Smile Politely

We need an honest conversation about the planned U of I micro-reactor

In May of 2021, the Institute for Sustainability, Energy, and Environment hosted a “critical conversation” about the future of nuclear power generation. The first session included a discussion of public trust in nuclear technology, and a recurring subject was how engineers and policy makers approach interactions with the public. Panelists noted that experts usually dismiss public skepticism as ignorance or an irrational fear of radiation (“radiophobia”). When responding to concerns, rather than acknowledge the nuances and inherent risks of the technology, they usually regurgitate simplistic descriptions of how plants work and cite the rare occurrence of large-scale accidents. The panel concluded that such tactics are unproductive: the public will remain distrustful until experts are forthright about the technology’s difficulties and directly address the public’s misgivings, many of which are reasonable. The technology will stagnate until this lesson is learned, but the debate surrounding the proposed micro-reactor on the University of Illinois campus is demonstrating that the University and federal regulators have not yet learned it.

I believe in the necessity and potential of nuclear power. Even as the Chernobyl and Fukushima Daiichi accidents and the ever-present possibility of weapons proliferation cast an ominous shadow, nuclear power generation extracts high amounts of energy from very small amounts of matter and releases nothing into the environment (when it operates as designed), making it hard to ignore as the climate situation continually worsens. I was excited when I learned of the planned research reactor, and I confess I fell into the “radiophobia trap” as I followed the heated debate in this publication. My background is in physics, so I found it difficult to maintain an objective eye when I read that the reactor would introduce radiation to our community (we’re exposed to radiation every time we step outdoors) and uranium-235 cannot be safely stored because it has a very long half-life (ignoring that this substance is not the main concern in radioactive waste, a long half-life means it emits radiation at a very low rate, and the alpha and beta particles it emits are easy to contain).

However, advocates never directly respond to the arguments made by skeptics: they restate the same vague claims that nuclear is the “safest” form of energy production and environmental harm is highly unlikely. Worse, upon examining records of public interactions with the university and the Nuclear Regulatory Commission (NRC) — the federal regulators responsible for licensing the reactor and overseeing its operation — I found that they blithely dismiss public concerns, usually with an assertion that they’re experts who know what they’re doing.

A telling exchange occurred in October when several members of the public, including retired U of I professor of engineering mechanics Bruce Hannon and then-co-director of Eco-Justice Collaborative Pamela Richart, sent a letter of opposition to the NRC. They argued that the planned location, Abbott Power Plant, makes derailed trains from the nearby Canadian National Railway tracks a significant safety concern. I could see their point until I learned that the reactor would be housed underground. However, the NRC’s response never addressed the signatories’ concern. Instead, they affirmed that they are responsible for “the Nation’s civilian use of radioactive materials to provide reasonable assurance of adequate protection of public health and safety, to promote the common defense and security, and consistent with environmental and other statutes. A potential UIUC nuclear reactor facility would fall within the NRC’s licensing and regulatory authority.” Loosely translated: “buzz off and leave it to the professionals.” Such blatant condescension with no effort to engage and earn trust can only lead to further distrust and hinder the project’s development. (Neither Professor Hannon nor Ms. Richart responded to my requests for comment.)

A computer rendering of the proposed MMR micro-reactor. A domed cylindrical tube on the left houses the nuclear fuel and supports control rods, which regulate the fission chain reaction. A metal pipe connects this structure to the heat exchange vessel on the right, allowing the gaseous helium coolant to transfer heat from the core to the outside environment to be used in energy production. Image from Ultra Safe Nuclear Corporation.

I encountered the same attitude when I began researching this piece. Watching the only recorded public session and reading the public materials released since, I found that both University representatives and employees of Ultra Safe Nuclear Corporation (USNC) — the private company contracted to construct and install the reactor — insist that the planned Micro Modular Reactor (MMR), a registered trademark of USNC — will be completely safe and foolproof since the radioactive core’s maximum temperature will be “limited by physics” and therefore cannot melt down. They also insist that the USNC-developed fuel, Fully Ceramic Microencapsulated (FCM®) particles, make proliferation impossible.

A computer rendering of an FCM TRISO fuel particle. A small grain the size of a chia seed containing a chemical compound of uranium is surrounded by a buffer layer to contain fission products. There are also layers of silicon carbide and other ceramics, which are designed to contain the contents of the TRISO particle at extreme temperatures. Image from Ultra Safe Nuclear Corporation. 

I come from a family of engineers: if something is claimed to be foolproof, their response is “give me a screwdriver and five minutes alone with it.” Needless to say, I found these claims dubious. I contacted someone from the Department of Nuclear, Plasma, and Radiological Engineering (NPRE) at U of I, hoping to hold a more nuanced discussion of the technology. In our first exchange, they outlined the same features discussed in public presentations and insisted that the design was absolutely safe. They did not mention any expected difficulties or motivate the planned safety features.

Trying to form a more balanced view, I found the report from the Union of Concerned Scientists referenced in the opinion piece authored by Hannon an excellent resource. It claims that designs like USNC’s are unlikely to be safer or more secure than current reactor technology. While I don’t support this conclusion, the report presented a comprehensive and accessible analysis of the technology and its shortcomings, and it references the technical reports containing the key data and observations. The main concern with a reactor like the MMR is its fuel design. (Warning: science content ahead!) It will be a high temperature gas reactor (HTGR), which is the most established “advanced reactor” technology. The idea predates the widely used light water design. They have been used to generate commercial power in the United States and Germany before, and research reactors have operated in China and Japan. They all use tristructural isotropic (TRISO) particles, in which a chemical compound of uranium is enclosed by multiple layers of cladding designed to contain the variety of byproducts produced as a fission chain reaction is sustained.

Safety depends on the integrity of these particles: they must be consistently manufactured so defects occur at a very low rate. Safety tests for these particles involve subjecting them to accident-scale temperatures and observing how well they contain fuel and byproducts. Recent tests conducted by the Electrical Power Research Institute suggest that TRISO particles with uranium dioxide cores may release substantial amounts of cesium-137 (the substance responsible for long-term environmental harm) at 1700 degrees Celsius, and the maximum design temperature for HTGRs is typically 1600 degrees Celsius. Moreover, between the US and Germany, only Germany has demonstrated a consistently high-quality TRISO manufacturing process.

When I approached the NPRE department representative with my findings, they maintained that the USNC design is completely safe, but they were more forthcoming with information about the design. It became clear that USNC’s innovation to address this concern is encapsulating the TRISO particles in silicon carbide (SiC) (the FCM design), which has been shown to retain its structure for hundreds of hours at 3600 degrees Celsius: well above the MMR “physics-limited” core temperature of 1100 degrees Celsius and the point where TRISO particles lose their integrity. This does inspire more confidence in the design. However, it was unclear if FCM fuel particles have undergone containment tests TRISO particles have, showing that they retain their contents at high temperatures in addition to their physical structure. One would hope the NRC considers this uncertainty as it decides on appropriate safety measures for this project, including reactor encasement and an emergency planning zone around the reactor.

It is also argued that FCM TRISO fuel is completely immune to proliferation, as it is impossible to extract enough the fuel and waste from assortment of chia seed-sized fuel pellets embedded in pellets of SiC. This is not entirely true: such a process was demonstrated on TRISO particles in the 1980s, but never fully developed because there was little interest in HTGRs at the time. In addition, the high temperatures at which the reactor would operate necessitates fuel with a greater fraction uranium-235 than what is found in commercial plants, making it more appealing to a proliferator. The Department of Energy maintains that such a process would be technically challenging (and beyond the capabilities of paramilitaries and terrorists), but it would not be impossible.

I included this detailed and technical discussion to illustrate that nuclear power generation, especially the newer “advanced” technology, is far from a no-brainer: like every other form of large-scale power generation, including so-called renewables, it has its drawbacks and difficulties. And this information is far from accessible: I had to immerse myself in the literature jargon of the field to engage an expert in a more nuanced discussion of the technology, a situation that cannot foster public confidence.

The USNC MMR will probably be safe to the surrounding area. The difficulties I encountered as I tried to gather enough information to form this conclusion, however, raises concerns about trust between experts and the public. Nuclear power should be considered in our energy overhaul for the high energy density of nuclear fuel, the technology’s cleanliness and safety, and its sixty-year track record as a reliable technology (unlike other options receiving more attention). While it certainly has difficulties and questions of practicality (I haven’t even touched on the issue of economic feasibility), we simply cannot afford to overlook it. But an honest assessment of its utility cannot occur until its advocates trust the public’s judgement enough to engage in candid discussions of its risks and benefits. Until this happens, the public will never fully support the technology and it will continue to stagnate.

Top image: A concept of the proposed MMR micro-reactor installed adjacent to Abbott Power Plant on the U of I campus. The MMR reactor and its encasement is about two stories high and is completely underground. If installed, it would generate both electricity and steam for heating. Image from Ultra Safe Nuclear Corporation.

More Articles