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
Materials Science & Technology
The objectives of MSTD are: promote the advancement of materials science in Nuclear Science Technology; support the multidisciplines which constitute it; encourage research by providing a forum for the presentation, exchange, and documentation of relevant information; promote the interaction and communication among its members; and recognize and reward its members for significant contributions to the field of materials science in nuclear technology.
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!
Latest Magazine Issues
Dec 2024
Jul 2024
Latest Journal Issues
Nuclear Science and Engineering
January 2025
Nuclear Technology
Fusion Science and Technology
Latest News
Christmas Night
Twas the night before Christmas when all through the houseNo electrons were flowing through even my mouse.
All devices were plugged in by the chimney with careWith the hope that St. Nikola Tesla would share.
Heba K. Louis
Nuclear Technology | Volume 188 | Number 1 | October 2014 | Pages 1-7
Technical Paper | Fission Reactors | doi.org/10.13182/NT13-120
Articles are hosted by Taylor and Francis Online.
The lifetime of prompt neutrons is a basic characteristic of reactors since it determines the neutron kinetics of the reactor in all transient processes. This paper focuses on calculation of the prompt neutron lifetime for pressurized water reactors (PWRs). The calculation was performed using two independent methods. The first method uses the fundamental definition of the neutron lifetime with adjoint weighting that has recently been included in MCNPX. The second method is the 1/v absorber insertion method, where a 1/v absorber such as 10B is placed uniformly throughout a nuclear reactor and the change in reactivity is calculated. This prompt neutron lifetime is then extracted from the changes in the reactivity as the 10B concentration approaches zero. The results of the two methods are compared together at two points in the operation cycle [at beginning of cycle (BOC) and at end of cycle (EOC)]. The values of the prompt neutron lifetime as calculated with MCNPX are compared to values calculated with another independent method, and the results are in reasonable agreement with each other. Also, these results compared with the PWR final safety analysis report show good agreement. In the two methods of calculation, the prompt neutron lifetime was determined to be longer at EOC when compared to that at BOC.