Solids Accumulation Scouting Studies

The objective of Solids Accumulation activities was to perform scaled testing to understand the behavior of remaining solids in a Double Shell Tank (DST), specifically AW-105, at Hanford during multiple fill, mix, and transfer operations. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles containing plutonium could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste staging tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids: Gibbsite, Zirconia, Sand, and Stainless Steel, with stainless steel particles representing the heavier particles, e.g., plutonium, and supernatant were charged to the test tank and rotating liquid jets were used to mix most of the solids while the simulant was pumped out. Subsequently, the volume and shape of the mounds of residual solids and the spatial concentration profiles for the surrogate for heavier particles were measured. Several techniques were developed and equipment designed to accomplish the measurements needed and they included: 1. Magnetic particle separator to remove simulant stainless steel solids. A device was designed and built to capture these solids, which represent the heavier solids during a waste transfer from a staging tank. 2. Photographic equipment to determine the volume of the solids mounds. The mounds were photographed as they were exposed at different tank waste levels to develop a composite of topographical areas. 3. Laser rangefinders to determine the volume of the solids mounds. The mounds were scanned after tank supernatant was removed. 4. Core sampler to determine the stainless steel solids distribution within the solids mounds. This sampler was designed and built to remove small sections of the mounds to evaluate concentrations of the stainless steel solids at different special locations. 5. Computer driven positioner that placed the laser rangefinders and the core sampler in appropriate locations over solids mounds that accumulated on the bottom of a scaled staging tank where mixing is poor. These devices and techniques were effective to estimate the movement, location, and concentrations of the solids representing heavier particles and could perform well at a larger scale The experiment contained two campaigns with each comprised of ten cycles to fill and empty the scaled staging tank. The tank was filled without mixing, but emptied, while mixing, in seven batches; the first six were of equal volumes of 13.1 gallons each to represent the planned fullscale batches of 145,000 gallons, and the last, partial, batch of 6.9 gallons represented a full-scale partial batch of 76,000 gallons that will leave a 72-inch heel in the staging tank for the next cycle. The sole difference between the two campaigns was the energy to mix the scaled staging tank, i.e., the nozzle velocity and jet rotational speed of the two jet pumps. Campaign 1 used 22.9 ft/s, at 1.54 rpm based on past testing and Campaign 2 used 23.9 ft/s at 1.75 rpm, based on visual observation of minimum velocity that allowed fast settling solids, i.e., sand and stainless steel, to accumulate on the scaled tank bottom

Mass Transfer And Hydraulic Testing Of The V-05 And V-10 Contactors With The Next Generation Solvent

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent. To support this integration of NGS into the MCU facilities, Savannah River Remediation (SRR) requested that Savannah River National Laboratory (SRNL) perform testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing differs from prior testing by utilizing a blend of BOBCalixC6 based solvent and the NGS with the full (0.05 M) concentration of the MaxCalix as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. Stage efficiency and mass distribution ratios were determined by measuring Cs concentration in the aqueous and organic phases during single contactor testing. The nominal cesium distribution ratio, D(Cs) measured for extraction ranged from 37-60. The data showed greater than 96% stage efficiency for extraction. No significant differences were noted for operations at 4, 8 or 12 gpm aqueous salt simulant feed flow rates. The first scrub test (contact with weak caustic solution) yielded average scrub D(Cs) values of 3.3 to 5.2 and the second scrub test produced an average value of 1.8 to 2.3. For stripping behavior, the “first stage” D Cs) values ranged from 0.04 to 0.08. The efficiency of the low flow (0.27 gpm aqueous) was calculated to be 82.7%. The Spreadsheet Algorithm for Stagewise Solvent Extraction (SASSE) predicted equivalent DF for MCU from this testing is greater than 3,500 assuming 95% efficiency during extraction and 80% efficiency during scrub and strip. Hydraulically, the system performed very well in all tests. Target flows were easily obtained and stable throughout testing. Though some issues were encountered with plugging in the coalescer, they were not related to the solvent. No hydraulic upsets due to the solvent were experienced during any of the tests conducted. The first extraction coalescer element used in testing developed high pressure drop that made it difficult to maintain the target flow rates. Analysis showed an accumulation of sodium aluminosilicate solids. The coalescer was replaced with one from the same manufacturer’s lot and pressure drop was no longer an issue. Concentrations of Isopar™ L and Modifier were measured using semi-volatile organic analysis (SVOA) and high performance liquid chromatography (HPLC) to determine the amount of solvent carryover. For low-flow (0.27 gpm aqueous) conditions in stripping, SVOA measured the Isopar™ L post-contactor concentration to be 25 mg/L, HPLC measured 39 mg/L of Modifier. For moderate-flow (0.54 gpm aqueous) conditions, SVOA measured the Isopar™ L postcontactor to be ~69 mg/L, while the HPLC measured 56 mg/L for Modifier. For high-flow (0.8 gpm aqueous) conditions, SVOA measured the Isopar™ L post-contactor to be 39 mg/L. The post-coalescer (pre-decanter) measurements by SVOA for Isopar™ L were all less than the analysis detection limit of 10 mg/L. The HPLC measured 18, 22 and 20 mg/L Modifier for the low, medium, and high-low rates respectively. In extraction, the quantity of pre-coalescer Isopar™ L carryover measured by SVOA was ~280-410 mg/L at low flow (4 gpm aqueous), ~400-450 mg/L at moderate flow (8 gpm aqueous), and ~480 mg/L at high flow (12 gpm aqueous). The amount of post coalescer (pre-decanter) Isopar™ L carryover measured by SVOA was less than 45 mg/L for all flow rates. HPLC results for Modifier were 182, 217 and 222 mg/L for the post-contactor low, medium and high flow rates. The post-coalescer (pre-decanter) samples were measured to contain 12, 10 and 22 mg/L Modifier for the low, medium, and high flow rates. The carryover results and droplet size measurements were used to determine the decanter performance utilizing the decanter model developed by the ARES Corporation. Results show for the targeted salt flow rate of approximately 8 gpm, that over 93% of the solvent carryover from stripping is predicted to be recovered and over 96% solvent carryover from extraction is predicted to be recovered. This translates to a predicted solvent carryover of <3 ppm from stripping and <20 ppm solvent carryover from extraction. This projected performance at MCU is expected to be well within the operating limits and the historical performance for the baseline BOBCalixC6 based solvent. Droplet-size data obtained by MicroTrac™ S3400 analyzer consistently shows that the droplet size post-oalescer is significantly greater than the post-contactor or pre-coalescer samples. Increased flow rates did not show a consistent impact to the droplet size results. For the extraction testing, droplet size analysis showed that the post-contactor and pre-coalescer samples were essentially the same. The mean droplet sizes post-coalescer were less than the mean droplet sizes pre-coalescer with a very slight upward trend in the mean droplet size as the flow rate was increased. This result is probably due to the method of sampling. The larger post-coalescer drops immediately rise to the surface after leaving the coalescer element. The downstream sampling point was horizontally in-line with the element and therefore would only capture those organic droplets well mixed in the flowing aqueous stream

HIGH ASPECT RATIO ION EXCHANGE RESIN BED - HYDRAULIC RESULTS FOR SPERICAL RESIN BEADS

A principal role of the DOE Savannah River Site is to safely dispose of a large volume of liquid nuclear waste held in many storage tanks. An in-tank ion exchange unit is being considered for cesium removal to accelerate waste processing. This unit is planned to have a relatively high bed height to diameter ratio (10:1). Complicating the design is the need to cool the ion exchange media; therefore, the ion exchange column will have a central cooling core making the flow path annular. To separate cesium from waste the media being considered is made of resorcinol formaldehyde resin deposited on spherical plastic beads and is a substitute for a previously tested resin made of crystalline silicotitanate. This spherical media not only has an advantage of being mechanically robust, but, unlike its predecessor, it is also reusable, that is, loaded cesium can be removed through elution and regeneration. Resin regeneration leads to more efficient operation and less spent resin waste, but its hydraulic performance in the planned ion exchange column was unknown. Moreover, the recycling process of this spherical resorcinol formaldehyde causes its volume to significantly shrink and swell. To determine the spherical media's hydraulic demand a linearly scaled column was designed and tested. The waste simulant used was prototypic of the wastes' viscosity and density. This paper discusses the hydraulic performance of the media that will be used to assist in the design of a full-scale unit

Morbilliviruses in aquatic mammals: report on round table discussion.

A workshop was organised to ascertain the current situation with regard to morbillivirus infections in aquatic animals. The great interest generated by the discovery of these new virus infections in 1988 has to some extent abated but much high quality research has continued in this field as the workshop showed. There is some serological evidence that the viruses have continued to circulate in most areas since the initial epizootics. As to their origin, it appears that the most likely source of the European seal morbillivirus (PDV-1) is the North Atlantic and Artic seal populations. As to the origin of the Mediterranean dolphin morbillivirus and the morbilliviruses isolated from porpoises, there is serological evidence that the viruses are widespread in many cetacean species in the Atlantic and 93% of long-finned pilot whales (Globicephala melas) which mass stranded between 1982 and 1993 were morbillivirus seropositive. The epizootic in freshwater seals in Lake Baikal was unrelated to events in the European marine mammal populations. The virus which infected these animals (PDV-2) is indistinguishable from canine distemper field strains. Serological and molecular biological studies provided evidence for the presence of the virus in the seals, at least as late as the Summer of 1992 when the animals were last sampled

Solids Accumulation Scouting Studies

The objective of Solids Accumulation activities was to perform scaled testing to understand the behavior of remaining solids in a Double Shell Tank (DST), specifically AW-105, at Hanford during multiple fill, mix, and transfer operations. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles containing plutonium could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste staging tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids: Gibbsite, Zirconia, Sand, and Stainless Steel, with stainless steel particles representing the heavier particles, e.g., plutonium, and supernatant were charged to the test tank and rotating liquid jets were used to mix most of the solids while the simulant was pumped out. Subsequently, the volume and shape of the mounds of residual solids and the spatial concentration profiles for the surrogate for heavier particles were measured. Several techniques were developed and equipment designed to accomplish the measurements needed and they included: 1. Magnetic particle separator to remove simulant stainless steel solids. A device was designed and built to capture these solids, which represent the heavier solids during a waste transfer from a staging tank. 2. Photographic equipment to determine the volume of the solids mounds. The mounds were photographed as they were exposed at different tank waste levels to develop a composite of topographical areas. 3. Laser rangefinders to determine the volume of the solids mounds. The mounds were scanned after tank supernatant was removed. 4. Core sampler to determine the stainless steel solids distribution within the solids mounds. This sampler was designed and built to remove small sections of the mounds to evaluate concentrations of the stainless steel solids at different special locations. 5. Computer driven positioner that placed the laser rangefinders and the core sampler in appropriate locations over solids mounds that accumulated on the bottom of a scaled staging tank where mixing is poor. These devices and techniques were effective to estimate the movement, location, and concentrations of the solids representing heavier particles and could perform well at a larger scale The experiment contained two campaigns with each comprised of ten cycles to fill and empty the scaled staging tank. The tank was filled without mixing, but emptied, while mixing, in seven batches; the first six were of equal volumes of 13.1 gallons each to represent the planned fullscale batches of 145,000 gallons, and the last, partial, batch of 6.9 gallons represented a full-scale partial batch of 76,000 gallons that will leave a 72-inch heel in the staging tank for the next cycle. The sole difference between the two campaigns was the energy to mix the scaled staging tank, i.e., the nozzle velocity and jet rotational speed of the two jet pumps. Campaign 1 used 22.9 ft/s, at 1.54 rpm based on past testing and Campaign 2 used 23.9 ft/s at 1.75 rpm, based on visual observation of minimum velocity that allowed fast settling solids, i.e., sand and stainless steel, to accumulate on the scaled tank bottom

The effect of surface gas injection on film boiling heat transfer

A database was developed for heat transfer from a horizontal plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. At the highest superficial gas velocity measured, approximately 8.5 cm/s, and for a constant surface temperature, the heat transfer increases by a factor of two over the heat transfer with no enhancement by gas flux. Further, as the superficial gas velocity approached zero, the data approach the stable film boiling asymptote. A semi-empirical model was developed and correlated to the database. The result is an equation which represents better than 90% of all the measured data within {plus_minus}15% bounds

Judging the impact of leadership-development activities on school practice

The nature and effectiveness of professional-development activities should be judged in a way that takes account of both the achievement of intended outcomes and the unintended consequences that may result. Our research project set out to create a robust approach that school staff members could use to assess the impact of professional-development programs on leadership and management practice without being constrained in this judgment by the stated aims of the program. In the process, we identified a number of factors and requirements relevant to a wider audience than that concerned with the development of leadership and management in England. Such an assessment has to rest upon a clear understanding of educational leadership,a clearly articulated model of practice, and a clear model of potential forms of impact. Such foundations, suitably adapted to the subject being addressed, are appropriate for assessing all teacher professional development

Single Stage Contactor Testing Of The Next Generation Solvent Blend

The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%

Emerging and recurring diseases in cetaceans worldwide and the role of environmental stressors. Scientific Committee Document SC/60/DW5, International Whaling Commission, June 2008, Santiago, Chile

Emerging and recurring infectious diseases known or suspected to have the potential to significantly impact cetacean populations, and possible synergistic effects of environmental factors are reviewed. Cetacean morbilliviruses and papillomaviruses and brucellosis may affect population densities through high mortality rates or interference with reproduction. Evidence is available for the role of environmental factors in the emergence/recurrence and severity of at least six infectious conditions i.e. lobomycosis, toxoplasmosis, tattoo skin disease, generalized bacterial infections, miscellaneous skin diseases and morbillivirus epizootics. Other micro-parasites of potential importance include rhabdo-, herpes- and parainfluenza-viruses as well as Helicobacter spp., Streptococcus spp., Salmonella spp. and Mycobacterium marinum. The population impact and aetiology of newly emerging skin diseases in South America are unknown and represent a cause of concern

Cetacean <i>Morbillivirus</i>: Current knowledge and future directions

We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USA and Australia. It represents a distinct species within the Morbillivirus genus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemically infected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported