|Van der Merwe, Petrus Gerhardus
|Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.
|The Pebble Bed Modular Reactor (PBMR) is a revolutionary small, compact and safe nuclear
power plant. It operates on a direct closed Brayton cycle. One of the unique features of this
concept is its load following capability enabled by extracting or injecting of the working fluid
(in the PBMR's case Helium) from or to the system during operation.
The Reserve Shutdown System (RSS) is one of the essential subsystems of the PBMR. The
RSS is used as a maintenance and secondary shutdown system for the PBMR. Small Absorber
Spheres (SAS) containing boron are used to perform the shutdown. When shutdown is
required, the spheres flow into eight borings in the centre reflector of the reactor core. To
continue the reactor operation, the spheres are removed from the borings in the centre
reflector and transported back into the storage containers. As the RSS is a safety-related
system, the functioning and components of the system must be tested in a non-nuclear
environment, before the design can be finalized for the demonstration plant. A test set-up for
the RSS was designed and forms part of the Helium Test Facility (HTF) for the PBMR.
A method had to be identified and a process developed which can be used to perform a
thermo-hydraulic analysis and determine the specifications of the components in the test
facility that will enable the test facility to perform all the required tests at the required
conditions. This method also had to predict the performance of the test facility before the
building of the actual plant. The method of simulation was identified as the most suitable
method to perform the thermo-hydraulic analysis on the proposed test facility. The process
developed included the set-up of a thermal fluid network with the use of Flownex Nuclear, a
thermal fluid software package. With the method that was used for the thermo-hydraulic
analysis of the RSS test facility, it was possible to obtain the process data for the components
and to predict the functioning and performance of the proposed test facility. This method and
process can be used widely in the industry for the design and performance prediction of large
industrial plants and testing facilities. It can also be used in the design process of plants to
optimize the layout and performance of the plants and processes.
|Method for the thermo-hydraulic analysis of the test facility for the PBMR reserve shutdown system