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Division Spotlight
Young Members Group
The Young Members Group works to encourage and enable all young professional members to be actively involved in the efforts and endeavors of the Society at all levels (Professional Divisions, ANS Governance, Local Sections, etc.) as they transition from the role of a student to the role of a professional. It sponsors non-technical workshops and meetings that provide professional development and networking opportunities for young professionals, collaborates with other Divisions and Groups in developing technical and non-technical content for topical and national meetings, encourages its members to participate in the activities of the Groups and Divisions that are closely related to their professional interests as well as in their local sections, introduces young members to the rules and governance structure of the Society, and nominates young professionals for awards and leadership opportunities available to members.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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!
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Latest News
First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
J. H. Shaffer, W. R. Grimes, and G. M. Watson
Nuclear Science and Engineering | Volume 12 | Number 3 | March 1962 | Pages 337-340
Technical Paper | doi.org/10.13182/NSE62-A28083
Articles are hosted by Taylor and Francis Online.
Control of a molten salt reactor by adjustment of the concentration of a nuclear poison which can be readily added to and removed from the circulating fuel is an attractive possibility. This chemical control can be used, if necessary, in addition to the negative temperature coefficient of reactivity which plays a major role in the control of liquid fueled reactors. Gaseous boron trifluoride (enriched in B10 if desired) may serve as a nuclear poison soluble in the fuel mixture of a molten salt reactor. The concentration of boron trifluoride in the liquid is proportional to and can be controlled by its partial pressure over a free surface in the circulating system. The solubility behavior of BF3 as a function of pressure and temperature defines the capacity of the fuel for BF3 and establishes the limits of possible usefulness of this compound as a removable reactor poison for reactor control. Experimental measurements of the solubility of BF3 in a molten fluoride mixture suitable for Molten Salt Reactor Experiment (MSRE) applications were determined. The MSRE is a 10 Mw (th) circulating fuel reactor moderated with unclad graphite in contact with a mixture of molten fluoride salts containing uranium tetrafluoride. Values of Henry's law constants were obtained (in moles of BF3 per liter of solution per atmosphere) of 0.265, 0.145, 0.0846, and 0.0351 at 500, 550, 600, and 700°C, respectively. These high solubilities indicate that BF3 should be suitable for control purposes of a molten salt reactor even at very moderate partial pressures. At reactor temperatures, and with a BF3 partial pressure of one atmosphere, an average atomic ratio of boron to U235 of 0.4 in the liquid has been estimated. Simplified calculations of the distribution of boron between the fuel and the graphite moderator have been made. Indications have been obtained, neglecting adsorption effects, that 85% of the boron would remain in the liquid even assuming complete equilibrium intrusion of the graphite pores by gaseous BF3. Various related problems have been listed which remain to be investigated before the use of BF3 can be recommended for the MSRE.
