ANALYSIS OF EXPERIMENTS PERFORMED AT UNIVERSITY OF HANNOVER WITH RELAP5 - MOD2 AND CATHARE CODES ON FLUID DYNAMIC EFFECTS IN THE FUEL ELEMENT TOP NOZZLE AREA DURING REFILLING AND REFLOODING
The experimental data of flooding and CCFL in the fuel element top nozzle area collected at the University of Hannover are analysed with RELAP5/MOD2 and CATHARE V.1.3 codes. Preliminary sensitivity calculations are performed to evaluate the influence of various parameters and code options on the results. An a priori rational assessment procedure is performed for those parameters which are non specific in experimental data (e.g.energy loss coefficients in flow restrictions), based on single phase flow pressure drops. The reported experimental data demonstrate the complex relationship between the physical quantities involved (film thickness, pressure drop etc.) even in a simple geometrical condition with well defined boundary conditions. In the application of the two advanced codes to the selected CCFL experiments it appears that sophisticated models do not simulate the measured phenomena satisfactorily when situations similar to nuclear reactors are considered (rod bundles). The work performed demonstrates that further applications of present codes to CCFL experiments do not appear to be useful. New models should be tested and implemented before any attempt to reproduce CCFL in experimental facilities by system codes. A theoretical model previously developed for a cylindrical geometry has been adapted and gives reasonable agreement with data collected for high injected liquid flow rates. The results of experimental work for one single-channel test section and for multi-channel test sections are compared to some existing models.
Bibliographic Reference: EUR 12407 EN (1989) 134 PP., FS, ECU 11.25 ISBN 92-826-1185-X THE OFFICE FOR OFFICIAL PUBLICATIONS OF THE EUROPEAN COMMUNITIES, L-2985 LUXEMBOURG
Availability: Can be ordered online
Record Number: 1989128076100 / Last updated on: 1990-11-09
Available languages: en