2012 Annual Report: Simulate and Evaluate the Cesium Transport and Accumulation in Fukushima-Area Rivers by the TODAM Code

Pacific Northwest National Laboratory initiated the application of the time-varying, one-dimensional sediment-contaminant transport code, TODAM (Time-dependent, One-dimensional, Degradation, And Migration) to simulate the cesium migration and accumulation in the Ukedo River in Fukushima. This report describes the preliminary TODAM simulation results of the Ukedo River model from the location below the Ougaki Dam to the river mouth at the Pacific Ocean. The major findings of the 100-hour TODAM simulation of the preliminary Ukedo River modeling are summarized as follows

Evaluation of Shear Strength Threshold of Concern for Retrieval of Interim-Stored K-Basin Sludge in the Hanford Site

K-Basin sludge will be recovered into the Sludge Transport and Storage Containers (STSCs) and will be stored in the T Plant for interim storage (at least 10 years). Long-term sludge storage tests conducted by Pacific Northwest National Laboratory show that high uranium content K Basin sludge can self-cement and form a strong sludge with a bulk shear strength of up to 65 kPa. Some of this sludge has "paste" and "chunks" with shear strengths of approximately 3~5 kPa and 380 ~ 770 kPa, respectively. High uranium content sludge samples subjected to hydrothermal testing (e.g., 185°C, 10 h) have been observed to form agglomerates with a shear strength up to 170 kPa. After interim storage at T Plant, the sludge in the STSCs will be mobilized by water jets impinging the sludge. The objective of the evaluation was to determine the range of sludge shear strength for which there is high confidence that a water-jet retrieval system can mobilize stored K-Basin sludge from STSCs. The shear strength at which the sludge can be retrieved is defined as the "shear strength threshold of concern." If the sludge shear strength is greater than the value of the shear strength threshold of concern, a water-jet retrieval system will be unlikely to mobilize the sludge up to the container’s walls. The shear strength threshold of concern can be compared with the range of possible shear strengths of K-Basin stored sludge to determine if the current post interim-storage, water-jet retrieval method is adequate. Fourteen effective cleaning radius (ECR) models were reviewed, and their validity was examined by applying them to Hanford 241-SY-101 and 241-AZ-101 Tanks to reproduce the measured ECR produced by the mixer pumps. The validation test identified that the Powell-3 and Crowe-2 ECR models are more accurate than other ECR models reviewed. These ECR models were used to address a question as to whether the effective cleaning radius of a water jet is sufficient or if it can be readily expanded to cover the range of possible shear strengths. These results will assist CH2M HILL Plateau Remediation Company (CHPRC) to establish the technical basis of the feasibility of the sludge retrieval and storage plan and to develop an adequate water jet system to retrieve the stored K-Basin sludge in the STSCs. The STSCs are 2:1 elliptical-head vessels, 58 inches in diameter and 105 inches tall. Each STSC will contain 0.5 to 2.1 m3 of settled sludge with the specific loading dependent upon sludge type

Analysis of Percent On-Cell Reformation of Methane in SOFC Stacks: Thermal, Electrical and Stress Analysis

This report summarizes a parametric analysis performed to determine the effect of varying the percent on-cell reformation (OCR) of methane on the thermal and electrical performance for a generic, planar solid oxide fuel cell (SOFC) stack design. OCR of methane can be beneficial to an SOFC stack because the reaction (steam-methane reformation) is endothermic and can remove excess heat generated by the electrochemical reactions directly from the cell. The heat removed is proportional to the amount of methane reformed on the cell. Methane can be partially pre-reformed externally, then supplied to the stack, where rapid reaction kinetics on the anode ensures complete conversion. Thus, the thermal load varies with methane concentration entering the stack, as does the coupled scalar distributions, including the temperature and electrical current density. The endotherm due to the reformation reaction can cause a temperature depression on the anode near the fuel inlet, resulting in large thermal gradients. This effect depends on factors that include methane concentration, local temperature, and stack geometry

Sampling Point Compliance Tests for 325 Building at Set-Back Flow Conditions

The stack sampling system at the 325 Building (Radiochemical Processing Laboratory [RPL]) was constructed to comply with the American National Standards Institute’s (ANSI’s) Guide to Sampling Airborne Radioactive Materials in Nuclear Facilities (ANSI N13.1-1969). This standard provided prescriptive criteria for the location of radionuclide air-sampling systems. In 1999, the standard was revised (Sampling and Monitoring Releases of Airborne Radioactive Substances From the Stacks and Ducts of Nuclear Facilities [ANSI/Health Physics Society [HPS] 13.1-1999]) to provide performance-based criteria for the location of sampling systems. Testing was conducted for the 325 Building stack to determine whether the sampling system would meet the updated criteria for uniform air velocity and contaminant concentration in the revised ANSI/HPS 13.1-1999 standard under normal operating conditions (Smith et al. 2010). Measurement results were within criteria for all tests. Additional testing and modeling was performed to determine whether the sampling system would meet criteria under set-back flow conditions. This included measurements taken from a scale model with one-third of the exhaust flow and computer modeling of the system with two-thirds of the exhaust flow. This report documents the results of the set-back flow condition measurements and modeling. Tests performed included flow angularity, uniformity of velocity, gas concentration, and particle concentration across the duct at the sampling location. Results are within ANSI/HPS 13.1-1999 criteria for all tests. These tests are applicable for the 325 Building stack under set-back exhaust flow operating conditions (980 - 45,400 cubic feet per minute [cfm]) with one fan running. The modeling results show that criteria are met for all tests using a two-fan configuration exhaust (flow modeled at 104,000 cfm). Combined with the results from the earlier normal operating conditions, the ANSI/HPS 13.1-1999 criteria for all tests are met for all configurations: one, two, or three fans (normal)

Bulk Vitrification Performance Enhancement: Refractory Lining Protection Against Molten Salt Penetration

Bulk vitrification (BV) is a process that heats a feed material that consists of glass-forming solids and dried low-activity waste (LAW) in a disposable refractory-lined metal box using electrical power supplied through carbon electrodes. The feed is heated to the point that the LAW decomposes and combines with the solids to generate a vitreous waste form. This study supports the BV design and operations by exploring various methods aimed at reducing the quantities of soluble Tc in the castable refractory block portion of the refractory lining, which limits the effectiveness of the final waste form

Pulse Jet Mixer Overblow Testing for Assessment of Loadings During Multiple Overblows

The U.S. Department of Energy (DOE) Office of River Protection’s Waste Treatment Plant (WTP) is being designed and built to pretreat and then vitrify a large portion of the wastes in Hanford’s 177 underground waste storage tanks. The WTP consists of three primary facilities: pretreatment, low-activity waste (LAW) vitrification, and high-level waste (HLW) vitrification. The pretreatment facility will receive waste feed from the Hanford tank farms and separate it into 1) a high-volume, low-activity liquid stream stripped of most solids and radionuclides and 2) a much smaller volume of HLW slurry containing most of the solids and most of the radioactivity. Many of the vessels in the pretreatment facility will contain pulse jet mixers (PJMs) that will provide some or all of the mixing in the vessels. This technology was selected for use in so-called “black cell” regions of the WTP, where maintenance capability will not be available for the operating life of the WTP. PJM technology was selected for use in these regions because it has no moving mechanical parts that require maintenance. The vessels with the most concentrated slurries will also be mixed with air spargers and/or steady jets in addition to the mixing provided by the PJMs. This report contains the results of single and multiple PJM overblow tests conducted in a large, ~13 ft-diameter × 15-ft-tall tank located in the high bay of the Pacific Northwest National Laboratory (PNNL) 336 Building test facility. These single and multiple PJM overblow tests were conducted using water and a clay simulant to bound the lower and upper rheological properties of the waste streams anticipated to be processed in the WTP. Hydrodynamic pressures were measured at a number of locations in the test vessel using an array of nine pressure sensors and four hydrophones. These measurements were made under normal and limiting vessel operating conditions (i.e., maximum PJM fluid emptying velocity, maximum and minimum vessel contents for PJM operation, and maximum and minimum rheological properties). Test data collected from the PJM overblow tests were provided to Bechtel National, Inc. (BNI) for assessing hydrostatic, dynamic, and acoustic pressure loadings on in-tank structures during 1) single overblows; 2) multiple overlapping overblows of two to four PJMs; 3) simultaneous overblows of pairs of PJMs

Results of Large-Scale Testing on Effects of Anti-Foam Agent on Gas Retention and Release

The U.S. Department of Energy (DOE) Office of River Protection’s Waste Treatment Plant (WTP) will process and treat radioactive waste that is stored in tanks at the Hanford Site. The waste treatment process in the pretreatment facility will mix both Newtonian and non-Newtonian slurries in large process tanks. Process vessels mixing non-Newtonian slurries will use pulse jet mixers (PJMs), air sparging, and recirculation pumps. An anti-foam agent (AFA) will be added to the process streams to prevent surface foaming, but may also increase gas holdup and retention within the slurry. The work described in this report addresses gas retention and release in simulants with AFA through testing and analytical studies. Gas holdup and release tests were conducted in a 1/4-scale replica of the lag storage vessel operated in the Pacific Northwest National Laboratory (PNNL) Applied Process Engineering Laboratory using a kaolin/bentonite clay and AZ-101 HLW chemical simulant with non-Newtonian rheological properties representative of actual waste slurries. Additional tests were performed in a small-scale mixing vessel in the PNNL Physical Sciences Building using liquids and slurries representing major components of typical WTP waste streams. Analytical studies were directed at discovering how the effect of AFA might depend on gas composition and predicting the effect of AFA on gas retention and release in the full-scale plant, including the effects of mass transfer to the sparge air. The work at PNNL was part of a larger program that included tests conducted at Savannah River National Laboratory (SRNL) that is being reported separately. SRNL conducted gas holdup tests in a small-scale mixing vessel using the AZ-101 high-level waste (HLW) chemical simulant to investigate the effects of different AFAs, their components, and of adding noble metals. Full-scale, single-sparger mass transfer tests were also conducted at SRNL in water and AZ-101 HLW simulant to provide data for PNNL’s WTP gas retention and release modeling

Pretreatment Engineering Platform Phase 1 Final Test Report

Pacific Northwest National Laboratory (PNNL) was tasked by Bechtel National Inc. (BNI) on the River Protection Project, Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to conduct testing to demonstrate the performance of the WTP Pretreatment Facility (PTF) leaching and ultrafiltration processes at an engineering-scale. In addition to the demonstration, the testing was to address specific technical issues identified in Issue Response Plan for Implementation of External Flowsheet Review Team (EFRT) Recommendations - M12, Undemonstrated Leaching Processes.( ) Testing was conducted in a 1/4.5-scale mock-up of the PTF ultrafiltration system, the Pretreatment Engineering Platform (PEP). Parallel laboratory testing was conducted in various PNNL laboratories to allow direct comparison of process performance at an engineering-scale and a laboratory-scale. This report presents and discusses the results of those tests

2012 Annual Report: Simulate and Evaluate the Cesium Transport and Accumulation in Fukushima-Area Rivers by the TODAM Code

Pacific Northwest National Laboratory initiated the application of the time-varying, one-dimensional sediment-contaminant transport code, TODAM (Time-dependent, One-dimensional, Degradation, And Migration) to simulate the cesium migration and accumulation in the Ukedo River in Fukushima. This report describes the preliminary TODAM simulation results of the Ukedo River model from the location below the Ougaki Dam to the river mouth at the Pacific Ocean. The major findings of the 100-hour TODAM simulation of the preliminary Ukedo River modeling are summarized as follows

Evaluation of Shear Strength Threshold of Concern for Retrieval of Interim-Stored K-Basin Sludge in the Hanford Site

K-Basin sludge will be recovered into the Sludge Transport and Storage Containers (STSCs) and will be stored in the T Plant for interim storage (at least 10 years). Long-term sludge storage tests conducted by Pacific Northwest National Laboratory show that high uranium content K Basin sludge can self-cement and form a strong sludge with a bulk shear strength of up to 65 kPa. Some of this sludge has "paste" and "chunks" with shear strengths of approximately 3~5 kPa and 380 ~ 770 kPa, respectively. High uranium content sludge samples subjected to hydrothermal testing (e.g., 185°C, 10 h) have been observed to form agglomerates with a shear strength up to 170 kPa. After interim storage at T Plant, the sludge in the STSCs will be mobilized by water jets impinging the sludge. The objective of the evaluation was to determine the range of sludge shear strength for which there is high confidence that a water-jet retrieval system can mobilize stored K-Basin sludge from STSCs. The shear strength at which the sludge can be retrieved is defined as the "shear strength threshold of concern." If the sludge shear strength is greater than the value of the shear strength threshold of concern, a water-jet retrieval system will be unlikely to mobilize the sludge up to the container’s walls. The shear strength threshold of concern can be compared with the range of possible shear strengths of K-Basin stored sludge to determine if the current post interim-storage, water-jet retrieval method is adequate. Fourteen effective cleaning radius (ECR) models were reviewed, and their validity was examined by applying them to Hanford 241-SY-101 and 241-AZ-101 Tanks to reproduce the measured ECR produced by the mixer pumps. The validation test identified that the Powell-3 and Crowe-2 ECR models are more accurate than other ECR models reviewed. These ECR models were used to address a question as to whether the effective cleaning radius of a water jet is sufficient or if it can be readily expanded to cover the range of possible shear strengths. These results will assist CH2M HILL Plateau Remediation Company (CHPRC) to establish the technical basis of the feasibility of the sludge retrieval and storage plan and to develop an adequate water jet system to retrieve the stored K-Basin sludge in the STSCs. The STSCs are 2:1 elliptical-head vessels, 58 inches in diameter and 105 inches tall. Each STSC will contain 0.5 to 2.1 m3 of settled sludge with the specific loading dependent upon sludge type