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
Aerospace Nuclear Science & Technology
Organized to promote the advancement of knowledge in the use of nuclear science and technologies in the aerospace application. Specialized nuclear-based technologies and applications are needed to advance the state-of-the-art in aerospace design, engineering and operations to explore planetary bodies in our solar system and beyond, plus enhance the safety of air travel, especially high speed air travel. Areas of interest will include but are not limited to the creation of nuclear-based power and propulsion systems, multifunctional materials to protect humans and electronic components from atmospheric, space, and nuclear power system radiation, human factor strategies for the safety and reliable operation of nuclear power and propulsion plants by non-specialized personnel and more.
Meeting Spotlight
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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
Apr 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
June 2024
Nuclear Technology
May 2024
Fusion Science and Technology
Latest News
Commercial nuclear innovation "new space" age
In early 2006, a start-up company launched a small rocket from a tiny island in the Pacific. It exploded, showering the island with debris. A year later, a second launch attempt sent a rocket to space but failed to make orbit, burning up in the atmosphere. Another year brought a third attempt—and a third failure. The following month, in September 2008, the company used the last of its funds to launch a fourth rocket. It reached orbit, making history as the first privately funded liquid-fueled rocket to do so.
Dingkang Zhang, Farzad Rahnema
Nuclear Science and Engineering | Volume 182 | Number 3 | March 2016 | Pages 369-376
Technical Paper | doi.org/10.13182/NSE15-15
Articles are hosted by Taylor and Francis Online.
The coupled stochastic deterministic COarse MEsh radiation Transport (COMET) method requires a library of incident flux response expansion coefficients for its whole-core calculations. These coefficients are calculated using a stochastic method because of its high accuracy and robustness in modeling geometric complexity. However, the stochastic uncertainty inherent in response coefficients is unavoidably propagated into the whole-core calculations, and consequently, its effects must be quantitatively evaluated. The current method in COMET based on the error propagation significantly overpredicts uncertainty since the correlations among response coefficients are ignored. In this paper, a new adjoint-based method is developed to take into account the uncertainty and correlations of response coefficients. In this approach, forward calculations are first performed to obtain whole-core solutions such as the core eigenvalue and forward partial currents crossing mesh surfaces. Low-order adjoint calculations are then performed to determine the sensitivity of response coefficients. The core eigenvalue uncertainty is finally computed by taking into account the variances of surface-to-surface response coefficients, response fission production, and absorption rates as well as their correlations. The eigenvalue uncertainty predicated by the new method agrees very well with the reference solution, with a discrepancy <3 pcm, while the original error propagation method significantly overestimates the uncertainty. It is also found that the new method’s computational efficiency is comparable to that of the current error propagation method in COMET since the computation time spent on the adjoint calculations is negligible. As an additional benefit, since the covariances among response coefficients are absorbed into the variance of the response net gain rates and the variance of the effective leakage terms, no extra computer memory is needed to store these covariances.