Analysis of Rod Removal Transient Experiments in VVER Reactors at Zero Power
Within the context of the Fissile Materials Disposition Program of the U.S. Department of Energy we analyzed rod removal transient experiments performed at the Kurchatov Institute in a full-scale mockup of VVER reactors, The transients were started (via water inlet) in slightly (few cents) supercritical configurations with all the control rods withdrawn. After a few minutes, control rods banks or individual control rods were f and t inserted and later withdrawn (returning to the initial state). Available experimental data include the relative time profiles of nine incore and excore detectors. Because of the mild nature of the transients (very low power and no more than 2 $ reactivities) we decided to use a quasistatic approach. The time-dependent flux is factorized into two terms: a function of phase space, given by the solution of the static equation with parametric excitation; and a function of time, given by the solution of the point kinetic equations with time-dependent kinetics para meters. Due to the nature of the experiment, cold conditions, control rods withdrawn and critical state with water level, the power distributions, measured and calculated, are quite unusual, with the inner part of the core heavily shielded. Measured power levels at the center of the reactor are almost 20 times smaller than similar regions at the periphery. Transport and diffusion calculations of the power distributions are in reasonable agreement, so the division code BOLD-VENTURE was used to calculate the kinetics parameters and the relative changes of the detector field of view. The numerical integration of the time-dependent part of the solution was made with the LSODE package using ENDFIB-V and VI delayed neutron data. Very good results were obtained for the nine lime profiles.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Fissile Materials Disposition (MD) (US)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 751424
- Report Number(s):
- ORNL/CP-106007; TRN: US0005380
- Resource Relation:
- Conference: PHYSOR 2000, Pittsburgh, PA (US), 05/07/2000--05/11/2000; Other Information: PBD: 7 May 2000
- Country of Publication:
- United States
- Language:
- English
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