ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
Meeting Spotlight
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Apr 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
May 2024
Nuclear Technology
Fusion Science and Technology
Latest News
Glass strategy: Hanford’s enhanced waste glass program
The mission of the Department of Energy’s Office of River Protection (ORP) is to complete the safe cleanup of waste resulting from decades of nuclear weapons development. One of the most technologically challenging responsibilities is the safe disposition of approximately 56 million gallons of radioactive waste historically stored in 177 tanks at the Hanford Site in Washington state.
ORP has a clear incentive to reduce the overall mission duration and cost. One pathway is to develop and deploy innovative technical solutions that can advance baseline flow sheets toward higher efficiency operations while reducing identified risks without compromising safety. Vitrification is the baseline process that will convert both high-level and low-level radioactive waste at Hanford into a stable glass waste form for long-term storage and disposal.
Although vitrification is a mature technology, there are key areas where technology can further reduce operational risks, advance baseline processes to maximize waste throughput, and provide the underpinning to enhance operational flexibility; all steps in reducing mission duration and cost.
Lawrence N. Oji, Keisha B. Martin, Mary E. Stallings, Martine C. Duff
Nuclear Technology | Volume 154 | Number 2 | May 2006 | Pages 237-246
Technical Paper | Reprocessing | doi.org/10.13182/NT06-A3731
Articles are hosted by Taylor and Francis Online.
The laboratory conditions used to synthesize the uranyl silicate minerals are almost identical to the evaporator conditions under which high caustic nuclear wastes are processed to reduce total liquid waste volume. The only significant difference is in the sodium ion concentration in such caustic nuclear wastes, which typically averages ~5.6 M Na+. The goal of this study was to experimentally determine whether uranium silicate minerals can be produced under nuclear waste evaporator conditions. If the formation of these uranium minerals is possible, it may not only lead to the clogging of the evaporators but also result in the accumulation of fissile 235U and thus present a criticality problem.In this investigation, synthetic uranyl silicate minerals (sodium weeksite, sodium boltwoodite, and uranophane) were produced only under low Na+ concentration (<0.02 M), while attempts to synthesize these same uranyl silicate minerals in the presence of high Na+ concentration (high ionic strength reacting media), which is typical of caustic nuclear waste evaporator processing conditions, proved unfruitful. In the presence of high Na+ concentration, the main product for the same soluble silica-uranium reaction mixture shifts toward the formation of mainly clarkeite (Na[(UO2)O(OH)](H2O)0-1), a hydrated sodium uranate, and not toward the formation of uranyl silicates.Thus, the presence of high Na+ concentration in the reaction mixture of dissolved uranium and silica inhibits or suppresses the formation of crystalline uranyl silicates. The conclusion is therefore made that evaporator fouling by uranyl silicate minerals is not easily attained under nuclear waste processing conditions because of the high Na+ concentration in the liquid wastes.