Factors such as war, climate change, technology, and public opinion are causing significant disruption and change in power generation. In this second of a two-part story, SCT’s Mario Pierobon identifies solutions for resilience development and possible operational drawbacks.
Stout et al. [i] identify that power sector resilience solutions often include a combination of resource or technological diversity, redundancy, decentralization, transparency, collaboration, flexibility, and foresight considerations. “A mix of solutions should be considered because no single intervention will address all potential vulnerabilities,” they state.
According to Gilbert & Bazilian [ii], recent innovations in advanced nuclear designs could make nuclear power a distributed energy solution for the first time. “As a dispatchable and resilient energy source, distributed nuclear could complement and accelerate the ongoing distributed energy revolution,” they say. “Although decarbonization imperatives are recognized, the role of distributed energy in addressing energy poverty and energy resilience is worth considering.”
In a 2018 paper by Juan A Vitali, Joseph G. Lamothe, Charles J. Toomey, Jr., Virgil O. Peoples, and Kerry A. Mccabe entitled ‘Study on the Use of Mobile Nuclear Power Plants for Ground Operations’[iii] it is proposed that, beyond revolutionizing commercial distributed energy, distributed nuclear might be a game changer for military applications. The US Army has investigated the use of mobile reactors to support ground operations, to reduce the risk of casualties from fuel convoys.
The US DOD has signed engineering contracts with mobile reactor vendors, observe Gilbert & Bazilian. “Mobile reactors could also serve as disaster response, with distributed nuclear replacing damaged power plants or bypassing damaged transmission lines,” they say.
Microreactors, or micro-modular reactors (μMRs), are a significant departure from conventional nuclear designs, according to Gilbert & Bazilian. “Derived from reactor designs originally investigated in the 1950s and 1960s, microreactor designs feature innovations inspired by the drawbacks of conventional designs,” they say. “While a conventional reactor is 1 GW-electric or larger and a small modular reactor (SMR) is 50–300 MW-electric, μMRs are usually 10 MW-electric or less. This is equivalent in power output to 1–5 wind turbines or a small solar farm. At the extreme end, the Department of Energy and NASA are developing Kilopower for space exploration, with a size as low as 1 kW electric.”
New fuel types, fission cycles, passive safety features, and other changes could enable ultra-small reactors to improve safety, report Gilbert & Bazilian. “Their small sizes decrease the heat to surface area of the reactor, allowing for passive cooling instead of the complex active cooling required for light-water reactors. By using new fuel forms and requiring vastly smaller amounts of uranium, off-site risks from a microreactor accident are limited. The designs used by small reactors are often termed as featuring inherent or passive safety,” they say.
For Gilbert & Bazilian, there are also potential operational disadvantages to downsizing nuclear power. The greater ratio of surface area to reactivity and reduced number of neutrons decreasing fuel efficiency means that activated materials may pose a greater issue. “Materials innovation and the use of HALEU could mitigate such challenges. More worryingly, the largest constraint for distributed nuclear remains one of the factors motivating their innovation: economics,” they say.
According to Gilbert & Bazilian, distributed energy addresses some main public policy challenges of the electric industry, as carbon-free sources of energy, they concur to climate mitigation. “If microreactors are to substantially contribute toward bolstering energy resilience and alleviating energy poverty, they have many barriers they must overcome. As with other energy technologies, future projects are expected to drive costs down as innovations and production economies of scale are achieved,” they affirm.
According to the Organisational Capability Working Group in a 2018 document ‘The UK Nuclear Industry Guide To: Organisational Capability and Resilience’ published on behalf of the Nuclear Industry Safety Directors’ Forum [iv], the industry faces key challenges in maintaining organisational capability and resilience. Among the challenges, the critical shortage of individuals with specific skills has driven competition between organisations in their quest to secure the personnel they need. “Nuclear facilities are generally located away from high density population areas so localisation is an issue,” the document says. “Recruitment is often hampered by long lead times due to security vetting. Delivery of goods, works and services may be outsourced to the supply chain so sustaining an effective intelligent customer capability is vital."
While operational drawbacks to downsizing nuclear power need to be considered and the nuclear and power sector has faced various challenges and issue, there are solutions – such as new fuel types, fission cycles, passive safety features, and other changes – that could improve the resilience of the nuclear and power sector.
[i] Sherry Stout, Nathan Lee, Sadie Cox, and James Elsworth, Jennifer Leisch, POWER SECTOR RESILIENCE PLANNING GUIDEBOOK - A Self-Guided Reference for Practitioners, 2018. https://www.nrel.gov/resilience-planning-roadmap/.
[ii] Alexander Q. Gilbert and Morgan D. Bazilian, Joule 4, 1839-1851, September 2020 Elsevier Inc.
[iii] Vitali, J.A., Lamothe, J.G., Toomey, C.J., Jr., Peoples, V.O., and Mccabe, K.A. (2018). Study on the Use of Mobile Nuclear Power Plants for Ground Operations (US Army). https://apps.dtic.mil/dtic/tr/fulltext/u2/ 1064604.pdf.
[iv] The Organisational Capability Working Group on behalf of the Nuclear Industry Safety Directors’ Forum (SDF) (September 2018), The UK Nuclear Industry Guide To: Organisational Capability and Resilience.