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Division Spotlight
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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
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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.
Ashlea V. Colton, Blair P. Bromley, Daniel Wojtaszek, Clifford Dugal
Nuclear Science and Engineering | Volume 186 | Number 1 | April 2017 | Pages 48-65
Technical Paper | doi.org/10.1080/00295639.2016.1273021
Articles are hosted by Taylor and Francis Online.
Thorium, a fertile nuclear fuel that is nearly three times as abundant as uranium, represents a long-term energy source that could complement uranium and eventually replace it. To facilitate the gradual transition from uranium-based fuels to thorium-based fuels, it may be advantageous in the near term to introduce small amounts of thorium (˂7% of the total fuel mass) into uranium-based fuels in pressure tube heavy water reactors (PT-HWRs). Downblending natural or slightly enriched uranium dioxide with thorium dioxide for fuel pellets placed at the ends of the fuel stack of a conventional 37-element fuel bundle could help reduce axial power peaking for fresh fuel, while incorporating thorium dioxide into the central element of the fuel bundle could reduce coolant void reactivity (CVR).
A series of two-dimensional lattice physics simulations was carried out as part of conceptual scoping studies to evaluate the potential performance and safety characteristics of uranium-based fuel bundles with small amounts of thorium fuel added. The simulation results were complemented by an approximate model for evaluating the potential economic characteristics. The cases studied involve modifications to fuel composition, central element materials, and the addition of thorium dioxide to the fuel stack. In addition, a set of preliminary three-dimensional MCNP simulations was performed where fuel bundles were modeled to assess the effect of thorium end pellets and graded axial enrichment on end power peaking.
Results suggest it should be possible to incorporate thorium into the fuel cycle using existing 37-element fuel bundle geometry. Advantages to incorporating thorium include a reduction in the CVR through a thorium central element, breeding of small amounts of 233U, maintaining front-end fuel costs at or below the price of natural uranium (NU) fuel, and maintaining maximum linear element ratings within 6%of those achieved using NU 37-element fuel.