Original scientific paper

OPTIMIZATION OF OPDT PROTECTION FOR OVERCOOLING ACCIDENTS

VESNA BENČIK ; University of Zagreb Faculty of Electrical Engineering and Computing
DAVOR GRGIĆ ; University of Zagreb Faculty of Electrical Engineering and Computing
NIKOLA ČAVLINA ; University of Zagreb Faculty of Electrical Engineering and Computing
SINIŠA ŠADEK ; University of Zagreb Faculty of Electrical Engineering and Computing

Abstract

Overcooling accidents are typically resulting in power increase due to
negative moderator feedback. There are more protection set points responsible for
terminating power increase. OPDT protection set point is typically protection from
exceeding fuel centre line temperature due to reactivity and power increase. It is
important to actuate reactor trip signal early enough, but to be able to filter out
events where actuation is not necessary. Different concepts of coolant temperature
compensation as part of OPDT set point protection were studied for decrease of
feedwater temperature accident and for small main steam line breaks from full
power for NPP Krško. Computer code RELAP5/mod 3.3 was used in calculation. The
influence of different assumptions in accident description as well as nuclear core
characteristics were described.

Keywords

OPDT protection; overcooling accident; RCS temperature measurement; RELAP5; RTD bypass

Hrčak ID:

199284

URI

https://hrcak.srce.hr/199284

Publication date:

15.9.2017.

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