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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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The Sodium Reactor Experiment
In February 1957, construction was completed on the Sodium Reactor Experiment (SRE), a sodium-cooled, graphite-moderated reactor with an output of 20 MWt. The design of theSRE had begun three years earlier in 1954, and construction started in April 1955. On April 25, 1957, the reactor reached criticality, and the SRE operated until February 1964.
B. P. Bromley, Z. Cheng, A. Nava Dominguez, A. V. Colton
Nuclear Technology | Volume 207 | Number 10 | October 2021 | Pages 1511-1537
Technical Paper | doi.org/10.1080/00295450.2020.1827658
Articles are hosted by Taylor and Francis Online.
This paper reports the results of subchannel thermal-hydraulic studies (using the ASSERT-PV code) of the effects of variations and uncertainties in operating/boundary conditions and geometry on the predictions of pressure drop, dryout power, and dryout location for two types of advanced, nonconventional fuels in a pressure tube heavy water reactor (PT-HWR) fuel channel with 12 fuel bundles. The fuel bundles tested include a 37-element fuel bundle made with SEUO2 (1.2 wt% 235U/U), with a central fuel element made of ThO2, and 35-element fuel bundle made with (LEU,Th)O2, using 5 wt% 235U/U low-enriched uranium (LEU), 50 wt% LEUO2, and 50 wt% ThO2. Results indicate that for a range of flow conditions, the dryout power for the thorium-based 35-element fuel bundle is 10% to 26% higher than that for the uranium-based 37-element fuel bundle. Variation/uncertainty in the pressure tube diameter has the most significant impact on the pressure drop, dryout power, and dryout location. Results from these studies may have implications for the operations of PT-HWRs with advanced fuels, and further modifications may be desirable to further enhance thermal-hydraulic margins.