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All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Annual Report for Los Alamos National Laboratory Technical Area 54, Area G Disposal Facility – Fiscal Year 2011

As a condition to the Disposal Authorization Statement issued to Los Alamos National Laboratory (LANL or the Laboratory) on March 17, 2010, a comprehensive performance assessment and composite analysis maintenance program must be implemented for the Technical Area 54, Area G disposal facility. Annual determinations of the adequacy of the performance assessment and composite analysis are to be conducted under the maintenance program to ensure that the conclusions reached by those analyses continue to be valid. This report summarizes the results of the fiscal year 2011 annual review for Area G. Revision 4 of the Area G performance assessment and composite analysis was issued in 2008 and formally approved in 2009. These analyses are expected to provide reasonable estimates of the long-term performance of Area G and, hence, the disposal facility's ability to comply with Department of Energy (DOE) performance objectives. Annual disposal receipt reviews indicate that smaller volumes of waste will require disposal in the pits and shafts at Area G relative to what was projected for the performance assessment and composite analysis. The future inventories are projected to decrease modestly for the pits but increase substantially for the shafts due to an increase in the amount of tritium that is projected to require disposal. Overall, however, changes in the projected future inventories of waste are not expected to compromise the ability of Area G to satisfy DOE performance objectives. The Area G composite analysis addresses potential impacts from all waste disposed of at the facility, as well as other sources of radioactive material that may interact with releases from Area G. The level of knowledge about the other sources included in the composite analysis has not changed sufficiently to call into question the validity of that analysis. Ongoing environmental surveillance activities are conducted at, and in the vicinity of, Area G. However, the information generated by many of these activities cannot be used to evaluate the validity of the performance assessment and composite analysis models because the monitoring data collected are specific to operational releases or address receptors that are outside the domain of the performance assessment and composite analysis. In general, applicable monitoring data are supportive of some aspects of the performance assessment and composite analysis. Several research and development (R and D) efforts have been initiated under the performance assessment and composite analysis maintenance program. These investigations are designed to improve the current understanding of the disposal facility and site, thereby reducing the uncertainty associated with the projections of the long-term performance of Area G. The status and results of R and D activities that were undertaken in fiscal year 2011 are discussed in this report. Special analyses have been conducted to determine the feasibility of disposing of specific waste streams, to address proposed changes in disposal operations, and to consider the impacts of changes to the models used to conduct the performance assessment and composite analysis. These analyses are described and the results of the evaluations are summarized in this report. The Area G disposal facility consists of Material Disposal Area (MDA) G and the Zone 4 expansion area. To date, all disposal operations at Area G have been confined to MDA G. Material Disposal Area G is scheduled to undergo final closure in 2015; disposal of waste in the pits and shafts is scheduled to end in 2013. In anticipation of the closure of MDA G, plans are being made to ship the majority of the waste generated at LANL to off-site locations for disposal. It is not clear at this time if waste that will be disposed of at LANL will be placed in Zone 4 or if disposal operations will move to a new location at the Laboratory. Separately, efforts to optimize the final cover used in the closure of MDA G are underway; a final cover design different than that adopted for the performance assessment and composite analysis will likely emerge from that investigation. All of these changes will require re-examination of the assumptions upon which the performance assessment and composite analysis are based and, in all likelihood, revision of those analyses.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Development of a multi-purpose container system for the storage, transport and disposal of PWR spent fuel in the UK - 15466

Radioactive Waste Management Limited (RWM) is a wholly owned subsidiary of UK's Nuclear Decommissioning Authority, and is responsible for implementing UK Government policy on geological disposal of higher activity radioactive waste. An aspect of the generic work programme that underpins the current generic disposal concepts includes the development of the associated disposal containers. To date RWM has focused on the development of a range of disposal container designs that fulfil the requirements for transport and disposal in a Geological Disposal Facility (GDF) for legacy high heat generating wastes, one of which includes legacy Pressurised Water Reactor (PWR) spent nuclear fuel (SF). In line with a number of European countries exploring deep geological disposal, the conceptual disposal container solution developed for this waste type has a capacity of 4 PWR fuel assemblies. Since 2013, the feasibility of developing an alternative higher capacity disposal container design based around the Multi-Purpose Container (MPC) concept has been explored. In general terms, MPCs are containers that are designed to meet requirements for safe containment of radioactive waste during storage, transport and disposal. The fundamental design philosophy of the MPC is that once the waste is packaged in an MPC, it would not need to be handled again. That is, after a period of initial cooling in a fuel pond, the SF could be packaged for long term dry storage and would not require direct handling for its eventual transport to, and disposal in, a GDF. The novel feature of the MPC system design considered is the inclusion of an additional overpack specifically for the final deep geological disposal phase. The conceptual MPC and its associated storage, transfer, transport and thick walled carbon steel disposal overpack have been developed to a conceptual level of design detail to demonstrate concept feasibility, with the final design solution confirming a MPC system with a capacity of 12 PWR SF assembles. This represents the highest capacity PWR MPC system that complies with the mass and rail gauge limits of the UK W6a rail gauge. Such a capacity realises a contents loading three times that of the standard PWR disposal container and presented technical challenges from both a structural performance and thermal perspective; necessitating the need for the inclusion of features to enhance heat transfer from the central fuel assemblies within the MPC and novel lid features on the transport container overpack to maintain structural integrity and containment during the hypothetical accident conditions of transport tests. In developing the MPC system conceptual design it is recognised that, depending upon the safety functions of the MPC disposal overpack, the choice of carbon steel material may not be suitable for all geological environments. Consequently, the MPC system design and its materials of construction will require further evaluation once detailed knowledge of the disposal concept to be implemented, its safety functions and geological environment are known. (authors)

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DOE OSTI2015

A proposed solution to the challenges of disposal of greater than class C low-level radioactive waste - 15172

In 1982, the US Nuclear Regulatory Commission (NRC) adopted rules for the disposal of low-level radioactive waste. These rules established new standards for the siting, construction, operation and closure of low-level radioactive waste disposal facilities. The new rules also set out a classification system for low-level radioactive waste based on half-life and concentration of the radionuclides in the waste stream. The defined classes - Class A, Class B and Class C - were based on increasing toxicity with Class A being the least hazardous and Class C being relatively more hazardous. Radioactive waste that could not fit the classification scheme due to its long half-life or its high concentration of radioactive material was deemed to be greater than Class C low-level radioactive waste, with the ascribed acronym 'GTCC' low-level radioactive waste. Such waste was deemed not suitable for shallow land disposal based on the design standards for low-level radioactive waste landfills in place at that time. This resulted in a radioactive waste stream that had no disposal option. To remedy this problem, the US Congress in 1985 stipulated that the US Department of Energy would be responsible for the disposal of GTCC waste. Subsequently, the NRC amended its regulations to require GTCC low-level waste to be disposed in a geologic repository unless the Commission approved proposals for disposal in a low-level radioactive waste disposal facility. The Commission did not concurrently establish any specific technical requirements for GTCC disposal in a low-level radioactive waste disposal facility, but did infer that a site-specific performance analysis could be conducted in support of any proposal for land disposal of such waste. In light of this, Waste Control Specialists LLC (WCS) has conducted such a site-specific performance analysis that has indicated the disposal facility at Andrews Texas will perform satisfactorily as a disposal facility for certain types and quantities of GTCC waste. Concurrently with this analysis, WCS has submitted to the Texas Commission on Environmental Quality a petition for rulemaking that will permit disposal of GTCC waste in their disposal facility. This paper summarizes the technical and legal analyses that were conducted in support of the proposed rulemaking. (authors)

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DOE OSTI2019

Development of the Waste Acceptance Criteria for the Idaho National Laboratory Remote-Handled Low-Level Waste Disposal Facility - 19143

The Idaho National Laboratory (INL) Remote-Handled Low-Level Waste (RH LLW) Disposal Facility has been constructed, has received operational approval from the Department of Energy (DOE), and is expected to receive its first waste shipment in FY 2019. The RH LLW Disposal Facility will support the needs of INL and the Naval Reactors Facility (NRF). RH LLW destined for the facility includes waste currently in storage from previous programs and projects conducted at INL; newly generated waste from programs and projects conducted at INL; and waste from NRF spent fuel processing activities. This new facility supports RH LLW disposal needs for the ongoing mission of INL and NRF. Waste to be disposed of at the RH LLW Disposal Facility may exhibit dose rates that range from 0.002 Sv/hr to 600 Sv/hr. Waste types include resins and activated metals as well as surface-contaminated debris generated from existing and new missions. The total number of canisters currently planned for disposal at the RH LLW Disposal Facility is 939 with the possibility of future expansion. The projected waste volume to be disposed of is 3,100 m{sup 3}. The RH LLW Disposal Facility will receive a wide variety of RH LLW and is in preparations to receive its first canisters in FY 2019. Waste acceptance criteria (WAC) and the radioactive waste management basis have been developed and implemented in accordance with the applicable DOE Order. In order to ensure that DOE requirements and guidance were appropriately implemented in the RH LLW Disposal Facility WAC, the project worked closely with the DOE Low Level Waste Disposal Facility Federal Review Group (LFRG) representatives and followed the applicable DOE standard. This paper provides an overview of the development of the WAC, including waste and waste generator certification requirements, for the RH LLW Disposal Facility. The paper illustrates the importance of maintaining strong ties to the development and revision of the RH LLW Disposal Facility Performance Assessment (PA), Documented Safety Analysis, Facility Procedures, Readiness Reviews, DOE Order, and applicable Technical Standards. The paper also provides an overview of the RH LLW Disposal Facility, WAC generator certification requirements, distinctive challenges to acceptance of legacy waste, and the unique approach the RH LLW Disposal Facility has taken to ensure compliance with PA driven limits. (authors)

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DOE OSTI2019

Performance Assessment Results for the Hanford Integrated Disposal Facility - 19134

In 2014, the US 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 Integrated Disposal Facility. The Hanford Integrated Disposal Facility is a doubly-lined landfill that was constructed between 2004 and 2006 to be the disposal facility for the vitrified low-activity waste containers that will be produced at the Hanford Waste Treatment and Immobilization Plant. The disposal facility is also expected to receive solid secondary waste produced at the Hanford Waste Treatment and Immobilization Plant and other solid wastes from site activities. The constructed facility is awaiting authorization to receive waste. Although no waste destined for the facility is currently being generated, operations cannot begin until the facility has received a Disposal Authorization Statement from US DOE and a permit modification from the State of Washington Department of Ecology. Both the Disposal Authorization Statement and permit modification require a demonstration that the system of engineered and natural features of the disposal facility will limit releases from the facility and be protective of human health and the environment for the next 1,000 to 10,000 years. Based on the analyses presented in the Integrated Disposal Facility Performance Assessment, US DOE issued a conditional Disposal Authorization Statement for the facility in June 2018. Demonstrating the long-term performance of the facility to be protective of human health and the environment was evaluated under the requirements of US DOE Order 435.1, Radioactive Waste Management. Computer simulations were performed to evaluate whether or not the disposal facility would comply with the performance objectives specified in the order. The evaluation was performed using numerical models to simulate source term releases from vitrified and cement-based waste forms. Source term releases were subsequently transported through an air pathway and a groundwater pathway to a point of compliance 100 meters from the disposed of waste. In addition, an analysis evaluating the consequences of an inadvertent intrusion into the waste was also performed. In accordance with US DoE's technical standard for performance assessments, deterministic and probabilistic analyses were performed to demonstrate that the Hanford Integrated Disposal Facility, together with the engineered features of the waste forms and natural features of the selected site, provides a reasonable expectation that the low-level waste and mixed low-level waste disposal will meet the radiological performance objectives established by US DOE. Post-closure doses to future members of the public were evaluated after the time of closure and included a 100-year period of institutional controls that limited exposure immediately following closure of the facility. Calculated doses to a future member of the public from the air pathway were below the 100 μSv/yr dose performance objective. Calculated doses to a future member of the public from all exposure pathways, including the air pathway and the groundwater pathway, were below the 250 μSv/yr dose performance objective. Doses following an inadvertent intrusion into the facility after the institutional control period were below the 5 mSv acute dose performance measure and the 1 mSv/yr chronic dose performance measure. (authors)

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DOE OSTI2020

Co-Disposal Waste Package Loading Options for DOE SNF and HLW - 20331

The U.S. Department of Energy (DOE) is responsible for managing spent nuclear fuel (SNF) that is currently in, or will in the future come into, its possession. DOE must continue to safely store that SNF, transport it to an interim storage site or a repository, and dispose of it. These fuels come from a wide range of reactor types with various cladding materials and enrichments. Many of these reactors, now decommissioned, had unique design features, such as core configuration, fuel element and assembly geometry, moderator and coolant materials, operational characteristics, and neutron spatial and spectral properties, resulting in a large diversity of reactor and fuel designs. Because of the wide variety and conditions of SNF, a robust DOE Standard Canister was proposed that would confine radionuclides and preclude moderator. The DOE Standard Canister had four variations: 3.05-meter (10-foot) or 4.57-meter (15-foot) length, and 45.7-cm (18-inch) or 61.0-cm (24-inch) diameter. For ultimate disposal in the Yucca Mountain Repository, these canisters were to be grouped with 61.0-cm (24-inch) diameter high level waste (HLW) canisters in a 2.13-meter (84-inch) diameter co-disposal waste package. The smaller 45.7-cm (18-inch) diameter DOE Standard Canister could be placed in the middle of five HLW canisters. The larger 61.0-cm (24-inch) diameter DOE Standard Canister would take the place of one of the five HLW canisters on the outer ring in the co-disposal waste package. No DOE Standard Canisters have been loaded. A preliminary evaluation has estimated the number of elements of a fuel type that can fit into the different sizes of the DOE Standard Canister, but no definitive loading configuration has been selected. Changing the loading configuration could impact the number of loadable DOE Standard Canisters and the number of co-disposal waste packages needed for eventual disposition. This paper conveys the ranges of DOE Standard Canisters and HLW canisters that may be produced under certain conditions. It also examines the differences in the estimated number of co-disposal waste packages produced for eventual disposal when using different loading strategies in the DOE Standard Canister for Advanced Test Reactor (ATR), Peach Bottom, and High Flux Isotope Reactor (HFIR) SNF. Changing the loading configurations of ATR, Peach Bottom, and HFIR SNF slightly impacted the number of co-disposal waste packages that may be needed for ultimate disposal. The change in loading configuration was more impactful when a different canister was used, as opposed to varying the number of elements that could fit inside the same size canister. In one case, a reduction of co-disposal waste packages could be achieved by allowing mixing of short HLW canisters with long DOE Standard Canisters. The main conclusion from this analysis is that the ratio between HLW canisters and DOE Standard Canisters will drive the total number of co-disposal waste packages. If too many HLW canisters (i.e., more than five times the number of 18-inch DOE standard canisters) or DOE Standard Canisters are produced, some co-disposal waste packages may not have all positions filled. A co-disposal waste package may be filled with all HLW with no DOE Standard Canister, or a co-disposal waste package could be filled with a single DOE Standard Canister. A ratio that does not closely align to optimum could allow for the design of waste packages that hold just HLW canisters or just DOE SNF canisters. (authors)

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NASA NTRS2018

Assessment and Verification of SLS Block 1-B Exploration Upper Stage State and Stage Disposal Performance

One of the SLS Navigation System's key performance requirements is a constraint on the payload system's delta-v allocation to correct for insertion errors due to vehicle state uncertainty at payload separation. The SLS navigation team has developed a Delta-Delta-V analysis approach to assess the effect on trajectory correction maneuver (TCM) design needed to correct for navigation errors. This approach differs from traditional covariance analysis based methods and makes no assumptions with regard to the propagation of the state dynamics. This allows for consideration of non-linearity in the propagation of state uncertainties. The Delta-Delta-V analysis approach re-optimizes perturbed SLS mission trajectories by varying key mission states in accordance with an assumed state error. The state error is developed from detailed vehicle 6-DOF Monte Carlo analysis or generated using covariance analysis. These perturbed trajectories are compared to a nominal trajectory to determine necessary TCM design. To implement this analysis approach, a tool set was developed which combines the functionality of a 3-DOF trajectory optimization tool, Copernicus, and a detailed 6-DOF vehicle simulation tool, Marshall Aerospace Vehicle Representation in C (MAVERIC). In addition to delta-v allocation constraints on SLS navigation performance, SLS mission requirement dictate successful upper stage disposal. Due to engine and propellant constraints, the SLS Exploration Upper Stage (EUS) must dispose into heliocentric space by means of a lunar fly-by maneuver. As with payload delta-v allocation, upper stage disposal maneuvers must place the EUS on a trajectory that maximizes the probability of achieving a heliocentric orbit post Lunar fly-by considering all sources of vehicle state uncertainty prior to the maneuver. To ensure disposal, the SLS navigation team has developed an analysis approach to derive optimal disposal guidance targets. This approach maximizes the state error covariance prior to the maneuver to develop and re-optimize a nominal disposal maneuver (DM) target that, if achieved, would maximize the potential for successful upper stage disposal. For EUS disposal analysis, a set of two tools was developed. The first considers only the nominal pre-disposal maneuver state, vehicle constraints, and an a priori estimate of the state error covariance. In the analysis, the optimal nominal disposal target is determined. This is performed by re-formulating the trajectory optimization to consider constraints on the eigenvectors of the error ellipse applied to the nominal trajectory. A bisection search methodology is implemented in the tool to refine these dispersions resulting in the maximum dispersion feasible for successful disposal via lunar fly-by. Success is defined based on the probability that the vehicle will not impact the lunar surface and will achieve a characteristic energy (C3) relative to the Earth such that it is no longer in the Earth-Moon system. The second tool propagates post-disposal maneuver states to determine the success of disposal for provided trajectory achieved states. This is performed using the optimized nominal target within the 6-DOF vehicle simulation. This paper will discuss the application of the Delta-Delta-V analysis approach for performance evaluation as well as trajectory re-optimization so as to demonstrate the system's capability in meeting performance constraints. Additionally, further discussion of the implementation of assessing disposal analysis will be provided.

Patrick, Sean↗
DOE OSTI2015

Texas authorizes disposal of large quantities of depleted uranium at wcs - 15626

The U.S. Nuclear Regulatory Commission (NRC) has been actively engaged in a rulemaking process that would revise Title 10 of the Code of Federal Regulations (CFR), Part 61, Licensing Requirements for Land Disposal of Radioactive Waste, to govern the disposal of large quantities of Depleted Uranium (DU) and Blended Waste (referred to as Unique Waste Streams). While the NRC plans to propose a Site Specific Analysis (SSA) rulemaking in early 2015, they have already issued guidance to Agreement States which identified general disposal criteria that could be used should a licensee propose to dispose of Unique Waste Streams before their rulemaking was completed. On August 5, 2013, Waste Control Specialists LLC (WCS) submitted a major license amendment application for review and approval to the Texas Commission on Environmental Quality (TCEQ). This major license amendment request proposed, among other things, authorization to dispose of large quantities of DU at its Federal Facility Waste Disposal Facility (FWF). Pursuant to Title 30 of the Texas Administrative Code (TAC), Rule 336.709, Technical and Environmental Analyses, disposal of waste must be sufficient to meet the radiological dose criteria for a minimum period of performance of 1,000 years after closure or the period where peak dose occurs, whichever is longer. These regulations are more stringent than those of any other state that hosts a facility authorized to dispose of Low-Level Radioactive Waste (LLW) in the U.S. On August 28, 2014, the TCEQ approved the major amendment request authorizing disposal of large quantities of DU. During the licensing review process, significant technical issues were successfully resolved ensuring that large quantities of DU could be safely isolated from the biosphere for long time periods after site closure. Many important lessons were learned during the licensing proceedings that have potential significant impacts to the licensed community. Namely that a modern, well designed disposal facility that is properly sited geologically and in an arid environment is ideal for ensuring that long-lived alpha emitting radionuclides are sufficiently isolated to protect public health for long into the future. The DOE is currently finalizing plans to complete a Supplemental Environmental Analysis (EA) to support shipments of DU for disposal at WCS' FWF as required under the National Environmental Policy Act of 1970. The DOE may begin shipments of DU for disposal to WCS FWF that was licensed and constructed to support disposal of waste that is the responsibility of the federal government as stipulated in the Low-Level Radioactive Waste Policy Amendments Act of 1985. This paper will present the regulatory history of events that initiated the NRC's rulemaking for Unique Waste Streams and the technical analysis that were conducted in support of WCS' major amendment that has been approved by the TCEQ. A description of the geological characteristics and engineering designs used to support the Performance Assessment will be included. (authors)

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DOE OSTI2013

Special Analysis for the Disposal of the Consolidated Edison Uranium Solidification Project Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

The purpose of this Special Analysis (SA) is to determine if the Oak Ridge (OR) Consolidated Edison Uranium Solidification Project (CEUSP) uranium-233( 233 U) waste stream (DRTK000000050, Revision 0) is acceptable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). The CEUSP 233 U waste stream requires a special analysis because the concentrations of thorium- 229 ( 229 Th), 230 Th, 232 U, 233 U, and 234 U exceeded their NNSS Waste Acceptance Criteria action levels. The acceptability of the waste stream is evaluated by determining if performance assessment (PA) modeling provides a reasonable expectation that SLB disposal is protective of human health and the environment. The CEUSP 233 U waste stream is a long-lived waste with unique radiological hazards. The SA evaluates the long-term acceptability of the CEUSP 233 U waste stream for near-surface disposal as a two tier process. The first tier, which is the usual SA process, uses the approved probabilistic PA model to determine if there is a reasonable expectation that disposal of the CEUSP 233 U waste stream can meet the performance objectives of U.S. Department of Energy Manual DOE M 435.1-1, “Radioactive Waste Management,” for a period of 1,000 years (y) after closure. The second tier addresses the acceptability of the OR CEUSP 233 U waste stream for near-surface disposal by evaluating long-term site stability and security, by performing extended (i.e., 10,000 and 60,000 y) modeling analyses, and by evaluating the effect of containers and the depth of burial on performance. Tier I results indicate that there is a reasonable expectation of compliance with all performance objectives if the OR CEUSP 233 U waste stream is disposed in the Area 5 RWMS SLB disposal units. The maximum mean and 95 th percentile PA results are all less than the performance objective for 1,000 y. Monte Carlo uncertainty analysis indicates that there is a high likelihood of compliance with all performance objectives. Tier II results indicate that the long-term performance of the OR CEUSP 233 U waste stream is protective of human health and the environment. The Area 5 RWMS is located in one of the least populated and most arid regions of the U.S. Site characterization data indicate that infiltration of precipitation below the plant root zone at 2.5 meters (8.2 feet) ceased 10,000 to 15,000 y ago. The site is not expected to have a groundwater pathway as long as the current arid climate persists. The national security mission of the NNSS and the location of the Area 5 RWMS within the Frenchman Flat Corrective Action Unit require that access controls and land use restrictions be maintained indefinitely. PA modeling results for 10,000 to 60,000 y also indicate that the OR CEUSP 233 U waste stream is acceptable for near-surface disposal. The mean resident air pathway annual total effective dose (TED), the resident all-pathways annual TED, and the acute drilling TED are less than their performance objectives for 10,000 y after closure. The mean radon-222 (222Rn) flux density exceeds the performance objective at 4,200 y, but this is due to waste already disposed at the Area 5 RWMS and is only slightly affected by disposal of the CEUSP 233 U. The peak resident all-pathways annual TED from CEUSP key radionuclides occurs at 48,000 y and is less than the 0.25 millisievert performance objective. Disposal of the OR CEUSP 233 U waste stream in a typical SLB trench slightly increases PA results. Increasing the depth was found to eliminate any impacts of the OR CEUSP 233 U waste stream. Containers could not be shown to have any significant impact on performance due to the long half-life of the waste stream and a lack of data for pitting corrosion rates of stainless steel in soil. The results of the SA indicate that all performance objectives can be met with disposal of the OR CEUSP 233 U waste stream in the SLB units at the Area 5 RWMS. The long-term performance of the OR CEUSP 233 U waste stream disposed in the near surface is protective of human health and the environment. The waste stream is recommended for disposal without conditions.

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DOE OSTI2015

Feasibility studies for the design of disposal vaults for multi-purpose containers (MPCs): construction, operation, ventilation and management of heat - 15175

The Nuclear Decommissioning Authority (NDA) subsidiary, Radioactive Waste Management Ltd (RWM) is responsible for the safe implementation of a Geological Disposal Facility (GDF) for radioactive waste in the UK. As part of their generic programme to underpin the planned designs for a GDF, work is ongoing to explore a range of possible geological disposal concepts. This work developed GDF concept designs for Multi-Purpose Containers (MPC) disposal in the generic host rock types considered: higher strength (crystalline), lower strength sedimentary (sedimentary / clay formations) and evaporite rocks. This paper is specific to concepts for the disposal of MPC for Pressurised Water Reactor (PWR) spent nuclear fuel (SF). The key outcomes of the feasibility studies to improve the understanding of the MPC disposal concept and the specific challenges to construct, operate, ventilate, manage heat and backfill associated with this concept are summarised in this paper. The management of the high loading of radiogenic heat (from 12 PWR SF assemblies in MPCs compared to 4 in 'standard' disposal containers) during an extended open phase (delayed backfilling of the disposal area) of up to 300 years was investigated. The concept designs developed demonstrate it is feasible to construct, operate and ventilate disposal vaults to accommodate open 'storage' periods required for transitional thermal decay of high heat generating waste in higher strength and lower strength sedimentary host rock types considered by RWM. This work focused on developing two contrasting disposal concepts which are applicable to both higher strength and lower strength rock environments; both of which illustrate how vault temperature, stability and groundwater inflows can be controlled to delay backfilling and allow MPC package thermal output to decrease. MPC disposal in evaporite rock does not require a cooling period due to its high thermal conductivity and favourable performance at higher temperatures; therefore the concept developed for this rock includes immediate backfilling of disposal tunnels. A clear understanding of the interactions and limitations associated with heat management during the open period was developed by investigation of a 'Heating Ventilation and Air-Conditioning System' (HVAC). It was concluded that removal of heat from the disposal tunnels / vaults is feasible, but introduces significant operational complexity. (authors)

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DOE OSTI2015

The use of underground research facilities for the demonstration of safety of geological disposal - 15094

Many countries are progressing towards developing research programmes related to the development of geological disposal facilities and as part of these research programmes many countries have constructed or are planning to construct Underground Research Facilities (URFs). The development of the safety case for geological disposal facilities, which covers both the operational phase and the post-closure phase, is built on the acquisition and integration of all necessary data including data on the natural and engineered barriers, on the facility itself (design), on the operation of the disposal facility, and in the specific case of geological disposal facilities, the conditions at the depth of disposal relevant for both in-situ and waste emplacement states. Taking these conditions into account can make the demonstration of safety more complex and demanding than for near surface disposal facilities. Most if not all of the countries well advanced in the development of geological disposal facilities have also developed underground research facilities to support the decision processes within their disposal facility development programme. Underground Research Facilities play an essential role in the demonstration of safety of geological disposal facilities and a distinction has to be made between data acquired from surface based investigations and boreholes and those data and experiments carried out in-situ. The use of in-situ data contribute to build confidence in the demonstration of safety and contribute to public confidence and acceptance of geological disposal facilities. Further discussion will elaborate on whether to use the URF as part of a future disposal facility or not, with an emphasis on the transposition of data from the experimental site to the disposal site and how this is addressed and validated in the demonstration of safety. (authors)

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DOE OSTI2015

A Preliminary Analysis on the Applicability of Deep Borehole Disposal for Spent Fuels in Korea - 15496

A deep geological disposal system, the disposal depth is about 500 m below ground, is considered as the safest method to isolate the spent fuels (SF) or high-level radioactive waste from the human environment with the best available technology at present time. The disposal safety of this system has been demonstrated with underground research laboratory and some advanced countries such as Finland and Sweden are implementing their disposal project on commercial stage. However, if these high-level radioactive wastes can be disposed of in deeper and more stable rock formation than deep geological disposal depth, it has several advantages. Therefore, as an alternative disposal concept, i.e., deep borehole disposal technology is under consideration in number of countries in terms of its outstanding safety and cost effectiveness. In this paper, the general concept for deep borehole disposal of spent fuels or high level radioactive wastes was reviewed. And the key technologies and challenges in development of this disposal method with the nuclear environment were analyzed. Also, very preliminary deep borehole disposal concept including disposal canister concept was developed according to the nuclear environment. These results will be used as an input for the analyses of applicability for DBD in Korea. (authors)

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DOE OSTI2018

National Plan for the Disposal of Existing and Future TRU Wastes - 18616

Now that the Waste Isolation Pilot Plant (WIPP) has re-opened, after being down for three years due to an accident the DOE National TRU Program has re-developed a plan for the disposal of existing and future TRU wastes. The National TRU Waste Management Plan (NTWMP) is an integrated plan to address the needs of DOE sites across the DOE Weapons Complex that create and store TRU waste, and is centered on the capability of WIPP to receive and dispose of TRU waste. The WIPP capability is planned as a weekly shipping rate and is defined by emplacement and receipt rate capabilities since WIPP is not permitted for long-term storage. And, shipping rates may be constrained by new WIPP Waste Acceptance Criteria (WAC) and future plans for repository configurations and disposal package capabilities over the next 30 years. Since WIPP is the only disposal system available to the DOE for TRU waste disposal, DOE has a newly projected life-cycle need for WIPP to remain open and available up to 2050. It is projected that the need for WIPP will continue up to the year 2050 for the disposition of the remaining legacy TRU inventories and for the disposal of TRU waste continuing to be generated at DOE's National Laboratories. In addition, there are several other potential new waste streams in which WIPP is being considered an alternative solution for their disposition. The NTWMP has been updated to reflect the short-term and long-term plans for TRU waste disposal at WIPP. The short-term plan is used by DOE for budget projection and integration purposes to facilitate and inform budget planning, both in DOE's Environmental Management (EM) and National Nuclear Security Administration (NNSA) organizations. Most legacy TRU waste (generated in the past and stored at DOE sites today) is owned and managed by EM. And, EM submits integrated budget requests for DOE sites, including the integration of resources for TRU waste management. NNSA and DOE's Office of Science (OS) funds TRU waste management as part of their mission funding and NNSA should eventually be the primary user of the WIPP resources as EM's legacy TRU waste is cleaned-up. Prior to the unexpected shutdown of WIPP in 2014, there was a small back-log of waste certified for WIPP disposal and shipments of TRU waste to WIPP were 'just-in-time' as waste was certified. After three years of WIPP being down, DOE sites have built significant back-logs of TRU waste to be certified for WIPP. That back-log built up to over 25,000 containers of TRU waste during that three-year period (Table 1). The backlog included both Contact-Handled (CH) TRU waste and Remote-Handled (RH) TRU waste, and even though WIPP re-opened in April of 2017, it is only open for TRU waste containers that can be stacked on disposal room floors. Plans for changing RH waste disposal packages and methods are in-the-works, but are not yet mature enough for significant planning. In addition, the WIPP underground facilities are now partially contaminated with radioactive particulate, which significantly reduces the WIPP operational efficiencies as compared to 2014. With a large back-log of waste ready for WIPP disposal and limited throughput for WIPP disposal rates, the focus of the NTWMP is to prioritize the selection of TRU wastes from the various sites based on WIPP waste emplacement rates and shipping rates to WIPP. Some TRU waste sites have a significant need to be top priority for shipments to WIPP, and that must be balanced with the need for all TRU waste sites to have some shipments to deplete their back-log of TRU wastes. Storage and management of TRU waste is very costly for DOE and many of those resources could be used to optimize the overall disposition of TRU waste and save DOE significant funding. In addition, the plan will show the possible transition of TRU Waste Management from primarily being an EM function to being an NNSA function in the coming years. As legacy TRU waste inventories are removed, and as NNSA mission-related TRU waste inventories are produced, DOE will be faced with deciding where the primary responsibility for TRU waste management should reside. (author)

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DOE OSTI2020

Key Technical Issues for Greater-Than-Class-C (GTCC) Waste Disposal - 20164

Greater-than-Class C (GTCC) waste is low-level waste (LLW) that exceeds the Class C concentrations tabulated in Title 10, Code of Federal Regulations (CFR), Part 61. Disposal of GTCC waste in the near surface (i.e. upper 30 m of the earth's surface) is prohibited in the United States. Though GTCC waste disposal is generally prohibited, the Commission can approve disposal according to 10 CFR 61.55(a)(2)(iv) on a case-by-case basis. The waste classification tables, developed in the early 1980's, were based on model projections of dose to an inadvertent intruder in agricultural, construction, and discovery exposure scenarios. The assumptions and parameters used were documented in a series of public reports. Though different disposal facility designs and site conditions were considered, the waste classification tables were based on a disposal facility design located in a specific environment. The tables were based on shallow (i.e., top few meters) trench facility designs and did not consider deeper facilities. To determine the suitability of GTCC waste disposal in the near-surface, site-specific analyses must account for differences between GTCC waste and Class A, B, and C LLW (hereafter, traditional LLW). GTCC waste can have concentrations of radionuclides that are much higher than traditional LLW. Because of these higher concentrations, processes that are typically not significant for traditional LLW may be significant with respect to disposal of GTCC waste. These processes include, but are not limited to, heat generation, criticality, and radiolysis. The form of the waste as well as the barriers to release of the waste (e.g. waste package) could be substantially different than they are for traditional LLW. These barriers need to be considered when assessing the impacts of accidents during receipt and placement and in evaluating long-term performance. Some GTCC radioactivity is either embedded in stainless steel or contained in stainless steel barriers. Stainless steel can have very low corrosion rates under a variety of environmental conditions. Finally, and possibly most importantly, GTCC waste would likely need to be disposed deeper than traditional LLW to reduce the probability of disturbance. The waste classification table values of traditional LLW are based on an inadvertent intruder excavating into the waste and bringing some of the material to the land surface. If waste is deeper than approximately 5 m, the excavation scenario becomes very unlikely. Therefore, other intruder scenarios, such as drilling exposure scenarios, need to be evaluated. This paper summarizes key technical issues for the disposal of GTCC waste. Our previous study shows that certain GTCC waste may be suitable for near surface disposal whereas others may not. This study may support ongoing technical analyses assessing potential disposal of GTCC in a near surface disposal facility. (authors)

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DOE OSTI2021

Annual Status Report (FY 2020): Performance Assessment for the Environmental Restoration Disposal Facility

DOE O 435.1 and DOE M 435.1-1 require that a determination of continued adequacy of the performance assessment (PA) (CP-60089), composite analysis, and disposal authorization statement (DAS) be made annually, and these guidelines must be used to consider the results of data collection and analysis from research, field studies, and monitoring as well as provide the need to update any radioactive waste management basis documents. Beginning in 1996, the Environmental Restoration Disposal Facility (ERDF) started accepting low-level radioactive, hazardous, and mixed wastes generated during cleanup activities at the Hanford Site. ERDF is composed of a series of cells or disposal areas and can accommodate future design expansions as needed. Currently, there are 10 cells. During this reporting period (fiscal year 2020, which extended from October 1, 2019, through September 30, 2020), approximately 3.39E+04 U.S. tons (3.07E+04 metric tons) of waste was disposed at ERDF. From ERDF inception through September 30, 2020, approximately 18.5 million U.S. tons of waste has been disposed at ERDF, which equates to the consumption of approximately 88% of the disposal volume. As a condition of the DAS, disposal operations within ERDF must be in accordance with the waste acceptance criteria (ERDF-00011) that provide specific radionuclide disposal limits, waste form restrictions, and descriptions of acceptable waste packages in compliance with DOE M 435.1-1 requirements. The ERDF waste acceptance criteria stipulate that waste destined for disposal at ERDF be controlled based on source, physical form, and contaminant concentration and activity levels. There have been no changes to the physical configuration of ERDF or to the waste forms (source, physical form, etc.). No new Unreviewed Disposal Question Screenings or Evaluations have been generated during this reporting period. Therefore, there are no noted impacts to the PA, composite analysis, DAS, or radioactive waste management basis documents resulting from the evaluations and screenings. Sum of fraction analysis shows that the disposed inventory meets both the concentration and inventory threshold requirements. A sum of fractions value is computed for ERDF sensitive radionuclides contributing to the all pathways and air pathway inventory limits. Computed values were 8.85E-02 and 1.78E-01, respectively. The disposed waste inventory remained well under the PA imposed limits. Required monitoring was satisfactorily completed during the fiscal year reporting period (fiscal year 2020). Compliance with performance objectives were met as each of the reported values were well below the established limit. Overall, there are no substantive changes to primary PA assumptions nor changes to the PA analysis conclusion; therefore, compliance with DOE O 435.1 and the DAS is maintained.

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DOE OSTI2023

Performance Assessment for the Environmental Restoration Disposal Facility (Annual Status Report FY 2022)

DOE O 435.1 and DOE M 435.1-1 require that a determination of continued adequacy of the performance assessment (PA) (CP-60089), composite analysis (CA), and disposal authorization statement (DAS) be made on an annual basis, and that the determination must consider the results of data collection and analysis from research, field studies, and monitoring as well as the need to update any Radioactive Waste Management Basis (RWMB) documents. Beginning in 1996, the Environmental Restoration Disposal Facility (ERDF) started accepting low-level radioactive, hazardous, and mixed wastes that were generated during cleanup activities at the Hanford Site. ERDF is composed of a series of cells or disposal areas and can accommodate future design expansions as needed. Currently, there are eight cells and two supercells in ERDF. Each supercell is the equivalent of two cells. During this reporting period (fiscal year 2022, extending from October 1, 2021, through September 30, 2022), approximately 8.52E+04 metric tons (9.39E+04 U.S. tons) of waste was disposed at ERDF. From ERDF inception through September 30, 2022, approximately 17.0 million metric tons (18.7 million U.S. tons) of waste has been disposed at ERDF, which equates to consumption of approximately 89.1% of the currently constructed disposal volume. According to the design of ERDF, the facility has the ability to be expanded as needed. As a condition of the DAS, disposal operations within ERDF must be in accordance with the waste acceptance criteria (ERDF-00011) that provide specific radionuclide disposal limits, waste form restrictions, and descriptions of acceptable waste packages in compliance with the requirements of DOE M 435-1.1. The ERDF waste acceptance criteria stipulate that waste destined for disposal at ERDF be controlled based on source, physical form, and contaminant concentration and activity levels. There have been no changes to the physical configuration of ERDF or to the waste forms (source, physical form, etc.). No new unreviewed disposal question screenings or evaluations have been generated in this reporting period. Therefore, there are no noted impacts to the PA, CA, DAS, or RWMB resulting from the evaluations and screenings. Sum-of-fractions analysis shows that the disposed inventory meets both the concentration and inventory threshold requirements. A sum-of-fractions value is computed for ERDF sensitive radionuclides contributing to the groundwater pathways and the air pathway inventory limits. Computed values were 5.50E-04 and 3.30E-03, respectively. The disposed waste inventory remained well under the PA imposed limits, as shown in Table 4 and Table 5 in the main text of this report. Required monitoring was satisfactorily completed during the fiscal year reporting period. Compliance with performance objectives were met as each of the reported values were well below the established limit. Overall, there are no substantive changes to primary PA assumptions or changes to the PA analysis conclusion; therefore, compliance with DOE O 435.1 and the DAS is maintained.

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DOE OSTI2022

Performance Assessment for the Environmental Restoration Disposal Facility (Annual Status Report FY 2021)

DOE O 435.1 and DOE M 435.1-1 require that a determination of continued adequacy of the performance assessment (PA) (CP-60089), composite analysis (CA), and disposal authorization statement (DAS) be made on an annual basis, and that the determination must consider the results of data collection and analysis from research, field studies, and monitoring as well as the need to update any Radioactive Waste Management Basis (RWMB) documents. Beginning in 1996, the Environmental Disposal Facility (ERDF) started accepting low-level radioactive, hazardous, and mixed wastes that were generated during cleanup activities at the Hanford Site. ERDF is composed of a series of cells or disposal areas and can accommodate future design expansions as needed. Currently, there are eight cells and two supercells in ERDF. Each supercell is the equivalent of two cells. During this reporting period (fiscal year 2021, extending from October 1, 2020, through September 30, 2021), approximately 9.14E+04 metric tons (1.01E+05 U.S. tons) of waste was disposed at ERDF. From ERDF inception through September 30, 2021, approximately 16.9 million metric tons (18.9 U.S. tons) of waste has been disposed of at ERDF, which equates to consumption of approximately 88.7% of the currently constructed disposal volume. According to the design of ERDF, the facility has the ability to be expanded as needed. As a condition of the DAS, disposal operation within ERDF must be in accordance with the waste acceptance criteria (ERDF-00011) that provide specific radionuclide disposal limits, waste form restrictions, and descriptions of acceptable waste packages in compliance with the requirements of DOE M 435-1.1. The ERDF waste acceptance criteria stipulate that waste destined for disposal at ERDF be controlled based on source, physical form, and contaminant concentration and activity levels. There have been no changes to the physical configuration of ERDF or to the waste forms (source, physical form, etc.). No new unreviewed disposal question screenings or evaluations have been generated in this reporting period. Therefore, there are no noted impacts to the PA, CA, DAS, or RWMB resulting from the evaluations and screenings. Sum-of-fractions analysis shows that the disposed inventory meets both the concentration and inventory threshold requirements. A sum-of-fractions value is computed for ERDF sensitive radionuclides contributing to the all pathways and the air pathway inventory limits. Computed values were 7.63E-03 and 1.49E-03, respectively. The disposed waste inventory remained well under the PA imposed limits, as shown in Table 4 and Table 5 in the main text of this report. Required monitoring was satisfactorily completed during the fiscal year reporting period. Compliance with performance objectives were met as each of the reported values were well below the established limit. Overall, there are no substantive changes to primary PA assumptions or changes to the PA analysis conclusion; therefore, compliance with DOE O 435.1 and the DAS is maintained.

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DOE OSTI2016

Pathways for Disposal of Commercially-Generated Tritiated Waste

From a waste disposal standpoint, tritium is a major challenge. Because it behaves like hydrogen, tritium exchanges readily with hydrogen in the ground water and moves easily through the ground. Land disposal sites must control the tritium activity and mobility of incoming wastes to protect human health and the environment. Consequently, disposal of tritiated low-level wastes is highly regulated and disposal options are limited. The United States has had eight operating commercial facilities licensed for low-level radioactive waste disposal, only four of which are currently receiving waste. Each of these is licensed and regulated by its state. Only two of these sites accept waste from states outside of their specified regional compact. For waste streams that cannot be disposed directly at one of the four active commercial low-level waste disposal facilities, processing facilities offer various forms of tritiated low-level waste processing and treatment, and then transport and dispose of the residuals at a disposal facility. These processing facilities may remove and recycle tritium, reduce waste volume, solidify liquid waste, remove hazardous constituents, or perform a number of additional treatments. Waste brokers also offer many low-level and mixed waste management and transportation services. These services can be especially helpful for small-quantity tritiated-waste generators, such as universities, research institutions, medical facilities, and some industries. The information contained in this report covers general capabilities and requirements for the various disposal/processing facilities and brokerage companies, but is not considered exhaustive. Typically, each facility has extensive waste acceptance criteria and will require a generator to thoroughly characterize their wastes. Then a contractual agreement between the waste generator and the disposal/processing/broker entity must be in place before waste is accepted. Costs for tritiated waste transportation, processing and disposal vary based a number of factors. In many cases, wastes with very low radioactivity are priced primarily based on weight or volume. For higher activities, costs are based on both volume and activity, with the activity-based charges usually being much larger than volume-based charges. Other factors affecting cost include location, waste classification and form, other hazards in the waste, etc. Costs may be based on general guidelines used by an individual disposal or processing site, but final costs are established by specific contract with each generator. For this report, seven hypothetical waste streams intended to represent commercially-generated tritiated waste were defined in order to calculate comparative costs. Ballpark costs for disposition of these hypothetical waste streams were calculated. These costs ranged from thousands to millions of dollars. Due to the complexity of the cost-determining factors mentioned above, the costs calculated in this report should be understood to represent very rough cost estimates for the various hypothetical wastes. Actual costs could be higher or could be lower due to quantity discounts or other factors.

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