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Understanding and Prediction of Thermal-Hydraulics Phenomena Relevant to SCWRs (I31025)


The Super-Critical Water-cooled Reactor (SCWR) is one of the innovative Water Cooled Reactor (WCR) concepts mainly for large scale production of electricity. By utilizing its high core outlet coolant temperature, the SCWR is expected to achieve much higher thermal efficiencies than those of conventional WCRs, and thereby promise improved economics.

The SCWR operates at a pressure higher than the thermodynamic critical point of water (i.e. 22.1 MPa). The SCWR system consists of a once-through reactor system, like PWRs and HWRs, and a direct cycle turbine system, like BWRs, allowing the simplest combination. The key technological advantages of the SCWR include its high thermal efficiency and the simplified system configuration, compared to conventional WCRs.

Currently, WCRs account for more than 95% of the electricity generated by nuclear power plants. In addition, there are hundreds of fossil-fired power units operating under supercritical conditions worldwide. SCWRs can be designed and constructed based on the well-established technologies. Thermal-hydraulics phenomena in SCWRs, however, are different from those in conventional WCRs, so there is research and development (R&D) need in the area of thermal-hydraulics of SCWRs.

There has been high interest in R&D of SCWRs worldwide, and several SCWR concepts have been under development in a number of IAEA Member States. In 2008, the IAEA officially started the CRP on "Heat Transfer Behaviour and Thermo-hydraulics Code Testing for SCWRs” "Heat Transfer Behaviour and Thermo-hydraulics Code Testing for SCWRs” , which promoted international collaboration among 16 institutes from 9 Member States and 2 International Organizations in total. The CRP was successfully completed in September 2012.

This new CRP on thermal-hydraulics of SCWRs aims to improve the understanding of thermal-hydraulics phenomena relevant to SCWRs and to benchmark numerical toolsets for their analyses to improve the prediction accuracy of thermal-hydraulics parameters of interest to SCWR analyses. Several key phenomena, such as heat transfer, pressure drop and flow stability, have been identified as crucial to the success in developing SCWRs. The identified scope of collaboration is considered as the applied R&D, as compared to the basis R&D in the former CRP.

This CRP will enhance the understanding of thermal-hydraulics phenomena, the sharing of experimental and analytical results, the prediction methods for key thermal-hydraulics parameters, and the cross-training of personnel between participating institutes through closer interactions and collaboration.

More details can be found under the Nuclear Power Technology Development Website:  http://www.iaea.org/NuclearPower/Technology/CRP/scwr-th-phenomena/index.html.

Comparison of Reactor Operation Range between SCWR and Conventional WCRs:

Schematic Diagram of the Canadian SCWR Conceptual Design:

(M. Yetisir, M. Gaudet and D. Rhodes, “Development and Integration of Canadian SCWR Concept with Counter-Flow Fuel Assembly”, Proc. 6th International Symposium on Supercritical Water-Cooled Reactors, ISSCWR-6, March 03-07, 2013, Shenzhen, Guangdong, China)

Reactor Coolant Flow of HPLWR, the European SCWR:

(T. Schulenberg & J. Starflinger (eds.), “HIGH PERFORMANCE LIGHT WATER REACTOR Design and Analyses”, KIT Scientific Publishing, 2012.)