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Nodal analysis for reactor kinetics and stability

Thesis/Dissertation ·
OSTI ID:6605573
General space kinetics models have been developed for more accurate stability analysis utilizing nodal analysis, a commonly used technique for analyzing power distributions in large power reactors. Kinetics parameters for use in these kinetics models have been properly derived by utilizing self-consistent nodal data and power distributions. The procedure employed in the nodal code SIMULATE has been utilized for power distribution, since that methodology is general and includes various commonly used nodal methods as special cases. Cross sections are correlated as functions of void fraction and exposure. A computer program investigating thermo-hydrodynamic stability, NUFREQ has been modified to accommodate general spatial kinetics models with an improved thermal-hydraulics model. The thermal-hydraulic models used are lumped and distributed parameter heated wall dynamics models with or without heat flux perturbations in the two-phase region. The assumptions used in the thermal-hydraulic models are separated flow, non-uniform heat flux including spacer effects. The Nyquist criterion has been utilized to obtain stability margins corresponding to the kinetics model. Development of general space kinetics model made it possible to evaluate more accurate stability margins, and it is possible to analyze the influences of operating conditions on stability for any system with void perturbations due to external perturbation.
Research Organization:
Rensselaer Polytechnic Inst., Troy, NY (USA)
OSTI ID:
6605573
Country of Publication:
United States
Language:
English