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
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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
Mar 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
April 2024
Nuclear Technology
Fusion Science and Technology
February 2024
Latest News
Can hydrogen be the transportation fuel in an otherwise nuclear economy?
Let’s face it: The global economy should be powered primarily by nuclear power. And it probably will by the end of this century, with a still-significant assist from renewables and hydro. Once nuclear systems are dominant, the costs come down to where gas is now; and when carbon emissions are reduced to a small portion of their present state, it will become obvious that most other sources are only good in niche settings. I mean, why use small modular reactors to load-follow when they can just produce that power instead of buffering it?
L. Pantera, P. Querre
Nuclear Science and Engineering | Volume 189 | Number 1 | January 2018 | Pages 56-68
Technical Paper | doi.org/10.1080/00295639.2017.1373519
Articles are hosted by Taylor and Francis Online.
The CABRI facility is an experimental pulse nuclear reactor funded by the French Nuclear Safety and Radioprotection Institute and operated by the French Atomic Energy Commission. It is designed to study the behavior of fuel rods at high burnup under reactivity-initiated accident (RIA) conditions, such as a control rod ejection. The distinctive feature of this reactor is its reactivity injection system. The fast depressurization into a discharge tank of 3He (strong neutron absorber) previously introduced inside 96 tubes (so-called transient rods) located among the fuel rods allows us to create a power burst from 100 kW to 20 GW with a full-width at half-maximum of 10 to 80 ms. The total energy deposit in the tested rod is adjusted by dropping the control and safety rods after the power transient. The neutron flux is measured online by compensated boron chambers located outside the reactor and operated in the current mode. These neutron detectors are calibrated during a commissioning phase thanks to standards given by a conventional heat balance. To assess the energy released into the test rod, we had to integrate the driver core power signal measured online. Thus, the beginning of the transient, called transient overpower (TOP) onset, has to be estimated. The TOP onset of a transient test is defined as the instant of the beginning of the test. It is determined by experimentalists during the processing phase. It corresponds to the beginning of the increase of the neutron detector signal, measured by the compensated boron chamber devices sufficiently sensitive at low current levels. So far, the choice of this instant has been realized by a visual choice zooming in the zone of interest, which may induce some shift according to experimentalists. In an attempt to overcome this issue, we put forward in this paper a theoretical method of determination to calculate the TOP onset. The main asset of the method is to formalize the TOP onset determination. Furthermore, it provides the possibility of associating an uncertainty, which is impossible by the manual process. The methodology relies on the fact that at the beginning of the RIA transient, the neutron flux at any point of the reactor core undergoes an exponential evolution as a function of the time. Then, a logarithmic transform allows us to show that the search for the TOP onset is equivalent to solving a nonlinear regression. The methodology has been validated in the last 14 experiments. Moreover, the reactor restarted in October 2015 and now gives us the opportunity to apply this methodology on signals recently acquired and pertaining to the power commissioning phase with a view to preparing the experiment foreseen next year.