Hanford Defined Wastes model
- Los Alamos National Lab., NM (United States)
This paper describes the methodology behind the Hanford Defined Wastes (HDW) model for estimating the contents of Hanford high level waste (HLW) tanks. The HDW model is based on historical process and transaction histories for each tank and has four major components: Waste Status and Transaction Record Summary (WSTRS), Tank Layer Model (TLM), Supernatant Mixing Model (SMM), and HDW Compositions. Three examples of the application of HDW model estimates are described, including comparisons with global site inventories, comparisons with per tank assays, and comparisons of HDW TOC (Total Organic Carbon) estimates with existing hydrogen watch list tanks. The HDW model provides a cross check on existing assumptions for the global site inventory of wastes. Note that existing inventories for Hanford are based on much the same source information as the HDW model, chemicals used and process flowsheet data. Despite that, the HDW model predicts that the sodium inventory for Hanford tanks is 40,300 MT (metric tonnes), which is only 58% of the previous baseline estimate of 69,000 MT. There are other significant differences for inventories of chromium, iron, and nitrate as well. There are two causes for these differences; (1) previous neglect of chemical inventory placed into the ground at Hanford; (2) double counting attributed to tank inventory that was retrieved, reprocessed, and returned to the tanks. This double-counted inventory was counted once when it first went into the tanks and then again after it was reprocessed. The HDW model estimates also can provide a basis for targeting tanks for organic safety issues. In particular, the HDW model has shown that 88% of flammable gas watch list tanks have HDW estimated organic concentrations in excess of 0.64 wt% TOC. Derivation of variabilities for the HDW model estimates and other potential uses will also be outlined.
- OSTI ID:
- 469813
- Report Number(s):
- CONF-960804--Vol.1
- Country of Publication:
- United States
- Language:
- English
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