ABSTRACT

The paper presents a short analysis of the effect of disturbances by various parameters on the critical heat flux with forced flow of the coolant. The physical fundamentals of the quasistatic method are given. The application limits of the quasistatic method for calculations of the critical heat flux in transient conditions are indicated.
Pressurized Water Reactors (PWR) are in many cases operated under transient conditions. The start-ups /shut-downs/, load increase /load reduction/ may influence the regularities of steam generation process and, consequently, the exchange processes. For PWR, exceeding of critical heat flux (CHF) is one of the most grave accidents. It is very likely that the CHF is brought about by the reduced coolant flow. The decrease of the flow can occur both at constant and varying values of pressure and heat flux. Of great importance are the velocity, depth and duration of disturbances. This may lead to considerable variations in the CHF values. This paper attempts to evaluate the possibility of calculating the q_cr values by the quasistatic method.