Naslov
Calculation of the QUENCH-02 Experiment with the ASYST Code Including the Uncertainty Evaluation

Autori
Šadek, Siniša ; Pavlinac, Renato ; Ivanjko, Karlo ; Grgić, Davor

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
NENE 2022 Conference Proceedings / Jenčič, Igor - Ljubljana : Nuclear Society of Slovenia, 2022, 1-10

ISBN
978-961-6207-53-9

Skup
31st International Conference Nuclear Energy for New Europe brought together (NENE2022)

Mjesto i datum
Portorož, Slovenija, 12.09.2022. - 15.09.2022

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
QUENCH-02 experiment ; ASYST code ; uncertainty analysis ; Pearson correlation coefficient

Sažetak
Uncertainties in the safety assessment of nuclear facilities are the result of random and systematic errors: variabilities in the values of the variables describing the system and its initial and boundary conditions, and the lack of precision of calculation models. Varying the input variables will cause the results of the calculation to be scattered depending on the predefined confidence level. The ASYST code, developed as part of an international nuclear technology ASYST Development and Training Program (ADTP) managed by Innovative Systems Software (ISS), is used to perform an uncertainty analysis of the QUENCH-02 experiment conducted at the Karlsruhe Institute of Technology. The code uses a probabilistic methodology based on the propagation of input uncertainties. The QUENCH facility consists of 21 fuel rod simulators, 20 of which are electrically heated. The aim of the QUENCH experiments is to examine hydrogen source term and the behavior of the fuel rod cladding during core reflood, in a typical PWR reactor. The QUENCH-02 experiment did not have a pre-oxidation phase ; thus the objective was the investigation of PWR fuel rods behavior with little oxidation. The experiment consisted of a heatup phase to temperature of 900 K, a transient phase in which the temperature rose to approximately 2300 K, and a quenching phase with mass flow of water 40-50 g/s. For selected input parameters, such as steam/water flow, electric power and other relevant boundary conditions, it is necessary to define their probability density functions. Input databases are then prepared for individual calculations based on the selected level and confidence interval. The number of calculations is large enough to ensure at least 95% coverage of expected output results and uncertainty limits. The results of the calculations are compared with the experimental measurements. The Pearson correlation coefficient is used to obtain correlation between the input uncertain parameters and the output data. Sensitivity analysis covered the influence of variations in the heater electric power on the hydrogen production and the maximum cladding temperature.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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