5

System Vulnerabilities

The preceding chapter outlined implementation challenges to the dilute and dispose program. Most of those risks and challenges involve project-level issues and their mitigation—such as operations scale-up, human resource availability, sustainable funding, security demands, facility modifications, and life extensions. System vulnerabilities are identified by considering the plan in the context of broader system issues across the Department of Energy (DOE) complex and questioning its approach, assumptions, and motivations that could ultimately threaten the successful, full completion of the program. This chapter outlines these vulnerabilities and suggests ways they could be addressed.

The system vulnerabilities to the dilute and dispose program have serious consequences if not addressed and in some cases can be considered deterministic of full mission success. The issues identified here are fundamental to designing, building, and sustaining the multidecade support that will be required for the full completion of the dilute and dispose plan. The issues, many of which are nontechnical, span policy, strategy, social, and political realms. Addressing them will require actions by both the current DOE’s National Nuclear Security Administration’s (DOE-NNSA’s) program management and higher levels of leadership.

5.1 UNCLEAR FUTURE FOR THE PMDA AND ITS IMPACT ON THE DILUTE AND DISPOSE PLAN

Several concerns regarding the Plutonium Management and Disposition Agreement (PMDA) between the Russian Federation and the United States, its uncertain future, and its relevance to the implementation and sustainability of the dilute and dispose plans for U.S. surplus plutonium are highlighted below.

The PMDA and its current status are described in Chapter 2. The salient points are the following:

• The Agreement applies to at least 34 metric tons (MT) of surplus plutonium for both countries;
• The Russian Federation and the United States disagree on the current status of the PMDA with the Russian Federation suspending the agreement in 2016 but the United States considering it in effect;
• Irradiated mixed oxide (MOX) fuel was the last agreed-to method for disposition and the United States has canceled its MOX program;
• The United States asserts that the dilute and dispose approach fulfills the intent of the agreement but the new disposition method requires agreement by the Russian Federation, which has not yet been provided; and
• Protocols for International Atomic Energy Agency (IAEA) monitoring and inspection (as per the PMDA) for disposal have not been developed and are not presently being pursued by DOE-NNSA for the 34 MT disposition.

Furthermore, DOE-NNSA’s recently updated conceptual plans no longer cite the PMDA in the mission need statement for the dilute and dispose program, leaving the future adherence to the PMDA timelines and disposition requirements in question (DOE-NNSA, 2016, 2018).

In Chapter 3, the committee presented the recovery barriers for the irradiated MOX option and the dilute and dispose option. Irradiated MOX fuel, which meets the spent fuel standard, has more barriers to recovery than the dilute and dispose option, which does not meet the spent fuel standard. Conceptually, recovery of diluted plutonium inventory emplaced in the underground requires two steps: (1) the presumed physical removal of the diluted waste form from the underground by the host country or third state or non-state actors, and (2) the presumed physiochemical processing of the diluted waste form to extract the plutonium.

It is a common misconception that nuclear waste—once emplaced in a sealed (i.e., post-closure) repository—is not easily removed especially in the case of salt repositories such as the Waste Isolation Pilot Plant (WIPP) because salt creep is intended to entomb the waste within a few decades of emplacement and closure, adding to the difficulty of removal.¹ However, WIPP, like many repositories in the world now in development, has a regulatory requirement for not precluding the possible post-closure removal of waste. Specifically, the Environmental Protection Agency’s (EPA’s) 40 CFR § 194.46 (Part 46: Removal of Waste) requires: “Any compliance application shall include documentation which demonstrates that removal of waste from the disposal system is feasible for a reasonable period of time after disposal. Such documentation shall include an analysis of the technological feasibility of mining the sealed disposal system, given technology levels at the time a compliance application is prepared” (EPA, 2014b, p. 46-1).

DOE’s Carlsbad Field Office (DOE-CBFO) proposed the following approach to comply with EPA “removal of waste” requirements in the original Compliance Certification Application (CCA; DOE-CBFO, 1996, Appendix WRAC):

• “[I]t is technically feasible to remove the waste any time during the [10,000-year] regulatory time frame” (DOE-CBFO, 1996, p. WRAC-1).
• “Regardless of when removal is initiated, the inventory of the waste documentation that will be accumulated by the DOE during operations and archived after closure will contain sufficient information to determine rather precisely the radioactivity levels to be anticipated and the locations of any containers of waste that may pose higher radioactivity hazards” (DOE-CBFO, 1996, p. WRAC-20, emphasis added).
• “A practical approach to CH-TRU removal is to excavate an area approximately three feet high directly below the waste and then, using a hydraulic breaker/scaler system … to dislodge the waste above” (DOE-CBFO, 1996, p. WRAC-32).

From the first CCA to the most recent 2019 Compliance Recertification Application (CRA), DOE-CBFO has asserted that it is possible to remove waste from the repository for a reasonable period of time after disposal (“during the regulatory time frame,” which is 10,000 years post-closure; DOE-CBFO, 1996, Appendix WRAC).² EPA has found DOE-CBFO to be in compliance with 40 CFR § 194.46 at each issued Certification Decision for the CCA and subsequent CRAs.³

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¹ Note that DOE-CBFO, who manages the WIPP site, distinguishes between waste removal and waste retrieval. Waste removal refers to actions taken after the repository is closed and sealed. Waste retrieval refers to recovering the waste prior to waste panel or repository closure and is essentially the reverse of emplacement. As DOE has suggested that emplacement in the subsequently closed and sealed repository is the barrier to meet the intent of the PMDA, we use the term waste removal. Additionally, the diversion, theft, or recovery of diluted surplus plutonium while in transit or storage is not addressed here.

² As examples, two emplaced waste containers have been retrieved (i.e., prior to panel closure) from WIPP; the State of New Mexico required DOE to retrieve a container in August 2007, and DOE elected to retrieve a container in June 2008. Both were returned to the generator site for remediation as they did not meet the waste acceptance criteria upon audit of the documentation.

³ The 2019 CRA is still in review, but nothing substantive has changed from all previous applications regarding waste removal.

Once emplaced and without in-place monitoring, the diluted surplus plutonium transuranic (DSP-TRU) waste could be retrieved not only by the United States; with sufficient mining expertise (which is becoming more common) and resources, non-state or third-state actors may also be able to retrieve emplaced DSP-TRU waste during the post-closure period with its absence left undetected without additional monitoring or sensors (Tracy, 2019).⁴

DSP-TRU waste removed from WIPP would still need to be processed to recover the plutonium—the barrier that exists from the plutonium mixed with the adulterant would need to be overcome. DOE-NNSA’s documents describe this barrier as “mixing surplus plutonium with an adulterant to ensure plutonium is not recoverable without extensive processing” (DOE-NNSA, 2016, p. 6). The composition of the adulterant is classified, and not much can be said about the processing that might be necessary to recover the plutonium. Regardless, presumably the U.S. government would have the resources and capability to recover plutonium from the diluted product if it were retrieved from WIPP. Given enough time and resources, the plutonium could be recovered from any process that dilutes the plutonium oxide with adulterant material(s) by employing a series of available procedures. As compared to the irradiated MOX fuel, the dilute and dispose waste form does not require the degree or complexity of remote and special handling equipment required to recover the plutonium.

5.1.1 Uncertain Protocols for International Inspection and Verification for Emplaced Waste

IAEA monitoring and inspections are an important component of the PMDA requirements and they could also provide enhanced public and international confidence that the material is properly accounted for and emplaced in WIPP. As noted in Chapter 2, the director of the Office of International Nuclear Safeguards at DOE-NNSA reported to the committee that DOE-NNSA is in the process of working with the IAEA to discuss what role, if any, IAEA involvement might play in the disposition of DOE’s Office of Environmental Management’s (DOE-EM’s) 6 MT (Veal, 2019). Typical international safeguards (monitoring and verification) use accountancy to ensure that declared nuclear material is present as intended, coupled with a containment and surveillance system to ensure that no changes occur between inspections. Implementation of IAEA protocols for verification and monitoring of materials for predisposal are well established, but IAEA verification protocols for material emplacement in any repository are still under development. Inspection and verification protocols for repository emplacement, where access for monitoring may be a challenge and remote devices may compromise required passive safety measures, could have a significant impact on both repository operations and design (Haddal et al., 2014).

The DOE-NNSA dilute and dispose Master Schedule for the 34 MT (see Figure 3-1) indicates verification protocols for the activities at the Savannah River Site (SRS) are to be in place in fiscal year (FY) 2022 and for WIPP in FY 2023, yet DOE-NNSA may emplace DSP-TRU waste with or without IAEA inspection protocols in place.⁵ Therefore, substantial uncertainty remains on the applicability and possible implementation of IAEA monitoring and verification protocols. Resolution of this uncertainty holds substantial implications for WIPP operations and future design changes (such as the new shaft and panels now under development), and therefore this issue remains a significant system vulnerability.

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⁴ WIPP does not currently have underground sensors to monitor the emplaced waste after closure (i.e., after the underground is sealed off by the movement of the salt bed). Post-closure monitoring and security details are not yet defined but previously emplaced wastes do not have sensors that would indicate removal of waste.

⁵ Discussion between dilute and dispose DOE-NNSA program manager, William Kilmartin, and National Academies study director Jennifer Heimberg on September 12, 2019.

5.1.2 Loss of Program Priority

DOE-NNSA’s dilute and dispose plan spans at least 30 years and therefore will require sustained support and recognized priority across several administrations, within DOE, and through congressional appropriations.

DOE-EM’s plans to dilute and dispose of 6 MT of surplus non-pit plutonium indicate that those activities will continue through 2046, presenting potential prioritization conflicts within DOE because DOE-EM and DOE-NNSA have different mission spaces and priorities within their organizations.⁶ Both projects are in their early stages of development and there are current indications that the two organizations are working closely together to support their combined goal of dilution and disposal of at least 40 MT and as much as 48.2 MT (see Figure 2-1) of surplus plutonium. However, long-term success depends on sustained, consistent budgets, for both DOE-NNSA and DOE-EM, allocated across multiple sites with competing demands and priorities. DOE-EM’s and DOE-NNSA’s dilute and dispose programs will both have to compete for resources and space with the new pit production mission, which DOE-NNSA has made its highest priority.⁷

Beyond the challenges of a sustained and coordinated budget and competing priorities, enduring social and political support from the affected states (e.g., New Mexico, South Carolina) will be needed. Adherence to an international agreement such as the PMDA provides the public, DOE-NNSA, and the U.S. government a compelling rationale for a sustainable program budget and priority.⁸ A renegotiated PMDA could provide a strong assurance over decades that the dilute and dispose program would receive congressional support it needs to meet its non-proliferation objectives. However, recovery of emplaced diluted surplus plutonium by the United States and the lack of established IAEA monitoring and inspection protocols add challenges to the renegotiation. Without the PMDA, the “good stewardship” of surplus plutonium would be the driving force and could lessen the focus and sustainability of the program.

While dilution and disposal of surplus plutonium has merit toward non-proliferation goals in general, the value of a revised PMDA embraced by both parties should not be discounted and would afford the opportunity to address uncertainties regarding safeguards and international monitoring and verification.

The committee maintains the pertinence of the PMDA to the non-proliferation objectives of the U.S. government, and to the dilute and dispose program in particular, must be resolved, as the particulars of a PMDA factor into decisions affecting significant implementation details (e.g., verification, program priority, and schedule).

FINDING 5-1 (Updated from INTERIM REPORT FINDING 5): The dilute and dispose option for surplus plutonium disposition is neither recognized nor approved by the existing Plutonium Management and Disposition Agreement (PMDA). Irradiated mixed oxide (MOX) fuel containing the surplus plutonium is the currently approved disposition option for plutonium within the PMDA and is an option that is consistent with the standard established with commercial spent fuel (i.e., that the plutonium would be as inaccessible for recovery for reuse in weapons by the host state as if it were in spent fuel, or the “spent fuel standard”). Disposition options that use chemical barriers alone, such as dilution or combining plutonium

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⁶ The DOE-EM mission is to complete the safe cleanup of environmental legacy resulting from five decades of nuclear weapons development and government-sponsored nuclear energy research (https://www.energy.gov/em/mission, accessed May 20, 2020), while DOE-NNSA’s mission is devoted to maintaining the stockpile, non-proliferation, counterterrorism, and the nuclear navy (https://www.energy.gov/nnsa/missions, accessed May 20, 2020).

⁷ See https://www.energy.gov/nnsa/articles/joint-statement-ellen-m-lord-and-lisa-e-gordon-hagerty-recapitalizationplutonium-pit (accessed February 25, 2020).

⁸ This rationale was evident in the initial congressional and public support for the MOX program, until the cost and schedule overruns became untenable.

with other elements, do not meet this standard. The physical barrier of deep geologic disposal is offered by the Department of Energy’s National Nuclear Security Administration (DOE-NNSA) as a necessary barrier to meet the intent of the PMDA. However, an approved approach for recovery of the emplaced diluted plutonium in the Waste Isolation Pilot Plant throughout the post-closure regulatory time frame (10,000 years) is a regulatory requirement that has been repeatedly established by DOE’s Office of Environmental Management’s Carlsbad Field Office and accepted by its regulator, the Environmental Protection Agency. Furthermore, international monitoring and verification of the dispositioned surplus plutonium is a requirement of the PMDA, but its adherence is unclear within DOE-NNSA’s dilute and dispose plans. International Atomic Energy Agency (IAEA) monitoring and inspection protocols for material emplaced in deep geologic repositories have not yet been developed, tested, and implemented. An approved approach for recovery by the United States of the emplaced diluted surplus plutonium waste form and lack of a clear plan for implementing IAEA inspections add further barriers to adherence of PMDA principles.

CONCLUSION 5-1: Although not required for the Department of Energy’s National Nuclear Security Administration’s dilute and dispose program to move forward, a renegotiated Plutonium Management and Disposition Agreement (PMDA) would provide a commitment to achieving program success defined by the agreed-upon methods for disposition of all 34 metric tons of material that the agreement identifies. For a program that is planned for at least 30 years, a renegotiated PMDA could improve the chances of successful completion.

RECOMMENDATION 5-1: Plans for the International Atomic Energy Agency (IAEA) or other monitoring and inspection protocols have not yet been established for the disposition of the material identified in the Plutonium Management and Disposition Agreement (i.e., 34 metric tons of surplus plutonium) as diluted surplus plutonium transuranic (DSP-TRU) waste in the Waste Isolation Pilot Plant. Prior to emplacement of the DSP-TRU waste by the Department of Energy’s (DOE’s) Office of Environmental Management or DOE’s National Nuclear Security Administration (DOE-NNSA), DOE-NNSA and higher-level DOE officials should clarify their intent with respect to whether there will be IAEA monitoring and inspections for this material (and preferably before DSP-TRU waste is disposed of).

5.2 WIPP AVAILABILITY

WIPP is the only deep geologic repository currently available in the United States for surplus plutonium disposal. Other potentially suitable disposal options for surplus plutonium (e.g., Yucca Mountain in Nevada or deep boreholes in as-yet unspecified locations) are not presently being pursued by the U.S. government.⁹ Development and licensing of additional disposal options are substantial social and political challenges (more so than a technical challenge) and thus increases the pressure on WIPP.

There are two aspects to the WIPP availability issue: (1) the availability of sufficient disposal volume—both statutory and physical space (see volume of record modification in Box 2-3)—in the underground to accommodate the dilute and dispose program objectives for up to 48.2 MT (see Figure 2-1), in addition to all other current and future demands for TRU waste disposal from throughout the DOE-EM program; and (2) the availability of WIPP as an operating facility.

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⁹ U.S. surplus plutonium was included in the inventory for the environmental assessments of Yucca Mountain, in the form of MOX and/or vitrified high-level waste. A deep borehole disposal demonstration program was also in progress until May 2017, when DOE announced: “Due to changes in budget priorities, the Department of Energy does not intend to continue supporting the Deep Borehole Field Test (DBFT) project and has initiated a process to effectively end the project immediately,” https://www.energy.gov/articles/studying-feasibility-deep-boreholes (accessed April 2, 2020).

5.2.1 WIPP Waste Volume Availability

As noted in Chapter 2 (Section 2.3.1, Disposal Capacity in WIPP), WIPP has a statutory disposal capacity of 175,564 m³ defined in the Waste Isolation Pilot Plant Land Withdrawal Act (LWA). The New Mexico Environment Department (NMED) approved in late 2018 a permit modification request by DOE-CBFO to alter the accounting and reporting of TRU waste volumes, as described in detail in Box 2-3. In summary, the change created two reporting volumes: a “Land Withdrawal Act TRU Waste Volume of Record” or LWA volume to refer to the volume as calculated using the gross internal volume of the disposal container for direct-loaded containers and the innermost disposal container for overpack containers and the “TRU Mixed Waste Volume,” or TMW volume, to refer to the physical volume of all of the containers. Since January 2019, DOE-CBFO has reported weekly the contact-handled (CH) TRU emplaced waste as a cumulative TMW container volume emplaced, and the LWA container volume emplaced. Table 5-1 is a snapshot of DOE-CBFO’s reporting, captured at the end of September 2019.

The change in TMW to LWA accounting resulted in an average ~28 percent volume recovery from all past waste emplacements. However, some waste forms contributed to the volume recovery much more than others, as shown by Box 2-3. The change in volume accounting for the pipe overpack containers (POCs) is a ~78 percent LWA volume recovery over TMW volume; and the criticality control container/criticality control overpack (CCC/CCO), which will be used for DSP-TRU wastes, yields an even greater recovery of volume (94 percent) due to the large LWA/TMW container volume ratio (0.013 m³/0.21 m³). The CCC/CCO has an increased fissile gram equivalent (FGE) loading of the CCC over the pipe overpack (380 grams versus 200 grams), which far exceeds the average amount of plutonium-239 in other containers at 14.4 grams.¹⁰ Despite the LWA volume savings through the volume of record recalculation, the TRU waste capacity discussion in Chapter 3 (see Table 3-2 and Figure 3-9) and Recommendation 3-1 make clear that LWA volume limits are still likely to be challenged—in particular with the addition of the pit production TRU wastes. These additional wastes put completion of the DSP-TRU waste emplacement plans at risk.

5.2.2 WIPP Operational Availability

Beyond sufficient waste volume capacity to fully support the dilute and dispose program objectives, another aspect of the WIPP availability issue concerns the mitigation of risks that threaten the ongoing and continuous availability of WIPP.

Exclusive reliance on WIPP for disposal is a single-point failure risk for the success of the dilute and dispose program. For example, the Risk and Opportunity Analysis Report (ROAR) identifies several moderate risks associated with WIPP; one is an unexpected outage for WIPP (associated with aging infrastructure of its hoist controller; SRNS, 2018e, table 5.3). Any unplanned shutdowns or suspensions of WIPP lasting more than perhaps a few weeks would have a substantial ripple effect in the upstream portions of the system, incurring disruptions, delay, and added cost in the processing of surplus plutonium into and out of the Savannah River Site. While each site (i.e., Los Alamos National Laboratory [LANL], SRS) and part of the dilute and dispose process flow has a certain amount of capacity (i.e., lag storage or curtailing shipping) to absorb disruptions, this excess capacity is generally small and finite.

Shipments to WIPP were suspended in February 2014 when two incidents, an underground salt haul truck fire and a radiological release that occurred as a result of an exothermic chemical reaction in a waste drum, caused the temporary closure of the facility. WIPP officially reopened in January 2017 with a reduced shipment schedule resuming in April 2017. This shutdown resulted in several upstream issues (e.g., shipping TRU waste containers to Waste Control Specialist in Texas for temporary storage, and missed compliance milestones at several DOE-EM sites) and efforts to re-establish operations (e.g., a new shaft and drifts and abandonment of the south end of WIPP) have proven costly. Although waste shipments were resumed in April 2017, WIPP cannot re-establish design waste receipt and emplacement rates until the new ventilation system and shaft are put into operation in the coming years. These incidents provide ample evidence of the sensitivity of the system to WIPP availability, and contrasts with the aggressive schedule and processing rates embedded in DOE-NNSA’s dilute and dispose summary master plan.

DOE-NNSA asserts that both dilution and disposal of the DSP-TRU are required to meet DOE’s non-proliferation goals and the intent (if not the letter) of the PMDA. The assured availability of the WIPP facility hinges on internal and external factors that must be addressed in order to exhibit the characteristics of “high-reliability organizations,” with the intent that system accidents and disruptions are not inevitable.

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¹⁰ Using data from September 30, 2019, from the Waste Data System/WIPP Waste Information System database, the total amount of plutonium-239 emplaced in WIPP was 5.36 MT. Of this total, 3.17 MT of plutonium-239 is emplaced in POCs, of which there are 27,060 POCs, or on average, 117 grams/POC. The remaining 2.19 MT of plutonium-239 is assumed to be equally distributed among the remaining emplaced containers (minus the POCs): 2.19 MT/152,524 containers, arriving at 14.4 grams/container.

Looking internally, the committee and DOE are mindful of the extraordinary efforts that are necessary to ensure a safety-conscious work environment and a nuclear safety culture that both exists and is sustained. Any of the contributing factors (e.g., accelerated shipping and disposal campaigns or complacency) that led to the WIPP accidents can recur, and over the next several decades of operations, similar conditions arising might be assumed.

The dilute and dispose program, as well as other waste streams, will drive the need to extend the operational lifetime of WIPP beyond its current operation permit by ~20 years. In addition to requiring approvals from New Mexico (through permit modification requests by DOE-CBFO to NMED, see Box 2-5) and most certainly additional appropriations from Congress, the facility will also need to operate safely beyond its original expected lifetime. WIPP has been operationally ready since 1988, though waste shipments and disposal emplacements were not permitted to commence until 1999. Parts of the facility and underground access ways are thus approaching 30 years old. Extending the operations lifetime of WIPP will require that some of its facilities, operation systems, and equipment be upgraded to ensure continued safe and secure operating conditions during the life of this program. This is most evident in the efforts to permit and construct a new shaft and drifts, abandon the south end, and alter the panel closures. Keeping a facility such as WIPP open, functional, and safe is a complex engineering and human resource endeavor.

In its Interim Report, the committee identified three barriers that would require resolution through permit modifications from NMED and/or changes to legislation through congressional action in order for DOE-NNSA’s conceptual plans for dilute and dispose to be viable. The first of those three, the volume of record permit modification, has been approved by NMED. The remaining two are still critical barriers, with both requiring NMED’s approval of future permit modification requests and approval by EPA through planned change requests (neither of which has been submitted):

1. Increasing physical capacity at WIPP by adding more disposal space, and
2. Extending the end date of WIPP to 2050 or later.

The technical issues associated with the expansion and extending the closure date of WIPP are expected to be complicated. The need to update the modeling code on which WIPP’s performance assessments are based is one example (see Box 5-1). NMED will either approve or reject these expected future permit modification requests, yet NMED has limited technical resources to perform a detailed technical review of either issue.

5.3 CHANGING NATURE OF WIPP

In the past, the TRU waste emplaced in WIPP has routinely been described as clothing, tools, rags, residues, debris, soil, and other items contaminated with small or moderate amounts of plutonium and other man-made radioactive elements, the unavoidable by-products of processes related to weapons production.¹¹ This notion extends to the original Compliance Certification Application where it is also noted that this type of waste is expected to be the largest category by volume:

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¹¹ This notion that TRU waste comprises things modestly contaminated with plutonium (as opposed to conditioned plutonium material) has been and continues to be pervasive. For example:

• DOE WIPP homepage (https://wipp.energy.gov/about-us.asp, accessed May 20, 2020): “TRU waste consists of clothing, tools, rags, residues, debris, soil and other items contaminated with small amounts of plutonium and other man-made radioactive elements.” and “Disposal of transuranic waste is critical to the cleanup of Cold War nuclear production sites.”
• WIPP Fact Sheet (https://wipp.energy.gov/pdfs/Why_WIPP.pdf, accessed May 20, 2020): “Generally, TRU waste consists of clothing, tools, rags, residues, debris, soil and other items contaminated with radioactive elements, mostly plutonium.”

TRU wastes consisting of scrap materials, cleaning agents, tools, piping, filters, plexiglass, gloveboxes, concrete rubble, asphalt, cinder blocks, and other building materials. This is expected to be the largest category by volume of TRU waste to be generated. (DOE-CBFO, 1996, Section 4.1.1, emphasis added)

In contrast to the common and historic notion that TRU waste consists of “clothing, tools, rags, residues, debris, soil and other items contaminated with” plutonium, the DSP-TRU waste is primarily plutonium oxide purposefully derived from up to 48.2 MT of surplus plutonium material that is then diluted by a classified adulterant (see Figure 2-1). The character and form of the DSP-TRU is different from typical TRU waste in many aspects.

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To illustrate these characteristics, the committee points to the nominal baseline performance assessment (which does not include any portion of the 48.2 MT), referred to as the APCS (Abandonment of Panel Closures in the South) performance assessment (PA).¹²Figure 5-1 shows the effect of adding surplus plutonium disposition (SPD) inventories (48.2 MT) to the EPA units¹³ and the total radioactivity in WIPP, both plotted as a function of time through 10,000 years. The SPD inventory increases the EPA units by a factor of 2 and increases the long-term radioactivity by nearly a factor of 4.¹⁴

In Table 5-2, the DSP-TRU waste stream for the 6 MT only increases the total radioactivity by 2.4 million curies, the majority of the increase of 2.9 million curies from CH-TRU waste between CRA-2014 and CRA-2019 (the 42.2 MT is not yet included in CRA-2019; DOE-CBFO, 2019b).¹⁵ The addition of the balance of the DSP-TRU surplus plutonium (42.2 MT) results in a total radioactivity (Ci) at WIPP closure greater than 9,000,000 curies, a three-fold increase in radioactivity at closure increasing to a fourfold increase at 10,000 years post-closure (Zeitler et al., 2018).

Table 5-3 shows that the combined SPD waste streams, SR-KAC-PuOx for the 6 MT and SR-KAC-SPD for the 42.2 MT, will occupy 19 percent of the total physical volume (measured by the outer container) of WIPP and will account for 85 percent of the plutonium-239 emplaced in WIPP (Dunagan, 2019).

TABLE 5-2 Increase in Total Radioactivity Reported by the Generator Sites for CH-TRU and RH-TRU Waste Between CRA-2014 and CRA-2109

NOTE: The majority of this increase (2.4 million Ci) is from SRS and is mainly due to the addition of the projected waste stream SR-KAC-PuOx representing the 6 MT DSP-TRU (accounted as ~4,200 m³ of TMW volume, and ~256 m³ of LWA Waste Container Volume). SOURCES: DOE-CBFO, 2014, 2019b, table 24-3.

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¹² Modified from the PA used in the CRA-2014.

¹³ For an explanation of EPA units, see Zeitler et al. (2018).

¹⁴ Zeitler, et al., refer to the diluted surplus plutonium as “surplus plutonium disposition (SPD) inventory” while the committee refers to it as “diluted surplus plutonium transuranic (DSP-TRU) waste inventory.”

¹⁵ For the recently submitted CRA-2019 (DOE-CBFO, 2019b) the PA was deferred until late 2019.

TABLE 5-3 Percentage of Total Initial Waste Inventory (Selected Radionuclides, Ci) for Two Waste Streams

NOTE: SR-KAC-PuOx is 6 MT of diluted non-pit plutonium TRU waste within DOE-EM’s program, and SR-KAC-SPD is 42.2 MT of diluted surplus plutonium TRU waste within the DOE-NNSA dilute and dispose plan. Sums in the table do not necessarily add up due to rounding errors (Dunagan, 2019). SOURCE: Dunagan, 2019, Day Two slide.

A summary of the characteristics and amounts between the DSP-TRU wastes and other TRU wastes is provided in Table 5-4. By almost any measure, the addition of two DSP-TRU waste streams (SR-KAC-PuOx for the 6 MT and SR-KAC-SPD for the 42.2 MT) from a total of ~500 existing waste streams introduces substantive changes to the character of the WIPP inventory. Worth noting and not included in the table is that these two waste streams also become the significant contributor to calculated releases due to human intrusion (Dunagan et al., 2019, slide 47). In the 2019 Annual Transuranic Waste Inventory Report (ATWIR; DOE-CBFO, 2019b), DOE has added a new waste stream, SR-KAC-PuOx-1, which accounts for 7.1 MT of surplus plutonium—a subset of SR-KAC-SPD in Table 5-3.

Several documents, reports, and briefings provided to the committee offered early insights into the safety and performance of WIPP in consideration of the transport, receipt, and emplacement of up to 48.2 MT of DSP-TRU wastes, such as Zeitler et al. (2018), discussed above. The timely completion and release of reports to the public (with or without the opportunity for public comment or independent review) are important in addressing public and regulator concerns and fostering trust and confidence in DOE’s plans for surplus plutonium disposition. However, in some cases, conducting studies before waste emplacement is inconsistent with established practice, regulations, and plans. The committee suggests that the following types of reports and analyses be conducted acknowledging and exploring the addition of 48.2 MT of surplus plutonium in WIPP and made available: criticality assessments, a post-closure performance assessment, and updates to the WIPP documented safety analysis.

5.3.1 Examples of Relevant Safety Analyses

One example of a safety analysis is the recent criticality assessment performed by Oak Ridge National Laboratory (ORNL) scientists for the full 48.2 MT of DSP-TRU waste (Saylor and Scaglione, 2018).¹⁶ A full nuclear criticality assessment had not previously been performed for WIPP inventories because historically the TRU waste streams were characterized as having generally more dispersed fissile material and the mechanisms to concentrate the dispersed fissile material were considered absent (Rechard et al., 2000). As designs for inventory, waste forms, and disposal packages have changed, new criticality analyses have been performed, and updates have been made to address any potential effects to the WIPP safety basis owing to the addition of large stocks of surplus plutonium.

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¹⁶ Nuclear criticality assessments examine the condition and configurations under which criticality can occur with the intent to support design and licensing considerations that ensure nuclear safety, such as was done for the CCC.

TABLE 5-4 Characteristics and Relevant Amounts and Volumes for Contact-Handled (CH) TRU and Diluted Surplus Plutonium (DSP) TRU Wastes Compared to Wastes in Other 55-Gallon Drum Containers

	Other TRU Waste	TRU Waste in Pipe Overpack Containers (POCs)	DSP-TRU Waste in Criticality Control Containers/Criticality Control Overpacks (CCC/CCOs)
Composition	Variable: contaminated clothing, tools, rags, residues, debris, soil, and other items	Plutonium residues, heterogeneous debris, salts, and sealed sources	Predictable composition of DSP-TRUa
Physical volume (outer container)	0.21 m3	0.21 m3	0.21 m3
LWA volume (inner container)	0.21 m3	0.046 m3	0.013 m3
Current total number of waste streams	202b	48b	3c
Total number of emplaced containers	97,928 (emplaced)d	27,025 (emplaced)d	160,667 (anticipated)e
Total amount of plutonium-239	1.6 MT (emplaced)	3.2 MT (emplaced)	48.2 MT (anticipated)
Percentage of plutonium-239 in total inventory at closure (10,000 years)f	15	[included in “Other TRU Waste”]	85
Average amount of plutonium-239 per container/fissile gram equivalent (FGE) limitg	14.4 g/£ 200 g	117 g/≤ 200 g	300 g (nominal)/ ≤ 380 g
Material attractiveness levelh	Level E	Varied	Level Di
Classification	Unclassifiedj	Unclassifiedj	Classified aspects (i.e., adulterant)i

^a Technical Baseline Description, SRNS, 2018b.

^b Number of waste streams derived from WDS/WWIS as of September 30, 2019, from https://wipp.energy.gov/WDSPA (accessed May 20, 2020).

^c SR-KAC-PuOx, SR-KAC-PuOx-1, SR-KAC-SPD (DOE-CBFO, 2019b; Dunagan et al., 2019).

^d Emplaced 55-gallon, direct loaded containers and POCs through September 30, 2019, see Table 5-1.

^e Assumes nominal 300g per container.

^f Dunagan et al., 2019.

^g Per WIPP WAC, table 1, DOE-CBFO, 2018c.

^h See Box 3-2 for a description of attractiveness levels.

ⁱ See System Requirements, DOE-NNSA, 2018.

^j A small number of emplaced containers are known to be classified (Sahd, 2019); no further details are available.

The ORNL nuclear criticality assessment developed models for optimally configured (i.e., an optimal environment for criticality), infinite arrays of CCC/CCOs that contain the maximum allowed quantity of DSP-TRU residing within an optimal environment for conservative results. Criticality occurs when the effective neutron multiplication factor is greater than or equal to unity (keff ≥ 1). The ORNL models predicted keff > 1 if the inner containers (pipes) in the infinite array were moved together (see top curve of Figure 5-2). To remove the potential for criticality (keff ≥ 1), it was determined that boron carbide (B4C) additive needed to be included as part of the overall mix of plutonium oxide and adulterant. The addition of boron carbide readily removes the potential for criticality as seen in Figure 5-2.¹⁷

The criticality safety assessment (evaluated over the 10,000-year compliance period) suggests that effective quality assurance and quality control are needed to ensure that boron carbide is added during the dilution process. Additionally, attention to load management within panels (i.e., deliberate distributed placement of CCC/CCO packages in the underground) is a prudent measure to eliminate the potential for the formation of large arrays of close-packed pipes containing DSP-TRU material.

While the committee concurs with the approach and conclusions of the nuclear criticality assessment report, the principal issue here is that concerns over post-closure criticality are renewed (particularly beyond the 10,000-year regulatory period), and DOE would be best served if such reports were made publicly and widely available.

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¹⁷ The CCC is designed and U.S. Nuclear Regulatory Commission certified to prevent criticality (hence its name) during loading, transport, and emplacement, as long as the condition and configuration (i.e., the stainless-steel flanged pipe) are kept intact. The design may contribute to but is not relied on for maintaining post-closure criticality, because the condition and configuration are expected to change over time. Thus, post-closure criticality is considered separately.

Post-closure performance assessments are another example of assessments and analyses that could be made available to the public to increase transparency. As noted in Chapter 2 of this report, EPA regulations call for a post-closure PA to demonstrate compliance with the long-term performance standards of 40 CFR Part 191 and to support CRA per 40 CFR Part 194. Congress requires EPA to recertify the facility every 5 years following the initial receipt of TRU waste until the end of its operational activities. This recertification requires DOE-CBFO to submit results of a PA with every CRA to EPA.¹⁸

While the demonstration of continued compliance with the post-closure performance criteria is fully expected, the CRA-2019 PA will be the first official and publicly available report to provide a complete understanding of the expected impacts from the addition of the 6 MT of DSP-TRU to the WIPP inventory.

The 6-MT inventory is now included in the WIPP and PA inventory upon issuance of the 2016 Surplus Plutonium Disposition Record of Decision (SPD ROD). Text in the announcement of the 2016 SPD ROD suggests that a special PA sensitivity analysis was performed, and if it were, it has not been made available to the committee or public (DOE, 2016a). Rather, DOE-NNSA appears to have relied on the basis for assessing environmental impact by pointing to the WIPP supplemental environmental impact statement (SEIS) and further supplements: “The potential environmental impacts of TRU waste disposal at WIPP are evaluated in the Waste Isolation Pilot Plant Disposal Phase Final Supplemental Environmental Impact Statement (WIPP SEIS-II) (DOE/EIS-0026-S-2, September 1997) and subsequent Supplement Analyses from 2005 (DOE/EIS-0026-SA-05) and 2009 (DOE/EIS-0026-SA-07)” (DOE, 2016a, p. 19590). Pointing to the SEIS is analogous to asserting the waste will meet the WIPP waste acceptance criteria (WAC).

In April 2019, the committee was given and briefed on a special PA sensitivity analysis report (Zeitler et al., 2018; Dunagan, 2019) that summarized performance analysis results for the inclusion of up to 48.2 MT of DSP-TRU waste in WIPP. Previously, the committee received the corresponding PA Inventory Report (LANL, 2017). Together these documents provided information and data into the effects that the added inventory of 48.2 MT might have on the repository performance metrics, as well as the likely continued compliance with the regulations for post-closure performance (see Tables 5-2 through 5-4 and Figure 5-1). These documents are publicly available by request through the National Academies’ Public Access Records Office (paro@nas.edu) but could be more widely accessible through, for example, a special section on the DOE WIPP website (similar to what was done for the recent accident recovery). This would serve to enhance transparency and outreach efforts.

A final example of assessments and analyses that could be made available to the public to increase transparency is the WIPP documented safety analysis (DSA). As noted in Chapter 2, the Defense Nuclear Facilities Safety Board (DNFSB) raised concerns regarding deficiencies in DOE Standard 5506-2007 (DOE, 2007) and its application to the WIPP DSA, and that could have bearing on the operational safety management for the large number of CCOs anticipated for the dilute and dispose program. In short, the DNFSB took issue with the assumed statistical variation of the density of plutonium in the waste streams arriving via generator site shipping campaigns. It noted that in some cases the variation within a room (there are seven rooms within each panel in WIPP) was not in accordance with the statistical variation

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¹⁸ This year, DOE-CBFO submitted the PA results after the March 2019 CRA submission—an unusual step since normally the PA results are submitted with the CRA. The PA was deferred due to schedule and resource limitations arising from the WIPP recovery efforts after the 2014 accident. From the CRA-2019 Executive Summary (DOE-CBFO, 2019c): “A PA has been included as part of the recertification application for all past recertification cycles, although it is not explicitly required for recertification by the LWA, 40 CFR 191 or 40 CFR 194. The DOE has decided, with agreement from EPA, not to include an updated PA in CRA-2019. The CRA-2019 contains all updated information and data required by 40 CFR 194.15, Content of compliance recertification applications. DOE plans to separately submit PA results based on CRA-2019 data in late 2019. The PA used in the CRA-2014 continues to be the baseline PA for the WIPP certification and is included in this CRA-2019 submittal by reference. This PA shows WIPP is compliant with 40 CFR 194.”

that is assumed in the Material at Risk (MAR) and the calculation of source term.¹⁹ The DNFSB cautioned that if use of the statistical MAR continued without additional administrative controls, there would be a high likelihood that future waste operations would continue to concentrate waste containers with higher-than-average fissile loadings and create the potential for accidents with higher consequences than analyzed (DNFSB, 2018). As shown in Tables 5-2 through 5-4, the DSP-TRU waste streams are likely to exacerbate the transfer campaign bias. Even within the current room/panel design, the DSP-TRU waste physical volumes require the space of nearly two equivalent panels and could, quite possibly, be more concentrated in the future for the as-yet unmined panels. One potential outcome is to revisit the room-level MAR as future room and panel configurations through a revision of DOE Standard 5506-2007 and the WIPP DSA to explicitly acknowledge the additional administrative controls that may be applied to ensure that the safety basis is in line with realistic assumptions for the receipt of the DSP-TRU.

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¹⁹ Within the WIPP DSA and according to DOE Standard 5506-2007, the MAR is the amount of radioactive material available to be acted on by a given physical stress (i.e., from a postulated accident scenario). The WIPP DSA expresses the MAR as the product of the number of waste containers (e.g., CCC/CCO) involved in a postulated event causing physical stress, and, with other factors, calculates the possible source term that could be released in that event.

Beyond the technical considerations and analyses, there is a “social contract” perspective that may be equally important to the long-term public support and sustainability of the dilute and dispose program objectives. The common presentation of WIPP TRU waste as modestly contaminated debris generated through defense activities related to nuclear weapons maintenance and development is incongruent with the characteristics of the DSP-TRU waste streams. Indeed, the DSP-TRU waste streams (SRS-KAC-PuOx, SR-KAC-PuOx-1, and SRS-KAC-SPD) could be viewed as closer to conditioned nuclear material than traditional TRU waste. In a 2002 letter to DOE Secretary Abraham, Senator Domenici foresaw the potential for diluted weapons material to be sent to WIPP when he wrote:

I want to ensure that high level or weapons material wastes can never be simply diluted in order to comply with criteria for WIPP disposal…. In fact, dilution of weapons materials, simply in order to facilitate disposal, raises serious questions about our adherence to the same international controls on weapon-related materials that we expect other nations to follow. (Domenici, 2002)

Similarly and more recently, Senator Udall²⁰ of New Mexico expressed concern over the volume of record change (see Box 2-3) when he noted that WIPP’s volume limits were critical to federal-state negotiations that led to WIPP’s creation “and were a major reason New Mexico agreed to this mission in the first place.… I am encouraging the new [State] administration to take a hard look at this action, and hopeful that it will pause and reconsider this last-minute change that has major ramifications for our state” (Oswald, 2019).

FINDING 5-4: By virtually any measure, the proposal to dilute 48.2 metric tons of surplus plutonium and dispose at the Waste Isolation Pilot Plant (WIPP) represents a substantial technical and “social contract” change for WIPP and the State of New Mexico.

Several other converging factors occurring in the next 5 to 8 years could further exacerbate the ability of the regulatory institutions (EPA, NMED) and the State of New Mexico to consider the significance of the dilute and dispose program in its entirety. These other factors include the following:

• The recent new shaft and access drift being developed are expected to lead to a request for new disposal panels to accommodate the space lost in the abandoned south end, the additional volumes of waste that are enabled by the LWA volume of record accounting change, and the SPD-TRU volumes (6 MT already in the WIPP-bound inventory). It is unclear where or what new room/panel configurations might be proposed, but they will introduce new asymmetries in the repository modeling and have to be reflected in the future PAs of long-term performance, EPA’s compliance recertification reviews, NMED review and approval, etc.
• The conceptual models and software code used in the performance assessment are expected to transition from BRAGFLO to PFLOTRAN, allowing greater fidelity in the PA modeling and allowing a three-dimensional analysis (see Box 5-1). It is unclear if this new code base will be relied on for the March 2024 or March 2029 recertification application.
• As noted earlier, the DSP-TRU waste inventory has caused a renewed look at the potential for criticality, and the simple features, events, and processes (FEP) screening arguments used in the past are now augmented by a full criticality safety assessment, but this work has not yet received regulatory review. The initial criticality safety assessment, which has noted that abatement of criticality concerns may require boron carbide additives or load management, is in the context of the current room/panel design and evaluated for the 10,000-year regulatory compliance period.

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²⁰ Senator Udall helped establish the legal limits in the Waste Isolation Pilot Plant Land Withdrawal Act that resulted following a lawsuit that New Mexico won against DOE when he served as Attorney General for New Mexico.

• The LWA volume of record change ostensibly translates to a greater total radionuclide inventory in WIPP (owing to the radionuclide quantity now being focused within an inner rather than outer container volume) which is intensified by the CCC/CCO configuration for diluted surplus plutonium (i.e., ~300 FGE in 0.013 m³ instead of 0.21 m³).

This confluence of events and changes, if approached in the traditional manner, will confound a transparent regulatory and public review of the full dilute and dispose program scope and deny the public and especially the State of New Mexico the opportunity to consider the significance of the dilute and dispose programs in their entirety.

CONCLUSION 5-3: The possible accommodation of the dilute and dispose program inventory, representing a significant demonstrable change in the character of the Waste Isolation Pilot Plant repository and the social contract with the State of New Mexico, warrants a strategic approach to seeking its technical evaluation, regulatory review, safety analysis, and public engagement.

An essential element to engender public trust and stakeholder acceptance is the use of independent oversight (versus regulatory) bodies with the capacity to conduct independent technical evaluation. The former Environmental Evaluation Group (EEG) is one such example (see Section 5.3.1, Examples of Relevant Safety Analyses).

The EEG was a part of the Environmental Improvement Division, a component of the New Mexico Health and Environment Department, funded by DOE and administered through the Board of Regents of the New Mexico Institute of Mining and Technology. Previously, the EEG has served as an independent technical advisor to NMED, and Section 74-4A-4 of the New Mexico State Statutes recognizes and defines the EEG as an independent state review organization (Walker and Silva, 2002). Important to its independence and credibility, the EEG was neither a proponent nor an opponent of WIPP and focused on reviewing and evaluating potential health, safety, and environmental impacts from WIPP.

Details of how the EEG was established were critical to its independence. These details can be found in Box 5-2.

FINDING 5-5: In addition to the implementation challenges outlined in Finding 4-1, several system vulnerabilities exist within the current plan. If not addressed, system vulnerabilities could have serious consequences to the program and its mission to dispose of at least 34 metric tons (MT)—and as much as 48.2 MT—of surplus plutonium in an efficient, safe, and secure manner. Addressing the system vulnerabilities will require actions by the current Department of Energy’s National Nuclear Security Administration’s (DOE-NNSA’s) program management and higher levels of government. System vulnerabilities include

• The Waste Isolation Pilot Plant (WIPP) as the single point of failure for the disposal of diluted surplus plutonium transuranic waste;
• Plans that span multiple DOE sites, offices, functions, and competing priorities without clear crosscutting leadership support;
• Shifting public opinion of DOE-NNSA’s plans and its handling of plutonium stockpiles and surplus inventory; and
• Reliance on a plan that changes the nature and function of the United States’ only operational deep geologic waste repository (WIPP).

FINDING 5-6 (updated Interim Report FINDING 7): The Department of Energy’s National Nuclear Security Administration and Office of Environmental Management do not have well-developed public outreach plans for each of the host sites for processes or for the transportation corridor states (i.e., the current plan is to follow public input requirements defined by the National Environmental Policy Act) for the dilute and dispose program.

CONCLUSION 5-4 (updated Interim Report CONCLUSION 2): Public trust will need to be developed and maintained throughout the lifetime of the dilute and dispose program because the program will change and evolve as new knowledge is obtained, and modifications and potential changes to legislation will be required for the Waste Isolation Pilot Plant. These changes will require assuring the regulators and the public of the safety and security of the Department of Energy (DOE) plans. This is particularly challenging for the dilute and dispose program because of several factors: security classification of aspects of the planning (constituents of the adulterant, processing steps, security and safeguards assessments); early stage of program development with changes likely to occur as more information is known; and potential impacts that cross many states and DOE sites.

RECOMMENDATION 5-2 (updated Interim Report RECOMMENDATION 2): The Department of Energy’s National Nuclear Security Administration and Office of Environmental Management should engage New Mexico and South Carolina as well as their congressional delegations prior to the public engagement required by the National Environmental Policy Act process to assess prospects for successfully amending the existing legal agreements to allow for the dilution and packaging of up to 48.2 metric tons of surplus plutonium at the Savannah River Site and its disposal in the Waste Isolation Pilot Plant.

RECOMMENDATION 5-3 (updated Interim Report RECOMMENDATION 3): If the Department of Energy’s (DOE’s) National Nuclear Security Administration’s dilute and dispose plan moves forward, DOE should reinstate the Environmental Evaluation Group (EEG), representing the concerns of the State of New Mexico, throughout the lifetime of processing up to 48.2 metric tons of surplus plutonium material. The independence of the EEG should be supported through mechanisms similar to those established in its original founding. Members of the technical review organization should be technically qualified to address the health and safety issues and a subset should have access authorizations that will allow thorough review of classified aspects of the plans and their implementation.

RECOMMENDATION 5-4 (updated Interim Report RECOMMENDATION 4): In addition to and separate from the independent review organization representing the State of New Mexico described in Recommendation 5-3, periodic reviews for Congress and the Department of Energy (DOE) by a team of independent technical experts should be required until classified aspects of DOE’s National Nuclear Security Administration’s and DOE’s Office of Environmental Management’s dilute and dispose plans, including the safety and security plans, are completed and implemented. Because DOE’s plans and decisions are expected to mature and evolve, these independent reviews would provide a mechanism to review classified aspects of the programs and would improve public trust in those decisions.

Because DOE-NNSA’s, DOE-EM’s, and DOE-CBFO’s plans and decisions are expected to mature and evolve, these independent reviews would provide a mechanism to review all aspects of the program, including the classified elements, and would do much to improve public trust in those decisions.

Several incremental actions taken by DOE, while administratively compliant, could be interpreted as obscuring the fact that as much as 48.2 MT of surplus plutonium is being proposed for dilution and disposal in an expanded (in physical space) and extended (in lifetime) WIPP. For example, numerous site-specific SEIS actions for smaller amounts of surplus plutonium material are confusing to track and have been proposed as the basis for the 34-MT National Environmental Policy Act (NEPA) actions (Richard, 2019; see also Box 2-2). DOE-NNSA’s NEPA strategy includes moving forward with a SEIS for the 34 MT of surplus plutonium material; this would be in addition to the SEIS for 6 MT of non-pit plutonium. A notice of intent for the disposition of 34 MT still has not been issued, an action that has been delayed by over a year. Another 7.1 MT is currently without a disposition pathway but associated with the ROD for the 6 MT (see below). Yet, another 1.1 MT could be considered for dilute and dispose but may also be dispositioned in the Defense Waste Processing Facility (see Figure 2-1). Any of these plans for smaller amounts of surplus plutonium when individually considered would appear to have little impact on WIPP, the environment, safety, or security. Yet, when considered in total, their impact is clear.

There are many reasons why implementation of programs responsible for the dilution and disposal of up to 48.2 MT may have to proceed in segments (e.g., 6 MT, 7.1 MT, 34 MT, and so on). Such an approach, while technically permissible, goes against the notion of transparency that could impact public support and thus represents a substantial system vulnerability. If DOE leadership, such as the Deputy Secretary, has decided on a strategic objective to disposition the majority (48.2 MT) of the surplus plutonium inventory in WIPP as DSP-TRU waste, actions could be taken to clarify these objectives and to transparently report their potential impacts. Members of the public and the State of New Mexico should be afforded the opportunity to consider the significance of the dilute and dispose program in its entirety. As noted previously, a new DSP-TRU waste stream was recently identified, SR-KAC-PuOx-1, and associated with the 7.1 MT of surplus pit plutonium material (DOE-CBFO, 2019b). This indicates that DOE is moving forward with another increment of DSP-TRU waste for WIPP rather than addressing the full amount in a single assessment.

In the examples in Section 5.3.1 and summarized in Findings 5-2 and 5-3, the analyses and results indicate that it is possible to emplace up to 48.2 MT of DSP-TRU in WIPP but that precautions may need to be taken and revisions of earlier WIPP analyses, which assumed more dispersed and far less fissile

material, may also be needed. The timely revision of these important safety documents, in particular, before waste receipt, would better improve DOE transparency and address public concerns over the potential effects and safety impacts of the dilute and dispose program.

NEPA sets requirements for major federal actions requiring the preparation of environmental impact statements (EISs). It is DOE policy to follow NEPA and to apply the NEPA review process early in program development. To date however, DOE and DOE-NNSA have leveraged or relied on existing EISs for a variety of sites, issuing supplements, amendments, and interim actions where necessary or expedient, while also trying to accommodate changes in an uncertain strategy toward the disposition of surplus plutonium. DOE-NNSA has issued a number of EISs, SEISs, and RODs for dispositioning surplus plutonium (see Box 2-2). Below, two federal actions and decisions relevant to the dilute and dispose programs are highlighted:

• The final programmatic EIS, FPEIS-0229, evaluated strategies and locations for storing and dispositioning weapons-usable²¹ fissile materials (DOE, 1996b); the associated ROD selected MOX and immobilization as the preferred options for surplus plutonium disposition. The Surplus Plutonium Disposition EIS-0283 (tiered from the FPEIS-0229, DOE, 1996b) evaluated site-specific alternatives for the construction and operation of facilities for disposition of up to ~45 MT of surplus plutonium (DOE, 1999a). The associated ROD in 2000 identified immobilization and irradiation of MOX fuel as the preferred dual alternatives for surplus plutonium disposal. Two years later, the immobilization program was canceled due to budget constraints and MOX was selected as the only method for plutonium disposition for the United States (DOE, 2002). The PMDA was later renegotiated with the Russian Federation and updated (DOS, 2010). Immobilization was removed from the listed disposition options; some of the material selected for immobilization was to be processed at the MOX plant to make it useable in MOX fuel.
• In 2015, dilute and dispose was specifically considered as one of the disposition options for surplus non-pit plutonium (referred to as “WIPP Disposal”) in the Final Surplus Plutonium Disposition Supplemental Environmental Impact Statement (DOE, 2015a).²² Under this disposition option, plutonium oxide would be “mixed/blended with inert material…. Inert material would be added to dilute the plutonium-239 content and inhibit plutonium recovery and could include dry mixtures of commercially available materials” (DOE, 2015a, p. S-31). The subsequent April 2016 ROD selected the dilute and dispose at WIPP option for dispositioning 6 MT of diluted non-pit plutonium and reserved a decision on the other 7.1 MT for a later time, though it seems likely the same option could be exercised (DOE, 2016a).

A point of the preceding two bulleted items is to illustrate the DOE efforts to comply with the NEPA requirements for major federal actions requiring the preparation of EISs, but it may also serve to illustrate the impacts such indirect paths have on public trust and transparency.

While DOE has moved forward with a ROD for 6 MT, there are still several more surplus plutonium stocks under consideration for disposal at WIPP, and totaling at least 42.2 MT, and will need to be actioned under NEPA. In the past, the DOE approach has been to

• Use SEISs covering the SRS: “prepare the SPD Supplemental EIS to evaluate the potential environmental impacts at the Savannah River Site (SRS) in South Carolina of disposition pathways for surplus weapons-usable plutonium (referred to as “surplus plutonium”) originally planned for immobilization” (DOE, 2015b, p. iii);

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²¹ A fissionable nuclear material such as uranium-235 or plutonium-239 that is pure enough to be usable in a nuclear weapon.

²² DOE/EIS-0283-S2 evaluates environmental impacts for disposition of 13.1 MT of surplus plutonium, including 6 MT of surplus non-pit plutonium (managed by DOE-EM) as well as 7.1 MT of plutonium from pits shown in DOE (2015a, fig. 1).

• Point to assurances the diluted waste will be compliant with the WIPP WAC: “This plutonium will be prepared and packaged to meet the WIPP waste acceptance criteria…” (DOE, 2016a, p. 19588); and
• Use the existing WIPP SEIS to maintain that the environmental impact of adding surplus plutonium at WIPP were evaluated: “The potential environmental impacts of TRU waste disposal at WIPP are evaluated in the Waste Isolation Pilot Plant Disposal Phase Final Supplemental Environmental Impact Statement (WIPP SEIS-II) (DOE/EIS-0026-S-2, September 1997) and subsequent Supplement Analyses from 2005 (DOE/EIS-0026-SA-05) and 2009.” (DOE, 2016a, p. 19590)

In a 2011 SRS Interim Action Determination, justification for the emplacement in WIPP of previous diluted plutonium amounts rested on the small amount of material relative to remaining capacity in WIPP (Moody, 2011).²³ Then for the 6-MT SEIS, DOE noted that small amounts of PuOx were similarly diluted and already emplaced at WIPP as justification for the expansion to 6 MT. Presumably the decision on the remaining 7.1 MT will point to the previous decision on the 6 MT. The April 2019 briefing on DOE-NNSA’s NEPA strategy indicated that DOE-NNSA would pursue a supplemental EIS for the 34 MT, which could potentially point to the small amounts of emplaced diluted material for justification (Richard, 2019).²⁴ The logic begins with justification of small amounts relative to the WIPP inventory and ends with the majority of surplus plutonium constituting 85 percent of the total plutonium-239 emplaced in WIPP.

The committee recognizes that such an incremental and disaggregated SRS SEIS approach may have the advantage of limiting scope and appear expedient, even if permissible by NEPA guidance. The committee further recognizes that realistically all of the surplus plutonium inventory has no real alternative at this time other than disposal at WIPP or “no action.”

However, with regard to following the same approach as was done for the 6 MT, the committee expresses concern that, when applied across the total 48.2 MT inventory including the remaining 42.2 MT, such an approach is counter to public transparency, and the development of a sustainable sociopolitical relationship.

In reviewing the implementing procedures governing NEPA (10 CFR Part 1021), and the related regulations requiring the preparation of EISs (40 CFR § 1502.4) for major federal actions (40 CFR § 1508.18), the committee notes the following (excerpted and edited for clarity, emphasis added):

• A programmatic NEPA document means a broad-scope EIS identifying and assessing the environmental impact of a DOE program²⁵;
• A program means a sequence of connected or related DOE actions or projects²⁶;

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²³Moody, 2011, p. 2: “WIPP has been safely disposing of TRU waste for more than 10 years, and the 880 cubic meters that would result from this action represents a small fraction, about 3%, of the unsubscribed WIPP disposal capacity.” NOTE: The 3 percent figure seems in error, and the volume would have been relative to the TMW (outer container) volume definition.

²⁴ DOE has not yet issued a notice of intent (NOI), an EIS, or ROD for dispositioning 34 MT of pit and non-pit surplus plutonium using the dilute and dispose process. The committee received information on NEPA plans (Richard, 2019, slide 2) that stated that DOE-NNSA planned to initiate a supplemental EIS for the 34-MT mission. Its plans include a posting of an NOI in the near future, public comment periods required by NEPA, plans to analyze dilute and dispose as the preferred alternative as well as the no-action alternative, and to complete the NEPA analysis by late 2020.

²⁵ See 10 CFR § 1021.104 Definitions: https://www.ecfr.gov/cgi-bin/text-idx?rgn=div5&node=10:4.0.3.5.14#se10.4.1021_1104 (accessed April 26, 2020).

²⁶ See 10 CFR § 1021.104 Definitions: https://www.ecfr.gov/cgi-bin/text-idx?rgn=div5&node=10:4.0.3.5.14#se10.4.1021_1104 (accessed April 26, 2020).

• When required to support a DOE programmatic decision, including the adoption of programs—such as a group of concerted actions to implement a specific policy or plan or systematic and connected agency decisions allocating agency resources to implement a specific statutory program or executive directive—DOE shall prepare a programmatic EIS²⁷; and
• “Proposals or parts of proposals [that] are related to each other closely enough to be, in effect, a single course of action shall be evaluated in a single impact statement.”²⁸

As such, when considering the whole of the surplus plutonium dilute and dispose program, the several connected sites directly affected by the plan (including at least SRS and WIPP, and possibly LANL), and the quantities that challenge the scope of the existing EIS, a broad-scope PEIS is warranted.

Simply, the total quantities of surplus plutonium now being considered for disposal at WIPP are far larger than those assessed in the 2015 Supplemental EIS. Additionally, while compliance with the WIPP WAC is required of all TRU waste, the existing WIPP SEIS did not contemplate either the quantity or character of the surplus plutonium or the future underground configuration. Finally, several processing facility changes must all happen to implement a dilute and dispose program. Recent efforts to expand the nation’s pit production capacity will also impact the sites and facilities that are being proposed in DOE-NNSA’s dilute and dispose plans. There is likelihood of conflicts across programs for human resources, infrastructure, and facilities usage, as noted in Chapter 4.

RECOMMENDATION 5-5: The Department of Energy should implement a new comprehensive programmatic environmental impact statement (PEIS) to consider fully the environmental impacts of the total diluted surplus plutonium transuranic waste inventory (up to an additional 48.2 metric tons) targeted for dilution at the Savannah River Site and disposal at the Waste Isolation Pilot Plant (WIPP). Given the scale and character of the diluted surplus plutonium inventory, the effect it has on redefining the character of WIPP, the involvement of several facilities at several sites to prepare the plutonium for dilution, a schedule of decades requiring sustained support, and the environmental and programmatic significance of the changes therein, a PEIS for the whole of surplus plutonium that considers all affected sites as a system is appropriate to address the intent and direction of the National Environmental Policy Act and would better support the need for public acceptance and stakeholder engagement by affording all the opportunity to contemplate the full picture.

RECOMMENDATION 5-6: The Department of Energy’s (DOE’s) National Nuclear Security Administration, DOE’s Office of Environmental Management, and DOE higher-level officials should take additional actions beyond those defined by the National Environmental Policy Act toward transparency and stakeholder engagement on the whole of the potential scope of surplus plutonium under consideration (48.2 metric tons) for disposal at the Waste Isolation Pilot Plant. Such actions include completing and publicizing the outcome of relevant safety analyses and cost estimates.

5.4 ENGAGE NMED AND EPA

A dual regulatory framework exists for WIPP, with EPA and NMED having separate but coupled roles in regulating worker, public, and environmental safety (see Chapter 2). A positive “regulator–permittee” relationship between DOE and NMED is a prerequisite for smooth general operation of the

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²⁷ See 40 CFR § 1508.18 (b.3) Major Federal Action: https://www.govinfo.gov/content/pkg/CFR-2010-title40vol32/pdf/CFR-2010-title40-vol32-sec1508-18.pdf (accessed April 26, 2020).

²⁸ See 40 CFR § 1502.4 Major federal actions requiring the preparation of environmental impact statements, part (a): https://www.govinfo.gov/content/pkg/CFR-1996-title40-vol18/html/CFR-1996-title40-vol18-sec1502-4.htm (accessed April 26, 2020).

WIPP, but it becomes especially important when potentially controversial issues come into play and public scrutiny and skepticism are likely to increase. Such was the case with the WIPP accidents and its subsequent recovery, the effort to change the accounting of waste volumes, and the occasional but recurring mention of accepting other TRU wastes (see Boxes 2-3 and 2-5).

One could argue that the anticipated changes to the WIPP underground configuration, its lifetime extension (both of which are likely even without the DSP-TRU waste), and the changes contemplated by the receipt of the DSP-TRU inventory place WIPP on the cusp of a new phase of operations. How DOE-CBFO, DOE-NNSA, and DOE decision makers approach the upcoming WIPP permit modification requests to NMED could have a demonstrable effect on the regulatory review duration and the degree of skepticism and scrutiny exercised by the public.

DOE-CBFO’s engagement with EPA, as with NMED, provides another critical opportunity to promote transparency and involvement with the public and interested stakeholders. The committee has given consideration to how and why DOE-CBFO might approach EPA beyond the requirements for the quinquennial recertifications, as DOE-EM and DOE-NNSA contemplate a future implementation of a dilute and dispose program.

As presented in Chapter 2, the principal WIPP EPA regulations of concern are the radiation protection criteria described in 40 CFR Part 191 (see Figure 2-5) and in 40 CFR Part 194, which lay out the compliance certification criteria.

As noted previously, the addition of the DSP-TRU inventory (up to 48.2 MT) is expected to involve the handling of more than 160,000 containers (i.e., CCC/CCOs), will require two additional underground panels (GAO, 2017), and at closure will have quadrupled the total radioactivity (curies) of disposed TRU waste (Zeitler et al., 2018).

Regarding compliance with post-closure performance criteria, the committee notes:

• Repository compliance is based on calculations of release fractions of selected radionuclides and the specified release limits scale with the quantity of waste in a repository (i.e., the more disposed waste, the more radiation that may be released).
• As demonstrated in all previous compliance certifications, the only releases are from the disturbed scenario (i.e., human intrusion through drilling) and have been within the compliance limits.
• Results of a special post-closure performance assessment (Zeitler et al., 2018) suggest continued compliance is expected with all of the DSP-TRU inventory (48.2 MT) included.²⁹

EPA now has the deferred PA associated with the 2019 CRA (see Chapter 2 for a discussion on the deferred PA) which is the first recertification application that includes a substantial portion (6 MT) of the surplus plutonium inventory that EPA will review.³⁰ The results of this regulatory review will be available in about a year from the writing of this report and may thus provide some technical or regulatory foresight on the inclusion of an additional 42.2 MT.

The volume and density of the total DSP-TRU inventory under consideration, combined with the pending inevitable changes in the surface and underground configurations, could be considered a significant change to WIPP’s inventory. Thus, EPA could seek a new determination of regulatory compliance (formally or informally) prior to program implementation to improve transparency on such a significant change.

In a briefing by EPA to the committee (Peake, 2019), it was noted that 40 CFR § 194.4 requires DOE to notify EPA of “any planned or unplanned changes in activities or conditions pertaining to the

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²⁹ The committee commentary should not be construed as supplanting the regulatory function or influencing the determination of safety by regulatory bodies.

³⁰ Recall that 6 MT is the waste stream SRS-KAC-PuOx (see Table 5-2), the second-largest contributor (after the SRS-KAC-SPD 42.2 MT) to total EPA units (11 percent) at closure and at 10,000 years.

disposal system that differ significantly from the most recent compliance application.” EPA reported that DOE has recently submitted to EPA several notices of planned changes to EPA:

• A notice of the new shaft and access drift, which will be reviewed as part of CRA‐2019 now under way;
• A notice on changing panel closures and the abandonment of panel 9 without waste, which was approved in March 2019; and
• A notice on the LWA volume of record change, which is currently under review by EPA.

The DOE-NNSA Master Schedule and the ROAR both indicate that DOE-CBFO will submit a planned change notice (PCN) to EPA in early FY 2022 (this is not the same as a recertification application); this is after mid-FY 2020, when DOE-NNSA expects to issue a ROD for the disposition of 34 MT of surplus plutonium (see the relevant portion of the Master Schedule in Figure 3-1). The full scope and extent of this PCN, or how it will be managed by EPA, is not clear, although the Master Schedule indicates that EPA will review the PCN throughout FY 2023 and is expected to approve the PCN by the end of the first quarter of FY 2024. The expected EPA approval is coincident with (and independent of) the DOE-CBFO submission of the 2024 CRA and the beginning of repository disposal of the 7.8 MT of non-pit plutonium.

After DOE-CBFO submits the PCN, EPA may request additional information, and if EPA determines that, in accordance with 40 CFR § 194.65, “changes in activities or conditions pertaining to the disposal system depart significantly from the most recent compliance application,” EPA would need to modify the existing certification (as opposed to waiting for the next 5-year recertification). EPA would then need to propose a rulemaking to modify the certification and take public comment. This has raised in the EPA and elsewhere the question, At what point would a change “depart significantly from the most recent compliance application”?

In its briefing to the committee, EPA noted that if the certification needs to be modified, a rulemaking would take more than 2 years and indicated that such activities need to be coordinated with recertification applications as much as possible to minimize multiple reviews.

It remains to be seen whether EPA will seek a rulemaking or other form of review, before or after various RODs trigger the inclusion of increments of the total SPD-TRU inventory. However, this sequence raises some uncertainty as to how EPA would evaluate, in full, the sum total of DSP-TRU inventory and its effect on WIPP compliance.³¹

Given the significance of the issues and their potential consequences for WIPP and the State of New Mexico, and in the interest of fostering a positive, sustained sociopolitical acceptance of the future WIPP, it is prudent to seek a high level of confidence that the dilute and dispose program as proposed and emplaced under a revised WIPP configuration will be or is compliant with all WIPP regulations including post-closure safety. A sufficiently high level of confidence could be established through EPA formal certification or other means that provides the same level of technical review and public participation.

FINDING 5-7: A segmented and incremental approach to revealing the full inventory under consideration for disposal as diluted surplus plutonium transuranic waste in the Waste Isolation Pilot Plant (WIPP) (initially 6 metric tons [MT], then 7.1 MT, and 34 MT, and so on) obfuscates the total anticipated inventory expected for WIPP and its consequences. An

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³¹ Although the results of Zeitler et al. (2018) suggest that WIPP can demonstrate compliance with the full inventory of 48.2 MT of diluted surplus plutonium, a decision to accept and support a future WIPP with all of the discussed surplus plutonium inventory will rely on a determination by EPA. Note that Zeitler et al. (2018) make clear that this is not a substitute for evaluating compliance: “The analysis is not in support of a planned change request (PCR) or planned change notice (PCN) to be submitted by the DOE to the EPA, and was not performed as a compliance calculation. Instead, the planned use of the analysis is as input into a National Environmental Policy Act (NEPA) analysis” (p. 13).

incremental approach inhibits a comprehensive review by regulators and the public of the full impact of the proposed dilute and dispose program on a future WIPP. The punctuated (5-year) Environmental Protection Agency compliance recertification schedule and limited scope of the New Mexico Environment Department’s reviews (which exclude nuclear material) add to these challenges.

RECOMMENDATION 5-7: The Environmental Protection Agency, the Department of Energy, and the State of New Mexico should engage in developing a mutually agreed-upon strategy for vetting the effects of the dilute and dispose inventory, in its entirety (and as added to the rest of the projected and emplaced inventory), on the Waste Isolation Pilot Plant. This vetting could be through a special demonstration of compliance and certification, or other means all agree to, but should occur before committing the substantial resources that will be needed to implement an integrated (48.2 metric tons of surplus plutonium) dilute and dispose program.