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 Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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
Aug 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
October 2024
Nuclear Technology
Fusion Science and Technology
August 2024
Latest News
New laws offer nuclear industry incentives for existing power plant uprates
This year, the U.S. nuclear industry received a much-needed economic boost that could help preserve operating nuclear power plants and incentivize upgrades that extend their lifespan and power output.
Signed into law in 2022, the Inflation Reduction Act offers production tax credits (PTCs) for existing nuclear power plants and either PTCs or investment tax credits (ITCs) for new carbon-free generation. These credits could make power uprates—increasing the maximum power level at which a commercial plant may operate—a much more appealing option for utilities.
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.