ph: (865) 576-8401 fax: (865) 576-5728 email: reports@adonis.osti.gov Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161 ph: (800) 553-6847 fax: (703) 605-6900 email: orders@ntis.fedworld.gov online ordering: http://www.ntis.gov/ordering.htm AbstractBuoyant displacement gas release events (BDGRE) are spontaneous gas releases that occur in a few of the Hanford radioactive waste storage tanks when gas accumulation makes the sediment layer buoyant with respect to the liquid. BDGREs are assumed to be likely if the ratio of the predicted sediment gas fraction and neutral buoyancy gas fraction, or buoyancy ratio, exceeds unity. Based on the observation that the buoyancy ratio is also an empirical indicator of BDGRE size, a new methodology is derived that formally correlates the buoyancy ratio and the peak headspace hydrogen concentration resulting from BDGREs. The available data on the six historic BDGRE tanks, AN-103, AN-104, AN-105, AW-101, SY-103, and SY-101, are studied in detail to describe both the waste state and the corresponding distribution of BDGREs. The range of applicability of the buoyancy ratio-based models is assessed based on the modeling assumptions and availability of tank data. Recommendations are given for extending the range of the models' applicability.iv v

This study evaluated the feasibility of transferring waste stored in Hanford Tank 214-SY-101 (SY-101) in the 200 West Area to a storage tank in the 200 East Area through a 6.2-mile, 3-inchdiameter stainless steel pipeline. The Wasp slurry transport model was used for this assessment. We first conducted validation testing of the Wasp slurry pipe flow model, then applied the Wasp model to calculate the critical velocity and expected pressure drop to determine 1) whether current SY-101 waste can be transferred through the existing cross-site transfer pipeline without additional dilution with water or 2) how much dilution with water would be needed. This evaluation was subject to the following restrictions: Restriction 1: The slurry velocity must be greater than the critical velocity. Restriction 2: The slurry flow must be turbulent. Restriction 3: The pipeline pressure at the vent station must be less than 180 psi. Restriction 4: The pipeline pressure must not exceed 400 psi in any part of the pipeline. Restriction 5: The operating pressure of SY-101 transfer pump must not exceed 220 psi.

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The exact physical and chemical nature of 55 million gallons of radioactive toxic waste held in 177 underground waste tanks at the Hanford Site is not known with sufficient detail to support the safety, retrieval, and immobilization missions presented to Hanford. The purpose of this study is to estimate probability distributions for the inventory of each of 72 analytes in each of 177 tanks. This will enable uncertainty intervals to be calculated for inventories and should facilitate the safety, retrieval, and immobilization missions.The methodology presented in this paper is based on scientific principles, sound technical knowledge of the realities associated with the Hanford waste tanks, chemical analysis of samples from the tanks, historical data and other Hanford research. As a result of the processing histories, waste storage practices and historical records, some of the waste can be partitioned into more homogeneous subsets that can be identified to tanks and locations within tanks. Therefore, by using this we can maximize the information extracted from the relatively few samples we have for each tank, combining sample data information from similar tanks to generate a sample based estimate of the chemical and radionuclide concentrations of each of the many waste subsets. Then by multiplying the concentrations for a specific analyte (micrograms of the analyte per gram of waste, or microCuries of the analyte per gram of waste) by the density (grams per liter) by the volume in a tank (liters), we can get an estimate of the mass of a particular analyte (or radionuclide contribution) in each tank. This methodology does this in a probabilistic framework; thus using and generating probability distributions instead of single point estimate numbers.

SummaryPacific Northwest National Laboratory researchers developed a material balance assessment methodology based on conservation of mass to detect possible waste leaking and mis-routings during the pipeline transfer of double-shell tank waste with variable waste properties and tank conditions at Hanford. It is intended to be a backup method to pit leak detectors.The main factors causing variable waste properties and tank conditions are waste density changes caused by chemical reactions and gas generation/retention/release, the existence of a crust layer, and waste surface disturbance due to mixer pump operation during the waste transfer. If waste properties and tank conditions were constant, this mass-based material balance methodology could be simplified to a volume-based material balance.The material balance assessment methodology was applied to three waste transfers: AN-105 first transfer of 911,400 gallons of in-line diluted supernatant liquid; AN-105 second transfer with 673,000 gallons of liquid waste; and AZ-102 slurry transfer of 150,000 gallons. Three instrumentation setups were considered: (A) feed and receiver tank levels and diluent flow meter; (B) flow meter at the beginning of the transfer pipeline and receiver tank level; and (C) diluent, feed, and receiver tank levels.