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At least 1,297 records · Page 72
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DOE OSTI2016

Corrosion Kinetics of Stainless Steel by Hydrogen Measurement under Deep Geological Repository Condition - 16047

Spent fuel assemblies consisting of stainless steels are expected to be disposed of in a deep underground repository. The radionuclides release and gas generation from activated metallic wastes in a disposal system will be controlled by the corrosion reaction. Most studies on stainless steel corrosion have been investigated under corrosion rates around several μm.a{sup -1}. A recent study has revealed that the corrosion rate of stainless steel is extremely slow-less than nm.a{sup -1} at 303 K. In the present study, corrosion kinetics at different temperatures up to 353 K were evaluated from the oxidation reaction by hydrogen gas measurement using 18Cr-8Ni austenitic stainless steel in a deoxygenated glass ampoule filled with a dilute NaOH solution of pH 12.5 for 24 months. Uniform corrosion and a reaction of 3Fe + 4H{sub 2}O → Fe{sub 3}O{sub 4} + 4H{sub 2} were assumed. After 24 months, the corrosion rates, which decreased with time but increased with rising temperature, were on average 7.80 x 10{sup -4}, 2.65 x 10{sup -3}, and 7.62 x 10{sup -3} μm.a{sup -1} at 303 K, 323 K, and 353 K, respectively. The corrosion kinetics were found to follow a parabolic rate law, which suggests the corrosion process is under diffusion control. The activation energy evaluated by the Arrhenius relationship of the parabolic rate constants has been determined to be 82.5 ± 6.2 kJ/mol, which corresponds to the values at high temperatures down to 423 K. (authors)

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DOE OSTI2016

Remote-Handled TRU Storage Challenges at Sandia National Laboratories/ New Mexico - 16071

The events at the Waste Isolation Pilot Plant (WIPP) in February 2014 had a significant impact on the packaging, storage, and disposal options at Sandia National Laboratories/New Mexico (Sandia) as with other transuranic generator sites. In 2012, Sandia had identified accountable material for disposal, fresh and irradiated mixed oxide (MOX) and uranium oxide (UO{sub 2}), which had been used in experiments conducted in the 1970's and 1980's. During the 2012/2013 timeframe, discussions with WIPP determined the samples and experimental vessels qualified as remote-handled (RH) transuranic (TRU) waste for disposal at WIPP. Sandia began discussions with WIPP to determine the process to repackage and characterize the material for disposal at WIPP in addition to obtain funding to complete the project. By January 2014, Sandia had contracted with Nuclear Waste Partnerships, LLC (NWP) to provide Central Characterization Program (CCP) certified visual examination (VE) and dose-to-curie (DTC) support to package and certify the accountable material/waste. Work began on February 3, 2014 with the arrival of two VE operators. On February 5, 2014, a salt truck caught fire in the underground and on February 14, 2014, the radiological release occurred at WIPP initiating a suspension of shipments. The length of the suspension was not known at the time. Sandia was only a couple of days into this long-term project, had signed a contract with NWP for support, and was still responsible for meeting earlier negotiated milestones. There were 37 parent containers which included experimental vessels from 3 to 10 feet long and unused material pieces. The original plan was to package each of the 37 parent containers separately, but several issues, including the suspension of shipments, made it imperative that a new path forward be developed. Because space is limited in the Auxiliary Hot Cell Facility (AHCF), the storage configuration for criticality safety and material-at-risk was of the highest importance. Therefore, packaging in the fewest number of containers without exceeding WIPP limits, keeping the accountable items together, and not violating any safety basis requirements was Sandia's goal. (authors)

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DOE OSTI2016

Remote Dismantling and Packaging of the RPV and Thermal Shield at the Obrigheim NPP - 16073

The Obrigheim Nuclear Power Plant (KWO) is located in the Federal State of Baden- Wuerttemberg in Germany and was operated by the EnKK-KWO. The Nuclear Power Plant - a light water pressurized water reactor with 357 MW of electrical power - was operated from 1968 to 2005. In June 2009 the Energiewerke Nord GmbH (EWN) was charged with the dismantling planning and dismantling of the reactor. According to the German nuclear and radiation protection law, several licenses will be required for the realisation of this task. This also applies to the disposal of the waste produced by dismantling, which must finally be stored in the German final repository for low and medium-radioactive waste (underground repository 'Konrad'). In spring 2010 EWN completed all application documents for the dismantling of the reactor pressure vessel (RPV) and the RPV internals and EnKK-KWO delivered them to the responsible Environmental Ministry of Baden-Wuerttemberg. Since then it has been worked intensively on the design, construction and manufacturing of the facilities for dismantling. With a separate notification of amendment, it was applied for the license to install and commission the facilities for the dismantling of the RPV and the RPV internals at the Environmental Ministry of Baden-Wuerttemberg in October 2010. This notification of amendment was confirmed in summer 2012. In September 2011 the work process and test plan and the technical information about the campaign for the removal of the radioactive waste resulting from the RPV with internals, peripheral components and secondary waste with the aim of final disposal in the Federal Repository 'Konrad' was submitted to the Federal Office for Radiation Protection. The evaluation and assessment of the work process and test plan was concluded in August 2013, when it was audited by TUV Nord EnSys without any further measures and indications. On September 10 the work process and test plan was released by the Federal Office for radiation protection. The dismantling of the RPV internals upper core and lower core structure started in September 2013 in the wet cutting area in room 01.106/306 and were finished in October 2014. In the presentation 'Dismantling of the Obrigheim NPP Reactor and Waste Management' held on the WM Symposia in Phoenix, 2014, an overview about the remote cutting and packaging of the upper and lower core structure was given. In today's presentation the subsequent dismantling activities will be outlined and evaluated. The presentation will start with the short description of the basic frame conditions for the nuclear licensing procedure, important procedural principles, and necessary plant-specific conditions. After the remote cutting and packing of the reactor internals of the upper and lower core structure was completed, the wet cutting area 'reactor room 01.106/306' was cleaned and the reactor room rebuilt into a cutting area for peripheral components. After the peripheral components were dismantled, all preconditions were set to lift the RPV from its mounting position and to arrange it in the upper reactor room 01.306. After these activities were completed, the lifting of the RPV was prepared and the cutting area 'Dismantling of the RPV insulation in the reactor room 01.106/306' was set up. To carry out this task, a strand jack unit with connection block was installed on the bridge of the reactor building crane. The opening created by the dismantling of the pool plate was closed with a flap door. The manipulators used for the wet cutting of the RPV internals were also used for the remote dismantling of the RPV insulation and mounted in the cutting area. The remote facilities were handled from a control centre and/or control stand. The air-technical housing which has already been used for the remote dismantling of the RPV internals was designed for the dismantling of the RPV insulation and was extended for this dismantling scope with appropriate ventilation systems. A special feature is the fixation of the RPV insulation at the RPV corpus. The RPV insulation consists of insulation wool, wire mesh and metal-sheet insulation. This 'Sandwich Construction' is detached with a steel corset at the RPV corpus and partly tightened. The insulation of the RPV bottom dome is tightened at the supporting frame. Due to the activation of the material in the core area and the resulting high ambient dose rate the RPV insulation can only be dismantled remotely. Additionally, as asbestos fibers are expected to be found in the insulation the dismantling has to be performed according to the Technical Rules for hazardous substances. The demolition, restoration or maintenance works have to be performed remotely according to the Technical Rules for hazardous substances when the RPV is located in the cutting area. But in case of dismantling of a power reactor no such experience can be found. Beginning with the explanation of the technical, radiological and substantial boundary conditions this presentation will not only impart knowledge about the dismantling of the RPV insulation but also about the remote controlled packaging of the metal sheet insulation and the manual conditioning of the RPV insulation. Subsequently, reports on the remotely controlled cutting and packaging of the RDB are given. Here is particularly interesting that cutting methods have been used and how the activity determination of the segments was carried out. On the basis of the evaluation of the realisation the subsequent dismantling activities will be lined out. In parallel to the dismantling tasks, the waste package documentation for the final repository was issued, checked and confirmed for the containers loaded with parts of the RDB internals. The most important stages are exemplified in this presentation. (authors)

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DOE OSTI2016

The Recommendation of Public Engagement Commission on Spent Nuclear Fuel in Korea - 16074

The Public Engagement Commission on Spent Nuclear Fuel Management was lunched and embarked on public engagement activities with an aim of presenting recommendations on the method for managing spent fuel to the government by June 2015. Therefore, a national policy, strategy and management plan for spent fuel will be presented in detail in the Basic Plan for Radioactive Waste Management where the results of public engagement activities will be incorporated. In consideration of Korea's circumstances, permanent disposal facilities should be constructed and operated with the goal of 2051. For this reason, Underground research laboratory (URL) in the same area and on-site and site conditions of disposal facilities by selecting the site and construction process in 2020 should be started and the empirical study should be initiated in 2030. This study is expected to transfer experience of and lessons from determining national policy to countries that have not established their final management policy for spent fuel, based on Korea's solutions to shortage of spent fuel pools and the formation of national consensus. (authors)

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DOE OSTI2016

Directional Drilling Technology for HLW Disposal - Outline of System and its Application - 16078

During high-level waste (HLW) disposal site selection, borehole measurement and logging to investigate the hydro-geological and geo-mechanical conditions of the host rocks is a very important way to examine the potential of the disposal candidates. In Japan, attention is being given to Neogene soft sedimentary rock as the host rock for HLW disposal. In particular, the soft sedimentary rock in coastal areas is thought to be one of the best candidates, because there is little driving force from underground water. Directional drilling is supposed to be efficient under limited topographic and geological conditions, and the Central Research Institute of Electric Power Industry (CRIEPI) has been conducting a project on directional drilling and logging/measurement technologies since 2000. Basic directional drilling system was developed and the system was applied to the Neogene normal sedimentary rock at the Hokushin area of the Horonobe town in Hokkaido. The borehole was drilled to the 700 m long and the applicability of the system was confirmed until 2004. A basic directional drilling system was developed, and the system was applied to the Neogene normal sedimentary rock in the Hokushin area, in the town of Horonobe in Hokkaido. A 700-m borehole was drilled, and the applicability of the system was confirmed in 2004. After conducting a seismic reflection survey for the Omagari fault distribution at the Kami-Horonobe area in the town of Horonobe, a drilling site was selected, and a borehole trace was planned to perpendicularly intersect the fault zone in 2005. Considering the planned trace, a 1000-m-long borehole was drilled to a depth of 450 m. From 750 m to the bottom (1000 m), the borehole was horizontal. The total core recovery was 99.8%, even though it was drilled in the fault zone. The geological, hydrological, geo-mechanical, geophysical, and geochemical data were collected using borehole logging/measurement/survey and core logging/measurement/analysis, and the Omagari fault was characterized. After conducting all the work in the borehole, a steel pipe was inserted into the borehole to case the wall. Open hole sections for monitoring were constructed considering the hydro-geological conditions throughout the hole. Then, the monitoring system was inserted and set up to obtain the initial conditions of the groundwater pressure and chemistry. (authors)

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DOE OSTI2016

Simulating Regional Groundwater Flow in the Vicinity of the Nevada National Security Site, Nye County, Nevada - 16104

The Death Valley Regional Groundwater Flow System (DVRFS) occupies an area of about 70,000 km{sup 2} in south-central Nevada and southeastern California. Interest in this system stems from the need to (1) understand the groundwater flow paths and travel times associated with potential migration of radioactive material from the Nevada National Security Site (NNSS) where underground nuclear testing was conducted from 1956 to 1992; (2) characterize the groundwater system in the vicinity of the proposed high-level radioactive waste repository at Yucca Mountain, Nev.; and (3) address a variety of potential effects from NNSS activities on users down gradient from the NNSS and Yucca Mountain. A single groundwater flow model of the DVRFS has been developed that integrates data and results of two previous regional-scale models and supports Department of Energy (DOE) programs at the NNSS. The numerical model was constrained by organizing hydrogeologic data and interpretations in three-dimensional (3D) geographic information systems and constructing a digital three-dimensional (3D) hydrogeologic framework model (HFM) to represent 27 hydrogeologic units (HGUs) and major structures in the DVRFS region. The 3D hydrogeologic data sets were discretized to 1,500 meters (m) grid cell resolution for input arrays required for the model. The DVRFS was simulated using the USGS 3D groundwater-flow modeling code MODFLOW-2000. Two examples showing how the DVRFS regional model is used by the DOE as part of waste management activities at the NNSS: (1) use of the regional model to provide the boundary conditions for site-scale models, and (2) use of the regional model to assess changes in hydraulic gradient and flow paths in the regional flow system resulting from changes in pumping in various areas of interest. (authors)

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DOE OSTI2016

Migration Rates of Some Cations in Unsaturated Layer around the Near-Surface Disposal Facilities of Radioactive Wastes - 16116

In the porous layer around the near-surface underground, the intermittent recharge process of rainwater forms a layer perfectly not saturated with liquid phase. Here, such a layer is simply called 'unsaturated layer'. In this study, the retardation effects of radionuclide migration were examined under an unsaturated condition by using a column packed with silica sand particles. As tracer ions, sodium (Na), europium (Eu) and cesium (Cs) were selected for estimating the retardation effects under both the saturated and unsaturated condition. Particularly, Cs is one of the key elements included in the contaminated soil due to Fukushima Daiichi Nuclear Power Plant Accident. These tracer ions were injected into column with the condition of constant flow rate or constant pressure flow. To quantify the influence of the unsaturated condition on the migration of radionuclides, retardation coefficient (R{sub d}) and Peclet number (P{sub e}) were estimated by applying advection diffusion equation to the experimental results. As a result, the conflicting effects on the retardation effect in the unsaturated layer were suggested; one is the decrease in the retardation effect by interrupting the sorption of ions with gas phase, the other is the increase in the retardation effect by the clogging with gas phase in flow paths. For the assessment of the radionuclide migration in the unsaturated layer, it is important to clarify such complicated behaviors with considering key parameters related to the migration of ions. (authors)

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DOE OSTI2016

Brownfields to Brightfields: A Sustainability Initiative at DOE'S East Tennessee Technology Park Cleanup - 16120

As DOE works toward completing their cleanup mission at the East Tennessee Technology Park (ETTP), the ultimate goal is to return property no longer needed for government use to the community for beneficial re-use. The vision for ETTP is to transform the former gaseous diffusion facility into a commercial industrial park, leveraging the site's infrastructure to attract businesses to the site. While hundreds of acres at ETTP have been transferred for re-use, areas within the former production footprint of the site have future use restricted due to the presence of residual contamination, underground structures and utilities and/or physical features that limit their reuse potential. Brownfield redevelopment with solar energy generation has proven to be an excellent option for beneficial reuse and sustainability thanks to the flexible nature of solar photovoltaic technology and design that can address the restrictions and limitations of the site. Developing a solar project on a cleanup site can be challenging due to a large number of stakeholders and regulatory compliance issues of the environmental legacy at DOE cleanup sites; however, the challenges can be offset by the available infrastructure and low cost property. The requirement for large amounts of land or surface area is a major constraint to the growth of photovoltaic solar systems. An average solar generating facility requires 2 or more hectares (5 acres) for each megawatt (MW) of power generated. Re-using land that is otherwise un-developable provides a cost effective site for renewable energy generation to innovative solar developers. At ETTP, DOE's Oak Ridge Office of Environmental Management and the community reuse organization (Community Reuse Organization of East Tennessee - CROET) supported a local small business (Restoration Services, Inc. - RSI) familiar with the site and environmental regulations to secure a power purchase agreement with the regional electric provider (Tennessee Valley Authority - TVA) for a 1 MW utility-scale photovoltaic solar facility. The solar facility, Powerhouse Six, was developed through a commercial partnership (RSI and Vis Solis, Inc.) that worked closely with the lead ETTP site cleanup contractor (URS-CH2M Oak Ridge LLC - UCOR) and the local government. The selected site at ETTP had limitations on subsurface disturbance to 10 feet below ground surface because of utility ducts and residual contamination. Near surface relics (facility foundation remnants) were also found to prohibit ground penetration. A photovoltaic solar design using a ballasted ground mount system was developed to conform to the restrictions. The ballasted system could follow existing land contours, eliminating the need for any extensive site preparation and avoiding the risk of ground penetration. The lead cleanup contractor's role in facilitating the completion of this project included making the necessary environmental assessment documentation available to obtain the construction notice to proceed from the regional electric provider. They accelerated the transfer of ETTP power lines and electric demand to the city electric department to accommodate connection to the electric grid and supplied the communication connection required for metering the electric power generation. DOE's support along with their cleanup contractor's re-industrialization program and power integration group provided regular communication with the project stakeholders for more than six months to facilitate the early transfer of the utility infrastructure. Powerhouse Six sustainability benefits: - Generates enough clean energy to power more than 100 homes or prevents pollution equivalent to removing 240 cars from the road annually (1,141 metric tons of carbon dioxide); - Provides Brownfield reuse/redevelopment at ETTP; - Eliminates the generation of wastes through excavation and saves money to cleanup other areas for re-use; - Supports regional electric provider's renewable energy initiative; - Offers community economic development/ jobs and property tax income to the City of Oak Ridge; - Demonstrates benefit of ETTP re-industrialization; - Provides long-term lease payments to the community reuse organization; - Supports DOE renewable energy goals; - Demonstrates collaboration between DOE and a public utility for renewable energy development. (authors)

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DOE OSTI2016

Evaluation and Impacts of Mercury in the SRS Liquid Waste System - 16121

The Savannah River Site (SRS) Liquid Waste System (LWS) stores radioactive waste in 43 underground tanks. The radionuclides in the waste are removed through a series of separation processes and the low-level fraction is immobilized in a grout waste form while the high level fraction is disposed in a glass waste form. Mercury originated from decades of canyon processing (used as a catalyst for dissolving the aluminum cladding of reactor fuel) and is present throughout the LWS (∼60 metric tons). Mercury has long been a consideration in the LWS, from both hazard and processing perspectives. Mercury is removed from the LWS in many ways including: 1) the Tank Farm evaporator condensates; 2) at the Defense Waste Processing Facility (DWPF) where it is steam-stripped and removed during the feed preparation processes; 3) it is removed at the Effluent Treatment Plant (ETP); and it is immobilized in the low-level, grout waste form. An integrated, system-wide evaluation and assessment of mercury behavior in the LWS is being performed. The recently completed Phase I evaluation focused on mercury inventory and speciation in the LWS; mercury holdup and chemical processing behavior; mercury impact Identification, including worker safety and equipment degradation; and mercury removal and disposal options. The mercury removal system at the DWPF has been unable to remove mercury successfully due to equipment and chemistry challenges since the 2008 timeframe. Phase I evaluations indicate that approximately 43 percent of the mercury in waste sent to the DWPF is now returning to the Tank Farm in the recycle stream and is concentrating to higher than expected levels (∼500 mg/l) around the 2H evaporator system. The chemical behavior of mercury is further complicated by the formation of higher than expected quantities of organomercury species, specifically methyl mercury, now present in the DWPF recycle evaporator system (2H Tank farm evaporator), which is used to volume-reduce the recycle stream. Phase II activities are building on the Phase I mercury activities, including additional sampling and characterization activities, a re-assessment of overall system knowledge, ranking and prioritizing critical gaps/information in mercury behavior across the flowsheet, assessing impacts of mercury removal and disposal options, and documenting an action plan for overall mercury management in the LWS. Phase II activities include two System Engineering Evaluations to 1) 'Reestablish Mercury removal Capability within DWPF', and 2) 'Determine the Best Alternative Mercury Removal Location with the LWS'. This paper provides the results of the Phase I and II mercury evaluations for the SRS LWS. (authors)

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DOE OSTI2016

Remote Geophysical Logging at the Hanford Single-Shell Tank Farms: Maintaining Efficiency and Reducing Personnel Hazards - 16190

Vadose zone characterization around groups of underground waste storage tanks (known as tank farms) at the US DOE Hanford Site in Washington State is conducted to assess the presence and extent of manmade gamma-ray emitting radionuclides. Boreholes around the tanks are characterized using a high-resolution spectral gamma logging system (SGLS). In the past, logging operations required workers to remain inside the tank farm boundary during data acquisition. This approach was effective; however, personnel were at risk of exposure to potential radiological hazards, chemical hazards, and/or vapor releases that can be associated with the tank farm environment. Limitations associated with this work environment necessitated a new approach in order to decrease the amount of time personnel spent in the farm without affecting work productivity and efficiency. In order to accomplish this, a new remote logging cable support (RLCS) was developed and implemented which effectively removed workers from the hazards associated with the tank farm environment. (authors)

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DOE OSTI2016

WTP Modifications to Support DFLAW: LAW, BOF, Lab - 16219

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is a one-of-a-kind nuclear waste treatment facility being designed and constructed for the U.S. Department of Energy by Bechtel National, Inc. and principal subcontractor URS to process and vitrify radioactive waste stored in underground tanks at the Hanford Site. The Tank Operations Contractor, Washington River Protection Solutions, has responsibility to retrieve, stage, pretreat, and deliver the tank waste feed to WTP. To treat tank waste as soon as practicable, a scenario is being considered to deliver pretreated feed straight to WTP's Low-Activity Waste (LAW) Vitrification Facility. This scenario is called the Direct Feed LAW (DFLAW) program. Balance of Facility utility and system facilities are designed for full WTP operation. Thirteen of these are needed to support reduced throughput during DFLAW operation, of which eight require moderate to extensive changes. Extensive changes include permanent plant modifications that allow DFLAW to operate if the Pretreatment (PT) Facility is unavailable. Under full WTP operation, effluents from the LAW Facility will be returned to the PT Facility for further processing and/or transfer to the Liquid Effluent Retention Facility/Effluent Treatment Facility. The PT Facility also handles all flush water from the tank farm transfers. To address these requirements, a Value Improvement Project was performed. The recommended approach is to provide a 'split stream' Effluent Management Facility (EMF) with an evaporator to support DFLAW. The required modifications for DFLAW facilities are discussed in this paper. (authors)

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DOE OSTI2016

Integrated Readiness Activities for the Direct Feed Low Activity Waste (DFLAW) Program - 16221

The WTP is a one-of-a-kind nuclear waste treatment facility being designed and constructed for the DOE by Bechtel National, Inc. (BNI) and principal subcontractor URS-AECOM, to process and vitrify radioactive waste stored in underground tanks at the Hanford Site. The Tank Operations Contractor (TOC), Washington River Protection Solutions (WRPS), has the responsibility to retrieve, stage, pretreat, and deliver the pretreated feed directly to the WTP Low-Activity Waste Vitrification Facility, scope referred to as Direct Feed Low Activity Waste (DFLAW). Extensive planning is in progress under the auspices of One System, an effort with joint participation by WTP and TOC personnel. To support an integrated approach to readiness for the DFLAW Program, an Integrated Operational Readiness Committee (IORC) was established to contribute to a safe and effective operational readiness of the WTP. The IORC, an advisory committee, comprising representatives from BNI, WRPS, and the Hanford interfacing partners for WTP operations, Mission Support Alliance (MSA) and CH2M HILL Plateau Remediation Company (CHPRC). In addition, an Operational Readiness (OR) workshop was conducted with several objectives accomplished to support an integrated approach to readiness with specific focus on the management of interfaces between the various contractors and facilities. This culminated in the development of a readiness strategy document called the Operational Readiness Support Plan (ORSP). This ORSP describes the joint approach to WTP startup operating in the DFLAW configuration. (authors)

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DOE OSTI2016

Progress Updates for the Hanford Waste Treatment and Immobilization Plant Project - 16281

The Waste Treatment and Immobilization Plant (WTP) Project is vital to the U.S. Department of Energy's (DOE) mission to clean up radioactive waste at the Hanford Site, located in southeastern Washington State. The overall WTP Project objective is to design, build, and commission the facilities and systems that will treat and immobilize approximately 56 million gallons of radioactive waste stored in Hanford's 177 underground storage tanks. The combination of technologies in the WTP makes it a first-of-a-kind facility at a scale larger than ever built for radioactive waste processing. The WTP includes several facilities that will contribute to waste processing: (1) the Pretreatment (PT) Facility, which is designed to receive waste retrieved from the Hanford tank farms and separate it into low-activity and high-level waste streams; (2) the Low-Activity Waste (LAW) Facility, which will vitrify the low-activity waste stream; (3) the High-Level Waste (HLW) Facility, which will vitrify the high-level waste stream; (4) the Analytical Laboratory (Lab), which will support both vitrification facilities' operations; and (5) the Balance of Facilities (BOF), which will provide industrial support capabilities and infrastructure, like electricity and steam, needed for WTP operations. In 2012, DOE suspended production work on the WTP's Pretreatment (PT) Facility and to a lesser degree the High-Level Waste (HLW) Facility because of unresolved technical issues associated with those facilities. DOE has established an approach that would facilitate immobilization of tank waste to begin as early as practicable without waiting for completion of work to resolve the technical issues associated with the PT and HLW Facilities. This approach enables LAW treatment to begin before the PT and HLW facilities are completed by transferring low activity waste directly from the Hanford tank farms to the LAW Facility - referred to as Direct Feed LAW (DFLAW). ORP has placed the highest priority on completing the Low Activity Waste Facility, Balance of Facilities, and Analytical Laboratory (collectively known as LBL) in support of the planned phased start to the Hanford Tank waste treatment mission. DOE has requested, and the WTP contractor has delivered contract modifications proposals for: (1) design of a permanent capability to accommodate DFLAW in WTP; (2) procurement and construction of modifications to enable DFLAW operations in WTP, and (3) completion of LBL work scope in the current contract through hot commissioning in a manner to accommodate a phased start toward completing the WTP mission. DOE is reviewing and approving contract modifications in a sequence and schedule that allows for an orderly completion of the LBL Facilities and to begin treating low-activity tank waste as soon as practicable. In August 2014, ORP authorized the WTP contractor to resume all engineering work necessary to finalize the design of the HLW Facility. Authorization for HLW equipment procurements and construction is forthcoming, based on conditions that must be satisfied for a full release of these activities, including completion of an update to the Preliminary Documented Safety Analysis. DOE has also established a comprehensive plan for resuming production activities for the PT Facility that is similar to the process established and implemented for the HLW Facility. Resolution of the technical issues and establishment of a revised safety basis are key prerequisites to resuming engineering, procurements, and construction. (authors)

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DOE OSTI2016

Determination of Erosion/Corrosion Rates in Hanford Tank Farms Radioactive Waste Transfer System Pipelines - 16395

The twenty-eight double-shell underground radioactive waste storage tanks at the U.S. Department of Energy's Hanford Site near Richland, WA are interconnected by the Waste Transfer System network of buried steel encased pipelines and pipe jumpers in below-grade pits. The pipeline material is stainless steel or carbon steel in 51 mm to 152 mm (2 in. to 6 in.) sizes. The pipelines carry slurries ranging up to 20 volume percent solids and supernatants with less than one volume percent solids at velocities necessary to prevent settling. The pipelines, installed between 1976 and 2011, were originally intended to last until the 2028 completion of the double-shell tank storage mission. The mission has been subsequently extended. In 2010 the Tank Operating Contractor began a systematic evaluation of the Waste Transfer System pipeline conditions applying guidelines from API 579-1/ASME FFS-1 (2007), Fitness-For- Service. Between 2010 and 2014 Fitness-for-Service examinations of the Waste Transfer System pipeline materials, sizes, and components were completed. In parallel, waste throughput histories were prepared allowing side-by-side pipeline wall thinning rate comparisons between carbon and stainless steel, slurries and supernatants and throughput volumes. The work showed that for transfer volumes up to 6.1 E+05 m{sup 3} (161 million gallons), the highest throughput of any pipeline segment examined, there has been no detectable wall thinning in either stainless or carbon steel pipeline material regardless of waste fluid characteristics or throughput. The paper describes the field and laboratory evaluation methods used for the Fitness-for-Service examinations, the results of the examinations, and the data reduction methodologies used to support Hanford Waste Transfer System pipeline wall thinning conclusions. (authors)

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DOE OSTI2016

Detection and Mitigation of Hanford Site Radioactive Waste Tank Surface Water Intrusion - 16396

The last single-shell underground radioactive waste storage tanks at the U.S. Department of Energy's Hanford Site, near Richland, WA, were removed from service in November, 1980. At that time the single-shell tanks contained 153,300 m{sup 3} (40.5 million gallons) of waste, including 34,400 m{sup 3} (9.1 million gallons) of liquids. Subsequently the Interim Stabilization Program and Waste Retrieval/Closure Project have removed 24,600 m{sup 3} (6.5 million gallons) of liquid from the tanks to reduce the potential for leakage to the environment. After interim stabilization, each tank was isolated by cutting and capping waste transfer lines, filling drains with grout, and covering likely surface water entry points. The minimum expected lifetime for the isolation features was 20 years, consistent with planned retrieval of all single-shell tank wastes by 2018. Since then the retrieval completion date has been extended. In 2011 the Tank Operating Contractor began a systematic review of the aging isolation barriers to determine if surface water was entering the single-shell tanks. This paper summarizes the results of the 2011 - 2015 activities including single-shell tank inspection results, methodologies used to identify intrusions and waste leaks masked by intrusion, and eventual deployment of a prototype forced ventilation exhauster in 2015 to evaporate water intrusion pools on the waste surface. Further efforts to limit water intrusion, including deployment of surface barriers, are discussed. (authors)

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DOE OSTI2016

Integrated Waste Feed Qualification Program for Direct LAW Feed to WTP - 16421

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is a one-of-a-kind facility being designed and constructed for DOE by Bechtel National, Inc. (BNI) and principal subcontractor URS, to process and vitrify radioactive waste stored in underground tanks at the Hanford Site. The Tank Operations Contractor (TOC), Washington River Protection Solutions (WRPS), has the responsibility to retrieve, stage, pretreat, and deliver feed directly to the WTP Low Activity Waste (LAW) Vitrification Facility. The Direct Feed LAW (DFLAW) scenario is being considered by DOE as a strategy to treat Hanford tank wastes as soon as practicable. Extensive planning is underway by One System, an effort with joint participation by WTP and TOC personnel. The initial focus of One System is to achieve the required integration to ensure the waste feed meets acceptance requirements for processing in the TOC Low Activity Waste Pretreatment System (LAWPS) and WTP LAW facilities. The integrated waste feed qualification program approach for DFLAW was defined by One System during a four-day workshop. The effort resulted in a feasible approach for integrating LAWPS and LAW feed acceptance requirements to vitrify low-activity waste while complying with facility design basis, safety basis, waste acceptance criteria, and glass product compliance. The defined qualification program will provide a systematic approach to test newly staged feed campaigns at bench-scale using actual tank waste samples. The required integration and basis for obtaining sufficient and necessary data to qualify the feed for DFLAW facilities are discussed in this paper. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Initial Testing of Off-Gas Recycle Condensate Liquid from the WTP Low Activity Waste Vitrification Process - 16432

The Waste Treatment and Immobilization Plant (WTP) under construction at the Hanford site is designed to treat and immobilize the inventory of High-Level Waste stored in the 177 underground storage tanks. The WTP process flow was designed to pre-treat this waste, separating it into High Level Waste (HLW) and Low Activity Waste (LAW) fractions for vitrification. Vitrification of the waste generates a condensate stream from the off-gas processes originating from two off-gas treatment unit operations, the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP). The baseline plan for disposition of the stream from the LAW melter is to recycle it to the Pretreatment facility where it gets evaporated and processed through the LAW melter again. If the Pretreatment facility is unavailable, this baseline disposition pathway is not viable. Additionally, chloride, fluoride, and sulfate are partially volatile in the melter, accumulating to high concentrations while recycling and impacting the glass waste loading and facility throughput. The primary radionuclide that volatizes and accumulates is {sup 99}Tc. The long half-life and environmental mobility of {sup 99}Tc complicates disposal options for this secondary aqueous waste stream. This task is investigating {sup 99}Tc removal to examine the potential for diverting this stream to an alternate disposition path and avoiding impacting the glass waste loading. Separation methods for {sup 99}Tc have focused on using inorganic precipitation agents that can remove it by reducing it from soluble pertechnetate ion, with a +7 oxidation state, to insoluble technetium dioxide in the +4 oxidation state. Stannous chloride (SnCl{sub 2}) has been found highly effective at causing the reduction and precipitating {sup 99}Tc for removal, but it also precipitates other components. The primary competitor that precipitates is chromium, which consumes the redox activity of the Sn(II), causing addition of more of the SnCl{sub 2}. Research has examined the optimum quantity of SnCl{sub 2}, mixing time, and the impact of other redox-active species. It is also important to know the stability of the precipitated {sup 99}Tc in process conditions, since it is expected it will eventually be re-oxidized by oxygen and dissolve. This work is expected to determine if a {sup 99}Tc removal step could be used to decontaminate the bulk of this stream, and make it suitable for other disposal paths so that the chloride, fluoride, and sulfate can be diverted away from the glass melter. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Transitioning from Construction to Startup at WTP from a Plant Engineering Perspective - 16461

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) is a one-of-a-kind facility being designed, built and commissioned for the U.S. Department of Energy by Bechtel National, Inc. and principal subcontractor URS to solidify liquid radioactive waste stored in underground tanks at the Hanford Site. WTP consists of 20 infrastructure facilities and structures, known as Balance of Facilities, designed to support the Plant's four major facilities - Pretreatment Facility, High-Level Waste Vitrification Facility, Low-Activity Waste Vitrification Facility and the Analytical Laboratory. As construction moves toward startup and commissioning, a turnover process facilitates the transition of facilities and systems between organizations. The transition from Construction is initiated by an approved Design Completion List, which documents that design and construction have been completed, and the facility or system is ready for startup testing. Qualified individuals perform an inspection to ensure the facility or system has been constructed per the design during an eight-week engineering walk-down. During this phase in turnover, Plant Engineering personnel are responsible for updating and maintaining the Master Equipment List, developing spare parts recommendations, developing and issuing instrument calibration data sheets, evaluating temporary modifications, and supporting plant operations and maintenance activities. As of 2015, two electrical switchgear buildings and the non-radioactive liquid waste disposal system have been turned over from Construction to Startup. This paper discusses the turnover process, organizational interfaces, and experiences from a Plant Engineering perspective. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗