Stability analysis of BWR nuclear-coupled thermal-hydraulics using a simple model

Linear stability analysis of flow instabilities with a nodalized reduced order model in heated channel

“…Applying state space approach, these nonlinear ODEs are used to determine the stability of the system. The results of the present model are compared with various existing models [33,34,36] which are closer to exact solutions [31]. The SBs obtained show good agreement with the said models.…”

“…And hence, this impacts the position of stability boundaries. In addition to these, it is evident from previous studies [31,33,36,38] that, stability boundaries obtained with linearelinear approximations of single phase enthalpy and twophase quality; only show the conventional L-fold trend. These SBs are far away from experimental data and exact solutions that lie on the left side of the obtained SBs (forced circulation system) in corresponding parameter plane (N pch eN sub plane).…”

“…The results of the present analysis are compared with linearelinear [36] and quadraticequadratic [33,34] density invariant models (Fig. 5aec).…”

“…In these models the density of the coolant is assumed to be saturated throughout the single phase region of the channel for all inlet subcooling numbers. As mentioned [36], linearelinear homogeneous model with invariant density assumption only shows the conventional trend of a typical stability map. The map predicted by the said model is far away from the quadratic models [33,34] which are closer to the exact solution [31] and experimental data [37].…”

“…However due to the presence of quadratic profiles, the system equations became highly complicated and even run for several pages. It should be noted that using linearelinear approximations of single-phase enthalpy and two-phase quality; a simpler model compared to the aforementioned models had also been presented by Karve et al [36], where though the model equations remain simpler, but the results obtained showed significant discrepancy with the experimental data sets [37].…”