The Generation IV International Forum has established several goals for the next
generation of nuclear energy systems, which are to be substantial improvements
over contemporary designs. In Canada Generation IV research efforts have
focused on developing the Pressure Tube type SuperCritical Water-cooled
Reactor (PT-SCWR), an evolution of CANada Deuterium Uranium (CANDU)
technology. An integral part of the PT-SCWR is the High Efficiency Re-entrant
Channel (HERC), wherein coolant first travels downward through a centre flow
tube and then upward around the fuel. The large density variation of
supercritical fluids, combined with the negative Coolant Void Reactivity (CVR),
make the concept similar to a Boiling Water Reactor (BWR). The objective of this
study was thus to apply the state-of-the-art in BWR analysis to the PT-SCWR.
Models were created using the DRAGON (neutron transport), DONJON
(neutron diffusion/spatial kinetics), and CATHENA (channel thermalhydraulics)
computer codes. A procedure for DONJON-CATHENA coupling was developed
to enable simulation of coupled transients. The specifications of the HERC
necessitated multiple coolant reactivity feedbacks be included in the model, in
turn requiring extensions to the DONJON source code. The model created for
this work is thus among the first to incorporate multiple coolant feedbacks in
core-level coupled spatial kinetics and thermalhydraulics transient analysis, and
is uniquely capable of simulating such transients in the PT-SCWR.
This work found that while the total CVR was negative as required, the reactivity
effect of coolant void solely around the fuel was positive. As a consequence
additional heat delivered from fuel to coolant, which decreases the coolant
density, has a positive reactivity effect making BWR-like coupled instabilities
impossible. On the other hand, in some postulated transients, such as Loss-OfCoolant Accidents (LOCAs) or Loss-Of-Flow Accidents (LOFAs), this positive
reactivity results in temporary power excursions. A fast-acting shutdown system
is potentially necessary to limit damage to the fuel in such transients. / Dissertation / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18363 |
| Date | 11 1900 |
| Creators | Hummel, David |
| Contributors | Novog, David, Engineering Physics and Nuclear Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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