The forerunner of the Nuclear Materials Focus Area was the Plutonium Focus Area (PFA), which was formed in October 1995 in response to a concern raised by the Defense Nuclear Facilities Safety Board about safe storage of nuclear materials across the DOE complex. Formerly managed by the Office of Environmental Management’s (EM) Office of Nuclear Material and Facility Stabilization (also known as EM-60), the Plutonium Focus Area has recently become more closely aligned with EM’s Office of Science and Technology (also known as EM-50 or OST). In April 1999, the focus area’s scope was expanded and, consequently, its new name became the Nuclear Materials Focus Area. In June and July, Initiatives spoke with the newly constituted focus area’s co-managers: Gary Roberson from DOE’s Albuquerque Field Office and Kenny Osborne from DOE’s Idaho Falls Field Office.
In response to the DNFSB Recommendation 94-1, DOE established the Nuclear Materials Stabilization Task Group, now known as the Nuclear Materials Stewardship Office. The task group issued an implementation plan for addressing DNFSB concerns and committed to a research and development program for converting and stabilizing its nuclear materials for safe storage. The Nuclear Materials Focus Area (originally known as the Plutonium Focus Area) formed to fund new and ongoing research projects to meet site needs for stabilizing and storing excess nuclear materials.
Roberson spoke to Initiatives about the uniqueness of NMFA. “All other EM focus areas are confined to the EM environment. While we’re managed and operated by EM and are supportive of the EM mission, there’s an element of this focus area that extends farther from the EM umbrella.” Because NMFA shares stewardship responsibilities for nuclear materials with other DOE programs outside the EM organization, the focus area must strive to integrate its program with other R&D programs that exist within DOE’s offices of Material Disposition, Defense Programs, Nuclear Energy, and Nonproliferation and National Security. Roberson also mentioned the opportunity this interaction affords for leveraging effort and funding and for conducting life cycle planning for these materials. (Click here to see the nuclear materials for which the NMFA share responsibilities.)
Roberson also discussed the value of basic research in the nuclear material stewardship arena. “Information becomes a valuable product of our focus area,” he said. As an example, Roberson told about a recent plutonium storage study that yielded a piece of information worth $1.7 billion—the amount avoided by not having to construct a new storage facility or to air-condition trucks to keep plutonium material at 100°C. The study provided the scientific basis to debunk a conservative standard about safe temperatures at which plutonium could be shipped and stored. User needs drive program From mid-February until mid-March of this year, NMFA visited sites to ascertain their needs and was successful in documenting 75 needs for nuclear material stabilization, packaging and storage, transportation, surveillance and monitoring, and disposition (reuse, transformation, or disposal as waste). NMFA tied the identified DOE user needs to the project baseline summary sheets and is in the process of matching needs to the technical capabilities and solutions from the national laboratories. Again, Roberson stresses NMFA’s uniqueness: “The other focus areas can look to commercial industry to meet needs; but in nuclear materials, the experts are in the national laboratories.” Evaluating progress, finding gaps To track progress in meeting stabilization goals and milestones, NMFA issues yearly updates to its research and development plan. The third update to the NMFA R&D plan (September 1998) not only provides a snapshot of the program, but also alerts stakeholders to pitfalls—specific risks, for example, that the program will fail to meet timelines due to slow maturity of technologies. The plan tracks development of sites’ preferred or baseline technologies for stabilizing and storing a wide range of fissile materials and also evaluates the chances that sites’ competitive alternative technologies and backup technologies will be ready to step in for lagging baseline technologies. Yearly updates also highlight requirements gaps—examples of inadequate or nonexistent DOE standards for defining performance of stabilization/storage/disposition options. For example, the September 1998 plan addresses how DOE’s current standard for stabilizing and storing plutonium metals and oxides containing greater than 50 wt % Pu (DOE-STD-3013-96) may not be adequate for validating moisture loss from impure plutonium oxides. From R&D plan to white papers Researchers from the national laboratories, sites, and the R&D community at large submit white papers to NMFA in response to programmatic risks and R&D, technology maturity, and requirements gaps identified in the most current update to NMFA’s R&D plan. Since 1995, NMFA has evaluated 120 technology proposals, resulting in 11 operational and 19 baseline or competitive technologies’ being actively under development to meet program needs in the areas of • plutonium solutions, Current thrusts Developing stabilization processes Given the complexity of nuclear materials and their variety of physical forms, no single stabilization method is applicable to all nuclear materials. NMFA develops stabilization processes that respond to users’ disposition paths for nuclear materials as reflected in Accelerating Cleanup: Paths to Closure. While a majority of Rocky Flats and Hanford plutonium-bearing residues will be treated for disposal to the Waste Isolation Pilot Plant (WIPP), smaller quantities of material from other sites must be readied to meet material acceptance criteria for the Office of Material Disposition (which conducts research associated with nuclear materials that are not under EM’s purview and are not considered waste). Chemically bonded phosphate ceramics—In FY99, NMFA funded research on the use of chemically bonded phosphate ceramics for stabilizing and encapsulating actinide residues (plutonium ash). Chemically bonded phosphate ceramics are formed when a common, inexpensive base (typically an alkaline earth oxide) reacts with a similarly cost-effective acid (typically a crystalline phosphate salt). The resulting acid/base cement holds the potential for not only physical stabilization of wastes but also chemical fixation of metals to lesser soluble forms. Osborne said that NMFA’s work on the use of ceramics for stabilizing Rocky Flats residues has been overcome by a policy decision to employ “pipe and go”—the direct repackaging of residues classified as low risk without stabilization in a pipe overpack container (POC). The Nuclear Regulatory Commission has approved the use of the POC for transporting low-risk residues inside the TRUPACT II shipping container. Testing has demonstrated that the POC is a robust container that increases the criticality limits of the TRUPACT II. Chemically bonded phosphate ceramics has become a backup technology for stabilizing plutonium ash. Working with Russians to
stabilize actinide solutions— In
FY99, NMFA began a collaboration with the Russians that
may have a big payoff in treating problematic actinide
solutions requiring stabilization under DNFSB
Recommendation 94-1. A joint research program has been
established with the Khlopin Radium Institute at St.
Petersburg and involves two other Russian institutes, the
Mining and Chemical Combine at Zheleznogorsk and the Actinide solutions requiring stabilization exist in various compositions at the Savannah River and Hanford sites. These solutions include isotopes of americium (Am) and curium (Cm) at SRS and plutonium nitrate solution and high-level waste solutions stored in tanks at Hanford. Other DOE waste and material streams that need a backup stabilization technology include Office of Material Disposition plutonium/uranium nitrate solutions that may need to be processed to oxides and residues from future decontamination. Future cleanup could generate additional solutions, requiring stabilization at facilities where processing capabilities have been dismantled. FY99 testing was completed at the Russian institutes and at INEEL, culminating in a joint U.S./Russian demonstration in June at INEEL. Solutions were tested for trapping by the gubka matrix, which contained cerium nitrate and lanthanide mixures in nitric acid as actinide surrogates and, in some cases, contained tracer 241Am. These tests resulted in maximum loading measured as mass percent (100 x cerium mass divided by sample mass) ranging from about 20 percent to 80 percent up to 39 saturation/drying cycles. The rates of actinide and lanthanide recovery were measured in nitric acid up to 60°C using simulated lanthanide solutions spiked by 241Am. Similar gubka behavior was observed using samples with a 20-fold difference in size. Hot-pressing densification tests produced material that resulted in a 40 percent volume reduction. As part of the FY 2000 program, a demonstration test will be completed at the Mining and Chemical Combine in Siberia.
Long-term storage of nuclear materials by DOE requires that the department develop and put into practice a system for monitoring nuclear materials over the long term. To better understand how nuclear materials can be expected to behave over time, EM has established a shelf-life program to gather representative samples of the plutonium inventory from Rocky Flats, Hanford, and Savannah River. NMFA has also initiated the Integrated Monitoring and Surveillance System as a test bed to provide information about the merits of alternative monitoring and surveillance technologies. One of the surveillance activities supported by the focus area during FY99 was testing a variety of sensors for use in nuclear materials vaults to detect problems such as gas generation, pressurization, and tampering. Osborne said, “We weren’t trying to create sensors—our work was to integrate different vendors’ sensors through software to allow the sensors to “talk” to each other. We were also validating that these sensors worked as advertised and that they could work together.” Questions about the Nuclear Material Focus Area can be directed to Gary Roberson at (505) 845-5805, groberson@doeal.gov, or to Kenny Osborne at (208) 526-0805, osbornkk@id.doe.gov. |
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on the Nuclear
Materials Focus Area
At the
end of the Cold War in the early 1990s when DOE’s
mission no longer included making nuclear weapons, many
fissile materials were left in the production line or
stored under conditions that did not ensure long-term
stability. Workers and the environment were being exposed
to dangers, such as unstabilized material generating
hydrogen gas, pressurization building inside tanks and
other containers, highly combustible materials
threatening ignition and spread of radioactive
contamination, and leakage from weakened containers of
radioactive acidic solutions. The Defense Nuclear
Facilities Safety Board (DNFSB), which oversees all DOE
activities affecting public health and safety, concluded
in Recommendation 94-1 that corrective actions were
needed to stabilize and repackage high-risk material
within two to three years and remaining material within
eight years. Additionally, DNFSB called for the
establishment of a research program to fill gaps in the
technology base for accomplishing stabilization. 
NMFA’s
End User Steering Committee represents seven DOE field
sites: 
Another difference
between NMFA and other focus areas is that NMFA focuses
on materials that have traditionally been considered
surplus assets. Instead of concerning itself with
products that are clearly designated as waste, NMFA
oversees the safe storage, packaging, and transportation
of materials that could potentially be recovered and
reused. Osborne pointed out, “The idea is to put
these materials into storage so whatever the ultimate
disposition might be, the materials are safely stored for
the interim.” Stabilization of these materials to
promote the safety of workers and the environment and to
prevent the proliferation of nuclear weapons is a
priority for this focus area.
Institute of Chemistry and Chemical
Technology at Krasnoyarsk. The collaboration will
determine the feasibility of a new Russian porous
crystalline matrix for stabilizing actinide residue
solutions. Russian researchers developed the porous
crystalline material from Siberian coal power plant fly
ash waste. It consists of glass/ceramic microspheres and
is referred to as gubka (sponge) because it absorbs at
room temperature metal salts, including radionuclides,
from acidic liquid residues and waste. 
Ensuring safe storage