McMaster University DOCTOR OF PHILOSOPHY (2022) Hamilton, Ontario (Engineering
Physics)
TITLE: Development and Evaluation of Polaris CANDU Geometry Modelling and of
TRACE_Mac/PARCS_Mac Coupling with RRS for CANDU Analysis
AUTHOR: Simon Younan, M.A.Sc. (McMaster University), B.Eng. (McMaster University)
SUPERVISOR: Dr. David Novog
NUMBER OF PAGES: xiv, 163 / In the field of nuclear safety analysis, as computers have become more powerful,
there has been a trend away from low-fidelity models using conservative assumptions, to
high-fidelity best-estimate models combined with uncertainty analysis. A number of these
tools have been developed in the United States, due to the popularity of light water
reactors. These include the SCALE analysis suite developed by ORNL, as well as the PARCS
and TRACE tools backed by the USNRC. This work explores adapting the capabilities of
these tools to the analysis of CANDU reactors.
The Polaris sequence, introduced in SCALE 6.2, was extended in this work to support
CANDU geometries and compared to existing SCALE sequences such as TRITON. Emphasis
was placed on the Embedded Self-Shielding Method (ESSM), introduced with Polaris. Both
Polaris and ESSM were evaluated and found to perform adequately for CANDU
geometries. The accuracy of ESSM was found to improve when the precomputed selfshielding
factors were updated using a CANDU representation.
The PARCS diffusion code and the TRACE system thermalhydraulics code were
coupled, using the built-in coupling capability between the two codes. In addition, the
Exterior Communications Interface (ECI), used for coupling with TRACE, was utilized. A
Python interface to the ECI library was developed in this work and used to couple an RRS
model written in Python to the coupled PARCS/TRACE model. A number of code
modifications were made to accommodate the required coupling and correct code
deficiencies, with the modified versions named PARCS_Mac and TRACE_Mac. The
coupled codes were able to simulate multiple transients based on prior studies as well as
operational events. The code updates performed in this work may be used for many
future studies, particularly for uncertainty propagation through a full set of calculations,
from the lattice model to a full coupled system model. / Thesis / Doctor of Philosophy (PhD) / Modern nuclear safety analysis tools offer more accurate predictions for the safety
and operation of nuclear reactors, including CANDU reactors. These codes take advantage
of modern computer hardware, and also a shift in philosophy from conservative analysis
to best estimate plus uncertainty analysis. The goal of this thesis was to adapt a number
of modern tools to support CANDU analysis and uncertainty propagation, with a particular
emphasis on coupling of multiple interacting models. These tools were then
demonstrated, and results analyzed.
The simulations performed in this work were successful in producing results
comparable to prior studies along with experimental and operational data. This included
the simulation of four weeks of reactor operation including “shim mode” operation.
Sensitivity and uncertainty analyses were performed over the course of the work to
quantify the precision and significance of the results as well as to identify areas of interest
for future research.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/28246 |
| Date | January 2022 |
| Creators | Younan, Simon |
| Contributors | Novog, David, Engineering Physics |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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