In Nuclear Power Plants the Design Extension Conditions are more complex and
severe than those postulated as Design Basis Accidents, therefore, they must
be taken into account in the safety analyses. In this study, many
hypothetical investigated transients are applied on KONVOI pressurized water
reactor during a 6-in. (182 cm2) cold leg Small Break
Loss-of-Coolant-Accident to revise the effects of all safety systems ways
through their availability/ nonavailability on the thermal hydraulic
behaviour of the reactor. The investigated transients are represented
through three cases of Small Break Loss-of-Coolant-Accident as, case-1,
without scram and all of the safety systems are failure, case-2, the normal
scram actuation with failure of all safety systems (nonavailability), and
finally case 3, with normal actuation scram sequence and normal sequential
actuation of all safety systems (availability). These three investigated
transient cases are simulated by creation a model using Analysis of
Thermal-Hydraulics of LEaks and Transient code. In all transient cases, all
types of reactivity feedbacks, boron, moderator density, moderator
temperature and fuel temperature are considered. The steady-state results
are nearly in agreement with the plant parameters available in previous
literatures. The results show the importance effects of the feedbacks
reactivity at Loss-of-Coolant-Accident on the fallouts power, since they are
considered the key parameters for controlling the clad and fuel temperatures
to maintain them below their melting point. Moreover, the calculated results
in all cases show that the thermal hydraulic parameters are in acceptable
ranges and encounter the safety criterion during Loss-of-Coolant-Accident
the Design Extension Conditions accidents processes. Furthermore, the
results show that the core uncovers and fuel heat up do not occur in KONVOI
pressurized water reactor in theses the Design Extension Conditions
simulations since, all safety systems provide adequate core cooling by
sufficient water inventory into the core to cover it.
Pressure Drop through Broken Cold Leg during Reflood Phase of Loss-of-Coolant Accident of Pressurized Water Reactor
