The Nuclear Materials Focus Area has grown a lot since being created just two years ago. The organization is still the smallest of the Office of Science and Technology’s focus areas in terms of personnel and budget, yet NMFA staff have successfully built an effective, end user–oriented program that is supporting the safe management and expeditious stabilization of nuclear materials through innovative technology.

NMFA’s accomplishments during its first years may be attributable to its unique mission. The focus area conducts integrated research and development programs to facilitate the development and deployment of technologies that support the processing, stabilizing, packaging, transporting, and storage of the Office of Environmental Management’s excess nuclear materials and spent nuclear fuel. Many of these materials and spent nuclear fuel are not considered waste, but surplus assets that could potentially be recovered and reused. This emphasis on “recycling” materials is different from other focus areas’ concentration on remediation and disposal.

“That is one of the first things we look at,” said Elizabeth Thiel, NMFA communications coordinator. “Is there a future use for that material?” Some exotic isotopes, for example, can be used in nuclear medicine.

Examples of NMFA’s work can be found across the EM complex, but NMFA staff are focusing their efforts on Rocky Flats, Mound, Fernald, and other sites that have aggressive schedules for facility closure. These sites cannot proceed with closure until all nuclear materials are removed. That means a lot of work for NMFA, especially considering the variety of nuclear materials (uranium, plutonium, thorium, etc.) across EM. Debris, ingots, fuel cores, compounds, oxides, and more must be processed, stabilized, and packaged to exacting standards before they can be dispositioned or disposed of. While NMFA is organized to address all of these steps, including special divisions for spent nuclear fuel and long-term storage, only the Stabilization and the Packaging and Transportation product lines were active this year. It is at sites like Fernald where NMFA’s impact is most visible.

NMFA selects project sites through a needs assessment process. Every year NMFA conducts outreach activities and site visits to identify nuclear materials needs around EM. The results are evaluated, and then the focus area develops technology responses describing how it thinks the needs should be addressed. These technology responses are used to solicit technology proposals that address the needs. While other focus areas can often look to the commercial world for innovative technologies, the nature of nuclear materials limits NMFA’s search for solutions to DOE labs. Special attention is also given to proposals that promise cheaper, faster, and safer innovations. Once a technology proposal is funded, NMFA oversees the development and coordinates evaluation efforts through the use of an End User Steering Committee and a Technical Advisory Group.

Fernald was a production site for high-grade uranium metal products that were used in Cold War nuclear weapons. Today, nearly 200 metric tons of uranium (MTU) compounds and more than 220 MTU of enriched metallic uranium still require inspection, sorting, size reduction, stabilization, and repackaging for shipment off site.

NMFA began working with Fernald last year after it was determined that the site’s manual repackaging productivity could be improved with innovative technologies which, in turn, would help meet or accelerate the site closure schedule. Funded projects included technology development proposals from the Fernald Environmental Management Project, Sandia National Laboratories, and Los Alamos National Laboratory.


One highlight at Fernald was the recent deployment of the Vacuum Transfer System (Tech ID 3028), a technology designed to use automation for repackaging enriched, powdered uranium. Repackaging is necessary because much of Fernald’s uranium is in containers that do not meet shipping standards. Similarly, each storage facility or disposal site has its own specifications for nuclear material and its packaging. Fernald will use the Vacuum Transfer System to repackage approximately 96 MTU of uranium trioxide, two MTU of uranium hexafluorate, and possibly 71 MTU of uranium oxide, depending on disposition paths chosen. Site workers are protected from radioactive contamination and radiation exposure because the vacuum transfer is performed within a closed system. These systems may be transferable to other sites when their use at Fernald is completed.

“We are highly focused on Fernald right now,” said Marty Molecke, Packaging and Transportation Product Line Manager. “We’re basically speeding up their site closure schedule by about 18 months.”


While the material transferred through the Vacuum Transfer System is headed for disposal, NMFA is also supporting other processing and repackaging technologies at Fernald to prepare materials for future reuse. A common problem in sealed containers is radiolysis of water that generates hydrogen gas and can create added pressure within the drums over time. So some containers must be carefully vented, inspected, and—if necessary—purged. A project at Sandia called Automated Packaging of Nuclear Materials—Robotics is adding automation enhancements to Fernald’s existing manual drum inspection and repackaging lines. The project automates drum puncturing and gas sampling with pressure and position sensors fitted onto a hydraulic puncturing system. “We’re modifying a system that had no sensors on it at all,” said Brian Kast of Sandia.

“There are similar problems in other areas,” Molecke said. “The automation enhancement techniques could be used elsewhere.”

A short-term NMFA goal is for Fernald to integrate the inspection and repacking technologies along with a low-enriched uranium materials processing system that would include dry blending of uranium oxide products. Such processed material would be readily available for reuse rather than disposal. “They [Fernald site] have a tremendous amount of uranium material,” Molecke said. “They would like to get it back into the commercial fuel cycle if possible.” All of Fernald’s nuclear materials are targeted for removal from the site by about July 2005 so that Fernald can be decommissioned and closed.


Yet another innovative technology was needed to stabilize some aqueous radioactive solutions at Fernald. Because nuclear material cannot be shipped in liquid form, Idaho and Russian scientists have been working with a stabilizing technology called Gubka, or “sponge” in Russian (Tech ID 2343). The Gubka material, a type of fly ash formed into a block, will also adsorb components such as plutonium, americium, curium, and high-level waste. The stabilized solid waste form is suitable for storage, shipping, and disposal. In the Fernald demonstration, Gubka porous crystalline matrix blocks passively neutralized an acidic cesium-barium solution. Stabilization with Gubka, which requires fewer workers and offers reduced radiation exposure, could be used to process and stabilize liquid nuclear materials at many other EM sites.


While Gubka has met some high quality needs at Fernald, Stabilization Product Line Manager Kevin Ramsey said that Gubka is not appropriate for all nuclear materials stabilization. Moreover, materials bonded to Gubka cannot be retrieved for reuse. NMFA is supporting various research projects outside of Fernald to develop technologies and processes for stabilizing other nuclear materials.


NMFA is funding a time-and money-saving stabilization project at Hanford called the Plutonium Thermal Treatment Furnace Loadout System (Tech ID 3022). It is a modified, automated furnace for thermal stabilization of plutonium materials before shipping and storage. Normally, the furnace temperature must be lowered so that the stabilized material can cool enough for removal. The specially designed furnace has two heating chambers, along with a cool-down chamber, to make this process much faster. The design of the cool-down chamber allows for the rapid cooling of the stabilized plutonium material, enabling faster and safer unloading of material from the furnace. “It allows you to keep these furnaces up to temperature without having to cycle them,” said Ramsey. “They can actually operate these furnaces up to 1000 degrees Celsius.”


Another promising technology developed at Hanford—the Remote-Reading Surveillance System for 3013 Containers (Tech ID 3026)—is designed to continuously monitor pressure changes and ensure that pressure buildup does not exceed limits inside the transportation and storage container. “It has wide applicability at other DOE sites,” Molecke said. “I view this surveillance system for nuclear material containers as a major NMFA technology breakthrough.”

The 3013 containers are equipped with a magnetically coupled, pressure-measuring instrument (called a “puck”) located in a sealed inner container. A wireless, radio frequency tag device (called a “pod”) is capable of collecting and transmitting data from a number of inputs and is installed outside the outermost container. The pod detects pressure-induced changes from the puck and transmits this data and other container-related information to an external data-monitoring computer. The integrated surveillance system uniquely identifies each container and provides safety-related data (pressure and temperature) for each container. Other safeguards-related data also can be monitored.


NMFA is also supporting the development of technologies to measure moisture in plutonium oxides. Just as there are pressure standards for sealed nuclear material containers, each package of up to five kg of plutonium oxide must contain less than 0.5 weight percent moisture. A technology deployed at the LANL Plutonium Facility, called the Neutron Moderation Analysis System (Tech ID 3004, 3005, 3006), samples the entire container without affecting the material. The NMAS system exploits the moderating properties of hydrogen to determine the moisture content in the container. Moisture-produced hydrogen will moderate the neutrons and will result in a lower energy component in the spectrum.

NMFA is supporting advanced research related to the issue of hydrogen gas generation in sealed nuclear materials transportation and storage containers. Specialists at Los Almos National Laboratory are gathering experimental data and developing computer models to reliably predict hydrogen gas generation concentrations and pressures in a variety of stored nuclear materials.

The canister containing the plutonium oxide is placed in the center of the counter. A 10-microgram Californium neutron source, inserted into the bottom of the assay instrument, emits a hard spectrum of spontaneous fission neutrons with an average energy of about 2.1 MeV. If hydrogen is present in the oxide, an increase in the neutron count rate will occur. The changes in the neutron count are measured by four helium detectors and then analyzed to determine the moisture content.

A traditional moisture measurement method, called “loss on ignition,” involves comparing the weights of a sample before and after heating in a furnace. The disadvantage, in addition to the necessary cooling time, is that the sample occasionally contains salts. These salts burn off in the furnace, resulting in additional weigh loss. “You have an erroneous number, and you have to go back and reprocess it,” said Ramsey.


This overview provides only a sample of NMFA-supported technologies and partnerships. NMFA has come a long way, completing the transition from the former Plutonium Focus Area and adding the Spent Nuclear Fuel Product Line to its services.

It is likely that NMFA will always be different from other focus areas and may continue to be the youngest. With continued success, however, its reputation will grow.

For further information on the Nuclear Materials Focus Area, visit http://emi-web.inel.gov/NMFA or contact Elizabeth Thiel at ethiel@inel.gov.