Westinghouse targets fast licensing, tiny footprint for new SMR
Westinghouse’s eVinci heat pipe reactor design will provide cost and siting advantages and high technology readiness should accelerate design licensing approval, project directors told Nuclear Energy Insider.
The U.S. Department of Energy (DOE) recently allocated Westinghouse $12.9 million of DOE funding to develop its eVinci micro reactor design based on sodium heat pipe technology.
Westinghouse aims to design, test, manufacture and site a demonstration unit by 2022 and will provide $15.7 million to the project. The company is currently developing an electrical demonstration unit and plans to demonstrate manufacturing capability by 2020.
The advanced heat pipe design will simplify the plant structure and reduce the number of moving parts, creating significant cost and safety benefits, Yasir Arafat, Principal Engineer, Advanced Reactor Development at Westinghouse, told Nuclear Energy Insider.
The compact design will also have a small boundary footprint, opening up new siting opportunities closer to industrial facilities and population centers.
Westinghouse is communicating with U.S. and Canadian nuclear regulators and aims to license the design for commercial deployment by 2025, pending a successful testing phase.
This would position Westinghouse near the forefront of micro reactor deployment.
Canada aims to build at least one demonstration advanced reactor plant by 2026, at a Canadian Nuclear Laboratories (CNL) site. In February, high-temperature gas reactor developer Global First Power became the first developer to advance to the third stage of CNL’s design selection process which involves non-exclusive negotiations on land arrangements, project risk management, and contractual terms.
Canada's key SMR markets
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Source: 'A Canadian Roadmap for Small Modular Reactors' (NRCan, November 2018).
According to Westinghouse, the small size and high technology readiness of the eVinci heat pipe reactor design should accelerate the licensing process.
“The fundamental technology that differentiates it from other nuclear reactor designs is the removal of heat from the core (fuel) via heat pipes,” Ryan Blinn, Advanced Reactor Program Manager, Westinghouse, said.
“This technology (heat pipes) has been used for decades and was demonstrated by Los Alamos National Laboratory in the [NASA] KiloPower nuclear test,” he said.
The eVinci reactor is designed to provide 200 kWe to 5 MWe of combined heat and power.
The design is built around a solid monolith with channels for both heat pipes and fuel pellets. Each fuel pin in the core is adjacent to three heat pipes, giving an overall one-to-two heat pipe-to-fuel ratio. The heat pipes remove heat from the core using a primary heat exchanger.
According to Westinghouse, the heat pipe design eliminates the need for a reactor coolant pump and associated auxiliary systems, reducing plant size and component costs.
A 2 MWe reference design can be packaged and transported within standard 20-foot shipping containers.
The plant is designed to require less than 1 acre at the site boundary and the emergency planning zone would be limited to within the unit boundary, Blinn said.
The entire plant can be built and fuelled in factory, and the heat pipe structures can be manufactured along assembly lines to maximize serial production gains.
The heat pipes offer 70 times more linear thermal conductivity than a solid copper rod, Arafat told Nuclear Energy Insider.
“The ability of heat pipes to efficiently remove the heat enables the cost competitiveness of the micro reactor,” he said.
Interest in heat pipe reactor technology is on the rise. Last month, light water reactor SMR developer NuScale announced it was also developing heat pipe reactor technology to expand its SMR design portfolio.
NuScale is developing a 1 to 10 MW heat pipe reactor and a 10 to 50 MW micro NuScale power module to access new markets, Tom Mundy, Chief Commercial Officer of NuScale Power, told the SMR and Advanced Reactor Summit in Atlanta on April 2.
The Westinghouse micro reactor can provide process heat of up to 600 degrees C. Heating applications are seen as a key selling point for SMRs, particularly as companies and governments strive to meet carbon reduction targets. Storage efficiency, power-heat switching capability and infrastructure readiness will all influence the competitiveness of these plants.
SMR developers are also looking to maximize load following capabilities in response to rising renewable energy capacity.
The heat pipes within the eVinci design enable passive core heat extraction and inherent power regulation, allowing load following capabilities and autonomous operation and shutdown.
The design also encapsulates fuel to reduce proliferation risk and avoids safety risks associated with faults in primary coolant flow systems.
The plant can operate for 10 years without refuelling but shorter refuel cycles of around five years “greatly improve the economics,” Blinn said.
“There is interest in having a unit run for a very long period of time without refueling, especially in remote locations. However, financing all of the fuel costs for the unit upfront greatly impacts the economics (levelized cost of energy),” he said.
Refueling would be performed in factory alongside the refurbishment of non-fuel parts.
In February 2018, Westinghouse applied to Canada’s pre-licensing vendor design review (VDR) process. The company applied to enter phase 1 and phase 2 of the VDR process simultaneously and is currently awaiting a response from the CNSC.
Westinghouse is yet to formally enter the U.S. licensing process for non-light water reactor designs.
Many advanced reactor developers are targeting first plants in Canada, where there are numerous deployment opportunities and the licensing process is considered less prescriptive than in the US.
“Westinghouse is coordinating with both the U.S. Nuclear Regulatory Commission (NRC) and the Canadian CNSC,” Blinn said.
Westinghouse will select the licensing route “based on the leading commercial customer interest,” he said.
Canada's current SMR pre-licensing reviews
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Source: Canadian Nuclear Safety Commission (CNSC), May 2019.
Licensing is a major challenge for advanced reactor developers as they must provide in-depth performance and safety data for first of a kind technologies.
Westinghouse plans to leverage existing data on heat pipe technology, from nuclear industry and other sectors, to expedite the licensing process.
"Liquid metal heat pipe technology is mature and robust with a large experimental test database to support implementation of the technology into commercial nuclear applications," the company said in a statement.
Westinghouse can also clearly benefit from significant resources and global experience in licensing earlier reactor designs.
"Westinghouse plans to leverage the lessons learned and experiences from the AP1000 plant licensing process and utilize that for the licensing phase of the eVinci micro reactor," Blinn noted.
According to Westinghouse, remote communities, military and mining sites are potential early markets for micro-reactors.
"The landscape for micro reactors continues to evolve,” Blinn said.
“In the past few years…remote communities supported by governments appeared to have the most interest and support for early adoption. However, in recent months, there has been a lot of momentum and interest building relative to remote mining," he said.
By Neil Ford