COMPARISON OF THE ACCURACY OF DIFFERENT METHODS OF MEASURING THE EFFECTIVENESS OF EMERGENCY PROTECTION SYSTEM IN VVER-1000
24th Symposium of AER on VVER Reactor Physics and Reactor Safety (2014, Sochi, Russia)
Core surveillance and monitoring
Abstract
COMPARISON OF THE ACCURACY OF DIFFERENT METHODS OF MEASURING THE EFFECTIVENESS OF EMERGENCY PROTECTION SYSTEM IN VVER-1000
Afanasiev D.V., Pinegin A.A.
National Research Centre “Kurchatov Institute” Moscow, Russia
ABSTRACT
Measuring the effectiveness of the emergency protection system (EPS) in a VVER-1000 is one of the difficult tasks of start-up experiments. Usually experiments are carried out by the emergency protection reset while holding one, the most effective control rods above the core. Such experiments have a number of disadvantages. They, in particular, have significant methodological error. Systematic error of such experiments can be eliminated only by special methods involving computational programs. Another disadvantage of these experiments is their low sensitivity to deviations in multiplying properties of the central part of the core from the nominal values. This fact decreases informativeness of these experiments.
There is a method of determining the effectiveness of the emergency protection system by measuring the effectiveness of individual groups of control rods. Systematic error of this method is significantly less, but it requires some additional calculations.
Both methods are accurate in the absence of measurement errors, calculation errors, constant uncertainty, etc. The accuracy of determining the effectiveness of EPS using these methods has been investigated in the statistical model of experiments, created on the basis of the program NOSTRA. Statistical model of experiments, created on the basis of the program NOSTRA, takes into account the uncertainty of both the properties of the core, and experimental error. The report presents a comparative analysis of the accuracy of determining the EPS by both methods and informativeness value of the results.