This section provides an overview of (1) the legal framework governing mixed HLW, (2) the status of EM’s IWTU reengineering project, (3) EM’s requirements for capital asset projects and operations activities, (4) DOE’s policy for the review of projects with start-up risks, and (5) our best practices for assessing cost and schedule estimates. The treatment and disposal of mixed HLW at INL is governed by a number of federal laws that define the roles of federal agencies and states in managing mixed HLW, as well as cleanup agreements among DOE, the state of Idaho, and other parties. DOE primarily regulates radioactive components of HLW under the Atomic Energy Act of 1954, as amended, and the Nuclear Waste Policy Act of 1982, as amended. These acts define HLW as (1) the highly radioactive waste material resulting from the reprocessing of spent nuclear fuel, including liquid waste produced directly in reprocessing and any solid material derived from such liquid waste that contains fission products in sufficient concentrations, and (2) other highly radioactive material that the Nuclear Regulatory Commission determines by rule, consistent with existing law, requires permanent isolation. DOE considers calcine waste HLW because it is solidified liquid waste produced during the reprocessing of spent nuclear fuel. EM manages the SBW as mixed HLW because, according to reports from DOE and National Academies, (1) the SBW was produced in the later stages of spent nuclear fuel reprocessing, (2) the tanks in which the SBW is stored previously held HLW, (3) the SBW is stored in a location at INL where waste is managed as HLW, and (4) the waste contains hazardous chemicals subject to RCRA and EPA’s implementing regulations or authorized state programs that operate in lieu of the federal program. HLW must be disposed of in a geologic repository unless the Nuclear Regulatory Commission approves an alternative disposal site. DOE Order 435.1 and Manual 435.1-1 describe the department’s policy and requirements for managing DOE’s radioactive waste, including HLW, to ensure that it is managed in a manner that is protective of worker and public health and safety and the environment. Manual 435.1-1 also established processes to determine whether waste resulting from reprocessing spent nuclear fuel can be managed as transuranic waste or low-level waste if certain criteria are met, which is referred to as a determination that the waste is incidental to reprocessing. According to the manual, HLW is waste incidental to reprocessing if, among other things, the waste has been processed, or will be processed, to remove key radionuclides to the maximum extent technically and economically practicable. Hazardous components of mixed HLW are regulated by EPA or authorized states under RCRA. EPA’s regulations require hazardous waste to meet certain treatment standards before land disposal of the waste unless a variance is granted. The regulations specify that the treatment standard (i.e., the required method for treatment) for Idaho’s mixed HLW is vitrification—the immobilization of waste in glass. Where EPA has authorized states to implement hazardous waste management programs, those state programs operate instead of the federal program. EPA, under RCRA, has authorized the state of Idaho to administer its own hazardous waste management program. EPA has also authorized New Mexico to administer its own hazardous waste management program. Pursuant to such authorization, New Mexico’s Environment Department issues the permit for hazardous waste storage and disposal at WIPP under the New Mexico Hazardous Waste Act. As of March 2019, EM’s IWTU reengineering project was in phase two of the four-phased approach to get the facility operational, according to EM Idaho Cleanup Project officials. According to project reports, phase one focused on identifying fixes to resolve problems with the facility’s equipment and waste treatment process, for example, by performing engineering analyses and chemistry studies. Phase two has focused on implementing these fixes, for example, by modifying a piece of equipment that separates solidified waste before it is moved to storage canisters, according to the contractor’s project plan. Figure 1 summarizes the four- phased approach for the IWTU reengineering project. According to EM documents, as of February 2019 total expenditures on phases one and two were approximately $150 million, about $64 million more than original costs estimated for those two phases combined, and the project was over 1 year behind schedule. Phase two has taken longer and cost more than initially estimated because of additional problems and required modifications to the facility as the work has progressed, according to EM Idaho Cleanup Project officials. Appendix II provides information on the actual costs of phases one and two compared to estimated costs. As previously noted, EM officials with the Idaho Cleanup Project estimated in March 2019 that phase three may begin in summer 2019. Further, these officials stated that phase three will involve a 6- month outage to continue implementing changes to the facility prior to the start of a 60-day performance test using a simulated waste form. EM Idaho Cleanup Project officials stated that phase four could begin in early 2020 and that EM and Fluor Idaho had yet to determine whether an outage would need to occur before starting testing with a small amount of the SBW. EM divides its cleanup work into capital asset projects and operations activities, two types of activities governed by different applicable project management policies: Capital asset projects. DOE Order 413.3B governs EM’s program and project management activities for the acquisition of capital assets, with the stated goal of delivering fully capable projects within the planned cost, schedule, and performance baseline. The order establishes five critical decision points of project development that each end with a major approval milestone that cover the life of a project. The order specifies requirements that must be met, including developing and managing project cost and schedule estimates to move a project past each critical decision milestone. EM capital asset projects include construction projects and cleanup projects, such as soil and water remediation and facility decommissioning and demolition. Operations activities. Operations activities are recurring facility or environmental operations, as well as activities that are project-like, with defined start and end dates, according to EM policy. EM operations activities include operating waste processing facilities and the stabilization, packaging, transportation, and disposition of nuclear waste. EM manages operations activities based on requirements listed in a cleanup policy that it issued in July 2017. In February 2019, we found that EM cleanup site managers have discretion in how to classify cleanup work because DOE and EM have not established requirements on what work should be managed as an operations activity under EM’s cleanup policy or as a capital asset project under DOE Order 413.3B. Further, we found that operations activities have less stringent management requirements than capital asset projects. We recommended that EM establish requirements for classifying work as an operations activity and revise its cleanup policy to follow program and project management leading practices. DOE generally agreed with our recommendations. Beginning in January 2005, EM managed the development and construction of the IWTU facility as a capital asset project. Once EM determined that construction on the facility was complete in April 2012, the project exited the capital asset oversight process established in DOE Order 413.3B and has since been managed as an operations activity, according to EM Idaho Cleanup Project officials. DOE officials also told us that the IWTU reengineering project has been managed as an operations activity because the facility has been constructed and is now in a period of maintenance and repair. Figure 2 shows a picture of the exterior of the IWTU facility. In August 2016, DOE’s Deputy Secretary of Energy issued a memorandum establishing a new oversight requirement for selected projects for which an extended period of transition to operations is likely— the phase after construction is complete but before full operational capability is attained—called the operational release milestone. According to the memorandum, DOE created the operational release milestone in the department’s project life cycle to provide additional oversight after the completion of the project under DOE’s Order 413.3B. DOE officials from the Office of Project Management stated that the operational release milestone was largely created in response to EM’s experience with the IWTU facility not operating as expected. Under these new requirements, program offices are to provide DOE’s Project Management Risk Committee (PMRC) with regular updates on selected projects until full operational capability of each facility is attained. Specifically, program offices are required to (1) develop and execute a plan that describes how the program will reach operational capability, which is referred to as an operational release plan, and (2) provide progress updates to the PMRC on the project, as described below. Operational release plan. Officials from DOE’s Office of Project Management—which serves as the secretariat for the PMRC—stated that the purpose of the operational release plan is for the program office to describe what steps are required for the project to reach its operational capability. According to EM’s guidance, the operational release plan should present the key processes, activities, interrelationships, risks, management and oversight, decision milestones and approvals, and overall schedule to achieve operational release. Progress updates. According to the memorandum and the PMRC’s standard operating procedures, program offices are to provide the PMRC with quarterly progress updates on selected projects, including lessons learned, until full operational capability is attained. The GAO’s cost guide and schedule guide compiled best practices corresponding to the characteristics of high-quality and reliable cost and schedule estimates. According to the cost guide, a high-quality, reliable cost estimate has four characteristics: comprehensive, well-documented, accurate, and credible. A comprehensive cost estimate has enough detail to ensure that cost elements are neither omitted nor double-counted. If a cost estimate is not comprehensive (that is, complete), then it cannot fully meet the other characteristics (i.e., well-documented, accurate, or credible). In addition, according to the schedule guide, a high-quality, reliable schedule has four characteristics: comprehensive, well- constructed, controlled, and credible. A comprehensive schedule captures all government and contractor activities necessary to accomplish a project’s objectives, and a well-constructed schedule sequences all activities using the most straightforward logic possible. If a schedule is not comprehensive, with all activities accounted for, it is uncertain whether all activities are scheduled in the correct order, resources are properly allocated, missing activities will appear on the critical path, or a schedule risk analysis can account for all risk. If a schedule is not well-constructed, it will not be able to properly calculate dates and predict changes in the future, among other things. EM has not fully followed selected project management best practices for cost and schedule estimates for the IWTU reengineering project. EM generally followed best practices for a reliable EVM system to measure the performance of the reengineering project. However, in analyzing IWTU reengineering project data from March 2017 through February 2018, we found that the system is producing unreliable data, which may limit EM’s ability to measure the project’s performance. Further, EM has taken some steps toward meeting requirements under DOE’s process for monitoring projects with start-up risks. EM has not fully followed (i.e., has partially met) selected best practices in developing the cost and schedule estimates we reviewed for phases one and two of the IWTU reengineering project and future planned IWTU operations. We made the following observations based on our analysis of these cost estimating documents and a March 2018 project schedule: Comprehensive cost estimate (partially met): EM partially met best practices for a comprehensive cost estimate. According to our cost guide, a comprehensive cost estimate should reflect the project’s technical requirements and current schedule and account for all possible costs. While the cost estimate was based on documented technical information, it was not based on a standardized work breakdown structure. Without a standard, product-oriented work breakdown structure to facilitate the tracking of resource allocations and expenditures, EM may not be able to reliably estimate the cost of future similar programs. While assumptions are listed in EM’s documents describing the cost estimates, no document discusses whether the assumptions came from inputs from technical subject matter experts or whether the assumptions are associated with specific risks. Since assumptions are best guesses, best practices state that the risk associated with any of these assumptions changing need to be identified and assessed. Further, the IWTU reengineering project’s cost estimate was not complete because it did not account for all possible costs. According to our cost guide, a life cycle cost estimate provides an exhaustive and structured accounting of all resources and associated cost elements required to develop, produce, deploy, and sustain a particular program. The project’s cost estimate did not reflect all life cycle costs, in part because estimates for phases three and four of the project had not been developed at the time of our review. Best practices state that all costs be included in an estimate, even in early stages, such as at a rough order of magnitude. EM officials from the Idaho Cleanup Project said that a cost estimate was not developed for the total cost of the IWTU reengineering project because of the approach for negotiating the cost and schedule baseline prior to the start of each phase. Without developing a cost estimate for the IWTU reengineering project that is comprehensive (e.g., accounts for all possible costs), EM will not have reasonable assurance that it can successfully plan program resource requirements. Well-constructed schedule estimate (partially met): EM partially met best practices for a well-constructed schedule. According to our schedule guide, a well-constructed schedule includes activities that are logically sequenced; a valid critical path; and a reasonable amount of total float, meaning an accurate reflection of the schedule’s flexibility. EM’s March 2018 schedule had minimal sequencing issues and a continuous critical path, with the exception of an external dependency, and the critical path was free of lags and constraints. However, there were long duration activities on the critical path that should be reevaluated to determine if they can be broken into more manageable pieces. Without a valid critical path, management cannot focus on activities that will detrimentally affect the key program milestones and deliveries if they slip. Additionally, the schedule estimate included unreasonably large values of positive and negative float. According to best practices, a schedule should identify reasonable values of float so that the schedule’s flexibility can be determined to help accommodate for delays. EM officials from the Idaho Cleanup Project explained that the amount of total float was a result of the methods they used to structure the logic of the schedule estimate, which according to our best practices may have caused the schedule to be overly optimistic. According to scheduling best practices, without accurate values of total float, the schedule cannot be used to identify activities that could be permitted to slip and thus release and reallocate resources to activities that require more resources to be completed on time. Inaccurate values of total float also falsely depict true program status, which could lead to decisions that may jeopardize the program. In addition, the March 2018 schedule contained 14 activities with large amounts of negative float, meaning that these activities were behind schedule. Without fully developing a well-constructed schedule estimate for the IWTU reengineering project, EM will not have reasonable assurance that it can successfully achieve its plans to reengineer the IWTU and begin treatment of the SBW without further delays. Comprehensive schedule estimate (substantially met): EM substantially met best practices for a comprehensive schedule. According to our schedule guide, a comprehensive schedule includes all activities for both the government and its contractors to accomplish their objective, assigns resources (e.g., labor and materials) to all activities, and establishes how long each activity will take. EM’s March 2018 schedule substantially captured all activities, but it may not have been planned to the level of detail for the work necessary to accomplish a program’s objectives as defined in the program’s work breakdown structure. For example, the schedule had activities that were described as level of effort but were not assigned the level of effort activity type. Level of effort activities represent effort that has no measurable output and, according to best practices, should be clearly marked so they do not interfere with the critical path. Further, the schedule substantially met the best practice of assigning resources to all activities. For example, the schedule assigned resources to specific materials and equipment as well as to travel, training, and labor. Appendix II contains the full results of our analysis of selected best practices for the cost and schedule of the IWTU reengineering project. As previously noted, EM is managing the IWTU reengineering project as an operations activity. We reported in February 2019 that EM manages operations activities using less stringent requirements than those used for capital asset projects, posing cost and schedule risks. For example, under EM’s 2017 cleanup policy, there is no requirement for operations activities to follow best practices for cost estimates developed during contract execution. We recommended that EM review and revise its 2017 cleanup policy to include project management leading practices related to scope, cost, schedule performance, and independent reviews. DOE concurred with our recommendation and stated that EM was already in the process of reviewing its policy for necessary updates, revisions, and modifications, and that EM would consider our recommendation, as appropriate, during this process. EM officials with the Idaho Cleanup Project acknowledged that they do not have an estimate for the total cost or a completion date for the IWTU reengineering project or a schedule for when waste treatment operations will begin and be completed. An EM Idaho Cleanup Project official told us that Fluor Idaho submitted cost and schedule estimates for phases three and four of the reengineering project in January 2019 and that EM requested an independent cost estimate for this work from the Defense Contract Audit Agency, with contract negotiations between EM and Fluor Idaho for these phases estimated to begin in spring 2019. In addition, EM officials from the Idaho Cleanup Project acknowledged that a schedule for waste treatment operations at the project has not been developed. Further, these officials noted that design modifications to the IWTU are expected to reduce its operating capability, lengthening the time needed to treat the SBW. As a result, EM and Fluor Idaho plan to renegotiate the cost of their contract related to the treatment of the waste in the project, according to EM Idaho Cleanup Project officials. Specifically, because of the modifications to the project, the rate at which the SBW is treated will be slower than initially estimated, according to EM officials from the Idaho Cleanup Project. Treatment of all 900,000 gallons of the SBW was originally estimated to be completed in 10 months, but agency officials now estimate that treatment may take from 3 to 7 years— as much as eight times longer than originally planned. As previously noted, EM has already experienced approximately $64 million in added costs and, as of February 2019, a delay of over 1 year. Without fully following best practices for a comprehensive cost estimate and well- constructed schedule estimate for SBW waste treatment operations, EM cannot be assured that it has reliable cost and schedule estimates for decision-making, placing it at risk of continued cost overruns and delays in achieving its plans to reengineer the IWTU and begin treatment of the SBW. We analyzed IWTU reengineering project data for March 2017 through February 2018 from EM’s EVM system and found that while EM has followed (i.e., fully met or substantially met) some best practices for a reliable EVM system, the system is producing unreliable data. These unreliable data may limit EM’s ability to measure the project’s performance. EVM is a management tool used to measure the value of work accomplished in a given period and compare it with the planned value of work scheduled for the same period and with the actual cost of the work accomplished. EVM data can alert project managers to potential problems sooner than expenditures alone can, and EVM’s use as a management tool is considered a best practice for conducting cost and schedule performance analysis for projects, according to our cost guide. EM requires the use of an EVM system under its contract with Fluor Idaho for the Idaho Cleanup Project. Overall, we found that EM followed best practices to ensure that its EVM data for the IWTU reengineering project were (1) comprehensive and (2) used by leadership for decision-making. However, EM did not follow (i.e., partially met) best practices to ensure that the data resulting from the EVM system are reliable. Specifically: EM substantially met best practices for a comprehensive EVM system by, for example, requiring the contractor’s EVM system to comply with the guidelines established by the Earned Value Management Systems EIA-748-D Intent Guide; EM conducted a compliance review of Fluor Idaho’s EVM system in March 2017 and found some areas in need of improvement. In addition, EM has an EVM surveillance system in place under its contract with Fluor Idaho, and EM officials from the Idaho Cleanup Project stated that they review data from the EVM system each month. EM substantially met best practices ensuring that leadership uses the EVM data for decision-making. For example, Fluor Idaho updated data in its EVM system monthly during the period we reviewed, and EM reported issues in a monthly review briefing between EM and the contractor, according to EM Idaho Cleanup Project officials. Agency management also tracked the causes of cost and schedule variances in the data. However, the monthly reports did not contain all the information that best practices recommended. Specifically, the performance measurement baseline was not included in the contractor performance reports provided, so we could not determine how the performance measurement baseline changed as the project evolved. EM partially met best practices ensuring that the EVM system provides reliable data because, for instance, the system contained numerous anomalies, leading the system to produce unreliable data. Specifically, we found one or more anomalies present in all months of data reviewed, such as missing or negative values. While EM was able to explain the causes for most of these anomalies, negative values should occur rarely, if ever, in EVM reporting because they imply the undoing of previously scheduled or performed work. According to best practices, all anomalies should also be identified and the reason for each should be fully explained in EM’s monthly EVM reports. However, EM did not document the reasons for these anomalies in its monthly reports. EM officials from the Idaho Cleanup Project said that most of the anomalies in the data were due to the phase two estimate including authorized unpriced work—that is, additional work that EM agreed to let the contractor perform without first negotiating or independently verifying the costs. If errors in EVM reports are not detected, then EVM data will be skewed, resulting in bad decision-making and limiting EM’s ability to use the EVM system to measure project performance. Appendix III provides detailed information on EM’s performance on each EVM best practice. An EVM system that produces unreliable data may contribute to EM’s challenges in measuring the performance of its operations activities. Our findings in this regard are consistent with our prior reports examining EM’s use of EVM systems in other contracts. For example, in February 2019 we reviewed the use of EVM systems in the 21 contracts EM uses to execute its operations activities, including Fluor Idaho’s contract for the cleanup at INL, and found that EM has not followed best practices to ensure that these systems (1) are comprehensive, (2) provide reliable data, and (3) are used by EM leadership for decision-making. We recommended that EM update its cleanup policy to require that EVM systems be maintained and used in a way that follows EVM best practices, such as ensuring the reliability of the data in the system. Without following best practices for ensuring EVM data reliability for the IWTU reengineering project’s EVM system, EM leadership may not have access to reliable performance data with which to make informed decisions as it manages billions of dollars’ worth of cleanup work and provides information to Congress and other stakeholders on the cleanup work every year. In 2016, DOE instituted independent review requirements to monitor facilities with commissioning or start-up risks, and EM has taken some steps toward meeting those requirements for the IWTU reengineering project. As previously noted, DOE’s policy requires program offices to (1) develop and execute an operational release plan and (2) provide progress updates to the PMRC on the project each quarter. We made the following observations on EM’s actions to meet these requirements for the reengineering of the IWTU project: EM developed an operational release plan for the IWTU project in December 2016, which preceded EM’s developing guidance for these plans. We found that the operational release plan included the majority of elements that EM’s guidance later required. EM has provided five progress update briefings to the PMRC on the IWTU reengineering project, according to DOE documents, but these briefings have not occurred each quarter as required by DOE’s policy. Officials from DOE’s Office of Project Management told us that briefings generally occur when progress has been made on a project. EM’s guidance for operational release plans also states, with regard to progress update briefings, that an alternate reporting schedule may be proposed for PMRC approval. The PMRC made recommendations in three of these five briefings. For example, the PMRC recommended that EM revisit and review documents to ensure that the delegated authority is clear, current, and appropriate prior to facility start-up and the introduction of radioactive materials. According to documentation prepared following EM’s most recent briefing to the PMRC in February 2019, the PMRC recommended an update on the project in July 2019. Based on our review of EM documentation and plans, the agency does not have a strategy or timeline to address its three main challenges for disposing of the SBW or for identifying an alternative disposal pathway. EM identified WIPP as its preferred disposal site for the SBW in a 2005 Record of Decision document, but in March 2019 EM officials told us that a final decision on the disposal path for the SBW had not been made. The three main challenges EM faces in its plan to dispose of the SBW at its preferred disposal site are: (1) the permit for WIPP prohibits the SBW from being disposed of at WIPP, (2) federal law prohibits HLW from being disposed of at WIPP, and (3) there are existing capacity limitations to disposal at the WIPP facility. EM has taken some steps to address these challenges, as discussed further below. WIPP permit’s prohibition of the disposal of certain tank waste. New Mexico amended its permit for WIPP in 2004 to prohibit waste that has ever been managed as HLW, including the SBW at INL, from being disposed at WIPP unless the disposal of such waste is specifically approved through a permit modification. In 2013, DOE and its contractor responsible for operating and managing the facility filed a request with the state of New Mexico to modify the WIPP permit to remove this prohibition, which could allow the SBW to be disposed of at WIPP if EM determined that the SBW is waste incidental to reprocessing. However, the process was put on hold following the suspension of operations at WIPP in 2014, according to officials from DOE’s Carlsbad Field Office and New Mexico’s Environment Department. In April 2019, officials from New Mexico’s Environment Department said that they anticipated holding discussions with DOE and its contractor for the facility regarding the prohibition after the renewal of the WIPP permit in July 2020. However, a representative from a New Mexico environmental organization said that this proposed modification would likely face strong public opposition. This representative noted that previous DOE attempts to expand the types of waste that could be disposed of at WIPP caused significant public concern in New Mexico. Further, New Mexico Environment Department officials told us that processing permit modifications of this nature would likely require public hearings and opportunities for input and may take as long as 2 years or more to complete. Federal statutory prohibition on HLW disposal at WIPP. The Waste Isolation Pilot Plant Land Withdrawal Act prohibits disposal of HLW at WIPP. Therefore, to enable EM to dispose of the SBW at WIPP, the SBW would need to be classified as non-HLW, or the act would need to be amended to remove the prohibition. DOE has a process for determining that certain waste resulting from reprocessing spent nuclear fuel, such as the SBW and calcine waste, could be managed as either transuranic waste or low-level waste, which are not HLW. Under DOE Order 435.1 and Manual 435.1-1, DOE may determine that waste is incidental to reprocessing and therefore manage the waste as transuranic waste or low-level waste if it meets certain criteria. EM began developing documentation supporting a waste incidental to reprocessing determination for the SBW in 2001. For example, in September 2001, EM requested consultation from the Nuclear Regulatory Commission, which oversees the nuclear power industry, on a draft waste incidental to reprocessing determination so that the SBW could be managed as transuranic waste and disposed of at WIPP rather than in an HLW repository. DOE’s Authority to Determine That Certain Waste Is Not HLW In 2002, while litigation over the Department of Energy’s (DOE) authority to use DOE Order 435.1 and Manual 435.1-1 was pending, DOE sought enactment of legislation clarifying its authority to manage portions of tank waste that have low levels of radioactivity as low- level waste. In response, Congress enacted section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 in October 2004. Under section 3116, radioactive waste resulting from the reprocessing of spent nuclear fuel is not high- level waste (HLW) if the Secretary of Energy, in consultation with the Nuclear Regulatory Commission, determines that it meets specified conditions. These conditions include that the waste does not require disposal in a deep geologic repository and has had highly radioactive radionuclides removed to the maximum extent practical. However, section 3116 only applies to waste stored at DOE sites in Idaho and South Carolina that is not transported from those states. Therefore, DOE cannot use section 3116 to classify the sodium-bearing waste (SBW) as transuranic waste for disposal as DOE’s agreements with Idaho require the SBW to be removed from the state. However, DOE’s authority to use Order 435.1 and Manual 435.1-1 to classify the SBW and other waste from reprocessing as non-HLW was challenged in a federal lawsuit in 2001, resulting in EM suspending its development of the waste incidental to reprocessing determination. Following the dismissal of the lawsuit on procedural grounds, EM restarted the internal process for developing the waste incidental to reprocessing determination for the SBW, according to EM officials and documents. For example, EM identified the waste incidental to reprocessing determination for the SBW as a priority item for executive decision-making in a 2017 EM study on mission operations. Internal discussions about this determination continued between EM and DOE into 2018, but the waste incidental to reprocessing determination was not finalized, according to EM officials. In October 2018, EM published a notice in the Federal Register seeking public comment on its proposed interpretation of the statutory definition of HLW, which EM officials said could help the agency make a decision about the classification of the SBW. EM also published a supplemental notice in June 2019 to modify the interpretation and provide additional information to the public, such as on the role of the Nuclear Regulatory Commission and states. Table 1 presents the statutory definition, the proposed interpretation from the October 2018 Federal Register notice, and the modified interpretation from the June 2019 Federal Register notice. EM officials told us that under the new interpretation, waste would be disposed of in accordance with its characteristics (which determines risk) instead of solely based on the source of the waste (which does not determine risk). Stakeholders, including members of the public, state and local governments, tribes, and the Nuclear Regulatory Commission, expressed a range of perspectives about EM’s proposed interpretation in public comments. For example, some stakeholders submitted comments expressing concern about the Nuclear Regulatory Commission being excluded from the determination of what is HLW under the interpretation. These comments also stated that the interpretation is contrary to federal law and that the interpretation will elicit legal challenges. Other stakeholders expressed support for the interpretation in comments submitted to EM stating, for example, that the proposed interpretation could accelerate the cleanup of tank waste at DOE sites and result in cost savings. According to an EM document, potential benefits of the interpretation, if implemented, include a more risk-based approach to waste classification, which could provide a more cost-effective and timely approach to DOE’s cleanup mission. However, EM officials stated that it was premature to discuss the administrative actions, such as revising orders or regulations that would be required to implement the new interpretation. The June 2019 Federal Register notice states that DOE will consider what actions may be needed and appropriate to update applicable DOE directives, such as Order 435.1 and Manual 435.1-1, in light of this interpretation and address any revisions in future actions. EM officials also told us that they did not have a timeline for implementing the new interpretation. Further, EM officials stated that if the HLW interpretation is implemented, alternative disposal options could also be considered for the SBW, but they declined to specify what those options could be. Limitations on disposal at WIPP. Further, existing limitations in the disposal space at WIPP could affect the disposal of the SBW at the facility. We reported in September 2017 that DOE does not currently have sufficient disposal space at WIPP for the waste identified in its 2016 annual inventory report—a document that tracks waste intended to be disposed of at the facility. Specifically, DOE will need to expand the repository to accommodate this waste as well as other potential waste, such as the SBW, for which DOE has yet to determine if it meets all of WIPP’s waste acceptance criteria. In March 2019, DOE officials stated that WIPP could be expanded within the current Waste Isolation Pilot Plant Land Withdrawal Act boundary for the site to accommodate the current planned waste and additional waste inventories. Specifically, DOE officials said that mining for a new disposal panel and design work for additional disposal panels was under way, and mining of the additional panel was scheduled to commence in 2021. Further, in September 2017 we also reported that additional potential waste beyond what is captured in the inventory could exceed WIPP’s statutory capacity. However, in December 2018, New Mexico’s Environment Department approved a modification to the WIPP permit—which was requested by DOE and its contractor that operates and manages WIPP—that will change the way waste volume is calculated to exclude empty space inside waste packing. According to DOE officials, this means that additional waste can be disposed of at WIPP under the existing statutory limit. Further, DOE officials stated that the revised counting methodology will reduce an overstatement in the volume of record for emplaced waste by about 30 percent. However, in January 2019 three environmental organizations filed lawsuits challenging the modification, which the court consolidated and, in May 2019, stayed pending mediation. EM officials said that if the office is not able to dispose of the SBW at WIPP, its plan is to dispose of the SBW—once it is treated to a solid form in the IWTU—with the calcine waste in an HLW geologic repository. However, there is still no HLW disposal site in the United States. In 2008, DOE submitted a license application to the Nuclear Regulatory Commission for an HLW repository at Yucca Mountain, Nevada, about 100 miles northwest of Las Vegas. In 2010, however, DOE terminated its efforts to obtain a license for the Yucca Mountain repository. Under the 1995 settlement agreement with the state of Idaho, DOE is required to treat the SBW so that it is ready for disposal outside of the state by a target date of 2035. An EM official responsible for the disposition of the SBW at INL told us that EM has not developed a strategy, including a timeline, for addressing challenges, including the WIPP permit prohibition, the federal law prohibition, and existing capacity limitations, that could affect EM’s ability to meet this target date. According to standards for internal control, federal agency management should identify, analyze, and respond to risks related to achieving a defined objective. Until it develops such a strategy, including a timeline, to implement the actions required to achieve its preferred disposal pathway, or an alternative, for the SBW, EM will not have reasonable assurance that it can achieve its preferred plan for disposal or begin identifying an alternative. Moreover, if EM implements its new interpretation of HLW and uses this definition to classify the SBW as non- HLW, there is significant risk for extended litigation, which may delay to EM’s plans to dispose of the SBW at its preferred disposal site. EM faces challenges implementing its selected treatment technology for calcine waste and faces uncertainties with a waste disposal pathway. As a result, the agency is suspending further development of its plan to treat calcine waste for land disposal, according to EM documents and officials. EM Idaho Cleanup Project officials told us that the agency is continuing to make progress toward its milestones for calcine waste disposal by considering alternatives for processing the waste for land disposal and conducting a pilot project to remove it from the oldest storage vessel. However, EM does not have a strategy or timeline for determining its next steps for the ultimate treatment and disposal of calcine waste. Because of challenges with implementing its chosen treatment technology as well as selecting a potential waste disposal pathway, EM is suspending further development of its plan to treat calcine waste for land disposal, according to EM documents and officials. In December 2009 EM identified hot isostatic pressing as its preferred treatment technology for preparing the calcine waste for land disposal outside of Idaho. Hot isostatic pressing is a manufacturing process that applies elevated temperatures and pressurized gas to materials in a containment vessel, resulting in a ceramic waste form. EM officials from the Idaho Cleanup Project told us that while hot isostatic pressing is a technology used in other industries, such as in industrial manufacturing, it has not been used before to treat HLW. Further, hot isostatic pressing would require a variance or an EPA regulation establishing a new treatment standard prior to land disposal. According to EM Idaho Cleanup Project officials and agency documents, EM selected hot isostatic pressing as the treatment technology because EM’s analyses assumed it would result in significant cost savings for disposal at Yucca Mountain compared to other methods. In February 2011, an independent DOE review team issued a preliminary technology readiness assessment for using hot isostatic pressing for calcine waste treatment as part of DOE’s process for managing capital asset projects. The review team identified several concerns, such as whether components of the technology would be mature enough to meet EM’s planned milestones and challenges with EM’s decision to retrofit and reuse the IWTU for the calcine waste treatment mission. EM officials from the Idaho Cleanup Project said that the decision to retrofit and reuse the IWTU for the calcine waste after treating the SBW resulted from reluctance within DOE to build another “first-of-a-kind” treatment facility. However, the review team’s report stated that the decision to retrofit the facility may result in logistical and physical maintenance challenges because of space limitations and height requirements. Based on the results of an independent analysis of alternatives for calcine waste disposition, published in April 2016, EM decided to suspend developing the hot isostatic pressing technology, according to EM officials from the Idaho Cleanup Project. DOE initiated this analysis of alternatives in response to a new requirement from the Secretary of Energy and because hot isostatic pressing is not a mature technology for HLW, according to EM’s summary report for the analysis. The report identified uncertainties and challenges with the use of hot isostatic pressing when compared to other potential treatment options given, including that hot isostatic pressing is significantly different than vitrification and would require the development and acceptance of testing protocols to validate that it produces a robust waste form, hot isostatic pressing had the second greatest estimated cost (more than $2 billion) of the options assessed in the analysis of alternatives, hot isostatic pressing represented the highest operational safety risk of all of the options assessed given its use of high pressures and temperatures, and other treatment options may perform better for managing the waste because of significant advances in technology since the selection of hot isostatic pressing in 2009. The independent team performing this analysis also concluded that uncertainties regarding plans for an HLW geologic repository also affect EM’s ability to move forward with selecting a treatment technology. According to EM officials from the Idaho Cleanup Project and documents, EM’s selection of hot isostatic pressing was based on assumptions developed based on sending the waste to the Yucca Mountain disposal facility. Specifically, an important factor in the selection of hot isostatic pressing as the treatment technology was its ability to provide the lowest volume of final waste, while producing a robust waste form, which would reduce disposal costs at Yucca Mountain. As previously noted, the licensing for developing the Yucca Mountain facility was terminated in 2010. The team performing the analysis of alternatives concluded that because selecting an appropriate treatment technology greatly depends on the calcine waste’s disposal path and associated waste form performance requirements, EM should defer making a final decision on the treatment technology until the performance objectives of the disposal path are better defined. While further decisions regarding a treatment technology for the calcine waste are suspended, EM officials from the Idaho Cleanup Project said that they are taking steps to demonstrate to regulators from Idaho’s Department of Environmental Quality that they are making progress to prepare the calcine waste for disposal outside the state. Under DOE’s 1995 settlement agreement with Idaho, treatment of all calcine waste is to be completed by a target date of December 31, 2035. Further, DOE is required to meet interim milestones for the cleanup of the waste under a site treatment plan that DOE developed for the Idaho Department of Environmental Quality. EM officials from the Idaho Cleanup Project told us that they planned to work with the Idaho Department of Environmental Quality to make changes to milestones specific to calcine waste in the site treatment plan, and Idaho Department of Environmental Quality officials stated in December 2018 that preliminary discussions on this topic occurred in September 2018. Further, EM Idaho Cleanup Project officials identified actions that EM is taking at the site to study alternatives to treatment and aspects of the disposal process. EM officials from the Idaho Cleanup Project stated that with the suspension of developing hot isostatic pressing, they are studying the potential packaging of the calcine waste for disposal without additional treatment, or “direct disposal.” The analysis of alternatives report identified direct disposal as having significant cost savings over other technologies. However, the team performing the analysis of alternatives also found that this method has a high degree of regulatory uncertainty and it is not clear whether it would be accepted by stakeholders, such as state regulators and the public. EPA officials told us that if EM wanted to proceed with plans for the direct disposal of the calcine waste in a geologic repository, EM would need, among other things, to seek a no-migration variance from EPA. A petition for a no-migration variance must demonstrate, to a reasonable degree of certainty, that the hazardous components would not leak or escape once the HLW is buried underground for as long as the waste remains hazardous. EPA officials added that there is a very high bar for such variances; only one such request has been approved since 1984, and it was later rescinded. In February 2019, an EM Idaho Cleanup Project official told us that EM has met with officials from the Idaho Department of Environmental Quality and EPA to receive their preliminary input on this approach. EM Idaho Cleanup Project officials said that they are focusing in the near term on developing and testing a system to retrieve the calcine waste from its storage vessels, called bin sets. According to EM documents, retrieval of the calcine waste from the bin sets is a precursor to treating or packaging the waste for disposal, and there are several challenges to address in developing an effective retrieval system. As a result, EM directed its contractor to conduct a project to retrieve calcine waste from the oldest bin set and move it to a partially empty bin set under EM’s contract for hazardous waste cleanup at INL. The project serves to both test different forms of technologies and also to cease use of the older bin set, which does not have the same structural integrity as the other bin set because of its design, according to EM officials from the Idaho Cleanup Project and documents. The project is estimated to cost $50 million over 5 years, according to these officials. Fluor Idaho’s plan for the calcine waste retrieval project involves developing a full-scale mock-up of the retrieval process for testing in fiscal years 2019 and 2020, with the commissioning and start-up of the full-scale system and transfer of the waste to occur in fiscal year 2021. In February 2019, an EM official told us that $6 million was obligated to the pilot project in fiscal year 2019 in part because of increased costs for the IWTU reengineering project and cleanup of transuranic waste at INL. Despite these efforts, EM officials from the Idaho Cleanup Project acknowledged that the agency has no plan to issue a new Record of Decision or amend the 2010 Record of Decision selecting the treatment option for calcine waste. Although EM identified challenges with using hot isostatic pressing for the treatment of the calcine waste in its technical readiness assessment in 2011 and analysis of alternatives in 2016, an EM official told us that the agency does not have a strategy for determining its next steps in treating this waste for land disposal. According to standards for internal control, federal agency management should identify, analyze, and respond to risks related to achieving a defined objective. Without developing a strategy, including a timeline, to identify and develop a treatment approach for the calcine waste, EM does not have reasonable assurance that it will meet milestones for the completion of treatment of all calcine by a target date of December 31, 2035. EM has been working since 2005 to construct and operate the IWTU to treat the SBW and calcine waste at INL. Despite declaring construction complete in 2012 at a cost of $571 million, EM is still working to repair and reengineer the IWTU following the discovery of facility problems during testing, with expenditures surpassing $416 million. EM has made progress in identifying the engineering problems plaguing the facility and implementing technical changes and expects to complete the second of the four phases of the reengineering project in mid-2019, with its next series of system testing to begin in early 2020. However, EM has experienced significant cost increases and schedule delays in phase two of the IWTU project, and additional engineering and testing remains to be completed before beginning a multiyear effort to treat the SBW. EM’s ability to achieve the project’s estimated cost and schedule in phase two may have been hampered because EM has not fully followed best practices for ensuring that the cost estimate is complete and the schedule estimate is well-constructed. By ensuring that the cost estimate for future phases of the IWTU reengineering project and the SBW treatment operations is comprehensive (e.g., account for all possible costs), EM will have greater assurance that it can successfully plan program resource requirements. Moreover, by developing a well-constructed schedule estimate for the IWTU reengineering project and the SBW treatment operations, EM will have greater assurance that it can successfully achieve its plans to reengineer the IWTU and begin treatment of the SBW without further delays. Further, while EM is using an EVM system to measure the performance of the project and generally followed best practices for EVM systems, the system produces unreliable data. By following best practices for ensuring EVM data reliability for the IWTU reengineering project’s EVM system, EM leadership will have better access to reliable performance data as it manages billions of dollars’ worth of cleanup work and provides information to Congress and other stakeholders on the cleanup work every year. EM faces long-standing challenges to implementing its preferred alternative for disposing of the treated SBW at WIPP. Key among these challenges are provisions in federal law and the WIPP permit that prevent EM from disposing of the SBW at WIPP. EM has taken some steps toward addressing these challenges, such as seeking public comment on its new interpretation of the statutory definition of HLW that according to EM could allow the waste to be disposed of at WIPP or an alternative to an HLW geologic repository. However, EM has no strategy or timeline for making any changes to DOE policies and regulations that may be required to implement its new interpretation or for making decisions regarding disposing of the SBW. Until it develops such a strategy, including a timeline, to implement the actions required to achieve its preferred disposal pathway, or an alternative, for the SBW, EM will not have reasonable assurance that it can achieve its preferred plan for disposal or begin the process of identifying an alternative. Further, if EM implements its new interpretation of HLW and uses this definition to classify the SBW as non-HLW, there is significant risk for extended litigation, which may delay EM’s plans to dispose of the SBW at its preferred disposal site. Moreover, EM faces challenges in completing treatment of the calcine waste by a target date of December 31, 2035, in light of its decision to suspend development of the selected treatment technology, hot isostatic pressing, and the absence of an HLW geologic repository. Even though EM is studying alternatives to using hot isostatic pressing to prepare the calcine waste for disposal, it has not developed a strategy or a timeline for determining its plans for treating this waste for disposal. Without developing such a strategy, including a timeline, for the treatment and disposal of the calcine waste to ensure that EM meets the milestone for completing the treatment of the waste by December 31, 2035, EM does not have reasonable assurance that it can meet its milestones. We are making five recommendations to DOE: The Secretary of Energy should direct the Assistant Secretary of EM to develop cost estimates for the IWTU reengineering project and the SBW treatment operations that meet best practices for being comprehensive (e.g., account for all costs). (Recommendation 1) The Secretary of Energy should direct the Assistant Secretary of EM to develop schedule estimates for the IWTU reengineering project and the SBW treatment operations that meet best practices for being well- constructed. (Recommendation 2) The Secretary of Energy should direct the Assistant Secretary of EM to follow best practices for ensuring the reliability for the IWTU reengineering project’s EVM system. (Recommendation 3) The Secretary of Energy should direct the Assistant Secretary of EM to develop a strategy, including a timeline, for implementing the actions required to achieve its preferred disposal pathway, or an alternative, for the SBW. (Recommendation 4) The Secretary of Energy should direct the Assistant Secretary of EM to develop a strategy, including a timeline, to identify and develop a treatment approach for the disposal of the calcine waste to ensure that EM meets the milestone for completing the treatment of this waste by the target date of December 31, 2035. (Recommendation 5) We provided a draft of this report for review and comment to the Secretary of Energy and the Administrator of the EPA. DOE provided written comments on the draft report, which are presented in appendix IV. EPA did not provide written comments. DOE and EPA both provided technical comments that we incorporated in the report as appropriate. DOE agreed with our recommendations related to the management of the IWTU reengineering project, including developing cost and schedule estimates that meet best practices and ensuring the reliability of the EVM system for the project. Regarding the cost estimate, DOE committed to developing cost estimates that meet best practices and stated that cost estimates for phases three and four of the IWTU reengineering project have been developed and reviewed by the Defense Contract Audit Agency. For the schedule estimate, DOE stated that the schedules for phases three and four have been developed and that the inclusion of these phases in the schedule is in accordance with best practices for the well-constructed characteristic. With regard to the EVM system, DOE stated that cost and performance data will be included in the EVM system in accordance with EVM best practices once contract negotiations are completed, which the agency estimated would conclude by December 31, 2019. DOE also agreed with our recommendations to develop a strategy, including a timeline, for the disposal of the SBW and calcine waste. DOE further stated that EM is in the process of developing a site options analysis for INL and other EM sites to identify opportunities to complete cleanup work through more efficient and innovative approaches over the next decade. This analysis is expected to be completed in fiscal year 2020, according to DOE. DOE stated that EM’s HLW interpretation issued in June 2019 could potentially open new disposal pathways for some reprocessing waste, such as SBW and calcine, while noting that decisions about whether and how this interpretation will apply to existing wastes have yet to be made. In its written comments, DOE disagreed with our recommendation to seek clarification from Congress on DOE’s authority to classify the SBW as other than HLW if such clarification is necessary to avoid extended litigation. DOE stated the agency does not require additional clarification from Congress to classify reprocessing waste as other than HLW. We are deleting our recommendation but continue to believe that there is significant risk for extended litigation if EM implements its new interpretation of HLW and uses this definition to classify the SBW as non- HLW. Extended litigation may delay EM’s plans to dispose of the SBW at its preferred disposal site. We are sending copies of this report to the appropriate congressional committees, the Secretary of Energy, the Administrator of the Environmental Protection Agency, and other interested parties. In addition, the report is available at no charge on the GAO website at http://www.gao.gov. If you or your staff have any questions about this report, please contact me at (202) 512-3841 or trimbled@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made significant contributions to this report are listed in appendix V. Our report examines (1) the extent to which the Department of Energy’s (DOE) Office of Environmental Management’s (EM) management of the Integrated Waste Treatment Unit (IWTU) reengineering project follows selected project management best practices; (2) challenges EM faces in the disposal of the sodium-bearing waste (SBW); and (3) challenges EM faces in the treatment and disposal of the calcine waste. To address these three objectives, we conducted a site visit to DOE’s Idaho National Laboratory (INL) in December 2017. During the site visit, we obtained documentation and interviewed officials from EM, which is responsible for hazardous waste cleanup at INL through its Idaho Cleanup Project. We also interviewed representatives from Fluor Idaho, LLC, which is the private contractor that manages hazardous waste cleanup at INL for EM, including the cleanup of the SBW and calcine waste. In addition, we conducted a site visit to Hazen Research, Inc., a subcontractor to Fluor Idaho, to observe pilot testing facilities for the IWTU reengineering project and discuss the status of the project with an EM official from the Idaho Cleanup Project and representatives from Hazen Research, Inc., and Fluor Idaho. To assess the extent to which EM’s management of the IWTU reengineering project meets selected project management best practices, we first identified areas deemed to be important to project management based on our previous work on DOE projects and leading practices from the Project Management Institute, which are generally recognized as leading practices for project management. Specifically, we reviewed the project management leading practices identified in the Project Management Institute’s A Guide to the Project Management Body of Knowledge—Sixth Edition. From this review, we selected project management practices related to developing cost and schedule estimates and conducting project monitoring through the use of earned value management (EVM) and independent reviews. We then conducted assessments of these best practices, as discussed below. Cost. To determine the extent to which the cost estimate for the IWTU reengineering project is reliable, we conducted an abridged analysis of the IWTU reengineering project’s cost estimate, focusing on its comprehensiveness. Typically, in analyzing a cost estimate against best practices in GAO’s Cost Estimating and Assessment Guide (cost guide), we examine four characteristics, each defined by multiple criteria: credible. For this review, we assessed the cost estimate for the IWTU reengineering project against the comprehensive characteristic, in part because EM officials told us that they had yet to develop a cost estimate for the program beyond phases one and two at the time of our review. Specifically, we reviewed the cost estimate for the operation of the IWTU and the IWTU reengineering project, which, at the time of our review, was only developed for phases one and two of the project. If a cost estimate is not comprehensive (that is, complete), then it cannot fully meet the well- documented, accurate, or credible best practice characteristics. For instance, if the cost estimate is missing some cost elements, then the documentation will be incomplete, the estimate will be inaccurate, and the result will not be credible because of the potential underestimating of costs and the absence of a full risk and uncertainty analysis. See appendix II for a summary assessment of the IWTU reengineering project’s cost estimate compared to selected best practices. Schedule. To assess EM’s schedule for the IWTU reengineering project, we conducted an abridged analysis of the IWTU reengineering project’s schedule, focusing on comprehensiveness and the degree to which it is well-constructed. Typically, in analyzing a schedule estimate against best practices in GAO’s Schedule Assessment Guide (schedule guide), we examine four characteristics, each defined by multiple criteria: controlled. For this review, we assessed the IWTU reengineering project schedule that EM provided in March 2018 against the well-constructed characteristic, in part because EM officials told us that they had yet to develop a schedule estimate for the totality of the reengineering project because of Fluor Idaho’s phased approach. If a schedule estimate is not well-constructed, it will not be able to properly calculate dates and predict changes in the future. When activities are missing logic links, the schedule will not be able to automatically transmit these delays to future activities that depend on them. When this happens, the schedule will not allow a sufficient understanding of the program as a whole, and users of the schedule will not have confidence in the dates and the critical path. In addition, we evaluated the comprehensive characteristic because it contributed to our analysis of EM’s EVM system, as described below. See appendix II for a summary assessment of the IWTU reengineering project’s schedule estimate compared to selected best practices. EVM. In addition, we analyzed EM’s use of EVM as a way to assess its monitoring of the IWTU reengineering project’s cost and schedule. EVM measures the value of work accomplished in a given period and compares it with the planned value of work scheduled for the period and with the actual cost of the work accomplished. It is an industry standard and is considered a best practice for conducting cost and schedule performance analysis for projects. Our EVM analysis focused on Fluor Idaho’s EVM data for the IWTU reengineering project contained in cost performance reports from March 2017 to February 2018 and the project schedule that EM provided in March 2018. Specifically, we compared this project documentation with EVM best practices as identified in our cost guide. Our research has identified a number of best practices that are the basis of effective EVM and should result in reliable and valid data that can be used for making informed decisions. These best practices have been collapsed into three high-level characteristics of a reliable EVM system, which are establish a comprehensive EVM system, ensure that the data resulting from the EVM system are reliable, and ensure that the program management team is using EVM data for decision-making purposes. See appendix III for our summary assessment of the IWTU reengineering project’s EVM data compared to best practices. EVM data are considered reliable if the overall assessment ratings for each of the three characteristics are substantially or fully met. If any of the characteristics are not met, minimally met, or partially met, then the EVM data cannot be considered reliable. Independent reviews. To assess the extent to which DOE has conducted independent reviews of the IWTU reengineering project, we examined DOE and EM policies to identify requirements for conducting reviews of operations activities. Specifically, we reviewed a 2016 DOE memorandum that established that DOE’s Project Management Risk Committee (PMRC) would provide independent review of selected projects in the operational release phase, the PMRC’s standard operating procedures, and EM’s guidance for projects in the operational release milestone. We examined documentation from the PMRC’s reviews of the IWTU reengineering project, including documentation that EM officials from the Idaho Cleanup Project prepared for these reviews and recommendations that the PMRC made to EM for the project. In addition, we spoke with officials from DOE’s Office of Project Management, which serves as the secretariat of the PMRC; EM’s Office of Acquisition & Project Management; and EM’s Idaho Cleanup Project about independent reviews of projects in the operational release phase. To examine challenges EM faces in the disposal of the SBW, we reviewed federal laws, regulations, and DOE policies on radioactive waste management, including those described in DOE Order 435.1 on radioactive waste management and its implementation manual. In addition, we examined EM’s October 2018 and June 2019 Federal Register notices, which provide DOE’s new interpretation of the statutory definition of high-level radioactive waste (HLW). We also reviewed documentation related to EM’s plans for disposing of the SBW at DOE’s Waste Isolation Pilot Plant (WIPP) in New Mexico, such as Record of Decision documents for proposed actions that require development of environmental impact statements, and the hazardous waste facility permit for WIPP that the New Mexico Environment Department issued. We interviewed DOE officials from the Office of the General Counsel; officials from EM’s Idaho Cleanup Project and Carlsbad Field Office, which is responsible for DOE’s oversight of WIPP; and officials from EM’s Office of Regulatory Compliance, Office of Nuclear Materials, and Office of Waste and Materials Management. We also interviewed officials from Idaho’s Department of Environmental Quality and New Mexico’s Environment Department, as well as representatives from two environmental advocacy groups in Idaho and New Mexico, to obtain their perspectives on the challenges facing EM’s SBW disposal efforts. To examine challenges EM faces in the treatment and disposal of the calcine waste, we reviewed federal laws, regulations, and documents that DOE and EM’s contractors for the Idaho Cleanup Project prepared related to the calcine waste cleanup mission. For example, we reviewed documents assessing treatment and disposal alternatives for calcine waste, including a 2016 analysis of alternatives report that EM prepared and a 2015 contractor-prepared report assessing the feasibility of the direct disposal of calcine waste. We interviewed officials from EM’s Idaho Cleanup Project and Office of Nuclear Materials; EM’s Chief Engineer; and representatives from EM’s contractor, Fluor Idaho, about plans for treating and disposing of the calcine waste and the retrieval pilot project. In addition, we reviewed Environmental Protection Agency (EPA) Resource Conservation and Recovery Act, as amended (RCRA) regulations, guidance, and documents concerning land disposal requirements. We also interviewed officials from EPA’s Office of Land and Emergency Management and Region 10 about EPA’s responsibilities for implementing RCRA. Lastly, we interviewed officials from the Idaho Department of Environmental Quality about how EM’s calcine waste treatment and disposal efforts address milestones in the Idaho Settlement Agreement. We conducted this performance audit from September 2017 to September 2019 in accordance with generally accepted government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. Table 2 describes the initial cost and schedule estimates for the four phases of the Integrated Waste Treatment Unit reengineering project compared to actual expenditures and schedule as of February 2019. Table 3 details our assessment of the Office of Environmental Management’s (EM) cost estimate for phases one and two of the Integrated Waste Treatment Unit (IWTU) reengineering project compared to selected best practices for cost estimating published in GAO’s Cost Estimating and Assessment Guide (cost guide). For this review, we assessed the cost estimate for the IWTU reengineering project against the comprehensive characteristic, in part because EM officials told us that they had yet to develop a cost estimate for the program beyond phases one and two, at the time of our review of these documents. We assessed the comprehensive characteristic for the IWTU reengineering cost estimate because if a cost estimate is not comprehensive—that is, complete—then it cannot fully meet the other best practice characteristics. According to our analysis, EM’s cost estimate for the IWTU reengineering project partially met best practices for a comprehensive cost estimate. Table 4 details our assessment of EM’s schedule for the IWTU reengineering project compared to selected best practices for project schedules published in GAO’s Schedule Assessment Guide (schedule guide). For this review, we assessed the schedule against the well- constructed characteristic, in part because EM officials told us that they had yet to develop a schedule for the totality of the reengineering project because of the contractor’s phased approach. We assessed the well- constructed characteristic because, among other reasons, if a schedule is not well-constructed, it will not be able to properly calculate dates and predict changes in the future. In addition, we evaluated the comprehensive characteristic as it is needed to evaluate an earned value management system. According to our assessment, EM’s schedule for the reengineering project partially met best practices related to the well- constructed characteristic and substantially met best practices related to the comprehensive characteristic. Table 5 details our assessment of March 2017 to February 2018 data from the Department of Energy’s (DOE) Office of Environmental Management’s (EM) earned value management (EVM) system for the Integrated Waste Treatment Unit (IWTU) reengineering project. EVM measures the value of work accomplished in a given period and compares it with the planned value of work scheduled for that period and with the actual cost of work accomplished. By using the metrics derived from these values to understand performance status and to estimate cost and time to complete, EVM can alert program managers to potential problems sooner than expenditures alone can. Our research has identified a number of best practices that are the basis of effective EVM and should result in reliable and valid EVM data that can be used for making informed decisions. Specifically, EM followed (i.e., substantially met) best practices to ensure that its EVM system is (1) comprehensive and (2) used by leadership for decision-making, but did not follow (i.e., partially met) best practices to ensure that the data resulting from the EVM system are reliable. In addition to the contact named above, Casey L. Brown (Assistant Director), Emily Ryan (Analyst in Charge), Juaná Collymore, Jennifer Echard, Richard P. Johnson, Jason Lee, Eli Lewine, Katrina Pekar- Carpenter, Karen Richey, Jeanette Soares, Sheryl Stein, Farrah M. Stone, Paul Sturm, and Sara Sullivan made key contributions to this report.