Thermosiphoning behaviour of a pressurized-water facility with CANDU-PHTS geometry

A series of tests has been performed in the RD-14 test facility at the Whiteshell Nuclear Research Establishment to provide information on two-phase thermosiphoning in a CANDU-type circuit geometry. RD-14 is a full-elevation-scale, 10-MPa, 11-MW, pressurized-water loop containing two steam generators, two pumps and two heated horizontal channels arranged in a symmetrical figure-of-eight configuration characteristic of the CANDUTM primary heat transport system (PHTS). This paper reviews the experimental results and describes the evolution of thermosiphoning flow as the loop inventory is progressively reduced. The observed flow behaviour is discussed briefly and compared with predictions made using a computer code for CANDU reactor analysis. (author)