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.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Mar 2026
Jan 2026
Latest Journal Issues
Nuclear Science and Engineering
March 2026
Nuclear Technology
February 2026
Fusion Science and Technology
April 2026
Latest News
NN Asks: What hurdles stand in the way of nuclear power’s global expansion?
Jake Jurewicz
Nuclear technology is mature. It provides firm power at scale with minimal externalities and has done so for decades. The core problem isn’t about the technology—it is how the plants are built. Nuclear construction has a well-documented history of cost and schedule overruns. Previous nuclear plants often spent more than twice what was first budgeted, making nuclear among the power technologies with the largest average cost overruns worldwide.
Recent projects illustrate how severe the problem can be. In South Carolina, the V.C. Summer nuclear expansion saw projected costs rise from roughly $10 billion to more than $25 billion before the project was abandoned in 2017, by which time more than $9 billion had already been spent and customers were stuck paying for a site they have yet to benefit from.
Mariano Tarantino, Pierdomenico Lorusso, Alessio Pesetti, Ivan Di Piazza, Daniele Martelli
Nuclear Technology | Volume 210 | Number 4 | April 2024 | Pages 725-739
Research Article | doi.org/10.1080/00295450.2023.2226525
Articles are hosted by Taylor and Francis Online.
Since the 2000s, the development of Generation-IV fast reactors cooled by heavy liquid metals (HLMs) has been pursued by several research activities and projects, many of which are co-funded by the European Commission. One of the key points of HLMs regards their good neutronic and thermophysical properties, allowing for the of design cores with a high pitch-to-diameter ratio. In terms of passive safety, with a properly designed configuration, it is possible to increase the system capability to remove the decay power in a natural circulation regime, reducing active safety systems involvement. Such a safety-related aspect has been experimentally investigated at the ENEA Brasimone Research Center within the European Union co-funded Euratom H2020 SESAME project.
An experimental campaign reproducing protected loss-of-flow accident (PLOFA) scenarios has been executed on CIRCE, a lead-bismuth eutectic-cooled pool-type facility reproducing in relevant scale the main components of HLM-cooled fast reactors. A test section named HERO has been installed in the CIRCE main vessel, hosting a double-wall bayonet tube steam generator scaled 1:1 in length with respect to the one envisioned for the ALFRED reactor. The tests reproduce the loss of primary coolant flow, while the power supplied by the heating source decreases according to a characteristic decay heat curve. The feedwater in the secondary system is regulated to operate the main steam generator as a decay heat removal (DHR) system.
This paper presents the PLOFA transient reproducing the worst case, where the steam generator feedwater is suddenly stopped, simulating the full loss of the heat sink (no DHR). The main phenomena occurring during the transition from forced to natural circulation are presented and discussed. The experiment shows that, despite the loss of the forced circulation regime in the primary loop and the full loss of the heat sink, the entire system is still capable of operating safely, assuring an effective long-term cooling, as long as the thermal heat losses from the main vessel balance the decay power supplied by the heating source.
