Nuclear Power Technology Development

IAEA Coordinated Research Projects (CRP)

Understanding and Prediction of Thermal-Hydraulics Phenomena Relevant to SCWRs


Summary

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 high core outlet coolant temperature, the SCWR is expected to achieve much higher thermal efficiencies than those of current WCRs, and thereby promise improved economics.

The objective of the CRP is to improve the understanding and prediction accuracy of thermal-hydraulics phenomena relevant to SCWRs and to benchmark numerical toolsets for their analyses. Several key phenomena, such as heat transfer, pressure drop and flow stability, have been identified as crucial to the success in developing SCWRs. Experimental and analytical information on these phenomena is being generated at several Member States and can be shared with others to advance the technology.

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.

Background

Currently, Water Cooled Reactors (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, and this technology is now very well established. The Super-Critical Water-cooled Reactor (SCWR) is an innovative WCR concept that operates at a pressure higher than the thermodynamic critical point of water (i.e. 22.1 MPa), allowing the core outlet coolant temperature to be much higher than that of the current generation of WCRs. The key technological advantages of the SCWR include its high thermal efficiency and a simplified system configuration, compared to conventional WCRs. These advantages were recognized in the 1950s, leading to significant research on nuclear reheated steam and a SCWR concept proposed by Russia in 1965.

There has been high interest in research and development of SCWRs 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, which promoted international collaboration among 16 institutes from 9 Member States and 2 International Organizations. The CRP was successfully completed in September 2012. Information generated from that CRP was documented in a TECDOC and numerous publications and reports. A database of thermal-hydraulics parameters of interest to SCWR development was compiled and is currently housed in the OECD/NEA central server..

Despite of the completion of the CRP, several collaborations continue between institutes participating in the CRP. Most of the institutes express their strong interest and support to initiate a new CRP on thermal-hydraulics of SCWRs to continue the momentum of international collaborations.

This new CRP on thermal-hydraulics of SCWRs aims to improve the understanding of thermal-hydraulics phenomena relevant to SCWRs and to improve the prediction accuracy of thermal-hydraulics parameters of interest to SCWR analyses. The identified scope of collaboration is considered as the applied R&D, as compared to the basis R&D in the former CRP.

CRP Overall Objective

The overall objective of the CRP is to improve the understanding of thermal-hydraulics phenomena and prediction accuracy of thermal-hydraulics parameters related to SCWRs and to benchmark numerical toolsets for SCWR thermal-hydraulics analyses.

Specific Research Objectives

  1. Improve predictive capability of heat transfer for SCWR fuel related geometries including separate effects;
  2. Improve predictive capability of pressure drop for SCWR fuel related geometries including separate effects;
  3. Improve predictive capability of parallel channel stability boundary;
  4. Improve predictive capability of natural circulation flow;
  5. Improve predictive capability of CHF at near critical pressures;
  6. Improve predictive capability of critical flow; and
  7. Improve predictive capability of subchannel and plenum mixing.

Expected Research Outputs

  1. A TECDOC synthesizing the results of the CRP;
  2. Joint papers in national/international scientific journals and conferences; and
  3. Experimental database.

Expected Research Outcomes

  1. Improved understanding of SCWR thermal-hydraulic phenomena;
  2. Improved prediction accuracy of SCWR thermal-hydraulic parameters;
  3. Co-ordinated strategy for SCWR thermal-hydraulic R&D;
  4. Enhanced interactions and co-operation among participating Member States; and
  5. Enhanced education and knowledge management in the area of WCR technologies.

This CRP will officially start in August, 2014, when the first Research Coordinated Meeting (RCM) will be held.


Please contact NENP Technology Development Section - Contact Point if you have any questions.