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
Human Factors, Instrumentation & Controls
Improving task performance, system reliability, system and personnel safety, efficiency, and effectiveness are the division's main objectives. Its major areas of interest include task design, procedures, training, instrument and control layout and placement, stress control, anthropometrics, psychological input, and motivation.
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
Jan 2025
Jul 2024
Latest Journal Issues
Nuclear Science and Engineering
February 2025
Nuclear Technology
January 2025
Fusion Science and Technology
Latest News
Reboot: Nuclear needs a success . . . anywhere
The media have gleefully resurrected the language of a past nuclear renaissance. Beyond the hype and PR, many people in the nuclear community are taking a more measured view of conditions that could lead to new construction: data center demand, the proliferation of new reactor designs and start-ups, and the sudden ascendance of nuclear energy as the power source everyone wants—or wants to talk about.
Once built, large nuclear reactors can provide clean power for at least 80 years—outlasting 10 to 20 presidential administrations. Smaller reactors can provide heat and power outputs tailored to an end user’s needs. With all the new attention, are we any closer to getting past persistent supply chain and workforce issues and building these new plants? And what will the election of Donald Trump to a second term as president mean for nuclear?
As usual, there are more questions than answers, and most come down to money. Several developers are engaging with the Nuclear Regulatory Commission or have already applied for a license, certification, or permit. But designs without paying customers won’t get built. So where are the customers, and what will it take for them to commit?
Karl Hornyik
Nuclear Technology | Volume 61 | Number 2 | May 1983 | Pages 296-312
Technical Paper | Second International RETRAN Meeting / Heat Transfer and Fluid Flow | doi.org/10.13182/NT83-A33198
Articles are hosted by Taylor and Francis Online.
A RETRAN model was developed for determining the stability of boiling water reactors operating with high power/flow ratios. This model was applied to Peach Bottom 2 and compared with the stability tests conducted at the end of fuel cycle 2. Because of the deterministic nature of the RETRAN model, it appears logical to select those transients produced by periodic setpoint switching rather than those where pseudorandom switching was employed. Comparisons were made in both the time domain and the frequency domain between the computed equilibrium cycle and a measured equilibrium cycle obtained as an average over a large number of cycles. The variables of interest are the system pressure measured in the steam dome and the average neutron flux measured by an average power range monitor. Comparisons in the time domain were adversely affected by an apparent, strong nonlinearity in the pressure controller and/or turbine control valve response. Since this effect could neither be identified nor appropriately simulated, a second model was developed, for which the measured system pressure is specified as time-dependent volume condition. The equivalence of these two models with regard to the pressure-to-flux transfer function was established. This provides the justification for using any arbitrary, simple pressure perturbation of the second model to determine this transfer function, which is commonly used to provide a measure of stability. Sensitivity studies revealed three groups of parameters with a strong influence on stability as well as the nature of this influence. These parameters are related to: heat conduction from the fuel pellet and through the helium-filled gap, the axial power profile, and the moderator feedback of reactivity. The choice of two-phase flow model also was shown to be very important; a case using the homogeneous equilibrium model option resulted in diverging oscillations, while corresponding calculations with the algebraic slip model exhibited considerable damping similar to that observed in the measured response.
