Very Small Nuclear Reactors

From the May 2015 print issue of Canadian Consulting Engineer, page 38
Canada is a top tier nuclear nation with more than 60 years of safe history in commercial nuclear power. Our CANDU reactors have produced more than 3,200 TWh of electricity during their years of operation without radiation health impacts. The industry is also credited with creating food and medical sterilization solutions, as well as medical diagnosis technologies.
While the Small Modular Reactor (SMR) industry in the U.S. experienced a series of setbacks in 2014 when some leading SMR developers scaled back their programs significantly, the recently held 3rd International Technical Meeting on Small Reactors in Ottawa was attended by more than 200 industry and government representatives. There, several companies such as Terrestrial Energy and StarCore Nuclear announced their plans to deploy very small reactors in Canada within the next decade.
These units are mostly generation IV nuclear reactors such as gas-cooled reactors, molten salt cooled reactors and lead-cooled fast reactors. They can be about the size of a small truck, with a power generating capacity of 5 MW(e) to 30 MW(e).
In Canada, the SMR industry is almost exclusively focused on niche market applications, such as providing electricity and heat to remote, off-grid communities and industrial facilities such as mines. Many of these remote communities and mining operations currently rely on diesel power plants for most of their electricity. Very small nuclear reactors are therefore expected to bring significant environmental and economic benefits as a low greenhouse gas (GHG) emission alternative for generating electricity.
Part of Canada’s climate change solution
The United Nations’ Intergovernmental Panel on Climate Change (IPCC) calculates that the world is on a trajectory to an increase in global mean temperature between 2.5°C and 7.8°C compared to pre-industrial levels by the end of the century. In order to meet the internationally agreed target of limiting the increase to less than 2°C to avoid the most catastrophic effects of climate change, the recent IPCC report calls for a profound transformation of energy systems by mid-century through a steep decline in carbon intensity in all sectors of the global economy. The report lists advanced nuclear power technology as one of the key technologies to achieve this target.
The mining industry in Canada is a significant contributor to the economy. It employs 418,000 workers and adds over $50 billion to Canada’s GDP. At the same time, mining’s GHG emissions and energy consumption account for 7.75% and 8.5% of our industrial GHG emissions and energy use. While the industry’s overall energy efficiency and GHG emissions in mining have improved in the past 20 years, the fossil fuel consumption for power generation is steadily growing at off-grid mining operations in Canada’s northern regions. In 2013, 259 million litres of petroleum fuel was consumed for power generation at northern off-grid mining operations, emitting 690,000 metric tons of CO2.
Canada is also home to 292 remote communities, with a total population of approximately 194,000 people, based on Natural Resources Canada estimates. Many of these communities are not connected to grids and are powered instead by local diesel generators. The total remote diesel generating capacity in these communities is 328 MW, consuming over 90 million litres of diesel annually, and emitting 240,000 metric tons of CO2 and a number of other air contaminants in the process.
Very small reactor benefits
Very small modular reactors have the potential to play an important role in the economic development of Canada’s remote northern communities and mining operations, while simultaneously leading to deep and transformative reductions in the greenhouse gas emissions of Canada’s North. On a life cycle basis, offsetting diesel production and combustion with nuclear power has the potential to reduce emissions by 690 gCO2 equivalent for each kWh generated. If applied to remote mines and communities, very small reactors could reduce CO2 emissions in Canada’s northern regions by up to 900,000 metric tonnes per year, which is equivalent to taking 190,000 cars off the road. The potential reduction represents about 1% of the CO2 reduction Canada needs to meet the Copenhagen Target.
Very small nuclear reactors also resolve the classic challenge of nuclear power projects: that is, cost overruns and schedule delays typically associated with mega projects. Because of their small physical size, the reactors and building components can be successfully modularized and pre-fabricated, then shipped to sites for assembly. This approach will bring construction schedule and cost certainty to a nuclear project.
Safety design features rely less
on human intervention
Nuclear power has one of the safest track records of any electricity source available based on nearly all quantitative safety measures. The industry expects small nuclear reactors to continue to improve the safety of nuclear power through additional intrinsic design safety features. The next generation of small reactors relies almost exclusively on inherently safe design features and less on human intervention and active components to assure a stable reactor state. Their smaller physical size, some about the size of a minivan, also allows the radiation to be securely contained for improved protection.
In the next decade, Canada could witness a few of these very small nuclear reactors providing stable base load electricity to our North while reducing our national GHG emissions. CCE
Brian Gihm, P.Eng. is with the nuclear technologies group of Hatch in Mississauga, Ontario.