Application of the NLOOP code for transient analysis of the 'Angra 2 inadverting opening of one steam generator safety valve'

This paper illustrates through a sample case calculation, the transient analysis methodology for Angra 2 Nuclear Power Plant using the computer code NLOOP, with the purpose to demonstrate that if a dynamic transient occurs in the plant it will be controlled safely by the control and limitation systems or the plant is brought to a safe condition by the Reactor Protection System. As demonstration calculation, the case inadvertent opening of one steam generator safety valve was chosen which causes a decrease of the primary and secondary temperature which consequent reactor power increase, due to the reactivity feedback and control rod withdrawal from the reactor coolant temperature control actuation. To analyse this transient three scenarios are considered, where some failures in the power plant systems are postulated. (author). 3 refs, 6 figs, 1 tab