Thermal Hydraulic Analysis of Pressurized Water Reactors

Thermal hydraulic analysis of pressurized water reactors (PWRs) addresses the coupled processes of heat transfer, fluid flow and phase change within the reactor coolant system. It underpins design and safety assessment by predicting coolant temperature distributions, pressure drops and two-phase flow behaviour under both normal operating and transient conditions. Modern approaches combine one-dimensional system codes, sub-channel models and three-dimensional computational fluid dynamics (CFD) to capture phenomena such as core inlet flow asymmetry, coolant mixing in the downcomer and pressurised thermal shock. Validation against scaled experiments and benchmark facilities ensures that numerical predictions remain reliable. This research is pivotal for maintaining thermal margins, preventing departure from nucleate boiling and optimising reactor performance. As global energy demand grows, robust thermal hydraulic methodologies support the safe operation of existing PWR fleets and inform the development of advanced designs, while ensuring compliance with regulatory acceptance criteria and enhancing accident-management strategies.

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Thermal Hydraulic Analysis of Pressurized Water Reactors publication trend

The graph below shows the total number of articles in thermal hydraulic analysis of pressurized water reactors across all publications each year (not limited to Nature Index journals).

Technical terms

Pressurized Water Reactor (PWR): A type of nuclear reactor in which water under high pressure acts as both coolant and moderator, preventing boiling within the core.

Computational Fluid Dynamics (CFD): Numerical methods for solving the Navier–Stokes equations to predict fluid flow and heat transfer in complex geometries.

Pressurized Thermal Shock (PTS): A transient event in which rapid injection of cold coolant into a hot, pressurised vessel induces steep thermal gradients and potential material stresses.

Two-Phase Flow: Simultaneous flow of liquid and vapour phases, common in reactor cores during heat removal and transient scenarios.

Reynolds-Averaged Navier–Stokes (RANS): A turbulence modelling approach that averages fluctuating velocity fields to make three-dimensional simulations computationally tractable.

References

1. Validation and Application of CFD Methodology for Core Inlet Flow Distribution in APR1000 Reactor. Energies (2025).
2. Assessment of Realistic Departure from Nucleate Boiling Ratio (DNBR) Considering Uncertainty Quantification of Core Flow Asymmetry. Energies (2021).
3. Numerical Analysis Related to the ROCOM Pressurized Thermal Shock Benchmark. Fluids (2022).
4. Modeling the process of mixing the coolant in the lower section and pressure mixing chamber of VVER-1200 (V-491). Proceedings of the National Academy of Sciences of Belarus Physical-Technical Series (2022).
5. BORA4-PTS: Experimental reproduction of a Pressurized Thermal Shock, and building of numerical simulation with the CATHARE Code. Nuclear Engineering and Design (2024).