Ray Conatser, Mark Dupont, Ed Burns
SRS

Doug Turner
Oak Ridge

Woody Stroupe, Al Hoskins, Eric Shaber, Doug Toomer, Paul Fairbourn, Bill Hurt
INEEL

Tom Weiss, Tony Suda
West Valley

Roger McCormack
Hanford

In July 1996, a DOE-Environmental Management (EM) Contractor led Integration Project (EMI) Team was chartered to review existing DOE baseline disposition plans, identify technically executable alternatives from a DOE complex-wide integrated waste stream perspective, and develop recommendations for more cost effective and accelerated life cycle disposition of the DOE spent nuclear fuels (SNF). Projected receipts of US origin foreign and domestic research reactor SNF are included within this scope, but commercial SNF is not. As part of this EMI program, similar assessments were conducted in parallel for the six major DOE Complex waste stream systems: transuranic (TRU), mixed low-level (MLLW), low-level (LLW), Environmental Restoration programs (ER), high-level (HLW), and SNF.

This paper characterizes three of the specific actions identified in the EMI SNF team report, "A Contractor Report to the Department of Energy on Opportunities for Integration of Environmental Management Activities Across the Complex (Discussion Draft)", (ref. 1), which have been proposed by DOE for inclusion in the DOE baseline plan "Accelerated Cleanup: Focus on 2006" (ACP / ref.2) and for consideration by stakeholders as opportunities to enhance the current program. The three actions include: 1) Accelerating the development of repository performance based acceptance criteria for DOE SNF, 2) Limiting transfer of SNF between DOE sites to only those fuels that are to be uniquely treated or packaged at the receiving site, and 3) Pursuing selected use of processing for small quantity, unique fuel types.

The actions recommended by the EMI SNF team provide a technically defensible, cost effective strategy for characterization, conditioning / treatment, interim storage and transportation of the DOE SNF within the complex, and eventually for disposal in the Federal Geologic Repository. These actions have the potential to yield the complex an estimated combined life-cycle cost savings and cost avoidance of more than $1.3 billion dollars. They would also accelerate the baseline stabilization schedule for many of the fuels by more than ten years.

The two principal objectives of the EMI team initiatives were to:

• Identify where potentially significant cost savings opportunities might exist within the DOE SNF baseline disposition plans, and where gaps exist in site-specific programs that might result in incomplete disposition for all of the DOE SNF types.
• Characterize, from a DOE integrated waste stream perspective, technically executable alternatives that could close the identified gaps or provide more timely and cost effective solutions.

In parallel with the efforts of the contractor led EMI teams, DOE’s Office of Environmental Management (EM) undertook a review of site cleanup actions that could be accelerated during the next ten years, resulting in significant savings to the taxpayer. The resulting baseline plan was documented as the DOE ACP. The EMI Team sought to ensure consistency between these two initiatives.

A systems engineering approach was used to identify alternative strategies and to evaluate them against a selected set of criteria, in order to characterize and prioritize net benefits and to develop a recommended strategy. Multiple alternative strategies to the existing DOE SNF baseline disposition plan were identified. Each of these incorporated technically executable actions, but with varying degrees of complexity in dealing with institutional policies, regulatory requirements, and stakeholder concerns. Specific "breakthrough actions" required to implement each of the alternatives were then identified.

Before 1992, the long term stabilization strategy for most DOE-owned SNF involved chemical reprocessing to remove the fission products and recover the special nuclear materials [i.e., high enriched U235 (HEU) and plutonium (Pu)] for national defense purposes. With the current political sensitivity to possible negative impacts on US non-proliferation policies from extended operation of SRS canyons, DOE is evaluating a strategy for stabilizing the remaining SNF legacy using ‘direct disposal’ to the extent feasible, with eventual transfer to the federal repository, when available.

DOE has stored much of its existing SNF inventory wet. The wet storage facilities were designed and operated for temporary staging of the SNF awaiting reprocessing - many were not suitable for extended storage of the SNF and some fuel degradation resulted. In addition, a small quantity of the legacy fuels were destructively examined and then packaged before storage. This created a potential for release of radioactive material, if the storage containers were to develop leaks. The condition of the storage facilities and the associated SNF inventories created a significant number of potential environmental, health, or safety vulnerabilities. The DOE therefore initiated an aggressive "Plan of Action to resolve SNF Vulnerabilities - Phase III" (ref. 3) at each of the DOE sites to rapidly resolve these vulnerabilities. These actions are included in the baseline of DOE’s ACP. Considering the progress made to date, and the site-specific nature of these vulnerabilities, minimal opportunity existed for EMI to further improve on the schedule or cost performance of these near-term actions.

Site specific responsibilities for disposition of DOE’s SNF were previously defined in the DOE Programmatic SNF Environmental Impact Statement (EIS) Record of Decision (ROD), May 1995 (ref. 4, and pictured in Fig. 1). One of the factors influencing the preferred alternative selected (i.e., "Regionalization by Fuel Type") was the need to maintain site / stakeholder equity for the SNF disposition programs. This EMI assessment did, however, provide a unique opportunity to consider this site equity equation in a broader context with other waste stream disposition activities.

Each of the site specific baseline plans were developed to satisfy a number of DOE, regulatory, and institutional requirements, as well as State-mandated agreements. Many of these requirements / restraints have significant impacts on cost and schedule, and those with the most significant impact on the SNF Disposition Program cost and schedule, either from an individual or cumulative perspective, include the following:

Initially, the EMI team focused on the four principle elements of the DOE SNF disposition baseline program:

• Characterization of DOE SNF inventories and planned future research reactor receipts,
• Preparation required for repository acceptance,
• Interim storage awaiting transfer to the repository, and
• Transportation between Sites and the repository.

The primary opportunities identified for improvement to the baseline program are associated with the longer-term actions required to address new interim staging requirements (i.e., preparations of the SNF to meet interim storage and projected repository acceptance criteria) and early shipment of the SNF from the individual DOE sites to the Federal repository for ultimate disposition. After considering the technical feasibility and difficulty of the regulatory and institutional restraints, the EMI SNF team recommended the following three actions for DOE’s immediate consideration and implementation:

• Establish performance-based repository storage and disposal criteria,
• Limit transfer of SNF between DOE Sites, and
• Process additional aluminum and small quantity, unique SNF where necessary and/or economical.

Each of these actions is discussed in detail below.

Preliminary repository acceptance criteria [10 CFR 60 (ref.12) as interpreted by the DOE Office of Civilian Radioactive Waste Management (OCRWM / RW)] call for an extensive analysis pedigree ("characterization") for each SNF element prior to acceptance at the repository. These current DOE-RW interpretations have been extended from commercial practice, where detailed traceability has been maintained for each fuel element throughout its lifetime and is readily available. The DOE research reactor SNFs, however, are considerably different from the commercial fuels in design, enrichments, material performance properties, and irradiation histories. Establishing criteria for acceptance of DOE-owned SNF that are based on overall repository performance, not on the performance of individual fuel elements or packages, will significantly lower overall life-cycle disposition costs.

Most of the DOE-owned SNF inventory can be grouped into about twelve categories based on similar long term behavioral properties of the cladding and fuel materials, chemical reactivity, combustibility, material degradation, criticality safety, etc. Conservative (bounding case) properties can then be assigned to these groups for use in the repository Performance Assessment (PA) to show compliance with the regulations, and thus allow the DOE to minimize extensive and costly characterization of individual fuel elements. DOE will develop a process to confirm that the values used bound all fuel elements in each group. As the repository PA matures, sensitivity studies will be performed to determine which parameters are important to the repository performance post-closure. Parameters important to safety will be assigned the highest levels of quality assurance, and other parameters will be assigned quality assurance levels appropriate to their impact on overall repository performance. For example, some initial sensitivity analyses of criticality events occurring post-closure indicate that they do not disturb the physical environment of the repository and result in a very low contribution to the radionuclide inventory. This could be the basis for alternate approaches to ensuring safe disposal of DOE SNF in the repository.

Timing for development of repository acceptance criteria for DOE SNF is a critical factor, both in the life cycle cost for interim management of DOE SNF and in the project schedule for assessment of the repository siting. An EIS for the repository is currently ongoing, with completion scheduled for 2000. A performance based approach for the DOE SNF must be addressed in the Total System Performance Assessment (TSPA) and the Viability Assessment (VA) scheduled for completion by 9/98, as well as the EIS. The existing vulnerabilities at the DOE SNF management sites do not, however, allow for extended delays to establish the repository acceptance criteria. The DOE-EM facilities are already well into an aggressive action plan to resolve these vulnerabilities. During the next three years, each of the three principal DOE SNF disposition sites will be procuring new fuel containment packaging and interim storage facilities for their respective SNF. For optimum DOE benefit [i.e., minimum radiation exposure to workers and cost to recondition and/or repackage the fuel post interim storage], the repository acceptance criteria must be established as early as possible during the procurement of any new DOE SNF treatment and packaging facilities.

It is therefore necessary that the DOE-RW & EM schedules for development of the fuel data input and establishment of acceptance criteria be closely integrated (see Fig. 2). The principal recommendation for utilizing performance based criteria would, when implemented, allow the DOE SNF management sites to proceed to prepare their SNF inventories for direct shipment to the repository. In addition, since DOE plans to package a majority of its SNF into disposal ready / "road ready" containers prior to shipment to the repository, acceptance criteria related to handling of bare fuel at the repository surface facility would also be minimized. The technologies necessary to accomplish these preparations would then be developed under a cohesive integrated program with less risk for costly rework after materials are packaged.

It is anticipated that the National Academy of Sciences (NAS) and the Nuclear Regulatory Commission (NRC) will be supportive of this approach for repository qualification of DOE SNF. Both have consistently advocated the use of risk-based (performance-based) approaches for developing facility requirements [e.g., NAS report, "Technical Bases for Yucca Mountain Standards"; and NRC SECY 97-095, "Risk-Informed Technical Specifications"]. The initial discussion with the NRC in July 1997 was encouraging, as the general approach appeared consistent with recent policy decisions for expanded use of Probabilistic Risk Analysis methods, in demonstrating compliance with regulatory requirements.

The EMI team, therefore, concluded that the performance based approach, coupled with grouping like-fuels for analysis, will dramatically lower life-cycle disposal costs by as much as $1.0 billion and enhance both public and regulator confidence in the resulting DOE disposition plans for SNF.

Baseline disposition plans for each of the three major DOE SNF management sites were developed from guidance provided in the Programmatic SNF ROD. In this ROD, DOE selected the "Regionalization by Fuel Type" alternative and assigned responsibility for interim management of its SNF based on the SNF type, with some modifications as agreed to in a subsequent Settlement Agreement reached with the State of Idaho in 1995 (ref. 7). The aluminum based SNF will be accumulated at the Savannah River Site (SRS); the graphite, stainless steel, and zirconium clad SNF will be accumulated at the Idaho National Engineering & Environmental Laboratory (INEEL); and the Hanford SNF inventory will be retained there, with the exception of a small quantity of sodium-bonded SNF that will be shipped to INEEL for treatment.

Under this regionalization concept, the majority of the DOE SNF will be managed at its current DOE site until the repository is available, however, some quantities of SNF will be transferred between sites to economize on unique site treatment capabilities. Transportation of SNF, although proven safe by decades of experience, is very costly and time consuming. The process requires development and coordination of an extensive Transportation Plan involving the regulators, the DOE, and experienced shipping contractors as well as coordination between shipper and receiver, preparation of emergency responders along the shipping route, etc. Any potential for reduction of the number of shipments provides a good opportunity for significant cost savings.

Shipping only SNF that will undergo special treatment or processing upon receipt has several advantages:

• It may provide some flexibility relative to the shipment constraints established by the Settlement Agreement between the State of Idaho, DOE, and the Navy (which sets annual limits on the number of shipments that can be made into Idaho). This would permit adjustments in shipments from domestic and/or foreign research reactors for earlier shutdown of facilities at these sites.
• It would prevent further strain on the commercial cask fleet for any shipments made prior to completion of the FRR return campaign.
• Transportation costs would be reduced. The cost for a single truck cask shipment between SRS and INEEL is estimated to be $150 thousand.

The majority of the SNF inventory that will be transferred between DOE sites is currently in storage at the SRS and INEEL: an estimated 121 shipments from SRS to the INEEL and 114 shipments from INEEL to the SRS (a total of 235 shipments). Current interim management plans call for these fuels to be packaged, with little or no treatment for interim storage prior to the inter-site shipments (which are expected to occur after 2010), and then transferred to the DOE regionalization site to await release for repository disposal. In the cases where the SNF does not require special handling or treatment at the receiving site, little technical advantage exists in transferring the SNF, and direct transfer from its current location to the repository would provide significant cost savings and have the least impact on the public and environment. Shipping only fuels that will undergo special treatment or processing upon receipt would likely lower the total shipments to less than 75, for savings of greater than $40 million.

Any decision that would alter the planned transfer of SNF from the INEEL to the SRS for treatment must occur in conjunction with the disposition technology selections at these two sites. While assumptions have been made as to particular fuels, implementable decisions have not. A supplemental SNF Programmatic ROD would be needed to effect the changes in distribution of the SNF recommended by this strategy. The proposed concept does, however, appear consistent with Stakeholder preferences indicated to date. The Idaho - DOE/DOD Settlement Agreement specifically allows for bringing Fort St. Vrain SNF into Idaho, if it is to be treated. South Carolina stakeholders have voiced a similar desire that SRS management plans for SNF be closely integrated with existing processing capability.

Another important and timing sensitive element of the EMI recommended disposition strategies is the stabilization of selected fuel forms with either the existing SRS processing capability or with the Argonne National Laboratory (ANL) Electrometallurgical process. The SRS facilities are currently processing aluminum fuel and target materials identified as "at risk" in the Interim Management of Nuclear Materials EIS ROD (ref. 10). The continued availability of SRS processing capability is, however, subject to many factors, not the least of which are long term budget impacts and the retention of experienced staff. The Electrometallurgical treatment process is undergoing final performance evaluation at ANL for the treatment of the sodium-bonded fuels stored at the INEEL and at Hanford.

As EM has increased its knowledge of repository disposal requirements for DOE-owned SNF, difficulties with repository licensing of certain fuels have been identified. These include:

• A general lack of historical documentation for most DOE research reactor SNF, potentially precipitating extensive and costly characterization,
• Many DOE SNF types have high fissile enrichments that complicate modeling of criticality within a repository (resulting in severely restrictive fissile loading limits), and
• Varying interpretations of chemical stability requirements (pyrophoricity, reactivity).

Solutions for each of these issues exist that retain repository disposal as an option, but such solutions have been argued as very expensive and / or involving high-technical risks to repository licensing.

Processing of the Al-based SNF in the SRS facilities, followed by vitrification of the HLW products, provides a viable option to direct disposal, due to its known costs and high confidence in repository acceptability of its waste product. Several of the smaller Al-based SNF groups were identified as candidates for processing in the Research Reactor SNF Task Team report, "Technical Strategy for the Treatment, Packaging, and Disposal of Al-based SNF" (ref.14). This option has, however, been consumed under the weight of broader discussions over efficient methods for site cleanup vs. the political sensitivity (nuclear materials proliferation policies) of continued canyon operations. SRS is currently preparing the SNF Management EIS that will select the technology for disposition of all remaining Al-based SNF, and thus determine whether additional DOE Al-based SNF should be stabilized in the SRS canyons. In parallel with the EIS, DOE has commissioned independent assessments of the nuclear nonproliferation, cost, and scheduling implications from processing Al-based research reactor SNF beyond the current facility stabilization campaign (DNFSB 94-1). Additionally, DOE has initiated an accelerated technology development program at SRS to evaluate alternative non-reprocessing waste forms that might be suitable for geologic disposal of Al-based SNF ["repository ready"]. The DOE ROD, selecting the technology to be used for the "repository ready" preparation of all remaining Al-based SNF, is planned for late 1998.

The decision on which SNF are to be treated at the INEEL will be made in conjunction with completion of the Electrometallurgical treatment demonstration. This demonstration continues into 1999 and will determine the suitability of this technology for treating selected DOE fuels. Current INEEL baseline plans for SNF treatment are limited essentially to the Electrometallurgical treatment of sodium-bonded SNF (primarily Experimental Breeder Reactor - II SNF). As the overwhelming bulk of this fuel already resides in Idaho, few shipments into the state would be needed.

For the SNF not processed, agreement must be reached as to the repository acceptability of the interim storage package / waste form. While evaluations are underway in conjunction with the 1998 Viability Assessment for the repository, firm commitments on acceptable waste form(s) for DOE-owned SNF will not be available until NRC’s review of the repository license application. The DOE-RW plans to submit the repository license application in 2002, with NRC approvals anticipated in 2006 (construction) and 2010 (operation).

A timely decision is therefore needed to identify those fuels that present legitimate technical challenges to direct repository disposal and those small quantity / unique fuel types with significant cost penalty for characterization or treatment. Timely implementation of this limited processing could potentially avoid the expenditure of more than $300 million.

Implementation of the three SNF Program Breakthrough Actions identified during this DOE EMI Contractor exercise is projected to generate a potential savings of about $180 million during the ten-year window of the DOE ACP baseline and avoid additional life-cycle cost of about $1.1 billion over the 30-40 year interim management period, for scope currently not included in the ACP. These cost savings are summarized in Table 1.

The actions precipitated by the three recommendations of the EMI report are being evaluated by Hanford, INEEL, SRS, and the National Spent Nuclear Fuel Program (NSNFP). A DOE complex-wide programmatic EIS for SNF disposition has been completed with the Records of Decision issued (calling for regionalization), and the necessary site specific NEPA assessments have been implemented or are in progress for the management of SNF. The EIS for a proposed repository in Nevada is being prepared. The opportunities identified by the EMI effort are being examined and appropriately incorporated into the DOE Accelerated Cleanup Plan (ACP).

The DOE SNF Management sites and the NSNFP continue to work closely with the DOE-RW to develop a licensing strategy based on the concept of repository performance based criteria. This strategy is based on grouping the large number of DOE fuels into about twelve groups based on properties of the fuel material and cladding, and the condition of the fuel. For each of these fuel groups, studies are underway to determine which parameters are important to the safety of the public, workers, and the environment and to identify and bound the performance of DOE fuels in a repository. The important parameters and bounding performance criteria will then be provided to DOE-RW and the NRC in a manner suitable for licensing. The NRC has been generally supportive of the performance based criteria approach during the preliminary meetings held to date. The DOE SNF management sites and the NSNFP are responsible for providing acceptable documentation to DOE-RW which demonstrates acceptability of this approach for a subsequent repository license application.

SRS and INEEL are examining alternate treatment technologies for SNF that may not be suitable for direct placement in a geologic repository. These fuels include the Al-based fuel that is at risk for further degradation while in storage, fuel that contains sodium, and very small quantities of fuels and fuel debris for which gathering the necessary characterization information may be prohibitively expensive. Currently, the use of the SRS canyons, the electrometallurgical process at Argonne-West, and other alternatives (including direct disposal of the HEU and a melt - dilution process) are under evaluation. These studies will determine which fuels, if any, require treatment (and the process for treatment) before the fuels are packaged and shipped to the repository. Final disposition of the aluminum-based SNF will be determined in the ROD for the SRS SNF Management EIS, currently in development.

DOE-EM and DOE-RW have completed a Memorandum of Agreement (MOA) for the placement of DOE SNF in a geologic repository. This MOA assigns responsibility for the design and purchase of the transportation packages (canisters and casks) to DOE-EM and the transportation to DOE-RW. The DOE-EM National Transportation Program, the NSNFP, DOE-EM Integration Team, DOE-RW and the DOE SNF management are closely integrating their activities, as they examine the feasibility of designing a system capable of shipping SNF. The goal of this effort is to have a system of transportation casks for use throughout the DOE complex.

The three breakthrough actions identified by the EMI SNF team have the potential to yield the complex an estimated combined life-cycle cost savings and cost avoidance of more than $1.3 billion dollars. These actions would also be accompanied by an acceleration in the overall schedule for SNF stabilization by more than ten years. Recommendations provided by the EMI Team require evaluation by stakeholder groups, states, regulatory agencies, and the DOE prior to full implementation. The recommendations will also require detailed cost analysis to validate anticipated cost savings and review by all affected stakeholders to ensure that site equity, political, social and economic needs are properly addressed. The results from some initial discussions with stakeholders and regulators have been encouraging.

The work described in this paper was conducted between July 1996 and May 1997 at the request of the DOE Assistant Secretary for Environmental Management, as part of the DOE Contractor EMI initiative. The team of participants included the co-authors identified previously.

1. G. Frandsen, et.al., "A Contractor Report to the Department of Energy on Opportunities for Integration of Environmental Management Activities Across the Complex (Discussion Draft)", INEEL/EXT-97-00493, May 1997.
2. "Accelerating Cleanup : Focus on 2006", (Discussion Drafts) June 1996 and June 1997, (Update) October 1997.
3. "Plan of Action to resolve Spent Nuclear Fuel Vulnerabilities - Phase III", U.S. Department of Energy, October 1994.
4. "Programmatic Spent Nuclear Fuel Management and Idaho National Engineering Laboratory Environmental Restoration and Waste Management Programs, Record of Decision ", 60 FR 28680, U.S. Department of Energy, June 1, 1995.
5. Nuclear Waste Policy Act, As Amended (42 U.S.C. 10101 et seq.).
6. "U.S. Non-proliferation and Export Control Policy", September 1993.
7. Agreement in the Matters of Public Service Co. of Colorado v. Batt, No. CV 91-0035-S-EJL (D. Id.) and United States v. Batt, No. CV-91-0054-S-EJL (D. Id.), October 17, 1995.
8. "Record of Decision for the Final Environmental Impact Statement on a Proposed Nuclear Weapons Nonproliferation Policy Concerning Foreign Research Reactor SNF", 61 FR 25092, May 17, 1996.
9. "Hanford Federal Facility Agreement and Consent Order, ‘Tri-Party Agreement’", as amended, April 1997.
10. "Record of Decision for the Interim Management of Nuclear Materials at the Savannah River Site," 60 FR 65300, December 19, 1995; "Supplemental Record of Decision, " 61 FR 6633, February 21, 1996; and "Supplemental Record of Decision and Supplement Analysis Determination", 62 FR 17790, April 11, 1997
11. "Defense Nuclear Facilities Safety Board Recommendation 94-1 - Implementation Plan", U.S. Department of Energy, February 28, 1995.
12. 10 CFR Part 60, "Disposal of High-level Radioactive Wastes in Geologic Repositories"
13. "Programmatic Spent Nuclear Fuel Management and Idaho National Engineering Laboratory Environmental Restoration and Waste Management Programs, Amendment to Record of Decision", 61 FR 9441, U.S., Department of Energy, March 8, 1996.
14. J.C. DeVine, Jr., et.al., "Technical Strategy for the Treatment, Packaging, and Disposal of Aluminum-Based Spent Nuclear Fuel", June 1996.
15. Hoskins, R. Pahl, J.C. Devine, Jr., et.al., "Technical Strategy for the Management of INEEL Spent Nuclear Fuel, March 1997.

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