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DOE OSTI2021

International collaboration in disposal research: comparative modeling of coupled processes in the DECOVALEX project

Abstract. This presentation gives an overview of an international research collaboration for advancing the understanding and modeling of coupled thermo-hydro-mechanical-chemical (THMC) processes in geological systems. The creation of the international DECOVALEX project, now running for more than 25 years, was motivated by the recognition that prediction of these coupled effects is an essential part of the performance and safety assessment of geologic disposal systems for radioactive waste and spent nuclear fuel. DECOVALEX emphasizes joint analysis and comparative modeling of state-of-the-art field and laboratory experiments, across a range of host rock options and repository designs. Participating research teams are from radioactive waste management organizations, national research institutes, regulatory agencies, universities, and consulting groups, providing a wide range of perspectives and solutions to these complex problems. The presentation provides examples of the research contributions made collectively in past DECOVALEX tasks and also touches on the unique modeling challenges tackled in the ongoing project phase, referred to as DECOVALEX-2023. The current phase comprises 17 partner organizations, about 50 modeling teams, and 7 modeling tasks, which cover a broad portfolio from fundamental studies on gas migration to full-scale in situ heater experiments in different host rocks to performance assessment studies. Together, these examples illustrate that the insight and scientific knowledge gained within the DECOVALEX project would not have been possible if one group had studied these complex THMC modeling challenges alone rather than within a truly collaborative setting.

Birkholzer, Jens T.↗
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)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Panel Session 70: Nuclear Power Plant Waste Management, LLRW Processing Issues

This panel focused on senior utility managers discussing issues with commercial LLW processors. LLW processors had an opportunity to update utilities/NPPs on new or different services or technologies being offered to assist in their radioactive waste management goals, changes to their facility license, revisions to their acceptance guidelines, and emerging compliance issues. Panelists with presentations: UniTech - 'Expanding to Reduce Costs' LLW Processor Update (Gregg Johnstone); Veolia Nuclear Solutions Federal Services - Alaron Nuclear Services (Dave Garber); EnergySolutions Tennessee Processing Facilities (Fred Schulz); Complex Waste Management Issues Services and Treatment Facilities (George M. Taylor)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

lNAC's OPTIMUS{sup TM}-L Package - the Next Transformation - 19396

NAC has developed the OPTIMUS{sup TM}-L package, the newest addition to the OPTIMUS{sup TM} packaging product line. OPTIMUS{sup TM}-L is a Type B(U)F-96 transportation package designed for maximum flexibility and cost-efficiency to support shipment of a wide range of challenging low-activity wastes. The OPTIMUS{sup TM}-L package utilizes the same cask containment vessel (CCV) as its predecessor, OPTIMUS{sup TM}-H, packaged inside lightweight outer packaging. The large cavity size of the CCV, which can accommodate a 110-gallon drum, combined with the small size and modularity of the OPTIMUS{sup TM}-L package provides unmatched flexibility for the user. OPTIMUS{sup TM}-L can accommodate more radioactive waste in each drum (up to a Fissile Gram Equivalent (FGE) limit of 395 g Pu-239) than larger packages can in 10 drums. Furthermore, because of its small size and weight, up to ten (10) OPTIMUS{sup TM}-L packages can be accommodated per legal-weight truck shipment. Thus, one Legal Weight Truck (LWT) shipment of 10 OPTIMUS{sup TM}-L packages can accommodate more than 10 times the FGE as a large package containing 10 drums. OPTIMUS{sup TM}-L contents include low level waste, mixed low-level waste, intermediate level waste and contact handled transuranic (CH-TRU) waste. Furthermore, all contents can include aerosol cans with compressed gas and liquefied gas propellants and standard Department of Transportation (DOT) 3E lecture bottles for shipment to treatment facilities. The OPTIMUS{sup TM}-L is also designed to accommodate irradiated fuel debris and other fissile material waste, which may be packaged inside shield inserts if required for supplemental radiation shielding. In this paper, NAC provides a technical overview of the OPTIMUS{sup TM}-L package and identifies the design features and technology advancements that makes the OPTIMUS{sup TM} product line a readily adaptable and flexible solution for packaging DOE and other orphan wastes and enables the integration of these wastes into the waste management system process and disposition infrastructure. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Panel Session 89: Progress on Deep Repository Around the World

This panel focused on the progress of deep repository programs, worldwide. While efforts on a deep geological repository for SNF/UNF and HLW in the USA were terminated in 2010, several other repository programs continue to make considerable progress 10 and deserve to be recognized. Panelists from national, multi-national, and international repository programs and organizations reported on the status and future plans as well as the perceived reasons underlying the success and the failure of components of their respective repository program. This session provided a forum for interested parties to present, exchange, and take advantage of, as appropriate, repository progress, challenges, concepts/designs and other lessons learned around the world, including site characterization, site selection, research and development, licensing, construction, operation, and public acceptance and participation. Panelists with presentations: Switzerland's Geological Repository Program for Radioactive Waste (Tim Vietor); Update on NWMO's Progress in Implementing Canada's Plan (Sarah Hirschorn); Cigeo Project Progress and Next Milestones (Corinne Bauer)

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

The criticality safety program of the Swedish nuclear fuel and waste management Co (SKB)

SKB is co-owned by the owners of the Swedish nuclear power plants (NPP) and is responsible for the back-end of all Swedish spent nuclear fuel and radioactive waste from the Swedish nuclear program. The responsibility starts from when the fuel leaves the NPP and ends at the planned final repository. That means that SKB has the responsible for the safety at the intermediate pool storage (Clab), the encapsulation plant (Clink), the Spent Fuel Repository and the transportation between these sites. In March 2011 SKB applied to the Swedish Radiation Safety Authority (SSM) for a permit to build a final repository for spent fuel and an encapsulation plant (Clink). The application contained a criticality safety analysis for the canisters to be used in Clink and the copper canister to be used in the final repository. In 2012 SSM requested several complements to the criticality safety analysis in the application and about the same time they also required Clab to modernise the Safety Analysis Report. Our owners (the NPPs) had also requested SKB to take care of higher enrichments and higher burnup fuel. A prerequisite to meet this was extended Burnable Absorber credit (peak reactivity) and Burn-up credit. Up to this stage SKB had relied heavily on consultants to do criticality safety analysis and had no specific criticality safety program or methodology. However it was now evident to SKB that we needed to take an overall view on the criticality safety area and not only lift the quality of the actual criticality analysis but also to handle organisational and competence issues. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Technology Development for Under Tank Inspection of Double-Shell Tanks - 20045

The Department of Energy (DOE) Office of River Protection (DOE-ORP) is responsible for management and cleanup of the tank farms located at the Hanford Site. Nuclear waste at Hanford is stored in 149 single-shell tanks (SSTs) and 27 double-shell tanks (DSTs). The vast majority of the liquid radioactive waste is stored in the DSTs. The 27 DSTs, located in six tank farms, were constructed from 1967 to 1986 and, compared to the SSTs, provide greatly improved protection from leakage and better accessibility for inspection. The DSTs and ancillary equipment are expected to exceed their design life before their waste is removed and sent to the Waste Treatment and Immobilization Plant. The DST Integrity Project (DSTIP) must ensure that the DST system can meet the River Protection Project mission goals. This paper provides a programmatic overview of the DSTIP with a focus on development of under-tank inspection technologies. Currently, two categories of nondestructive examination (NDE) techniques for DSTs are implemented on the Hanford site: (1) surface (SNDE) and (2) volumetric (VNDE). Further discussion on current inspection techniques is provided in this paper. The technology development approach for advanced VNDE techniques will also be generally discussed as a precursor for another more detailed WM2020 paper and presentation by PNNL. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Connecting particle interactions to agglomerate morphology and rheology of boehmite nanocrystal suspensions

Rheology imposes significant challenges on processing of complex suspensions such as nuclear waste slurries at the Hanford and Savannah River sites. Understanding rheology connecting to microstructures and underlying particle interactions in complex slurries is therefore important for both fundamental knowledge and practical applications. Here, we use suspensions of aluminum oxyhydroxide minerals in the form of boehmite as an analog of the radioactive waste slurry to gain physical insights on the correlation between particle interactions, microstructures, and slurry rheology. Specifically, we use a combination of Couette rheometry and small-angle scattering techniques (independently and simultaneously) to understand how the slurry microstructure changes under flow and how these structural changes manifest themselves in the bulk rheology of the suspensions. Our experiments show that the boehmite slurries are thixotropic, with the rheology and structure of the suspensions changing with increasing exposure to flow. In the slurries, particle aggregates begin as loose, system-spanning clusters, but exposure to moderate shear rates causes the aggregates to irreversibly consolidate into denser clusters of finite size. The microstructural changes directly influence the rheological properties of the slurries such as viscosity and viscoelasticity. More importantly, our study shows that solution pH affects the amount of structural rearrangement and the kinetics of the rearrangement process, with an increase in pH leading to faster and more dramatic changes in the bulk rheology. Such dynamic microstructural changes and resultant rheology are understood via correlations between particle interactions and strength of particle network, coupled with surface chemistry and anisotropic nature of particle interactions. Nearly identical structural changes are also observed in Poiseuille flow geometries, implying that the observed changes are relevant in the pipe flow conditions present during waste processing.

Weston, Javen S.↗
DOE OSTI2018

THM-Coupled Modeling of Barrier Integrity for HLW Disposal in Bedded Salt - 18289

Within the framework of the R and D project KOSINA in Germany, numerical studies analyzing the long-term integrity of a bedded salt barrier under the thermal loading of heat generating radioactive waste have been performed using different modeling approaches for various repository concepts and two geological structures. The THM-coupled calculations show an initially steep increase of temperatures in the vicinity of the HLW canisters which reduces an uplift above the repository. This in turn leads to a temporally and spatially limited reduction of horizontal stresses at the top of the salt, allowing for pressure-driven percolation of groundwater into the upper part of the hydraulic barrier. However, at any given time an undisturbed salt barrier of over 300 m remains, shielding the repository from groundwater inflow. (authors)

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DOE OSTI2020

Remediation of Temporary Storage Sites in Support of the Port Hope Area Initiative - 20295

The Port Hope Area Initiative is a community-based solution for the long-term management of historic low level radioactive waste (LLRW) resulting from 60 years of uranium and radium processing operations in the Town of Port Hope which is located in Ontario, Canada. The Eldorado refinery, on the north shore of Lake Ontario, began refining radium-226 from pitchblende ore, later transitioning to the refining of uranium. Through the history of the operation, LLRW was deposited throughout the town of Port Hope as a result of fugitive emissions from the plant and/or through the re-use of process residues as building material and backfill. Historical clean-up activities conducted in the late 1970's involved the remediation of approximately 400 properties and the relocation of 100,000 cubic metres of contaminated soil to a disposal facility in Chalk River operated by Atomic Energy of Canada Limited (AECL). Owing to space limitations at that disposal facility, any LLRW identified through construction monitoring since that time has been stored in the community at three temporary storage sites located throughout the town. These include: the Centre Pier mound that contained approximately of 19,800 m{sup 3} of LLRW-impacted soil that originated from the construction of a new water treatment plant; two mounds located at a licensed storage facility containing LLRW obtained from residential clean-up activities (11,000 m{sup 3}); and a small pad adjacent to the municipal sewage treatment plant containing 2200 m{sup 3} of LLRW-containing sludge. With the construction of a new long-term waste management facility (LTWMF) that has been designed to house all of the LLRW identified within Port Hope, the three sites were early candidates for remediation. The clean-up of the three temporary storage sites was a significant milestone for the Port Hope Area Initiative. After a decade of planning and consultation, this work represents the first sites in the municipality to be remediated with the waste being safety removed and transferred to the newly constructed LTWMF. This paper discusses the challenges associated with the clean-up activities for these three sites and the strategies employed to address those challenges. These included weather-related challenges, owing to the seasons over which the work was conducted as well as those associated with working within a closely-knit community. Canadian Nuclear Laboratories (CNL), working on behalf of the federal government, has worked diligently to develop a positive and trusting relationship with the community. Consequently, the successful execution of this project needed to be sensitive to, and respectful of the needs of the community. In addition to the usual Health, Safety and Environment training, project staff received community awareness training that spoke to the history of this community-based initiative and the expected behavior when working within the community. Transportation routes were defined based on safety and the need to minimize disruption to local traffic while haul-times where scheduled around school bus hours to enhance public safety. The successful completion of this first of many remediation projects to be completed under the Port Hope Area Initiative reflected years of careful planning. Nevertheless, there were a number of 'lessons learned' that have been applied on other ongoing projects be completed under the Port Hope Area Initiative. (authors)

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DOE OSTI2015

Conceptual Model and Risk Assessment of Waste Package Evolution - 15643

A generic disposal facility model was created to mirror disposal of low-level radioactive waste in a humid environment. The standard waste package used is a painted and primed carbon steel box stacked four high and placed next to one another within the disposal facility, preventing outward deformations of individual boxes. Waste is placed in the facility in sections, and as each section is filled it is covered with a layer of natural soil. It was assumed that boxes are exposed to natural precipitation rates for approximately 12 months, reduced to natural background infiltration to simulate the soil cover, and dropping to 1% of background infiltration when the facility is filled and a water-shedding interim cover is installed. It was also assumed that each box retains its structural integrity at the time of disposal, with the exception of the top box, which has its lid collapse inward from the overlying soil cover. Waste packages experience different rates of corrosion, differential amounts of infiltration, and fill with liquid at different rates based on when and where they are placed in the facility. Using historical literature and DOE site reports, calculations were made to estimate a range of waste package failure outcomes. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Considerations on the use of an Anti-Compton Suppression Technique for the Measurement of Low Energy Gamma Rays in Dense Waste Materials - 18144

The Anti-Compton Spectrometry (ACS) technique is a gamma-ray measurement method which, in the presence of gamma rays sources emitting at higher energies, may improve the signal-to-continuum ratio of lower energy photo-peaks. It is used to improve assay precision and statistical detection limits. The typical approach surrounds the collimated High Purity Germanium (HPGe) detector by a NaI(Tl) guard which vetoes detected gamma-rays scattered out of the Ge-spectrometer and therefore by definition events do not contribute to a full energy peak in the HPGe detector. The present publication focuses on the applicability, advantages and drawbacks of ACS when considered for the purpose of enhancing measurement performances of non-destructive waste assay systems. In particular, the applicability and benefit of implementing ACS for the quantification of {sup 241}Am in high density waste will be presented. Such an application is directly relevant to measurement scenarios where the accuracy of the {sup 241}Am quantification is central to the radioactive waste meeting some acceptance criteria for near surface disposal, such as total alpha decay activity limits in 300 years. This work is also relevant to any measurement applications for which the Compton background generated by higher energy nuclides present in the waste and interacting with the detector significantly degrade the performance of standard high resolution gamma spectroscopy for low energy nuclides. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Port Hope Are Initiative Port Granby Project - Water Management in Extreme Weather Conditions - 19257

The Port Granby Project is part of the Port Hope Area Initiative (PHAI) through which Canadian Nuclear Laboratory (CNL) is managing long-term historic low level radioactive waste (LLRW) resulting from 60 years of uranium and radium processing operations in the urban setting of Port Hope, Ontario. Port Granby remediation scope includes 1) constructing a new, secure long-term waste management facility (LTWMF) and supporting infrastructure, and 2) excavating and relocating LLRW and marginally contaminated soil from the Port Granby Waste Management Facility (PGWMF), which accepted waste until the 1980's, to the newly constructed LTWMF. This paper provides an overview of the challenges of water management (control of storm and groundwater at the LTWMF and PGWMF) on a large-scale construction project with changing and unpredictable weather patterns. Consistent with increased observations of extreme weather events, over two consecutive construction seasons, weather changed from one of the driest on record (high temperatures, dry conditions and strong wind) to one of the wettest on record (short duration high-intensity rainfall that flooded the LTWMF, excavations and on-site PGWMF and LTWMF retention ponds). This paper describes the collaborative approach among Wood (Constructor), AECOM (Engineer of Record), and CNL to adjust to extremes in weather to control dust and excessive water during construction. The summer of 2016, one of the driest summers on record in southern Ontario, was followed by one of the wettest in 2017. In 2016, the project team used water from the uncontaminated on-site storm water ponds, applied a polymer product for dust control across the site to augment water applications, obtained a Permit to Take Water from the provincial government to pump water from Lake Ontario, procured large tanks for storage of Lake Ontario water to meet peak demand, and retained additional water trucks/operators for day to day site operations. In stark contrast, to accommodate heavy rains in 2017 the project team installed ∼6 million liter aboveground storage tanks with secondary containment for contaminated water storage; procured 100+ mobile water storage tanks to supplement the on-site storage, utilized LTWMF cells sumps, excavations and retention ponds to store and manage onsite water; and adjusted additional staff resources (more staff and longer shifts) during anticipated periods of high-intensity rainfall, at times managing water around the clock. Recognizing the need to minimize the release of contaminated soil and water from the construction site at all times, these efforts illustrate the importance of anticipating and reacting to extreme weather events on a more regular basis. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Experience by BAM in the Transport Package Safety Assessment of German Waste Containers - 18469

Transport and storage containers for low and mid-level radioactive waste are getting more and more of relevance due to the nuclear phase out decision in 2011. For higher activities Type B(U) approved waste containers will be needed for the shut down and dismantling phases of NPPs. It is expected that large quantities are required in the near future. German waste containers are generally approved for transport and interim storage and are also intended for the final disposal in the Konrad repository. BAM is involved in the authority licensing of transport package designs in Germany. In this context, BAM is responsible for the assessment of safe containment, mechanical, thermal and quality management issues. BAM also operates test facilities and performs drop as well as thermal tests during package licensing procedures. This paper summarizes our experience in the transport package design assessment of Type B(U) waste containers. A general overview of the approval process, the requirements and approaches BAM applies are described. Some examples are used to illustrate different aspects and technical issues we are addressing during the package assessment. In the first part of the paper the specific design aspects of German waste containers are described. Here, a general overview is given e.g. about closure systems, impact limiter designs, and the handling concepts. Furthermore, the wide range of radioactive content and their physical behavior including the impact on the packages assessment are described. The second part is focused on questions about the licensing and assessment process of German waste containers from the BAM authority point of view. The general approaches for the strategy of demonstration are outlined on the basis of the test conditions according to IAEA Regulations SSR-6. Furthermore, particular issues of the mechanical and thermal assessment with respect to the specific test conditions are discussed. For accident conditions of transport, aspects to be mentioned are e.g. the assessment of the lid bolts, the axial gap applied between content and lid, and the thermal behavior of the wood filled impact limiter after the fire test. However, issues of the assessment for routine and normal conditions of transport are addressed in this paper, too. The intention of this paper is introduce recent approval procedure experience in Germany, describing technical evaluation issues and so reduce rounds of questions during applications. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Technetium oxidation in slag-based sodium salt waste forms exposed to water and moist Hanford soil - 15514

Several U.S. DOE sites use or plan to use waste forms and/or concrete containment structures for radioactive waste disposal that are designed to have a chemically reducing environment to immobilize selected contaminants such as Tc(VII)O{sub 4}{sup -} and Cr(VI)O{sub 4}{sup 2-}. These waste forms and containment structures are typically deployed in near surface unsaturated oxidizing environments. Consequently, the effect of exposure to air (oxygen) and water containing dissolved oxygen during production, during the period of institutional control, and over the long term period of performance is important for predicting the speciation and mobility of the redox sensitive radioactive and stable contaminants. Both the SRS and Hanford waste streams contain soluble technetium which may require stabilization to meet disposal requirements. Technetium stabilization is a difficult problem because: 1) Tc is soluble and very mobile in the oxidized form typical of near surface environments, and 2) Tc-99 is a long-lived isotope with a half-life of 2.1 E+05 years which places demanding requirements on the engineered barriers and environment to meet current regulatory disposal requirements. A depth-discrete sampling and leaching method approach for measuring contaminant oxidation rate (effective contaminant specific oxidation rate) was used in this study. The method was modified by coating all sides of a cylindrical sample with an impermeable epoxy and cutting a fresh surface 2 to 2.5 cm from the original top surface eliminates sample inhomogeneity as the result of settling as a reason from observed results and provides 1-D soluble ion transport and gas transport information. Soluble Tc was leached from all of the depth-discrete sub-samples from both Tc2-9 and Tc2-10 which strongly suggests that oxygen was present in the entire length of both samples. About 24 mass percent of the Tc in the original sample, was leached (soluble) from sub-samples between 0.8 and 46 mm below the exposed surface of Tc2-9 (exposed to Hanford sediment). The same percent (24%) was leached from the sub-samples between 0.8 and 11 mm below the exposed surface of Tc2-10 (exposed to DI water). This suggests that the rate of oxygen migration into the sample exposed to soil was faster than the rate of migration into the sample exposed to water which is consistent with the more rapid transport of ions through a gas phase as compared to a liquid phase. It is assumed that moisture in the Hanford sediment was not sufficient to completely block the surface pores with respect to gas transport across the soil-waste form boundary. Based on nitrate leaching results for the depth- discrete sub-samples, regions depleted in nitrates were identified from the top surfaces to 9.5 and 3 mm into samples Tc2-9 (exposed to moist Hanford sediment) and Tc2-10 (DI water). Low mass fractions of nitrate were leached from these depth-discrete samples compared to samples further from the exposed surface presumably because a significant portion of the nitrate had already migrated into the soil or water, respectively. Depth-discrete sub-sample leaching results for Na can be interpreted in the same way over the same regions in the two samples tested. In conclusion, leaching monolithic porous cementitious waste forms in water appears to be conservative for non-redox sensitive contaminants. However, leaching data obtained under saturated exposure conditions do not appear to be conservative for redox sensitive contaminants which are easily oxidized. Leaching crushed samples in water still seems to be a conservative approach to estimating the concentrations of soluble contaminants in a waste form. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Savannah River Remediation Liquid Waste Operations Lifecycle Savings through a Lean Business System at the Savannah River Site - 17245

Savannah River Remediation (SRR) was contracted by the U.S. Department of Energy (DOE) to manage its liquid waste project at the Savannah River Site. The liquid waste project is a unique, high hazard nuclear waste treatment and disposal facility consisting of 51 one million-gallon underground waste tanks, a solvent extraction processing unit, a vitrification facility for the highest radioactive waste, and a grout solidification and disposal facility for lower radioactive decontaminated salt solution. Our Project mission is to treat the nuclear waste and close the associated storage and treatment facilities, of which, 8 tanks have been closed to date. The Lean philosophy took root decades ago in the manufacturing sector and started with the work of W. Edwards Deming and his contemporaries. In more recent years the process has matured in the Toyota Production System and migrated into fields as diverse as services industries, health-care, and now the DOE complex. At SRR, a Lean business management system was adopted to address site inefficiencies, aging infrastructure concerns and budget constraints. With yearly escalation and flat budgets, continuous improvement is taking on a larger role - improving the work accomplished for each dollar. This paper focuses on the program results achieved to date, including the lifecycle savings identified through the Rapid Improvement Event (RIE) process. The RIE process is a Lean tool which creates a cross-functional team to analyze, develop and implement improvements for a given process. DOE-EM has recently emphasized the value of contractor's continuous improvement programs through their implementation of Plan of Action and Milestone (POAM): Goal 2 (Increase Efficiency/Improve Performance) Reduce EM Operations Cost in FY16. POAM Goal 2 was a FY 16 effort to achieve 5% cost savings across most programs. This past year's cost savings initiatives will likely become a trend as DOE and its contractors look to do more with less. In support of our own business objectives, as well as, DOE's motivation to improve efficiencies, SRR has held over one hundred formal Lean events and dozens of 5S events that have driven improvement across the Project, including tank closure and production facilities. These improvements have significantly reduced the time required to process material and achieve the overall goal of hazard reduction and tank closure. (authors)

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

Nuclear Fuel Traces Definition in Storage Ponds of Research VVR-2 and OR Reactors in NRC 'Kurchatov Institute' - 16022

The Gas Plant complex is the experimental base of the Institute of Nuclear Reactors, which is part of the Kurchatov Institute. In 1954 the commissioning of the first Soviet water-cooled water-moderated research reactor VVR-2 on enriched uranium, and until 1983 the complex operated two research water-cooled water-moderated reactors 3 MW (VVR-2) and 300 kW (OR) capacity, which were dismantled in connection with the overall upgrades of the complex. The complex has three storage ponds in the reactor building. They are sub-surface vessels filled with water (the volume of water in each is about 6 m{sup 3}). In 2007-2013 the spent nuclear fuel from storages was removed for processing to 'Mayak'. Survey of Storage Ponds by Underwater Collimated Spectrometric System shows a considerable layer of slime on the bottom of ponds and traces of spent nuclear fuel in one of the storage pond. For determination qualitative and the quantitative composition of radionuclide we made complex α-, β-, γ - spectrometric research of water and bottom slimes from Gas Plant complex storage ponds. We found the spent nuclear fuel in water and bottom slime in all storage ponds. Specific activity of radionuclides in the bottom slime exceeded specific activity of radionuclides in the ponds water and was closed to levels of high radioactive waste. Analysis of the obtained data and data from earlier investigation of reactor MR storage ponds showed distinctions of specific activity of uranium and plutonium radionuclides. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Special Analyses for the Hanford Integrated Disposal Facility Performance Assessment - 20102

In 2014, the Department of Energy (DOE) Office of River Protection and its contractors began to develop a performance assessment for the near-surface disposal of low-level and mixed low-level waste at the Hanford Site's Integrated Disposal Facility (IDF). The IDF is a doubly-lined landfill that was constructed between 2004 and 2006 to be the disposal facility for the vitrified low-activity waste that will be produced at the Waste Treatment and Immobilization Plant (WTP). IDF is also expected to receive solid secondary waste produced at the WTP and other solid wastes from site activities. The IDF has been in a preoperational state awaiting authorization from DOE and a RCRA permit modification from the State of Washington Department of Ecology to receive waste. Both the Disposal Authorization Statement and permit modification require a performance assessment demonstrating that the system of engineered and natural features will limit releases of radionuclides and hazardous chemicals from the IDF and be protective of human health and the environment. The simulated duration is 10,000 years. Based on the analyses presented in the 2017 Integrated Disposal Facility Performance Assessment, DOE issued a conditional Operating Disposal Authorization Statement for the IDF in June 2018. The long-term performance of the IDF to be protective of human health and the environment was evaluated under the requirements of DOE Order 435.1, Radioactive Waste Management. Computer simulations were performed to evaluate whether or not the IDF would comply with DOE requirements. In the time that has passed since the performance assessment was approved by DOE, new information has been discovered that had not been considered in the performance assessment. Since this new information has not been evaluated, the potential impact of the changes have not been taken into consideration in DoE's disposal authorization. DOE and its contractors follow a change control process to screen and, when necessary, evaluate new information that could potentially impact the conclusions of the completed performance assessment. This paper will describe the change control process and provide two examples of evaluations performed following the change control process. The first example evaluates a new waste form for liquid secondary waste that was not evaluated in the performance assessment. In the performance assessment, liquid secondary waste was assumed to be solidified with grout. A new recommendation to dispose of the liquid secondary waste after drying it to a powder was evaluated. The second example evaluates inventory implications from changes to the flow sheet that estimates the feed composition to the low-activity waste vitrification facility. The changes result in higher strontium concentrations in the vitrified waste stream. (authors)

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