Certifying Nuclear Reactors: How The NRC Approved Its First Small Modular Reactor Design

The US Nuclear Regulatory Commission (NRC) recently announced that it had approved certification of NuScale’s SMR (small modular reactor) design, completing its Phase 6 review of NuScale’s Design Certification Application (DCA). What this means is that SMRs using NuScale’s reactor design can legally be constructed within the US as soon as the rulemaking process completes. An NRC certification would also mean that certification of the design in other countries should pose no significant hurdles.

A question that remains unanswered at this point for most is how this certification process at the NRC actually works. Are there departments full of engineers at the NRC who have been twiddling their thumbs for the past decades while the US nuclear industry has been languishing? What was in the literally millions of documents that NuScale had to send to the NRC as part of the certification process, and what exactly are these six phases?

Stay tuned for a crash course in nuclear reactor certification, after a bit of SMR history.

From Soviet Russia With Love

SMR-powered Sevmorput container ship in 2007.

For as much fanfare the small modular reactor (SMR) concept is getting these days, it is not a new concept by any means. For example, the reactors which power military vessels and submarines for the US, France, China, and Russia are SMRs. They’re largely self-contained units, which in the case of naval reactors can use either low-enriched or high-enriched (mostly US) uranium fuel, thermal output of less than 100 MW to a few hundred MW and a fuel life of around 10-30 years.

The only nation to currently use SMRs in commercial service is Russia, whose first SMR (the EGP-6) is essentially a scaled-down version of the RBMK reactor (made popular by Chernobyl’s #4 reactor), with 12 MW electrical power. Four of these reactors were built in the 1970s at the Bilibino Nuclear Power Plant, of which three are still operational today. These reactors are scheduled to be replaced by the KLT-40S SMR onboard the Akademik Lomonosov, which generates about 52 MW of electrical power.

The world’s only nuclear-powered container ship, the Sevmorput, utilizes the KLT-40 SMR, as do Russian icebreakers like the Taymyr. The company behind the KLT-40 (OKBM Afrikantov) has recently seen its successor RITM-200 SMR go into commercial service first with the LK-60Ya series icebreakers. These SMRs are designed to be refueled every six to ten years, with 55 MW electrical output power (55 MWe) for the RITM-200, or 120 MWe in the case of the larger RITM-400 (315 MW thermal output power, or MWth).

Other nations have not had nearly as much experience with SMRs as Russia, although Argentina is in the final stages of construction with its 25 MWe CAREM SMR project, and China is constructing its first SMR in the form of the 125 MWe ACP100. Nations such as South Korea have licensed designs that still require an interested commercial party to construct them. Toshiba’s 4S SMR was scheduled for installation in Alaska until the project was cancelled in 2011.

Clearly, licensing an SMR has a lot of background history to reference when considering NuScale’s new SMR design.

Safety Determinations

Among the NRC‘s tasks since its creation in 1974 has been the regulating of commercial nuclear power plants. This includes certifying that a new reactor design is safe for construction and operation within the US. Such a design certification is valid for 15 years, with renewal required after that every 10 to 15 years.

In the NRC’s ‘Backgrounder on New Nuclear Plant Designs‘ some of the things which they are looking for in new designs are covered. These include designs that improve on existing designs by being simpler and using forces like gravity to their advantage. This is for example reflected in the Generation III+ reactor designs compared to the Generation II designs, where the former almost invariably uses gravity and thermal properties of the cooling loops for passive cooling.

Taking a look at the review schedule page for the NuScale SMR, we can see the various stages that the licensing process went through. After the initial application and the acceptance review, the safety review begins in earnest. For NuScale’s design, Phase 1 began in April of 2018 with the preliminary Safety Evaluation Report (SER). This was followed by Phase 2, which created a new SER based on newly provided information after questions raised during Phase 1. After phases 3-6, this culminated in the final SER (FSER), which was accompanied by this letter to NuScale from Anna H. Bradford, the director of NRC’s Division of New and Renewed Licenses.

In the NRC’s news release on the FSER completion, it was noted that they met the agency’s 42-month technical review schedule and that the next step will be the rulemaking process in which the design will be formally certified. This certificate would “[allow] a utility to reference the design when applying for a combined license to build and operate a nuclear power plant”.

It’s An Engineering Thing

An overview of the NRC’s tasks and responsibilities.

The FSER documents are all publicly available on the NRC website. Chapter 1 (‘Introduction and General Discussion’) covers a broad overview of the entire process that the NuScale application went through. It covers the graded review approach, with different aspects of the design being considered using one of four different norms depending on whether they are safety-related and risk significant (A1) down to not safety-related and not risk significant (B2).

Since LWRs (Light Water Reactors) and SMRs are not a new thing as we saw earlier, they were able to use a standard reference (NUREG-0800, “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition”, specifically the SMR section). During interviews and meetings with NuScale engineers, the NRC staff took pains to get answers on all pertinent points, including whether failures on a B2 level item might have implications for a B1 or A-level item.

For each item, NuScale’s claims are examined, using experimental data (provided by NuScale’s engineers) to back up said claims. NuScale’s NIST-1 (NuScale Integral System Test Facility) is an experimental facility created by NuScale to examine the conditions in the reactor vessel and elsewhere that would occur in a working reactor system. Over two million pages of data and other information were prepared by NuScale and send to the NRC to aid in the certification process.

Involving the Industry and Academia

Having a massive staff on hand at the NRC who would only handle NRC-related tasks would be rather nuts, ergo the NRC has a fairly small staff, with a lot of contracts being awarded to commercial firms, non-profit organizations, and universities each year, covering everything from technical assistance to research. This in addition to the research programs that are sponsored by the NRC, in order to enhance the agency’s understanding of any relevant topics, covering topics like materials science, safety approaches, and the exact properties of new technologies and materials.

This information is then captured in regulation documents (NUREGs), which are subsequently used by the licensing and re-licensing of nuclear reactors. The NRC maintains a large library section on their website which includes NUREGs. All of which serves to makes the entire nuclear power regulation process as transparent as possible to the public, while also providing valuable information on the technologies, materials, and processes involved.

Learning Lessons

The carbon footprint of energy sources compared.

One of the NRC’s tasks is of course also to respond to current events, such as when in 2011 a massive tsunami and earthquake hit Japan’s East coast, leading to the accidents at the Fukushima Dai-ichi nuclear plant. Although the Japanese Diet (the commission that investigated the event) concluded that it was a human-made accident, causing the company in charge (TEPCO) to be nationalized, the NRC took steps to ensure that any lessons that could be learned from this accident would be applied to all US reactors, whether existing or yet to be built.

Along with the nationalization of TEPCO, Japan also reformed its old and inadequate nuclear regulatory commission into a new agency, the Nuclear Regulation Authority (NRA). This agency is styled more after the NRC’s structure, ensuring that it can be as impartial and science-driven as possible.

Although commercial nuclear power is the safest form of electricity production, with a very low carbon footprint, its image has been heavily tarnished by anti-nuclear sentiment. This significantly ups the ante when start-up companies like NuScale seek to use SMRs to massively decarbonize not only the electrical grid, but also replace other carbon-intensive sources such as in heating or hydrogen production. The NRC’s transparency is helpful there, but few will take the time to read through their comprehensive library or otherwise educate themselves.

NuScale’s FAQ reflects a certain level of frustration with ‘the usual questions’ as well. Within the commercial nuclear industry, but also in related fields there exists the wish that the focus could be on the science and technology, instead of on incorrect and/or outdated information. The already addressed safety aspect is one item there, as is the incorrect use of the term ‘nuclear waste’ for spent LWR fuel, which really is just fuel for fast neutron reactors.

The NRC, but also e.g. Canada’s equivalent (CNSC) are testament to a well-regulated industry, where scientists, engineers and countless others work together to create a better, cleaner world for the benefit of everyone.

38 thoughts on “Certifying Nuclear Reactors: How The NRC Approved Its First Small Modular Reactor Design

  1. Before I die I know 1 of 2 things will happen.

    1. The world over will embrace nuclear energy averting serious enviormental damage and making things like electric cars actually help reduce carbon emissions.
    2. Serious enviormental damage will be done as well drive around in our coal powered electric cars.

    1. Coal power is in decline (at least in developed nations) as it continues to decrease in profitability compared to alternatives. With or without society embracing it, business is slowly moving to green energy just to maximize profits and then spin it as social responsibility.

  2. We are getting one on campus:

    There is kind of a long story about this that has played out over the last 10 years or so… The gist of it:

    The university of Illinois had a deal to buy low cost power from Illinois Power.
    Ameren purchased Illinois power, scrapped the deal.
    Imagine the power bill to just to run [Blue Waters] at the National Center for Supercomputing Applications.

    It was now more cost effective to bring the 1940’s campus coal power plant [Abbott] back on line (it was updated to run on natural gas, and/or fuel oil), and formed [Illini Power], which supplies 70-75% of the energy demand for the campus.
    This made Ameren very unhappy.

    Ameren lobbied the state government to mandate a percentage of all power companies to have renewable/green power, which they easily got passed.

    Ameren then lobbied the state government to include the nuclear power plants as renewable/green power (and also pay them the same subsidies they gave solar and wind, since the 80’s), by threating to shut down the nuclear power plants and lay everyone off… it also reluctantly passed.

    To meet the new renewable/green power requirements the university then proposed a large wind farm.
    The “community” convinced the Champaign county board to ban wind turbines as “eye sores”.

    The University then proposed and was able to build two solar farms…
    Before the “community” convinced the Champaign county board to banned large solar farms.

    It will be interesting to see how Ameren, er I mean the “community” convinces Champaign county board not to allow a nuclear power plant in city limits…
    Especially since Teaching Research Isotope General Atomic [TRIGA Mark II] fission reactor ran from 1960 – 1998.
    And they have a fusion reactor, Hybrid Illinois Device for Research and Applications [HIDRA], currently running since 2014.

    Typical Illinois Politics. ;D

  3. I am pro-nuclear because they could be humanity’s last hope for a reliable power grid where solar and wind must become the principle sources of energy. That said, the ‘total effect’ of nuclear energy is not more safe than compared to natural gas and solar and nuclear power is not always sutiable for peaking.

    The process for field tests per IEEE603 and the fault conditions per IEEE379 rely on “over-engineered” solutions and profoundly competent personnel. Humans are marginally competent at anything more complex than applying peanut butter to bread. Simulation of single-fault conditions are contrived and staged. The most reliable parts of reactors appear to be the electronics for control and monitoring systems.

    Solar panels/junctions/inverters and wind turbines/blades/power xfr and nuclear fuel production/used fuel handling all seem to have a decreasing ‘carbon footprint’ (whatever that really means), but they are not decreasing enough and are not decreasing in a consistent manner. And the NERC’s (mostly the western division) poor handling of power distribution/poor control of power availability manipulation by utilities indicates that no matter how reliable power production may become, problems with power distribution and end-user costs will increase.

      1. You can’t look at safety simply as the consequence of the worst-case failure. That’s what gets people thinking that nuclear is less safe—because they can think of greater harm, and this is a natural emotional response.

        Let me draw a different comparison for illustration:
        1. How many people have died in the US from nuclear accidents in the past five decades or more?
        2. How many people die daily in the US on average from drunk driving?

        Sure, it’s a contrived comparison, and they’re not even remotely related, but if you want to talk about actual risk of life and limb, just driving down the road after midnight on Friday night is probably a lot more dangerous than living near a nuclear power plant. Or for that matter, you’re probably more likely to have your house burn down on you than have it contaminated in a nuclear accident.

        I’ll also point out that just because something has engineered safety features (like circuit breakers in your house that prevent fires) or requires an operator to operate it safely (power tools, cars, soldering irons…), does not mean that it is less safe.

        1. It’s about personal risk management. People can choose to not drive drunk, so a major part of the risk of drunk driving is other people’s problem.

          Meanwhile, nuclear fallout is something that you cannot control and the fear/propaganda is that a nuclear accident two states over can still rain cancer down on you if the winds turn the wrong way. Plus, there’s a half-century of misinformation on the subject, such as the “hot particle” theory that states, if you inhale one radioactive particle you’re guaranteed cancer – it’s only a matter of time.

        1. Today is the bi-monthly barbecue of the Society For the Preservation of the Drunk and Disorderly. An august organization of retired and semi-retired engineers and physical scientists, and a singular token botanist.

          I read this comment and the Society’s sentiment is “its existence supports Brian’s supposition…”

          We will continue to eat (and drink). I shall advise upon any further insights; but this assumes that I will would be able to operate the keyboard.

    1. I have been pro-LFTR in the past, but lately I’ve read (maybe it was anti-LFTR propaganda) that they are not the “set and forget shipping container power plants” they were promoted to be a few years ago.
      While the initial LFTR at Oak Ridge worked, the experiment was shut down before any long term development occurred (which is what we need before real world deployment).

  4. >”the incorrect use of the term ‘nuclear waste’ for spent LWR fuel, which really is just fuel for fast neutron reactors.”
    While I agree with this, it’s only applicable if someone is willing to spend the money to build and run FNR’s. If nobody is willing to do that, it’s nuclear waste.

  5. While it can be discussed whether or not nuclear energy should play a role in the modern energy mix, I think the end of this article is not at all neutral in terms of nuclear energy. I appreciated the technical main part, but I’d prefer it if the authors opinion wasn’t mixed into the conclusion.

    For example, a source clearly states that any renewable energy is safer than nuclear, the author incorrectly quotes the source with “nuclear is the safest form of energy”, completely ignoring renewable energy although several countries, for example Germany, have reached significant levels of renewable energy production. [https://energy-charts.info/charts/renewable_share/chart.htm?l=en&c=DE&share=ren_share&partsum=0]. Also, comparing death tolls of such different hazards as pollution and radiation is in my opinion a tricky one; of course, most of the time nothing will happen, but the remaining risk cannot be zero and the damage is enormous.

    Also, many argue that nuclear energy has and never will be profitable without subsidies, a point usually made against renewable energy:
    [https://smartassets.one/nuclear-energy-is-never-profitable-new-study-slams-nuclear-power-business-case/ ; https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjNtfj2xZXsAhXSDmMBHUt1DKUQFjAFegQIBRAC&url=https%3A%2F%2Fwww.diw.de%2Fdocuments%2Fpublikationen%2F73%2Fdiw_01.c.670581.de%2Fdwr-19-30-1.pdf&usg=AOvVaw1HGWc4gxEn0za5_exrL-Eo%5D . Wind energy is already cheaper than nuclear, and solar PV is on the way to be too. The first large-scale PV plants are being built completely subsidy-free [https://www.baywa-re.com/en/news/details/baywa-re-builds-polands-biggest-subsidy-free-solar-park/].
    If someone wants to argue the decade-old point of “but what if there is no wind and no sun?”, there are solutions to this problem too. [https://www.researchgate.net/publication/259537683_Balancing_Fluctuating_Renewable_Energy_Generation_Using_Cogeneration_and_Heat_Pump_Systems, https://www.ise.fraunhofer.de/en/business-areas/power-electronics-grids-and-smart-systems/energy-system-analysis/energy-system-models-at-fraunhofer-ise/remod.html%5D

    Many countries have made significant renewable installations and are on a path towards 100% renewable energy in the electric grid. The solutions are there, there might be no need for nuclear power in the future.

    1. While we all have heard of the bird deaths caused by windmills, I recently read of other man made structures that cause more bird deaths. IIRC, the number of birds that die striking windows, for example.

      1. It turns out that burying things isn’t all that permanent. Maybe dump it in the subduction zone. But until it actually gets sucked in it is easy picking for anyone willing to build an ROV.

      2. You could use that approach for nearly every problem (toxic waste, anyone?). It’s simply and plain unresponsible to cash the money now and leave the big mess to clean up for later. Would you build your house in that way with a big pile of waste under the floor for your children?

  6. Rather scary stats in the bargraph on 2 and 3 % impact of gas leakage. It’s much more effective as a greenhouse gas. Natural gas was first exploited in eastern Indiana and west Ohio around the last turn of the century. It is estimated that 90% leaked into the atmosphere. They had flamboyant displays and it was mostly gone in less than a generation. It’s effect will keep on giving for a century or two more. In an age of coal power they jump-started the thermal runaway.

  7. Not mentioned in the piece is GE Hitachi’s BWRX-300 SMR, which is next in line to get to the same stage as NuScales SMR. It is based on the already certified GE Hitachi’s ESBWR and confidence is high that getting through certification for the BWRX-300 is as straightforward as it could possibly be.

    GE H have a customer in Estonia, Fermi Energia, who just 2 days ago said: “…We are deepening our cooperation and the coming weeks should bring interesting news about the BWRX-300 small reactor…”. There’s every chance an operational BWRX-300 will be generating low-carbon, 24/7/365 electricity for Estonian citizens in 2027/8.

    Maybe a year after that, Polish billionaire, Michal Solowow, will have the second one operational to supply electricity to his energy-intensive empire of tyre-producing factories. Pure commercial finance without Government money required in any shape or form.

    And the reason for this is the BWRX-300 is the simplest and most cost-effective design of Nuclear Power Plant (NPP) there has ever been or there is ever likely to be. It is a glorified kettle, using RPV components and BOP components that exist and have been used many times before. It uses 50% less concrete per MW than the ESBWR and can be built in just 2 years.

    This levels the playing field with Wind And Solar Plants (WASPs) and the cost-of-capital that has drained ‘low-carbon’ commercial investment out of nuclear power and into WASPs is utterly negated. In the UK, £1.00 invested in onshore wind would ‘earn’ £0.70, whereas £1.00 invested in a BWRX-300 would ‘earn’ £5.02 (7.2X more).

    By 2030, all of those pseudo-green fund managers will be clawing at one another’s throats to get their pots out of WASPs and into BWRX-300 NPPs. 2030 could signal the beginning of the end of the subsidy-driven decades of commercial investment in WASPs. An end to decades of wasted material and resources, waste mountains, scenic desecration, ecosystem destruction and species wipe-out wrought by ridiculous WASP technologies.

    The microscopic environmental impact of advanced NPPs beckons, which is exactly what today’s young people so desperately need, to mitigate climate change to the maximum and allay their fears in what the future holds for them.

    Search for: fund-managers-with-320-million-to.html

    1. Sure, leave the waste problem for someone else to solve (and pay for). The companies extract their profits now, and the legislators get elected on “cheap energy”. None of them want to save up for the inevitable cleanup and centuries of storage.

  8. This is not really an engineering update piece, but propaganda for industry. The unsupported statement of the author that the NRC is an example of safety in nuclear regulation nearly caused me to fall out of my chair laughing. Small nukes are not a magic bullet curing the problem of biospheric destruction secondary to our insatiable demand for more electricity. The lengthy list of unmentioned dangers separate from the on-site operation of the facilities demands intensive, thorough journalism.

  9. The ability of large corporations to corrupt the decision making process (eg did Ameren do that?) is the basis for my opposition to Nuclear power.

    It can be safe, but it needs cast iron guarantees that procedures and failsafes are adequate. When a large corporation gets involved, there’s no way they’ll observe anything that affects their short-term profit goals.

    Otherwise nuclear makes sense.

  10. If this was a Amazon review for the new NuScale NS2000, I’d report it as fake, and try to find the marketing material of the manufacturer where the parts where copied from.

    Sure, Maya may be enthusiastic about the upsides of nuclear energy. The article also goes a long way in explaining the certification process. But the closer it come to the end, the more it leans towards a strong smell of let’s say at least close friendliness towards the nuclear industry, with the newest actor NuScale.

    A few arguments where left out or just touched barely. One aspect that was not discussed transparently (which is important, isn’t it?) is total lifetime costs. Unfortunately not all radioactive material that is activated in a reactor can be thrown into a fast neutron reactor like in a organic waste bin. Lots of material, both volumetric and in weight, has to be stored somewhere for decades, centuries and even longer. This costs incredible amounts of money, with no viable perspective of a permanent solution that is available soon. The current operators are not charged for future costs, but allowed to cash the revenues and withdraw after some decades. Just compare the costs for cleanup of the the German Asse mine repository (2-6 billion Euro) – this does not even include the costs for storage of the removed material somewhere else.

    Another aspect that is often overlooked is the handling of Design Basis Events (DBE). There is a certain level of events that are considered just beyond the design, maybe very unlikely, but definitely uncontrollable. With a hydroelectric plant this would maybe be a ruptured damm and subsequent flooding, with a wind turbine it’s a collapsing tower or lost blade. With a nuclear reactor it’s wide stretches of polluted land and sea, cleanup personell and population with high elevated cancer incidence (and deaths). Sunken nuclear ships and submarines are a liability for centuries and more that we can not even fathom yet. Note that Design Basis Events are considered with a perfect response of personal. At least Three Mile Island and Chernobyl where caused by neglected safety procedures, not even external events.

    The governments are interested in cheap energy now, and in a business that is that costly and at the same time promises huge revenues during operation, money inevitably influences decisions.

    If I where to spend millions and billions in getting an approval of a new reactor design and build one, I’d naturally spend a small fraction of that money for positive media feedback.

  11. I can recommend “Atomic Accidents: A History of Nuclear Meltdowns and Disasters: From the Ozark Mountains to Fukushima” by James Mahaffey (ISBN: 978-1605984926) if interested in some history in this area. I got this as an eBook in a Humble Bundle awhile ago and have coincidentally started rereading recently. Although I am only back to the timeline where it is post WWII events, the common thread in accidents seem to be highly complex system interactions and human comprehension/tendencies. I recall a section of the book describing the set experiments specifically intended to cause accidents. I’m going to reread with a little more care given this post.

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