A CFD simulation of 5 × 5 rod bundles with split-type spacers

ASSERT-PV 3.2: Advanced subchannel thermalhydraulics code for CANDU fuel bundles

The diffuser of a reactor coolant pump was optimized using an orthogonal approach with numerical simulation to improve the pump hydraulic performance. Steady simulation was conducted by solving Reynolds-averaged Naiver-Stokes equations with the SST k-ω turbulence model using CFX code. The influence of the diffuser geometric parameters, namely, S, φ, α
 4, b
 4, δ
 2, R
 t and R
 4, on the pump performance were determined. L18 (37) orthogonal table was chosen for the optimization process. Best indicators were determined, and range analysis of energy losses, head, and efficiency at the rated condition was performed. Optimal parameters of the diffuser were S = 490 mm, φ = 36°, α
 4 = 30°, b
 4 = 200 mm, δ
 2 = 20 mm, R
 t = 5 mm and R
 4 = 565 mm. The final design was experimentally tested. Simulation results showed more remarkable performance than the experimental result. However, the numerical predictions and experimental results were consistent, validating the design procedure. Loading of the impeller and diffuser blades was analyzed to investigate the direct impact on the hydrodynamic flow field. The head was 14.74 m, efficiency was 79.6 %, and efficiency of the prototype pump was 83.3 % when the model pump functioned at the rated conditions. Optimization results showed that efficiency and head were improved at the design condition.

Numerical and experimental investigation on the diffuser optimization of a reactor coolant pump with orthogonal test approach

CFD analysis of flow and heat transfer in Canadian supercritical water reactor bundle

Modeling of spacer grid mixing effects through mixing vane crossflow model in subchannel analysis

Assessment of subchannel code ASSERT-PV for flow-distribution predictions

Assessment of ASSERT-PV for prediction of critical heat flux in CANDU bundles

Atomic Energy of Canada Limited (AECL) has developed the subchannel thermalhydraulics code ASSERT-PV for the Canadian nuclear industry. The most recent release version, ASSERT-PV 3.2 has enhanced phenomenon models for improved predictions of flow distribution, dryout power and CHF location, and post-dryout (PDO) sheath temperature in horizontal CANDU fuel bundles. The focus of the improvements is mainly on modelling considerations for the unique features of CANDU bundles such as horizontal flows, small pitch to diameter ratios, high mass fluxes, and mixed and irregular subchannel geometries, compared to PWR/BWR fuel assemblies. This paper describes the model changes or additions in the new version to improve predictions of flow distribution, dryout power and CHF location, and PDO sheath temperature.Crown Copyright © 2013

Y.F. Rao

Papers

ASSERT-PV 3.2: Advanced subchannel thermalhydraulics code for CANDU fuel bundles

Assessment of subchannel code ASSERT-PV for flow-distribution predictions

Assessment of ASSERT-PV for prediction of critical heat flux in CANDU bundles

ASSERT-PV 3.2: Improved Subchannel Thermalhydraulics Code for CANDU Fuel Bundles

Assessment of ASSERT-PV for prediction of post-dryout heat transfer in CANDU bundles