A Technical Committee Meeting on Natural Circulation Data and Methods for Innovative

Nuclear Power Plant Design was held at in Vienna in July 2000.

The meeting presentations and discussions were directed toward three related aspects of

natural circulation phenomena:

(a) Design considerations for development and deployment of innovative concepts using natural circulation phenomena;

(b) Computer codes and incorporated models for analysis of natural circulation phenomena;

(c) Experimental facilities and data for support of concept design and analysis.

Within the area of computer codes and models, two classes of models were discussed:

(a) Systems codes — Established systems codes are used to model complete plant systems, including instrumentation and control. These are typically one dimensional (1D) models with multi-dimensional phenomena addressed within component models where necessary;

(b) Multi-dimensional generic flow models — Two types of models were discussed:

— Computational fluid dynamic (CFD) models

— Large eddy simulation (LES) models.

Following the meeting presentations, a general discussion of the subject was held among

participants, resulting in the following conclusions and recommendations.