Fall 1996 Los Alamos National Laboratory • A U.S. Department of Energy Laboratory The Actinide Research T55A Quarterly o f t h e N u c l e a r M a t e r i a l s T e c h n o l o g y D i v i s i o n In This Issue NMT's Contributions to the Cassini Saturn Mission Follow Division's Space Exploration Tradition 1 NMT's Contributions Some of NMT Division’s handiwork will longer thereafter at reduced levels. For the to the Cassini Saturn be soaring across the solar system on its way Cassini mission, radioisotope thermoelectric Mission Follow to Saturn in the near future. Many NMT generators (RTGs) will provide the electrical Division's Space members, primarily in Actinide Ceramics and energy needed, while lightweight radioisotope Exploration Tradition Fabrication (NMT-9), have produced special heating units (LWRHUs, or RHUs for short), heat and energy sources to help keep things will keep equipment warm enough to 2 running aboard the Cassini orbiter and function. Managing and Huygens probe, which will be launched in Cassini will use three RTGs, which con- Minimizing Radioac- October of 1997 toward the Saturnian system vert thermal energy from plutonium decay tive Waste Continue to explore the gas giant, its mysterious rings, into electrical energy. Each RTG contains 72 to Challenge the DOE and some of its frigid moons. small pellets of plutonium-238 dioxide, each Complex Because Saturn is so far away from the about the size of a marshmallow and weigh- sun, solar rays there are only a small fraction ing 150 grams. Each pellet is encased in many 4 as strong as they are on earth. To gain enough layers of protective materials, and the com- Electrodialysis electrical energy and warmth to operate, plete unit is called a general purpose heat Reduces Waste in the Cassini would need solar panels so large that source (GPHS) module. All together these 72 Treatment of it would be nearly impossible to launch and heat sources put out 4400 watts of thermal Pyrochemical Salt maneuver. Hence, the orbiter and probe must energy at an operating temperature of 1200˚C Residues carry their own thermal and electrical to 1300˚C. Using a set of thermocouples, the generators to run the scientific RTG converts this heat energy to 6 experiments and other equip- about 285 watts of electricity. Volatile Halocarbons ment aboard. A conventional To maintain operating Get the Treatment in battery cannot be used because temperatures, the Cassini a One-Step Process of the mission’s long duration orbiter and Huygens probe and the prohibitive weight will use 157 RHUs distri- 8 of such an energy source. buted in various locations. Researchers Perform Long-lasting energy Each unit contains a Rapid, On-Line, without excess weight 2.7-gram pellet of Elemental Analysis can be provided by PuO2 encased in a Using Laser-Induced the natural radio- platinum- rhodium Plasma active decay of alloy, which, in turn, Spectroscopy plutonium-238. is protected inside a With a half-life graphite shell. This 11 of approximately 87 multilayer casing, as Recent Publications, years, this material Figure 1: 100-watt plutonium-238 heat well as that for the Presentations, and will reliably produce source used in the 1970s space missions. GPHSs, is designed Reports a constant flow of The source is about 250 g and about 3 cm to keep the PuO2 energy for at least 25 in diameter. safely contained 12 years and for even when subjected to NewsMakers accidental continued impacts on page or10 Nuclear Materials Technology Division/Los Alamos National Laboratory 1 The Actinide Research Quarterly Guest Editorial Managing and Minimizing Radioactive Waste Continue to Challenge the DOE Complex Over the past five decades, the Congress high-level wastes at two sites (Savannah River of the United States has promulgated numer- and West Valley) are being vitrified for ous environmental statutes applicable to all eventual geologic disposal. Ongoing environ- sectors of the U.S. economy. In 1969 the mental restoration, decontamination, and National Environmental Policy Act (NEPA) decommissioning of DOE facilities coupled initiated revolutionary changes to reduce with future operations within the weapons waste generation and prevent environmental complex, even though they will be limited, are pollution. A series of laws and regulations expected to generate another 78,000 m3 of TRU following NEPA has increased pressure on wastes during the next two decades. Current both industry and the government to be plans are to place all TRU wastes, both contact- responsible managers of the environment. handled and remote-handled, in the WIPP K.K.S. Pillay, After extensive public debate resulted in the facility in Carlsbad, New Mexico, when the Project Leader Nuclear Waste Policy Act of 1982, there have facility becomes available. It is now scheduled for Waste been many positive developments directed at to open in April 1998, almost 19 years after Management, long-term management of radioactive wastes WIPP construction was authorized by the U.S. NMT-DO in the U.S. Although several amendments to Congress. The opening of WIPP is contingent 1982’s landmark legislation have changed the upon DOE receiving EPA’s certificate of scope of the efforts, the ultimate goal conti- compliance and a favorable Resource Conser- nues to be isolation from the biosphere of vation and Recovery Act-related decision by long-lived radioactive nuclides in wastes. the State of New Mexico. Waste management of plutonium (and other Although many programs specifically actinide) processing is a subset of these and address the legacy wastes at the DOE sites, other regulatory requirements. The specific facilities that routinely generate wastes from topic addressed in this editorial is the manage- continued operation have been placed in an ment of primary waste generated from pluto- awkward position. In conformance with all nium processing. applicable mandates from the U.S. Congress During the past 55 years, the plutonium and the President, all federal facilities are inventory in the U.S. increased from half a required to reduce waste generation by 50% by microgram to nearly 400 M tons. The U.S. 1999, using baselines established several years defense sector produced an estimated 111.4 M ago. However, corrective actions mandated by tons of plutonium between 1944 and 1988, and the Defense Nuclear Facilities Safety Board for about 4% of that now exists in numerous safety issues, as well as insufficient financial waste forms. This estimate does not include resources, have limited their ability to comply the plutonium that was released to the envi- with the above laws and regulations in the ronment during nuclear explosions and is now near term. part of the natural background worldwide. It An unexpected new source of TRU wastes is estimated that the 100,000 m3 of transuranic headed for WIPP will result if one of the DOE wastes now stored at six DOE sites contain 3.4 sites declares a large portion of its actinide M tons of plutonium. Approximately 2 M tons residue inventory as waste. The alternatives of plutonium and other actinides are present proposed for managing the plutonium in high-level liquid wastes currently stored at residues at Rocky Flats have a common three DOE sites. A significant positive inven- feature: packaging and shipping from 3.1 M tory difference of nuclear materials within the tons to 6.3 M tons of plutonium from Colorado DOE complex includes an additional 2.8 M to New Mexico in the most expeditious tons of plutonium. At least some of this manner. This approach, if it takes place, will plutonium is likely to end up in transuranic merely transfer the problems of material (TRU) waste streams. The majority of TRU chemistry, confinement, and storage from the wastes is expected to be transferred to the present location to another location outside Waste Isolation Pilot Plant (WIPP), and the Colorado. It seems that the only criterion used 2 Nuclear Materials Technology Division/Los Alamos National Laboratory Fall 1996 in developing the strategies is a reduction in pollution prevention through major process the mortgage for on-site storage. The relative changes, resource recovery and recycling, and abundance of plutonium in these residues investments in new technologies. Because the would also pose serious nuclear material DOE was late in adopting the mission of safeguards concerns. The alternatives environmental management, a new strategy “Governments presented by Rocky Flats have the potential to is necessary to hasten progress in waste mini- may regulate, increase the plutonium content of WIPP mization within the DOE weapons complex. wastes by at least 100% (possibly 200%) of the According to recent reports by the General environmental- previous estimates. This dramatic change in Accounting Office and the National Research ists may agitate, the role of WIPP to that of a dump for excess Council, the ambitious plan now pursued by but it is only plutonium has the potential to create addi- DOE for waste minimization and pollution the technology tional problems and delays for opening WIPP. prevention is eclipsed by internal organiza- experts who Although there are large allocations of tional problems and unrealistic expectations. can innovate resources to manage legacy wastes, the An operating facility such as the Plutonium management of newly generated wastes has Processing Facility at Los Alamos must to solve the been relatively neglected in DOE’s planning. comply with all environmental regulations problems The present and future operating plans for and other mandates. However, the Defense of waste plutonium facilities within the DOE complex Program Office of DOE, which uses the generation.” require compliance with all existing environ- facility, has invested very little in new mental regulations and the special regulations technologies needed to meet these mandates.