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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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Latest News
Proving DRACO will deliver
The United States is now closer than it has been in over five decades to launching the first nuclear thermal rocket into space, thanks to DRACO—the Demonstration Rocket for Agile Cislunar Orbit.
Justin Mart, Andrew Klein, Alexey Soldatov
Nuclear Technology | Volume 188 | Number 1 | October 2014 | Pages 8-19
Technical Paper | Fission Reactors | doi.org/10.13182/NT13-135
Articles are hosted by Taylor and Francis Online.
The elimination of soluble boron in the operation of small modular integral pressurized water reactors creates several advantages. Most of these advantages are realized by the core simplification brought on by removing the corrosive effects of soluble boron. Piping, pumps, and tanks associated with soluble boron can be completely eliminated, bringing a significant economic and safety benefit. Additionally, a whole class of accidents related to boron dilution would be eliminated by design, and any loss-of-coolant event would not be affected by the presence of soluble boron. However, removing soluble boron creates its own set of specific challenges that must be overcome. In traditional pressurized water reactors, soluble boron is used in conjunction with burnable poisons to suppress excess initial reactivity. Since boron is diluted in the coolant, its presence is felt uniformly throughout the core, and thus it uniformly reduces the excess initial reactivity. In any boron-free design, an acceptable alternative to boron must be found through the use of the other two mechanisms for reactivity control: burnable poisons and control rods. However, both methods pose challenges. Control rods are actively controlled but are discrete absorbers, locally impacting the core where they are inserted. Since they are inserted from the top of the core, their presence negatively impacts the axial neutron flux profile. This axial flux imbalance creates undesirable peaking factors, leading to reduced operating margins. Thus, the main challenge in any boron-free design concerns excess reactivity suppression and active reactivity control while maintaining a proper axial flux profile and reduced peaking factors. This paper demonstrates that an advanced control rod algorithm with multiple control rod banks can be used for this purpose to satisfy the criteria for success.