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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
2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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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August 2024
Latest News
Nuclear new build procurement considerations
It may seem counterintuitive, but the best time to enhance the ability to support operations and maintenance for a new plant is before construction starts. This is one of many lessons learned by the currently operating nuclear fleet. As construction and startup of many nuclear facilities was completed, it quickly became evident that the ability to efficiently support operations and maintenance was limited. Most of the information necessary to establish and manage procurement of spare and replacement items, maintenance, and configuration of the facilities was unavailable and had to be gathered on a case-by-case, “on-demand” basis. Absence of necessary information and the associated challenges resulted in the need for staff augmentation and multiyear-long projects to develop equipment bills of material and maintenance programs and to perform technical evaluations for the huge quantities of spare and replacement items being requested.
Kazuki Kuwagaki, Jun Nishiyama, Toru Obara
Nuclear Science and Engineering | Volume 191 | Number 2 | August 2018 | Pages 178-186
Technical Note | doi.org/10.1080/00295639.2018.1463744
Articles are hosted by Taylor and Francis Online.
In the breed and burn (B&B) strategy, low-reactivity fuels are loaded in a core. It is difficult to keep criticality in operating a small core. To enhance the potential for achieving criticality, the neutron economy in a core should be improved. One improvement method is to increase the core size and reduce neutron leakage. If it is necessary to avoid the large-sized core, another method is to locate high-reactivity fuels in high-neutron-importance region continuously through an equilibrium burnup state. On the other hand, to stabilize the change of neutron flux and power distribution during the operation, the B&B regions need to be kept stationary in the same region.
In this study, a rotational fuel-shuffling concept was proposed. In this concept, fuel assemblies are moved to the next position step by step in a divided symmetry core region. Fresh fuel is loaded from the periphery and moved toward the center region, then moved outward and discharged. If the core could achieve an equilibrium state at which high-reactivity fuels are continuously placed in the core center region, it would be possible to keep the B&B regions stationary. In this kind of equilibrium state, high-reactivity fuels are placed in high-neutron-importance region stably. Simulations for this concept were performed using the continuous-energy Monte Carlo code MVP/MVP-BURN. A small lead-bismuth-cooled fast reactor with metallic fuel was adopted as the core design. As a result, a core with rotational fuel shuffling achieved an equilibrium cycle at criticality, and the change of multiplication factors in the equilibrium cycle was less than 0.1%. The neutron flux and power distributions were almost unchanged during the operation. In addition, high-reactivity fuels were constantly placed in the high-neutron-flux region. It was found that this concept can achieve criticality and a stable power profile.