Small Modular Reactors and Current Policy Initiatives

by Jim Hopf

Over the past year or so, there has been a lot of buzz about small modular reactors (SMRs). These are reactors whose electrical output ranges anywhere from ~25 MW to ~300 MW, as compared with over 1000 MW for large “conventional” nuclear power plants. With SMRs, the entire reactor (or possibly the entire nuclear island—NSSS) could be built in a factory and shipped to the site. Any site construction would be much more limited, and would only involve the (non-nuclear) balance of plant. Descriptions of some proposed SMRs can be found herehere and here.

Advantages of SMRs

NuScale's containment vessel showing the reactor pressure vessel (Graphic: NuScale Power)

Whereas SMRs start off with an apparent disadvantage due to lack of economy of scale, it is hoped that with volume production, assembly-line-produced reactors could wind up being cheaper than site-constructed large reactors. Performing the fabrication of the reactor and all other nuclear safety related components at a single, dedicated factory site may also result in a higher level of quality control and minimize construction defects.

In addition to the raw cost, SMRs may have less difficulty in obtaining financing than large reactors, and may enjoy lower financing costs (interest rates). This is due to several factors. The cost of each reactor would be much smaller compared with the overall financial assets of the utility, which lowers the risk of default. The construction period (i.e., the delay between borrowing the money and the generation of cash flow) would be significantly shorter for an SMR. In fact, down the road it may even be possible (particularly for the smaller SMRs) that the factory would have an inventory of reactors, allowing a reactor to be simply ordered and put into place. Finally, there would be a much lower risk of construction delays with an SMR, due to the very limited amount of on-site construction.

In addition to the economic benefits, SMRs may allow nuclear to be used in places where it otherwise wouldn’t. This would include in remote locations that don’t have enough demand for a large reactor, by utilities that are not large enough to take on a large reactor, or in regions where electricity demand is growing very slowly and large increments of new generation are not needed.

Potential SMR Drawbacks

Hyperion Power's SMR (Graphic: Hyperion Power)

Many of the potential drawbacks of SMRs revolve around the economy of scale issue mentioned earlier. In addition to the question of whether small reactors can achieve the same per-kW construction cost as large reactors, some requirements for running a nuclear plant, such as having sufficient in-house engineering expertise, plant site security, and emergency planning procedures, do not necessarily (or obviously) scale down with plant size. One of the main questions on the table is the extent to which the Nuclear Regulatory Commission will consider the fact that the potential source term (radioactivity release) from an SMR is much smaller than that of a large reactor, when determining the requirements for things like security and emergency planning.

Some of the above drawbacks may be minimized by deploying SMRs at existing reactor sites that already have security and emergency planning procedures in place. It’s not clear (in the continental United States, anyway) that there is any real need to increase the number of nuclear power sites, at least for now. That may also address the concerns, of some critics, that an increased number of nuclear sites would increase security risks. In any event, employing a large number of SMRs at a given site will certainly reduce these costs.

Continued in Part 2 on Tuesday, June 21, with perspectives on recently-introduced SMR legislation.


Jim Hopf is a senior nuclear engineer with more than 20 years of experience in shielding and criticality analysis and design for spent fuel dry storage and transportation systems. He has been involved in nuclear advocacy for 10+ years, and is a member of the ANS Public Information Committee. He is a regular contributor to the ANS Nuclear Cafe.

14 thoughts on “Small Modular Reactors and Current Policy Initiatives

  1. hemp

    .Small Modular Reactors No Panacea For What Ails Nuclear Power.The small modular reactor is being pitched by the nuclear power industry as a sort of production-line auto alternative to hand-crafted sports car with supposed cost savings from the mass manufacturing of modestly sized reactors that could be scattered across the United States on a relatively quick Staff Writers.Washington DC SPX Oct 01 2010…The same industry that promised that nuclear power would be too cheap to meter is now touting another supposed cure-all for Americas power needs the small modular reactor SMR …..The only problem is that SMRs are not only unlikely live up to the hype but may well aggravate cost safety and environmental problems according to a new fact sheet prepared by the Institute for Energy and Environmental Research IEER and Physicians for Social Responsibility PSR …..The small modular reactor is being pitched by the nuclear power industry as a sort of production-line auto alternative to hand-crafted sports car with supposed cost savings from the mass manufacturing of modestly sized reactors that could be scattered across the United States on a relatively quick basis…..The facts about SMRs are far less rosy. As the IEER PSR document notes Some proponents of nuclear power are advocating for the development of small modular reactors as the solution to the problems facing large reactors particularly soaring costs safety and radioactive waste. in engineering specialization nuclear fusion from the University of California at Berkeley…..He said Amidst the evaporating hopes for a nuclear renaissance nuclear power proponents are pinning their hopes on small modular reactors without thinking carefully about the new problems they will create such as inspecting production lines in China procedures for recalls or the complications and costs of a variety of new forms of nuclear waste. ….The supposed cost benefits of SMRs are also subject to debate.

  2. Bill Eaton

    @ Brucie B.
    I don’t know of any nuclear power plants in operation in the U.S.built by foreign owned entities. I may not understand the full intent of the question, but I can shed some light on the pedigree of most of the industry. The plant builders were large A/E firms like Bechtel, Sargent and Lundy, Stone and Webster, and Burns and Roe. They constructed the facilities and received delivery of the NSS components…reactors, steam generators, pressurizers, piping, etc. The large A/E’s also designed balance of plant systems, and various supporting systems such as HVAC, cooling water, and electrical systems. Most of the A/E’s had long term engineeirng support contracts with the owners for many years after commercial operation, although as the business shrunk some regional offices were shut down as early as the late 80’s.The NSSS’s were supplied by Babcock and Wilcocks, Combustion Engineering, and Westinghouse for the PWR’s and GE for the BWR’s. There were other “one-shot” designs such as Ft. St. Vrain that were supplied by others. The NSSS vendors also developed and licensed the design codes that quantified the performanc of their NSSS components to satisfy the top tier safety limits, the supporting accident analyses and operating technical specification requirements.The owners, regulated utilities, had contracts with both the component suppliers and the constructor.
    After TMI, when the new orders dried up and what work remained was to complete or restart partially completed plants, the merger and acqusition transition began. But not until the late 80’s and 90’s, since the NSSS vendors still had robust business in supporting post-TMI backfits and various other large scale upgrades to the NSSS. When the acqisitions got started though the pace was fast. The nuclear part of B&W was bought by AREVA. Combustion Engineering was bought by Westinghouse, and much later on a part of GE was bought into by Hitachi. With all that said I don’t know of any operating plant built by a foreign company. Just in the last few years there have been investments by foreign companies in refurbishing and building new large component facilities in the U.S. to support what is now appearing to be a very weak resurgence of nuclear technology. If you want a new steam generator or pressurizer, you’ve got to go to Japan, Korea, France, Spain or Italy for the forging and large scale manufacturing. We have shut down all of our large scale manufacturing due to lack of business. It is only now a glimmer on the horizon that we can reenter the markets with U.S. manufacturing.

  3. Brucie B

    PS. Can anyone tell me how many foreign owned nuclear industry NPP company builders built reactors in operation in the U.S?
    (GE company NPP’s built by Japan)

  4. Brucie B

    @Sam Hobbs-&-Bill Eaton;
    One of the reasons American technical expertise is in breakdown is due in part to the monopoly and politics of BIG.
    The nuke industry just like in the aerospace industry suffers under the rubric of monopoly, this was not the case in the decades noted. The business philosophy of nukes generating electrical power initially employed SMALL operations with many contractors in the U.S.
    Gov’t and private companies have tried to work under NASA’s COTS program an alternative to the typical arrangements Bill Eaton talks about. But as anyone can observe without military contract civilian space venture is without investment unless companies holding large contract and gov’t support are chosen (SpaceX). It remains to be seen if there is a U.S. expansive viable beyond LEO human flight launch system under this new arrangement. And the same goes for the small nuclear reactor industry. Unless the small nuclear business owner/contractor can qualify bid and gain access to build/participate in the nuke industry. I don’t see how there will be a prosperous nuke industry. Both aerospace and nuclear industries will continue to shrink to only a few large quasi public/private corporations.
    And ‘diminishing returns’ are on the menu in these sectors-if anyone has noticed.

  5. Bill Eaton

    I can’t think of a single commercial nuke that wasn’t built and operated to make money. The economic disadvantage of operating a single nuke ( in comparison to fleet level operations) has in fact made it a reality that bigger is better…the ability to dilute fixed costs into production cost, a stronger ability to afford large and sometimes unforeseen capital expenditures that routinely comes from new regulation or industry driven initiatives, and in being able to afford larger staffs that participate in and support R&D industry initiatives in problem solving, etc. I have worked for both large and small operators and can attest to the greater advantages of the fleet operator to afford to maintain design and operating margins well beyond regulatory requirements. The reason that single reactor companies have in fact contracted with the larger fleet operators, or sold out to them, is strictly economics. The organizational design factors come into play as well, with the recognition that maintaining standalone but small engineering, training, and licensing organizations, to list a few key staff functions that must be paid for as overhead may not make sense in the long run. The SMR may actually create a new paradigm of small owner contracting from day one to a larger entity. If this is the entry strategy I’m all for it. In that case, I wonder if just buying power from the larger organization might make as much sense. At some point the integration of ownership with regulatory and operational responsibility has a point of diminishing return generally defined by the cost of people.

  6. Sam Hobbs

    With regard to large operating companies vs small operating companies, why not approach things from the perspective of small company ownership with operation being contracted to larger operating companies. I can certainly think of many problems to this, but many benefits as well.

    Certainly, there have been minority co-owners of nuclear power plants in the past (a different thing), but with a relatively small plant, a small utility could opt for ownership and contract operations.

  7. Brucie B

    @ Eaton
    Uh… yea, Why bring up ‘Conspiracy Theory’ ?
    Reality is, just about every facet of Americana is ‘To big to fail’ it is the business/gov’t nexus mantra now. This is also true in the nuke industry.
    I agree, technical expertise and performance must be determinates to contract participation the ability to deliver specifications. I remember both gov’t (state/federal) and private companies (small/large) participated in Project ROVER/NERVA during 50’s-60’s-70’s. Nuke expertise in the U.S. grew with synergy even the Quaker Oats company participated in development of the nuclear rocket engine. This is not evident in nuke R&D or manufacturing currently. In fact you observe a breakdown in most technical fields in the United States. Please point to statistics where the number of American science and engineering grads is increasing in the U.S.-most are foreign.
    No sorry, you can’t have a valid point that BIG is better.
    No nuclear plant is perfect in fact no technical operation is 100% perfect. Risk mitigation and periodic evaluations are a necessary component in any nuke operation big or small maybe NRC should realize this.
    Please! A little less hype and more reality is what’s needed to build efficient, safe, prosperous & stable nuclear industry in the U.S.

  8. Bill Eaton

    Brucie B:
    I am stating that the history of managing commercial nuclear power technology suggests that the bigger operator has an advantage in delivering reliability and cost performance over the small operator for the reasons I noted. If the NRC or future regulators change the oversight and technical requirements then perhaps overhead and technical support costs might be reduced. My comments were based on 30 years of design and operational experience, and not meant to step on someones toes. Although, I do find the comment about government and big nukes keeping others out of the business a rather humorous and unique twist of conspiracy theory logic. Finally, I agree with Mr. Hopf that in all likelihood the buyers of SMR’s will be large entities that can afford to engage once again in risk taking with respect to a new technology with a new set of unrecognized technical issues. Some of us remember vividly the challenges in dealing with PWR Alloy 600 degradation and the BWR dryer vibration phenomena. As always I believe the right technical decisions will come from collaboration and strong technical expertise, regardless of how the politics of new nukes progresses.

  9. Brucie B

    tend to agree w/ ‘single shaft risk’ maybe that’s why there was NRC /utility Co. rush to insure large NPP’s along the Missouri River where updated to prevent flood shutdowns.
    Small SMR’s are better and timely yearly risk evals are good policy.

  10. JimHopf


    It is likely that SMRs will be deployed by large, experienced nuclear operators on sites where large reactors already exist, at least at first. Indeed, one of the first examples is TVA building up to six mPower reactors at one of their existing plant sites. This alleviates the lack of knowledge problem you refer to, as well as many of the security and site evaluation issues.

    As you point out yourself, in today’s financial environment, even big players are having trouble financing large reactors, and may have to turn to small reactors themselves. Small players are not likely to be able to finance even SMRs, at least for awhile. I also personally believe that given the regulatory hurdles to getting a new site qualified for nuclear generation, and the already sufficient number of nuclear sites in this country, we won’t see many new sites in any event. Instead, SMRs will be mostly deployed at existing reactor sites.

    Finally, it is hoped that the smaller size and higher degree of inherent safety in these designs will offset some of the effects you’re referring to with respect to operator experience in the field.

  11. Brucie B

    @ Bill Eaton;
    “…attactiveness of being able to afford an SMR might just lure a poorly qualified owner into a resultant ineffective and poorly managed operation.”

    Are you suggesting ONLY established Gov’t favored NRC licensed BIG nuke corps have exclusive right to enter the market sector to provide service?
    Excluding SBM small business market in nuke industry?

    “…mistakes of non-standardization and end up with loss of technical support and supply chain integrity.”

    Again, are you suggesting science/design/architecture monopoly be the sole determinate for NRC ops license?
    Countries that derive a percentage of small NPP operation nuke reactors do not follow a standardized science/design/architecture reactor type . The few determinate should be based on reprocessed spent fuel for planning.
    One reason nuke SMBs struggle is because gov’t and big nuke corps are busy chasing small businesses away from the nuke market sector.

  12. Sam Hobbs

    At least one advantage that is not discussed above is what is sometimes referred to as the “single shaft risk.” With a large unit, an outage takes out a large amount of generation. With a multi-module SMR, a module outage takes out only that module which may be significantly smaller than the total generating capacity of the plant. Related to this is the fact that refueling outages for each module can be staggered and also avoid having the entire generating capacity offline at the same time.

  13. Bill Eaton

    SMR’s have two significant problems that might play into safety issues.
    One is the proven inability of small utility organizations to consistently and cost effectivewly operate one reactor. Most of these organizations have sold the assets or turned over operation to larger and deeper organizations. The number of one reactor utilities has dwindled to just a few. The attactiveness of being able to afford an SMR might just lure a poorly qualified owner into a resultant ineffective and poorly managed operation. Economy of scale with respect to organizational ability was appropriately mentioned in the article. The second problem is with the predicted number of players in the manufacture and support of the technology. If the industry and the regulator allow more than one or two types to be licensed and built, we could repeat the mistakes of non-standardization and end up with loss of technical support and supply chain integrity. The days of large numbers of reactors being commissioned over the course of twenty years is not likely to be repeated in today’s financial environment and I would hate to see just a few of any particular design being left to fend for limited technical support. I believe a policy supported system of siting smaller reactors in order to better stiffen the grid and make smaller scale nuclear a more accepted technology is the right way to go, but we should be careful of promoting a new base load scheme that could result in the entry of numerous suppliers without a long term look at staying power and support.

  14. Brucie B

    To add to ANS member Hopf post here:
    Most of the public associates commercial NPP’s with huge BWR/PWR rankine nsss wet bulb type operations fueled by mine extraction milled Ur friendly which pile up spent fuel by the ton. That was ‘old style nukes’. It’s unfortunate that the NRC and DOE are late to the SMR industry push behind that Russia, India, Japan etc.
    It seems ironic American nuke research developed most SMR licensed & commercially available.
    I would like readers to look at SMR’s in a holistic frame because the future will require safe, efficient, cost effective, secure and multi-purpose NNP’s in developing economies.
    It seems shameful that some American SMR companies struggle financially.
    It’s nice to see late interest by the U.S. administration/gov’t it seems too little but not too late to assist & invest in the SMR nuclear industry.

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