ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
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Division Spotlight
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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!
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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.
Richard M. Bidwell
Nuclear Science and Engineering | Volume 18 | Number 4 | April 1964 | Pages 435-442
Technical Papers | doi.org/10.13182/NSE64-A18761
Articles are hosted by Taylor and Francis Online.
Losses of delayed-neutron precursors are estimated for liquid-metal-fueled reactor models in which the coolant is in direct contact with the flowing fuel. It is shown that as much as 90% of the precursors may be extracted by the coolant before decaying to supply neutrons. As a result, the excess reactivity corresponding to prompt critical can decrease by a factor of 10, leading to a considerable shortening of the reactor period corresponding to a given Δk. These conditions will, in actual operation at power, be alleviated by the contribution of the blanket's delayed neutrons and by the large negative temperature coefficient characteristic of liquid systems. The effects of mixing and reduced flow on delayed-neutron economy and resulting reactor period are evaluated. The benefits of reducing the flow are shown to be by far the greater, and a slower flow is recommended if enhanced control through delayed neutrons is needed at start-up.