In-core temperature measurement for the PBMR using fibre-bragg gratings
Date
2009-03
Authors
De Villiers, Gerrit Johannes
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
The PBMR has called for research into the possibility of distributed in-core
temperature measurement. In this thesis, several methods for distributed
temperature measurement in high-pressure, -radiation and -temperature environments
have been investigated by means of a literature study. The literature
study has revealed FBG temperature sensors as the most feasible solution
to the temperature measurement challenge.
Various parameters affecting the propagation of light in optical fibres
and consequently the FBG reflection profile was researched. The differential
equations describing FBG structures were solved and implemented in
Matlab in order to simulate WDM of a distributed FBG sensing system. Distributed
sensing with apodized FBGs written in sapphire optical fibre show
the most promise of becoming a solution to the measurement challenge.
However, practical testing of sapphire FBGs exposed to the environment
in the PBMR core is required. With this long-term goal in mind, a general
test platform for FBG temperature sensors was assembled. A heater controller
was built for a specialized fibre heating element capable of controlling
the temperature of a single FBG up to 1600 C. Temperature measurement
using wavelength division multiplexing of apodized FBGs written in silica
optical fibre were demonstrated in the test platform with great success. The
measured results corresponded very well with the theory.
Finally, the implementation of FBGs in the PBMR is discussed and recommendations
are made for future work
Description
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009.
Keywords
PBMR, Dissertations -- Electrical and electronic engineering, Theses -- Electrical and electronic engineering, Optical fibers, Pebble bed reactors, Temperature measurements