Analysis of a Natural Convection Loop for POST-LOCA GCFR Decay Heat Removal

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Report Date: December 2002
Appendices: No

Abstract

Interest has grown over the past few years in the re-assessment of gas-cooled fast reactors (GCFR) for service in the future evolution of the nuclear power industry. The GCFR has been identified as one of the six concepts deserving further
evaluation in the GEN-IV downselection process. It is widely recognized that the principal technical challenge for reactors of this type is the reliable removal of post- LOCA decay heat. This realization motivated the present study of a realistically modeled convection loop for such service in which energy is removed by a water boiler heat exchanger ten meters above the core thermal center.

The approach followed in this evaluation is to improve a pre-existing in-house computer code which carries out a quasi steady-state analysis of convection in a closed loop. Special attention has been paid to the selection of the correlations for friction factors and heat transfer coefficients, since the parameter space of interest spans virtually all convection flow regimes associated with sub-sonic gas flow.

Program:     GFR: Gas-cooled Fast Reactors

Type:     TR 

RPT. No.: 2