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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
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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!
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Mar 2025
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Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
Latest News
El Salvador: Looking to nuclear
In 2022, El Salvador’s leadership decided to expand its modest, mostly hydro- and geothermal-based electricity system, which is supported by expensive imported natural gas and diesel generation. They chose to use advanced nuclear reactors, preferably fueled by thorium-based fuels, to power their civilian efforts. The choice of thorium was made to inform the world that the reactor program was for civilian purposes only, and so they chose a fuel that was plentiful, easy to source and work with, and not a proliferation risk.
Seyed Ali Hosseini, Alireza Najafi, Amir Saeed Shirani, César Queral, Francesco D’Auria
Nuclear Technology | Volume 211 | Number 3 | March 2025 | Pages 607-623
Note | doi.org/10.1080/00295450.2024.2337313
Articles are hosted by Taylor and Francis Online.
Hydro-accumulators, as a passive part of the emergency core cooling system, have been upgraded in different types of VVER-1000s. The number and performance of these systems are modified in newer types of VVER-1000s to operate at different pressures and flow rates. The VVER-1000/446, as a distinguished design from the old generation (VVER-1000/320), utilizes two stages of hydro-accumulators. The second-stage accumulators (SSAs) are dedicated to improving the performance of the VVER-1000/446 under design extension conditions (DECs) and delaying the onset of core damage. During the upgrading of the VVER-1000/446, some orifices have been embedded as flow restriction components (FRCs) on the injection line of the SSAs to increase the water injection time during DECs.
This paper aims to assess the performance of the SSAs according to their orifice diameter changes during median-break (MB)– and large-break (LB)–loss-of-coolant accidents (LOCAs). Several cases of FRC arrangements were investigated to demonstrate the core damage times during MB-LOCA (200-mm break) and LB-LOCA (400-mm break) scenarios. The results show that although the current size of the installed FRCs on the VVER-1000/446 is quite suitable for the MB-LOCA, it is not a proper choice for the LB-LOCA. Therefore, this demonstrates that the core damage time is highly dependent on the FRC size arrangement.
This paper indicates an arrangement of FRCs that can modify the plant’s response in both MB and LB LOCAs without active injections. Therefore, as an additional finding, the sequential arrangement of FRCs can increase plant resilience against a broad range of LOCAs without operating active emergency cooling systems.
