Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Impact of the Parametric Effect on the Transient Stability in Modern Designs of Ship Reactor Plants

9/20/2024 2024 - #03 Thermal physics and thermal hydraulics

Kresov D.G.

DOI: https://doi.org/10.26583/npe.2024.3.03

UDC: 621.039.52

The new generation of ship and small nuclear power plant reactors for a wide range of applications, along with increased safety requirements, combines high specified endurance characteristics. Under certain conditions, design transients can be accompanied by prolonged alternating deviations of the reactor plant parameters from specified values, which is indicative of insufficient parametric margins to the stability boundary. One of the provoking factors of the additional thermal and baric cycling caused by this to the reactor plant equipment is the connection of the remote pressure compensation system to the hot sections of the primary circuit. The addition of relatively cold coolant into the main circulation circuit at the pressure reduction stage increases the amplitude of the negative in-pile temperature fluctuation half-wave.

To accumulate the physical ideas of such a parametric effect, the paper considers two simplified reactor models, which differ greatly in terms of the pressure compensator connection point. The results of analyzing linearized models make it possible to conclude theoretically on the system stability area reduction as the result of coolants being mixed directly at the core outlet and, conversely, on the damping of overshoots in the event of coolants mixed at the core inlet. At the same time, the analysis has revealed a number of additional factors that affect considerably the resistance boundary. These include reactivity factors for coolant temperature and pressure, and a significant absolute value of the axial offset.

The presented calculations of one of the transients based on a nonlinear model, which confirm the obtained theoretical conclusions, illustrate the amplitudes of perturbations in some of the reactor plant parameters for different layout options, obtained from the data of draft studies for one of the designs.

The study has identified the factors that contribute to the stabilization of the reactor feedback system under self-control conditions.

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kinetics phase lag instability thermal-hydraulic inertia

Link for citing the article: Kresov D.G. Impact of the Parametric Effect on the Transient Stability in Modern Designs of Ship Reactor Plants. Izvestiya vuzov. Yadernaya Energetika. 2024, no. 3, pp. 32-43; DOI: https://doi.org/10.26583/npe.2024.3.03 (in Russian).

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