts in pertinent disciplines from SRNL and

Waste Control Specialists Technical Review Team Report

“…In the next section, the Figure 3-3 data will be coupled to a revised computational model originally developed for analysis of Drum 68660 [10] to gain insights into the potential for thermal runaway reactions as a function of storage conditions.…”

“…A computational model [10] developed originally for analysis of failed Drum 68660 was improved by calibrating with reaction rates with full-scale surrogate drum tests by LANL that were either vented or sealed [11]. The surrogate waste formulation (WB8) [12], which is composed of sWheat Scoop ® , neutralized acids, and metal nitrate salts, was designed to be reactive to demonstrate cookoff of RNS waste.…”

“…At thermal ignition, the predicted pressures using the impermeable and permeable bed assumptions are 0.7 MPa (102 psig) and 0.3 MPa (44 psig), respectively. These high pressures would cause breach of the drum as failure was shown to occur at 0.17 MPa (24 psig) in the original WIPP TRT report [10]. Drum 68660 was simulated with the boundary temperature shown in Figure 4-3(d) with the pressure exponent (n) set to zero to mimic a vented drum.…”

“…Although Drum 68660 contained approximately 2 gal of neutralized nitric acid, 28 other drums in the WCS population (25%) had more neutralized nitric acid than Drum 68660 [7]. • The sister drum (Drum 68685) to Drum 68660 showed no unique chemical components when processed [10] [1]. The CSB did not contain temperature control.…”

“…These reactions produced gaseous products that led to the breach of Drum 68660. As previously discussed [10], the LANL RNS waste at WCS arose from the nitric acid processing of plutonium that contained a mixture of metal nitrate salts with entrained nitric acid, neutralized liquids, and sWheat Scoop ® , a wheatbased absorbent composed of starch (65-70% by mass) and proteins/enzymes (14% by mass). The final composition of the metal nitrate salts, and the acidity of the residual liquid, was dependent on whether the process feed originated from ion-exchange, in which the salts were washed with 3.3 M HNO3 to remove residual plutonium, or oxalate precipitation, in which the salts were washed with water to reduce acid catalyzed decomposition of oxalic acid [5].…”