HEAT TRANSFER TO A DISPERSED TWO-PHASE FLOW AND DETAILED QUENCH FRONT VELOCITY RESEARCH
During the blow-down phase of a loss-off coolant accident in large pressurized water reactors the core will heat up dramatically. Water is injected into the system and by bottom flooding the core is cooled. This reflooding process can be subdivided into 3 stages: pre- quench, quench, and post-quench. The report is subdivided into 4 parts, one a synthesis. The results are as follows: Information is collected on the influence of an unheated shroud on prequench heat transfer in a tube, an annulus and a 4-rod bundle. By optical analysis information is obtained on the droplet size distribution and droplet concentration present during the dispersed two phase flow regime as part of the reflooding process. Models predicting the dependence of reflood heat transfer and mass carry-out fraction as a function of fuel bundle geometry have not been fully established. One-dimensional computer models for the calculation of the reflood process in a bundle need better justification. The ECN 36-rod bundle tests yield a data base suitable for code validation and development. Better understanding is obtained for the influence of the radial non-uniform temperature and/or power distributions on the reflood process. Heat transfer improvement induced by the presence of spacer grids is observed.
Bibliographic Reference: EUR 10074 EN (1985) MF, 623 P., BFR 1050, BLOW-UP COPY BFR 3115, EUROFFICE, LUXEMBOURG, POB 1003
Availability: Can be ordered online
Record Number: 1989124016100 / Last updated on: 1987-01-01
Available languages: en