SMALL MODULAR NUCLEAR REACTORS IN CANADA

BY STEVEN BROOKS PMP, ANDREW FRASER P ENG & FRED BERANEK PHD ENG, FLUOR CANADA LTD.

INTRODUCTION

The challenge of reducing Canada’s carbon emissions while simultaneously meeting projected growth in energy demand will require a fundamental shift in energy production. Nuclear and more specifically Small Modular Nuclear Reactors (SMNRs) are an attractive solution to help meet this future state (Canada Energy Regulator, 2020). Unlike wind and solar which suffer from intermittency concerns and the associated green-house gas (GHG) emissions associated with gas-fired generation, nuclear power can provide a steady baseload to the grid, is capable of load following improving overall grid stability and does not emit any GHGs (Office of Nuclear Energy, 2021). Unlike previous generations of nuclear power generation, the smaller footprint, scalable nature, and improved safety of SMNRs makes them attractive for niche energy markets, such as remote mines and communities, allowing for a much broader deployment than present, including implementation at oil sands mines and upgraders (Natural Resources Canada, 2021). WHAT IS AN SMNR?

SMNRs are essentially small versions of traditional nuclear facilities, physically requiring a smaller footprint and typically with a capacity no larger than 300 MWe per module (International Atomic Energy Agency, 2020). The modular nature of SMNRs means that components can be mass produced in factories and shipped to site for final assembly and installation, providing faster, cheaper, higher quality and more reliable construction than conventional nuclear facilities (International Atomic Energy Agency, 2020) (NuScale Power, 2021) (Natural Resources Canada, 2021). The small size of each SMNR module allows for energy production to be tailored to the requirements of any given application – whether in single or multiple module configuration, SMNR plants can be scaled (to varying degrees) to meet energy needs and optimize operating costs, and in certain cases modules can be added incrementally to grow with demand (NuScale Power, 2021) (International Atomic Energy Agency, 2021) (Office of Nuclear Energy, 2021).

Canada’s SMNR Action Plan envisions the key markets for SMNRs being on-grid power, heavy industry, and power for remote communities (Natural Resources Canada, 2021). Other potential SMNR applications include process heat, power for water desalination and hydrogen production, and powering remote jobsites such as oil refineries and mines (World Nuclear News, 2019).

“SMNR plants can be scaled... to meet energy needs and optimize operating costs.”

Figure 2: Three Streams for SMNR Development in Canada SMNR Action Plan

EVOLUTION OF NUCLEAR TECHNOLOGY

Nuclear power technologies are often categorized into “generations”, in which each generation represents a step change in reactor technology (World Nuclear Association, 2021). Generation I reactors are those developed in the 1950s and 1960s, all of which have been decommissioned as of 2015 (World Nuclear Association, 2021). Generation II reactors are those currently in operation across the globe (World Nuclear Association, 2021). Generation III reactors are considered “advanced” reactor technologies and are currently under construction or in the final stages of research and development (World Nuclear Association, 2021). Compared to Generation II, GenerationIII reactors have greater resilience against operational upsets, higher efficiency, longer operating life and less waste production (World Nuclear Association, 2021). Generation IV reactors are in early research and development or conceptual stages. Several SMNRs utilizing GenerationIII technology are anticipated to begin commercial operations in the late 2020s through mid-2030s (International Atomic Energy Agency, 2020). SMNRs utilizing Generation IV technologies are in development and will provide opportunities for higher temperature applications such as cogeneration and steam electrolysis when ready for commercial use, anticipated around 2040 (International Atomic Energy Agency, 2020). CANADA’S SMNR ACTION PLAN

Recognizing the opportunity for SMNRs in the Canadian market, the Canadian government launched Canada’s SMNR Action Plan in December 2020 (Natural Resources Canada, 2021). Developed in partnership with more than 100 organizations including municipalities, provincial governments, Indigenous communities, and industry leaders, the Action Plan establishes a set of plans and actions to realize the potential of SMNRs for Canada (Natural Resources Canada, 2021). Central to the Action Plan are three streams for SMNR development, intended to pave the way for bringing SMNRs online in Canada. These streams are: • Stream 1: Construct the first grid-scale SMNR of approximately 300 MWe capacity at Ontario Power Generation’s Darlington

Nuclear Generating Station site in Ontario by 2028, to be followed by units in Saskatchewan coming online starting in 2032 (Natural Resources Canada, 2021). • Stream 2: Deploy two advanced reactor designs at NB Power’s

Point Lepreau Nuclear Generating Station, with demonstration units complete by 2035 (Natural Resources Canada, 2021). • Stream 3: Develop and construct new micro SMNRs intended to replace diesel generators in remote communities and mines, bringing a 5 MWe demonstration unit into service at Chalk River

Laboratories in Ontario by 2026 (Natural Resources Canada, 2021).

SMNR TECHNOLOGIES

There are over 70 different SMNR technologies in development globally, which fall into four main technology types: • Water-cooled • High temperature gas-cooled • Liquid metal-cooled fast neutron spectrum • Molten-salt cooled All four designs contain the same key components: a nuclear core in which the nuclear reaction takes place, a cooling medium that transfers the radiated energy for steam production, a moderator to capture excess heat from the core and a heat exchanger that converts the nuclear energy into steam (which then is used directly in a process or turns a turbine for power production). Table 1 below provides a comparison of the key differences between the technologies. This article will focus on water-cooled and high temperature gascooled designs due to the utility in the oil sands market and design maturity (International Atomic Energy Agency, 2020), (Reyers, 2020). Water-cooled SMNR Technologies The water-cooled SMNR technology is the most like operating power and naval reactor designs today, and as a result has the lowest technological risk compared to the other SMNR designs (World Nuclear Association, 2021). Although light water reactor designs vary, this paper will depict a light water reactor design based on the NuScale technology. The core is situated at the bottom of the reactor (Figure 3) where water is heated as it passes over the core and into the steam generators. The reactor water (coolant) is used to heat a separate supply of water within tubes of the steam generator to generate steam. This steam can be used for power generation or thermal applications and the coolant returns to the core to repeat the process. Each reactor is placed within an

Figure 3: NuScale Reactor Pressure Vessel

TECHNOLOGY WATER-COOLED HIGH TEMPERATURE GAS-COOLED LIQUID METALCOOLED FAST NEUTRON SPECTRUM MOLTEN SALTCOOLED

Coolant

Light/Heavy Water Helium Various metals Various Salts

Moderator Electrical Output (MWe)

Light/Heavy Water Graphite Lead, Sodium or Helium Graphite or Heavy Water

30 to 380 250 to 633 10 to 300

Core Outlet Temperature (oC) 287 to 327

750 to 900 485 to 850

Table 1: SMNR Technologies Comparison (Source: International Atomic Energy Agency, 2020) 0.1 to 300

590 to 750

Figure 4: Example Water-Cooled SMNR Design

underwater pool filled with cold water to moderate the temperature of the reactors as illustrated in Figure 4. (NuScale, 2021). High Temperature Gas-Cooled SMNR Design High Temperature Gas-Cooled (HTGC) SMNRs utilize a similar design philosophy as water-cooled SMNR designs, but due to the Tri-Structural Isotropic Particle Fuel (TRISO) coated fuel, helium coolant and graphite moderator, HTGCs can produce significantly higher temperatures (750-900ᵒC) than the water-cooled design (International Atomic Energy Agency, 2020) (Gen IV International Forum, 2020). Helium is heated as it passes over the TRISO coated particle core, cooling the reactant. The helium then passes through the steam generation unit, generating steam from the water within the steam generation tubes. This steam can be used for power generation or thermal applications and the cooled helium returns the core to repeat the process. The reactors are surrounded by graphite to moderate the reactor temperature (Gen IV International Forum, 2020). A figure of the HTGC design can be found in Figure 5. SMNR DESIGN SAFETY

SMNRs deploy several common passive safety features independent of the coolant technology, each technology type does have technology specific safety features which overarchingly result in SMNRs being significantly safer than historical designs. The extensive use of passive safety features in SMNRs promise to make these plants highly robust, protecting both the general public and the owner/investor. The result being that the Emergency Planning Zones (EPZs) which extend many kilometers around current operating power reactors are projected to be significantly reduced which has a significant impact on the infrastructure required to deploy an SMNR. SMNRs should allow nuclear power to be used confidently for a broader range of customers and applications than currently possible (worldscientific.com).

Some of the inherent safety features of SMNRs are as follows (World Nuclear Association): • Small power and compact architecture and usually (at least for nuclear steam supply system and associated safety systems) employment of passive concepts. Therefore there is less reliance on active safety systems and additional pumps, as well as AC power for accident mitigation. • Lower power leading to reduction of the source term as well as smaller radioactive inventory in a reactor (smaller reactors). • Potential for sub-grade (underground or underwater) location of the reactor unit providing more protection from natural (e.g., seismic or tsunami according to the location) or man-made (e.g., aircraft impact) hazards. • Ability to remove reactor module or in-situ decommissioning at the end of the lifetime.

“SMNRs should allow nuclear power to be used confidently for a broader range of customers and applications than currently possible.” “SMNR technology can supply 19,000 MW of Canada’s power generation by 2050.”

“Hydrogen can be used to reduce carbon emissions in both the energy and transportation sectors.”

FUEL DISPOSAL

The fuel disposal from water-cooled SMNR designs is very similar to those of water-cooled reactors. Typically, waste treatment and temporary storage facilities are provided on the reactor site but this varies between countries and fuel disposal waste programs (International Atomic Energy Agency, 2020). For example, for the SMART program in Saudi Arabia, the liquid waste is placed through a demineralization package to reduce the amount of volume of solid waste. The gaseous radiation waste system performs a holdup to allow radioactive gases to decay and then releases the gas in a controlled manner (International Atomic Energy Agency, 2020). Further research is currently underway for on-site lifetime storage of dry waste (International Atomic Energy Agency, 2020). HTGC technology is more advantageous in its fuel disposal due to its higher temperatures resulting in 40 percent less waste per unit of energy produced. As such, overall spent fuel storage and disposal can be 50 times lower (per volume) than water-cooled SMNR designs, significantly reducing the complexity and cost of the storage and disposal facility (International Atomic Energy Agency, 2020). SMNR APPLICATION IN CANADA

Estimates show that SMNR technology can supply 19,000 MW of Canada’s power generation by 2050 (EnviroEconomics; Navius Research). It is anticipated that SMNR power will have significant benefits in grid base power along with hydrogen production from electrolysis or steam methane (MIT, 2018). With the generation of hydrogen and steam, SMNR technology can also be utilized for oil sands in-situ extraction and upgrading. These SMNR technologies can be operated by any group with the adequate licensing and training, including oil sands producers.

Base-Grid Power Generation: By sending the steam produced in the steam generator to a steam turbine, SMNR technology generates power that can be delivered to the grid. With its modular design and grid inertia, SMNRs can be installed in remote parts of Alberta, away from existing infrastructure and fuel sources, enabling high quality power throughout Alberta and at remote worksites.

Hydrogen Production: Hydrogen can be used to reduce carbon emissions in both the energy and transportation sectors; either as an energy storage medium or a fuel for hydrogen fuel-cell vehicles, trains, ships, and airplanes (Reyers, 2020). There are two main types of hydrogen production: green hydrogen through electrolysis from clean or renewable energy sources and grey hydrogen from steam methane reforming (blue hydrogen if it is in conjunction with carbon capture and storage) (Giovannini, 2021). Both water-cooled and HTGC SMNR technologies can be used for green hydrogen production. An oil sands producer would be able to supply enough hydrogen to their entire vehicle fleet with one SMNR. Because of the higher temperature, HTGC SMNRs can also be used for grey/blue hydrogen production (International Atomic Energy Agency, 2021).

Figure 6: Anticipated Timeline for Commercial Operation of Select SMNR Technologies

Oil Sands Facility: Utilization of steam and heating medium is vital in oil sands extraction and upgrading. It is possible to use both water-cooled and high temperature gas-cooled SMNR designs as both can achieve the high temperature steam requirements for in situ oil sands extraction (Reyers, 2020). High temperature gas-cooled SMNR designs, with their higher outlet temperature, can provide high temperatures for various processes within the upgrader along with in situ steam. With the additional ability to provide grey or blue hydrogen, the high temperature gas-cooling SMNR designs provide significant opportunities for an oil sands facility. With adequate standards and trained employees, oil sands operators could operate a SMNR technology at their oil sands mine / upgrader. Detailed evaluation of both the technology and licensor are required to ensure the specific vendor meets the technological application and government regulations. DEPLOYMENT TIMELINE

As of Q3 2021, China’s CNP-300 and Russia’s floating Akademik Lomonosov are the sole SMNR technologies currently in operation (World Nuclear News, 2019). Demonstration units for both China’s Linglong One SMNR and Russia’s BREST-OD-300 SMNR began construction in Q2 2021 (China National Nuclear Corporation, 2021) (Rosatom, 2021). Further SMNR technologies currently in development are anticipated to begin commercial operation in the late 2020s to mid2030s, including NuScale, GE Hitachi and KAERI (International Atomic Energy Agency, 2020). Generation IV SMNR technologies, including those from TerraPower, ARC Nuclear Canada and Terrestrial Energy among others, will bring higher temperature production capabilities when available for commercial use in the mid-2030s to 2040s (International Atomic Energy Agency, 2020). GLOSSARY OF TERMS & ACRONYMS

CNSC: Canadian Nuclear Safety Commission HTGC: High Temperature Gas Cooled IAEA: International Atomic Energy Agency SMART: System-integrated Modular Advanced Reactor SMNR: Small Modular Nuclear Reactor TRISO: Tri-Structural Isotropic particle fuel REFERENCES

Comprehensive references for this article are located online.

Steven Brooks, PMP

Steven Brooks, PMP, is a project controls specialist at Fluor. He has a Bachelor of Science (Engineering Chemistry) from Queen’s University. Steven has over eight years of experience in project controls and project management, including debottlenecking of an oil sands refinery and construction of nuclear waste storage facilities. Steven has recently been engaged in the review and analysis of Canadian and Global SMNR applications and opportunities. Steven can be reached at steven.brooks@fluor.com.

Andrew Fraser, P. Eng Alberta Andrew Fraser, P.Eng Alberta, is a process engineer at Fluor. He has a Bachelor of Chemical Engineering from Queen’s University and a Master of Chemical and Petroleum from the University of Calgary. During his time at Fluor, he has worked on a variety of projects in the Energy Sector; from site experience at a refinery, utilities at an oil sands upgrader, to designing a petrochemical facility. Most recently, Andrew has been actively reviewing Canadian and Global SMNR application as part of a study for a Canadian energy producer. Andrew can be reached at andrew.fraser@fluor.com

Fred Beranek, PhD Eng

Fred Beranek received his PhD in Nuclear Engineering in 1978 at the University of Wisconsin – Madison. Subsequently, he started his career that has now spanned over 43 years within the governmental nuclear industry, in the US, UK and Canada, primarily in the areas of Environmental, Safety, Health and Quality Assurance (ESH&QA), project management, engineering management, laboratory R&D, nuclear safety and management activities. 32 cHOA JOUrNAL — OctOber 2021

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