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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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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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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.
He Liaoyuan, Xia Shaopeng, Chen Jingen, Liu Guimin, Wu Jianhui, Zou Yang
Nuclear Science and Engineering | Volume 195 | Number 2 | February 2021 | Pages 185-202
Technical Paper | doi.org/10.1080/00295639.2020.1798728
Articles are hosted by Taylor and Francis Online.
The molten chloride salt fast reactor (MCFR) with Th-U fuel cycle is attracting more and more attention because of its excellent performance, such as high solubility of actinides, superior breeding capacity, low waste production, and high inherent safety. First of all, the breeding capability of an MCFR at equilibrium state was optimized by an in-house automated optimization program. Based on an optimized MCFR, an investigation of Th-U cycle performance was performed. Due to the lack of available 233U in nature, transuranium (TRU), low-enriched uranium (LEU), and Pu were employed as the startup fissile materials, and two different transition scenarios, a breeding and burning (B&B) scenario and a pre-breeding and burning (PBB) scenario were studied. The results show that the breeding performance in an MCFR is attractive and that the Th-U fuel transition can be achieved smoothly by using LEU, Pu, or TRU as startup fissile materials. In the B&B scenario, the average net 233U production rate in the LEU-started, TRU-started, and Pu-started modes during 200-year operation is 374, 321, and 323 kg/a, respectively, at the reprocessing rate of 200 L/day. While in the PB&B scenario the average annual 233U production is about 570 kg for all startup cases at a reprocessing rate of 40 L/day, and the corresponding doubling time is about 9.6 years. Besides, the values of the fuel Doppler coefficient and density coefficient are negative, and the total temperature coefficient of reactivity in all scenarios is below −8 pcm/K. In addition, the value of radiotoxicity of the Th-U cycle in an MCFR is lower than that in other molten salt reactors like the molten-salt breeder reactor and the molten fluoride salt reactor due to the lower buildup of fission products and TRU under its hard spectrum.