Leap Frog and Time Step Sub-Cycle Scheme for Coupled Neutronics and Thermal-Hydraulic Codes

Conference · Mon Jul 01 04:00:00 EDT 2002

OSTI ID:21064600

Lu, S ^[1]

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1. U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 (United States)

As the result of the advancing TCP/IP based inter-process communication technology, more and more legacy thermal-hydraulic codes have been coupled with neutronics codes to provide best-estimate capabilities for reactivity related reactor transient analysis. Most of the coupling schemes are based on closely coupled serial or parallel approaches. Therefore, the execution of the coupled codes usually requires significant CPU time, when a complicated system is analyzed. Leap Frog scheme has been used to reduce the run time. The extent of the decoupling is usually determined based on a trial and error process for a specific analysis. It is the intent of this paper to develop a set of general criteria, which can be used to invoke the automatic Leap Frog algorithm. The algorithm will not only provide the run time reduction but also preserve the accuracy. The criteria will also serve as the base of an automatic time step sub-cycle scheme when a sudden reactivity change is introduced and the thermal-hydraulic code is marching with a relatively large time step. (authors)

• Research Organization: The ASME Foundation, Inc., Three Park Avenue, New York, NY 10016-5990 (United States)
• OSTI ID: 21064600
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
ACCURACY
ALGORITHMS
COMMUNICATIONS
ERRORS
REACTIVITY
THERMAL HYDRAULICS
TRANSIENTS