TOBI: A nonlinear model for boiling water reactor stability analysis

Conference · Fri Jun 01 04:00:00 EDT 1990 · Transactions of the American Nuclear Society; (USA)

OSTI ID:6025540

Wehle, F ^[1]; Pruitt, D W

---

1. Siemens/KWU, Offenbach (West Germany)

The magnitude and the divergent nature of the oscillations during the LaSalle unit 2 nuclear power plant even on March 9, 1988, renewed concern about the state of knowledge on boiling water reactor (BWR) instabilities and was followed by many activities, e.g., the Idaho Stability Symposium. For appropriate representation of the physical processes, typical BWR time-domain stability calculations with, e.g., TRAC, RETRAN, or THERMIT require a large number of axial nodes and are very costly with regard to computer time. Linear models are inexpensive, but only valid as long as the parameters have no large deviation from the reference operating conditions. The objective of this work is the development of a physical model that is applicable for stability analysis in the nonlinear regime, but without the disadvantage of numerical problems and excessive computing times. The basic concept of the model TOBI is the integral study of the interaction between the time-dependent single- and two-phase regions. A series of calculations for purely thermal-hydraulic systems and BWRs has shown that TOBI is a convenient tool for stability analysis. Because of the simple but physically realistic modeling, it is very helpful in achieving an improved understanding of the mechanisms that affect BWR stability, and it is inexpensive, with regard to computer time, to perform extensive parameter sensitivity studies, even in the nonlinear regime.

• OSTI ID: 6025540
• Report Number(s): CONF-900608--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (USA) Journal Volume: 61
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210200* -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
BWR TYPE REACTORS
COMPUTER CALCULATIONS
COMPUTER CODES
DOPPLER EFFECT
ENERGY TRANSFER
FEEDWATER
FLOW RATE
FLUID MECHANICS
HEAT TRANSFER
HYDRAULICS
HYDROGEN COMPOUNDS
LA SALLE COUNTY-2 REACTOR
MECHANICS
NONLINEAR PROBLEMS
OSCILLATIONS
OXYGEN COMPOUNDS
POWER REACTORS
R CODES
REACTIVITY
REACTOR STABILITY
REACTORS
STABILITY
T CODES
TRANSIENTS
VOID FRACTION
WATER
WATER COOLED REACTORS
WATER MODERATED REACTORS