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Title: A RETRAN model of the Calvert Cliffs-1 pressurized water reactor for assessing the safety implications of control systems

Technical Report ·
DOI:https://doi.org/10.2172/6876587· OSTI ID:6876587

The failure mode and effects analysis of Calvert Cliffs-1 identified sequences of events judged sufficiently complex to merit further analysis in detailed dynamic simulations. This report describes the RETRAN model developed for this purpose and the results obtained. The mathematical tool was RETRAN2/Mod3, the latest version of a widely used and extensively validated thermal-hydraulics production code obtained by license agreement with the developer, Electric Power Research Institute, and installed on the ORNL BM-3033 computers. RETRAN2 is based on a first-principles methodology that treats two-phase flow with slip. Thermal equilibrium of phases is assumed except in the pressurizer, where non-equilibrium processes are important and special methodology is used. Heat transfer in solids is obtained from the conventional conduction equation. Point or 1-D kinetics is available for the reactor core. The fundamental methodology is supplemented with a broad list of process submodels that calculate heat transfer coefficients, fluid and metal state properties, choked flow, form and wall friction losses, and other parameters. Also supplied are component submodels for various types of valves and pumps, the latter of which incorporate four-quadrant characteristics for components in which two-phase or reverse flow may be expected, and head versus flow curves for others. Extensive input allows the code to be highly particularized to a specific plant. The major investment in time and manpower occurs in setting up the base case; changes are comparatively easy to implement.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
6876587
Report Number(s):
NUREG/CR-4758; ORNL/TM-10236; ON: TI87008420
Country of Publication:
United States
Language:
English