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
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
Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2025)
February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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
Three nations, three ways to recycle plastic waste with nuclear technology
Plastic waste pollutes oceans, streams, and bloodstreams. Nations in Asia and the Pacific are working with the International Atomic Energy Agency through the Nuclear Technology for Controlling Plastic Pollution (NUTEC Plastics) initiative to tackle the problem. Launched in 2020, NUTEC Plastics is focused on using nuclear technology to both track the flow of microplastics and improve upstream plastic recycling before discarded plastic can enter the ecosystem. Irradiation could target hard-to-recycle plastics and the development of bio-based plastics, offering sustainable alternatives to conventional plastic products and building a “circular economy” for plastics, according to the IAEA.
Beat Sigg
Nuclear Science and Engineering | Volume 57 | Number 4 | August 1975 | Pages 277-291
Technical Paper | doi.org/10.13182/NSE75-A15420
Articles are hosted by Taylor and Francis Online.
A modified truncation of the P1 equations for the treatment of multidimensional time-dependent neutron transport is presented that avoids some inconvenient features of the usual PL· approximation, such as the nonuniqueness of the stationary equations in vacuum and the discontinuity of certain moments at material interfaces. The mathematical properties of the original (PL) and modified (EPL) approximations, together with interface and vacuum boundary conditions, are compared. An approximate solution method for both types of equations is derived from a variational principle, and numerical results are given for time-dependent P1 and EP1 calculations in two-dimensional cylindrical geometry.
