Gas Generation from K East Basin Sludges and Irradiated Metallic Uranium Fuel Particles Series III Testing

Abstract

The path forward for managing Hanford K Basin sludge calls for it to be packaged, shipped, and stored at T Plant until final processing at a future date. An important consideration for the design and cost of retrieval, transportation, and storage systems is the potential for heat and gas generation through oxidation reactions between uranium metal and water. This report, the third in a series (Series III), describes work performed at the Pacific Northwest National Laboratory (PNNL) to assess corrosion and gas generation from irradiated metallic uranium particles (fuel particles) with and without sludge addition. The first test series (Series I; Delegard et al. 2000) focused on gas generation from K East (KE) Basin floor and canister sludge (size-fractionated and unfractionated samples collected using a consolidated sampling technique (Baker et al. 2000). The second series (Series II; Bryan et al. 2001) examined the gas generation behavior of KE Basin floor, pit, and canister sludge. Mixed and unmixed and fractionated KE canister sludge materials were tested, along with floor and pit sludge from areas in the KE Basin not previously sampled. The sludge material used in all three test series was saturated with water, consistent with sludge management plans. The work for all three test series was conducted under the direction of the Spent Nuclear Fuel (SNF) Sludge Handling Project managed by Fluor Hanford, and in accordance with the corresponding data quality objectives (Makenas 2000) and the sampling and analysis plan (Baker et al. 2000). The overall goal for the Series III testing was to evaluate the behavior and reactivity of the fuel particles, with and without K Basin sludge, under known conditions, through the evaluation of gas generation rate and composition data. Specific objectives for Series III included: The test matrix shown below displays the mass and size distribution of the fuel particles (and any associated cladding), the type and quantity of the added K Basin sludge, the test vessel size, test temperatures, and total test duration. The last column lists the fraction of the sample that was corroded at

Characterization of Compaction and Dryout Properties of KE Basin Sludge During Long-Term Storage

“…A mottled appearance for this sample, which may have been the same voids, also was noted after the vortex agitation testing (see Table 3.2). The self-agglomeration of 96-13, although more pronounced, was similar to the physical form of fuel pieces and fuel piece plus KE Basin sludge at the conclusion of gas generation testing conducted at 40°C to 95°C (Schmidt et al 2003). During recovery of sludge from reactor vessels at the conclusion of the tests, hard pan and sludge cake were encountered that required moderate effort to break up and mobilize.…”

“…The presence of residual unreacted uranium metal in the SNF Comp sample at the start of the testing was evaluated. The original SNF Comp materials came from two prior gas generation tests (SNF + Floor 60L and SNF + Can 60L; Schmidt et al 2003). These two tests originally contained 51.88 g of 0-to 6350-µm-diameter crushed irradiated fuel particles.…”

“…The quantities of hydrogen (arising from the reaction of uranium metal Delegard et al (2000) for the separate KC-2/3 P250 and M250 (plus and minus 250-µm particle size) fraction analyses and the weight fraction of solids reporting to the two fractions (28% and 72%, respectively; Bredt et al 1999). (c) SNF Comp came from residues of gas generation tests "SNF + Can 60L" and "SNF + Floor 60L" reported in Schmidt et al (2003). The "SNF + Can 60L" composite sludge was prepared from KC-1 (10.6 wt%), KC-2/3 M250 (69.8 wt%), and KC-2/3 P250 (19.6 wt%), settled sludge basis, and contained 66.98 g of sludge blend plus 26.36 g of crushed fuel particles.…”

“…The "SNF + Floor 60S" composite sludge was prepared from KC-4 (41.1 wt%) and KC-5 (58.9 wt%) settled sludge, and contained 98.87 g of sludge blend plus 25.52 g of crushed fuel particles. The SNF Comp composition is based on analyses presented in Poloski et al (2002) and Schmidt et al (2003) and these assumptions:…”

Segregation of Uranium Metal from K Basin Sludge: Results from Vendor Testing

“…It is likely that many of these larger particles are aluminum corrosion product 5.1 nodules, and a relatively simple, low-energy grinding process (e.g., ball mill) could be used to achieve the required size reduction. However, irradiated uranium metal fragments have been found to be remarkably tough in crushing and sieving tests (Schmidt et al 2003). A size reduction or prescreening step will not be necessary with the Gekko equipment.…”