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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.
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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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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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Retrieval of nuclear waste canisters from a borehole
Borehole disposal of spent nuclear fuel (SNF) and high-level waste (HLW) uses off-the-shelf directional drilling technology developed and commercialized by the oil and gas sectors. It is a technology that has been gaining traction in recent years in the nuclear industry. Disposal can be done in one or more boreholes (including an array) drilled into suitable sedimentary, igneous, or metamorphic host rocks. Waste is encapsulated in specialized corrosion-resistant canisters, which are placed end to end in disposal sections of relatively small-diameter boreholes that have been cased and fluid-filled. After emplacement, the vertical access hole is plugged and backfilled as an engineered barrier.
Jordi Freixa, Francesc Reventós, Carme Pretel, Lluís Batet
Nuclear Technology | Volume 160 | Number 2 | November 2007 | Pages 205-215
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT07-A3893
Articles are hosted by Taylor and Francis Online.
Rapid boron dilution transients have shown the need for accurate knowledge of the solute particle distribution in pressurized water reactors (PWRs). Small-break loss-of-coolant accidents (SBLOCAs) enable the formation of low-borated slugs in the loop seals. Low-borated water, if driven to the core, could cause a reactivity excursion. Since online boron concentration measurement is impractical in the primary system of PWR plants and quite difficult in test facilities, best-estimate codes should be seen as the most suitable tools. However, transport of a low-borated slug through the primary system requires accuracy of the methods. Several studies have shown high numerical diffusion introduced by the upwind difference schemes habitually used by system codes. Furthermore, most of the boron tracking models implemented in system codes at present do not consider physical diffusion. Nevertheless, to introduce physical diffusion, it is necessary to considerably reduce numerical diffusion. The implicit Godunov scheme, which is available in RELAP5, has proved its capability in almost eradicating numerical diffusion. However, the formulated equation in RELAP5 does not deal with physical diffusion. A new tracking model for the solute field is presented, along with results of its implementation in the RELAP5 code. To evaluate the new model, a numerical test has been performed that demonstrates both the reduction of numerical diffusion and the correct simulation of physical diffusion. Moreover, the UPC model has shown its consistency in experiment F1.1, which is an SBLOCA with boron dilution. The test was part of the OECD-PKL2 program directed by the Organisation for Economic Cooperation and Development (OECD).