DOE OSTI2019
The HTTF is an integral test facility, which has been designed to model the behavior of interest for a MHTGR during the Depressurized Conduction Cooldown (DCC) event. It also has the potential to conduct limited explorations into the progression of the Pressurized Conduction Cooldown (PCC) event and phenomena during normal operations. The facility is scaled 1:4 by height and 1:64 by volume. A scaling report has been developed and provides further detail into the scaling analysis for the HTTF. The maximum core power for the facility is approximately 2.2MW. The core region will be of a modular design to allow for both the prismatic block core and the pebble bed core designs to be tested. However, only the prismatic block design is discussed in this report. The HTTF consists of the following systems: A primary system consisting of the reactor pressure vessel (RPV), the circulator, cross over ducts and primary piping. The core internals sit inside the RPV and provide support for the core and core heaters. The purpose of the primary system is to maintain the pressure boundary, remove heat from the core through convection, conduction and radiation, and provide heat to the core through a series of electrical heaters. A secondary system consisting of a steam generator, feed water system and main steam system. The purpose of the secondary system is to remove heat from the primary system during heat up, cool down and normal operations. A reactor cavity simulation system consisting of a cavity tank, gas conditioning system and a series of break valves. Note that the prototypical MHTGR sits inside of a cavity. In the event of a break the helium will blowdown into this cavity. At the HTTF, the cavity is modeled as a separate tank, the reactor cavity simulation tank (RCST) and is connected to the RPV through break valves—hot-leg, cold-leg, upper break, and lower break. A reactor cavity cooling system (RCCS) consisting of a series of water cooled panels and the water supply system for these panels. The HTTF RCCS is not a scaled prototypical RCCS system for the MHTGR. It is provided in the HTTF in order to set the boundary condition for radiation heat transfer from the RPV. Various auxiliary systems including the city water supply system, the electrical power supply and distribution system, the chilled water system and the instrument air system.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗