UNB Nuclear Expertise Fuelling Industrial Interests
December 18th, 2015
THE DAMAGING EFFECTS of corrosion are a persistent problem for the power industry. Whether it is a water-cooled nuclear reactor or a fossil-fired power station, materials degradation and the build-up of corrosion products can have serious impacts on their operation, in some cases raising economic, health and environmental concerns. Thanks to a supportive, synergistic relationship between researchers at the University of New Brunswick (UNB) and the power industry in Canada and abroad, however, efforts to mitigate the consequences of corrosion are resulting in practicable solutions for power plant operation.
Derek Lister, Professor Emeritus at UNB and Research Chair in Nuclear Engineering, joined the University’s department of Chemical Engineering in 1992, bringing with him a wealth of knowledge and experience regarding water coolant chemistry and corrosion gained at his previous employment with Atomic Energy of Canada Limited. As well as playing a key role in establishing the Centre for Nuclear Energy Research (CNER) – a research institute within UNB with which Lister and his team work closely, undertaking fundamental research to complement CNER’s applications of research to industry – Lister established a research group that has garnered an international reputation for expanding the understanding of high-temperature corrosion of power plant materials.
COSTLY and INNEFICIENT
Lister’s research aims to understand why corrosion occurs, how it causes radiation field build-up in nuclear reactors and how it leads to reduced heat transfer in heat-exchange equipment. In learning the mechanisms behind these issues and how to predict them, Lister and the UNB Nuclear group help power plant operators reduce costs and improve efficiency.
Corrosion is expensive; its threat to the integrity of components exacts constant vigilance with periodic inspections by plant operators, usually involving shutdowns and loss of production. Corrosion products deposit around coolant circuits, increasing pressure drops and necessitating extra pumping power while at the same time reducing thermal efficiency and increasing emissions. Cleaning by mechanical and/or chemical methods also involves shutdowns but with the extra costs of chemicals and waste disposal.
Corrosion is minimised by controlling the chemistry of the system. This entails monitoring with instruments and analysing frequently to indicate the health of the plant. The information obtained is particularly useful in conjunction with predictions of the optimal conditions for inspection and/or cleaning, since shutdowns are costly. For instance, Lister has developed one of the first mechanistic models that can predict flow-accelerated corrosion (FAC), a phenomenon that affects all steam-raising systems. Unchecked, FAC can rupture a plant’s piping and in the past has caused severe injuries and even fatalities.
Research such as Lister’s is important. It enables the design of devices capable of measuring corrosion in real time while a plant is online. “We actually have one such instrument about to be commissioned in a fossil-fuelled power station,” states Lister. With it, the plant’s operators will be kept up to date on the health of the plant’s piping, minimising the chance for catastrophic failures to occur.
Receiving the majority of its funding from the Canadian Government and the CANDU Owners Group (COG), UNB Nuclear has a relationship with the power industry that is one of commitment and reciprocation. It investigates issues and develops solutions that have real-world impacts on the power industry, while the industry in turn strongly supports UNB Nuclear and requests technical advice and assistance.
In 2004, FAC caused a feedwater line to burst at the Mihama-3 pressurised water reactor (PWR) in Japan, killing and injuring workers at the plant. Owing to UNB Nuclear’s international reputation, Lister went at the request of the Japanese to get to the bottom of the accident. The result: a fruitful collaboration lasting several years; ideas to minimise the risk of FAC-induced ruptures in the future; and innovations to be implemented in PWRs.
Enjoying a reputation far beyond the confines of the UNB campus, and with the support it receives from institutes such as CNER and groups like COG, Lister and UNB Nuclear can continue to delve into the effects of corrosion, helping to provide safer and more efficient plants for their operators and the environment.