Numerical Analysis of 1/28 Scaled HTGR Reactor Building Test Facility Response to Depressurization Event
Abstract
Depressurized Loss of Forced Cooling (DLOFC) accident is an important type of accident
scenario in High Temperature Gas-Cooled Reactor (HTGR) design which is initiated
by a break in Helium Pressure Boundary (HPB). This class of accident scenarios results
in a depressurization of primary helium coolant system with subsequent release of helium
into the Reactor Building (RB) and to the atmosphere through Vented Low Pressure
Containment (VLPC). After the total depressurization of helium depending on the specific
accident scenarios, it is also possible that air enters into the Reactor Pressure Vessel (RPV)
through the RB which can potentially react with fuel and the reactor internal components
such as nuclear-grade graphite.
In this study, GOTHIC model of a 1/28-scaled simplified test facility was developed
to analyze the depressurization scenarios and validate them against the experimental data.
Simulations were conducted in three phases by following the experiment sequence. In
the first phase, natural leakage from the RB was modeled with two different methods to
prepare the model for further analysis. In the second phase, post-depressurization refill
of air into the RB compartments was analyzed and results were validated against experimental
data. In third phase, two hypothetical depressurization scenarios were analyzed
and results were compared with experimental data. Simulation results were found to be
consistent with experimental data.
Citation
Yildiz, Mustafa A (2017). Numerical Analysis of 1/28 Scaled HTGR Reactor Building Test Facility Response to Depressurization Event. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /173279.