Sensitivity of BWR stability calculations to numerical integration techniques

Conference · Sat Nov 01 04:00:00 EST 1997

OSTI ID:548854

Peiro, D G ^[1]; March-Leuba, J ^[2]

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1. Universidad Politecnica de Valencia (Spain). Departamento de Matematica Aplicada
2. Oak Ridge National Lab., TN (United States)

Computer simulations have shown that stability calculations in boiling water reactors (BWRs) are very sensitive to a number of input parameters, modeling assumptions, and numerical integration techniques. Following the 1988 LaSalle instability event, a significant industry-wide effort was invested in identifying these sensitivities. One major conclusion from these studies was that existing time-domain codes could best predict BWR stability by using explicit methods for the energy equation with a Courant number as close to unity as possible. This paper presents a series of sensitivity studies using simplified models, which allow us to determine the effect that different numerical integration techniques have on the results of stability calculations. The present study appears to indicate that, even though using explicit integration with a Courant number of one is adequate for existing codes using time-integration steps of less than 10 ms, second-order solution techniques for the time integration can result in significant improvements in the accuracy of linear (i.e., decay ratio) stability calculations.

• Research Organization: Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE Assistant Secretary for Nuclear Energy, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 548854
• Report Number(s): ORNL/CP--94956; CONF-9710101--; ON: DE98001056
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
22 GENERAL STUDIES OF NUCLEAR REACTORS
99 GENERAL AND MISCELLANEOUS
BWR TYPE REACTORS
COMPUTERIZED SIMULATION
DIFFERENTIAL EQUATIONS
NUMERICAL SOLUTION
SENSITIVITY ANALYSIS
STABILITY