Integral parameters in source-driven systems

Point kinetics equations for subcritical systems based on the importance function associated to an external neutron source

“…Furthermore, the point kinetics equations developed here are solved for two different transients, considering the parameters obtained with different importance functions. The results collected show that there is a similar behavior of the solution of the point kinetics equations, when used with the parameters obtained by the importance functions proposed by Gandini and Salvatores (2002) and Dulla et al (2006), specially near the criticality. However, this is not verified as the system gets farther from criticality.…”

“…The presence of an external source of neutrons introduces new considerations with respect to the mathematical description of the physical process that occurs in the core of the nuclear reactor (Dulla et al, 2006) as in the case of point kinetics.…”

“…The main difficulty for the complete physical description of subcritical systems lies in the choice of the importance function associated to a given integral quantity (Dulla et al, 2006). In the literature, the works of the major highlights are those proposed by Gandini and Salvatores (2002), that takes into account the presence of external sources and fission and the concept of generalized reactivity, Dulla et al (2006), which has the same structure as the classic point kinetic model, Nishihara et al (2003), which does not account for the presence of fission source to calculate the importance function, and lastly, Silva et al (2012), which is based on the choice of a hybrid importance function.…”

“…The importance function defined here is related to both the subcriticality and the external neutron source worth (which keeps the system at steady state). The kinetic parameters defined in this work are compared with the corresponding parameters when adopting the importance functions proposed by Gandini and Salvatores (2002), Dulla et al (2006) and Nishihara et al (2003). Furthermore, the point kinetics equations developed here are solved for two different transients, considering the parameters obtained with different importance functions.…”

Deterministic and Monte Carlo modeling and analyses of YALINA-THERMAL subcritical assembly.

“…The original proposal of Dulla at al. 110 included only source neutrons as prompt neutrons. The definition of the denominator of the kinetic parameters (F factor) is arbitrary.…”