| Summary: | 碩士 === 國立清華大學 === 核子工程與科學研究所 === 103 === On 11th March 2011, the Fukushima nuclear power plan in Janpan was destroyed by Earthquake and tsunami, then the severe accident happened. The core water level decreased caused by loss of heat sink and then the core uncovered. Due to the core uncovered and damaged, steam interacted with the exposed fuel cladding, and large amount of hydrogen was produced. High concentration of hydrogen gathering inside the top of reactor building induced a horrible explosion and caused the secondary containment broken. The containment integrity could not be maintained thereafter, and the radioactive substances leaked to outside environment. If the hydrogen recombiner can be set in the containment previously, it will depleting the concentration of hydrogen to avoid hydrogen combustion.
In this study, we verification of GOTHIC Code in hydrogen recombiner mode by
compare analysis result with the experiment of hydrogen recombiner designed by
AECL and KNT, the result show that the calculation in hydrogen depletion rate in
GOTHIC is conservative. Generation of Thermal Hydraulic Information for
Containment (GOTHIC) code is used as analyzed tool to perform the analysis of the
behavior of hydrogen diffusion and migration in MARK-III containment of Kuosheng
nuclear power plant. One of the boundary condition used in this simulation, the
production rate of hydrogen, was generated from the calculation of Modular Accident
Analysis Program 5 (MAAP5) code under station blackout event of Kuosheng nuclear
power plant under the same condition as Fukushima accident. Finding out whether the
concentration of hydrogen in each floor of containment reaches the safety limit or not.
In the SBO accident simulation, we use the recombiner designed by AECL in GOTHIC code,To find a suitable configuration of hydrogen recombiner in
containment, the result show that the total number of the hydrogen recombiner is 320,
uniform configuration and around the outside wall of containment, the hydrogen
concentration in second floor of the reactor building is below the 4%. Porosity equal
0.5 is a conservative setting ,then the number of 352 hydrogen recombiner is required.
, we obser that the hydrogen concentration is higher in top and down plane, so we added the amount of hydrogen recombiner in these region except a lower hydrogen concentration, but this configuration is not a good way to depleted hydrogen. The GOTHIC code predicts that the number of hydrogen recombiner is 352 the hydrogen concentration can be controlled under 4%, and the uniform configuration is a better way to set in the containment.
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