Non-linear time-dependent modelling of heterogeneous nuclear reactors
Ladda ner
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Management and economics of innovation (MPMEI), MSc
Publicerad
2023
Författare
Öhrlund, Fredrik
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This thesis is about time-dependent core-level neutronic simulations of nuclear re actors. In such systems, the neutron flux may oscillate in space and time due to
the production and consumption of given fission products, in particular Xenon-135.
This phenomenon is known as Xenon oscillations. A numerical simulator was devel oped to model such a phenomenon. The simulator numerically solves large systems
of non-linear equations, which in this case requires the use of implicit methods. The
way this has been accomplished uses techniques that are different from standard
practice. The tool capitalizes on a static solver earlier developed and uses the same
approximations in terms of spatial discretization and boundary conditions. The
simulator was demonstrated to produce physically-correct results when applied to
a realistic model of a pressurized water reactor. The simulator allows for time dependent perturbations defined in terms of insertions of control rod banks, and
the realistic PWR model includes realistic control rod insertions. Xenon oscillations
were predicted by the tool in some specific situations.
Beskrivning
Ämne/nyckelord
Nuclear energy, Light water reactors, Xenon oscillations, Diffusion the ory, Non-linear dynamics, Newton method.