Archive for the ‘REACTOR TYPES’ Category

The US Energy Department’s renewed promotion of plutonium-fueled reactors. 

May 3, 2021

Plutonium programs in East Asia and Idaho will challenge the Biden administration, Bulletin of the Atomic Scientists, By Frank N. von Hippel | April 12, 2021  ”’…………. The US Energy Department’s renewed promotion of plutonium-fueled reactors. The US plutonium breeder reactor development program was ended by Congress in 1983. A decade later, the Clinton Administration shut down the Idaho National Laboratory’s Experimental Breeder Reactor II for lack of mission. At the time, I was working in the White House and supported that decision.

The nuclear-energy divisions at the Energy Department’s Argonne and Idaho National Laboratories refused to give up, however. They continued to produce articles promoting sodium-cooled reactors and laboratory studies on “pyroprocessing,” a small-scale technology used to separate plutonium from the fuel of the Experimental Breeder Reactor II .

During the Trump administration, this low-level effort broke out. With the Energy Department’s Office of Nuclear Energy headed by a former Idaho National Lab staffer and help from Idaho’s two Senators, the Energy Department and Congress were persuaded to approve the first steps toward construction at the Idaho National Laboratory of a larger version of the decommissioned Experimental Breeder Reactor II.

 The new reactor, misleadingly labeled the “Versatile Test Reactor,” would be built by Bechtel with design support by GE-Hitachi and Bill Gates’ Terrapower. The Energy Department awarded contracts to the Battelle Energy Alliance and to university nuclear-engineering departments in Indiana, Massachusetts, Michigan, and Oregon to develop proposals for how to use the Versatile Test Reactor.

The current estimated cost of the Versatile Test Reactor is $2.6-5.8 billion, and it is to be fueled with plutonium. The Idaho National Laboratory’s hope is to convince Congress to commit to funding its construction in 2021.

The Energy Department also committed $80 million to co-fund the construction of a 345-megawatt-electric (MWe) “Natrium” (Latin for sodium) demonstration liquid-sodium-cooled power reactor proposed by GE-Hitachi and Terrapower which it hopes Congress would increase to $1.6 billion. It also committed $25 million each to Advanced Reactor Concepts and General Atomics to design small sodium-cooled reactors. And it has subsidized Oklo, a $25-million startup company financed by the Koch family, to construct a 1.5 MWe “microreactor” on the Idaho National Laboratory’s site to demonstrate an extravagantly costly power source for remote regions.


In all these reactors, the chain reaction would be sustained by fast neutrons unlike the slow neutrons that sustain the chain reactions in water-cooled reactors. The Energy Department’s Office of Nuclear Energy has justified the need for the Versatile Test Reactor by the fast-neutron reactors whose construction it is supporting. In this way, it has “bootstraping” the Versatile Test Reactor by creating a need for it that would not otherwise exist.

This program also is undermining US nonproliferation policy..………..https://thebulletin.org/2021/04/plutonium-programs-in-east-asia-and-idaho-will-challenge-the-biden-administration/?utm_source=Newsletter&utm_medium=Email&utm_campaign=MondayNewsletter04122021&utm_content=NuclearRisk_EastAsia_04122021

Assessing types of Non-Light-Water Nuclear Reactors

May 3, 2021

Assessing the Safety, Security, and Environmental Impacts of Non-Light-Water Nuclear Reactors, Union of Concerned Scientists, Edwin Lyman,  Mar 18, 2021

“Advanced” Isn’t Always Better

”………………..Assessments of NLWR Types

UCS has reviewed hundreds of documents in the available literature to assess the comparative risks and benefits of the three major categories of NLWR with respect to the three evaluation criteria (Table 2 on original).

Sodium-Cooled Fast Reactors

Safety and Security Risk: SFRs have numerous safety problems that are not issues for LWRs. Sodium coolant can burn if exposed to air or water, and an SFR can experience rapid power increases that may be hard to control. It is even possible that an SFR core could explode like a small nuclear bomb under severe accident conditions. Of particular concern is the potential for a runaway power excursion: if the fuel overheats and the sodium coolant boils, an SFR’s power will typically increase rapidly rather than decrease, resulting in a positive feedback loop that could cause core damage if not quickly controlled.

Chernobyl Unit 4 in the former Soviet Union, although not a fast reactor, had a similar design flaw—known as a “positive void coefficient.” It was a major reason for the reactor’s catastrophic explosion in 1986. A positive void coefficient is decidedly not a passive safety feature—and it cannot be fully eliminated by design in commercial-scale SFRs. To mitigate these and other risks, fast reactors should have additional engineered safety systems that LWRs do not need, which increases capital cost.

Sustainability: Because of the properties of fast neutrons, fast reactors do offer, in theory, the potential to be more sustainable than LWRs by either using uranium more efficiently or reducing the quantity of TRU elements present in the reactor and its fuel cycle. This is the only clear advantage of fast reactors compared with LWRs. However once-through fast reactors such as the Natrium being developed by TerraPower, a company founded and supported by Bill Gates, would be less uranium-efficient than LWRs. To significantly increase sustainability, most fast reactors would require spent fuel reprocessing and recycling, and the reactors and associated fuel cycle facilities would need to operate continuously at extremely high levels of performance for many hundreds or even thousands of years. Neither government nor industry can guarantee that future generations will continue to operate and replace these facilities indefinitely. The enormous capital investment needed today to build such a system would only result in minor sustainability benefits over a reasonable timeframe.

Nuclear Proliferation/Terrorism: Historically, fast reactors have required plutonium or HEU-based fuels, both of which could be readily used in nuclear weapons and therefore entail unacceptable risks of nuclear proliferation and nuclear terrorism. Some SFR concepts being developed today utilize HALEU instead of plutonium and could operate on a once-through cycle. These reactors would pose lower proliferation and security risks than would plutonium-fueled fast reactors with reprocessing, but they would have many of the same safety risks as other SFRs. And, as pointed out, most once-through SFRs would actually be less sustainable than LWRs and thus unable to realize the SFR’s main benefit. For this reason, these once-through SFRs are likely to be “gateway” reactors that would eventually transition to SFRs with reprocessing and recycling. The only exceptions—if technically feasible—are once-through fast reactors operating in breed-and-burn mode. However, the only breed-and-burn reactor that has undergone significant R&D, TerraPower’s “traveling-wave reactor,” was recently suspended after more than a decade of work, suggesting that its technical challenges proved too great.

High-Temperature Gas-Cooled Reactors

Safety and Security Risk: HTGRs have some attractive safety features but also a number of drawbacks. Their safety is rooted in the integrity of TRISO fuel, which has been designed to function at the high normal operating temperature of an HTGR (up to 800ºC) and can retain radioactive fission products up to about 1,600ºC if a loss-of-coolant accident occurs. However, if the fuel heats up above that temperature—as it could in the Xe-100—its release of fission products speeds up significantly. So, while TRISO has some safety benefits, the fuel is far from meltdown-proof, as some claim. Indeed, a recent TRISO fuel irradiation test in the Advanced Test Reactor in Idaho had to be terminated prematurely when the fuel began to release fission products at a rate high enough to challenge off-site radiation dose limits.

The performance of TRISO fuel also depends critically on the ability to consistently manufacture fuel to exacting specifications, which has not been demonstrated. HTGRs are also vulnerable to accidents in which air or water leaks into the reactor; this is much less of a concern for LWRs. And the moving fuel in pebble-bed HTGRs introduces novel safety issues.

Despite these unknowns, HTGRs are being designed without the conventional leak-tight containments that LWRs have—potentially cancelling out any inherent safety benefits provided by the design and fuel. Given the uncertainties, much more testing and analysis are necessary to determine conclusively if HTGRs would be significantly safer than LWRs.

Sustainability: HTGRs are less sustainable than LWRs overall. They use uranium no more efficiently due to their use of HALEU, and they generate a much larger volume of highly radioactive waste. Although pebble-bed HTGRs are somewhat more flexible and uranium-efficient than prismatic-block HTGRs, the difference is not enough to overcome the penalty from using HALEU fuel.

Nuclear Proliferation/Terrorism: HTGRs raise additional proliferation issues compared with LWRs. Current HTGR designs use HALEU, which poses a greater security risk than the LEU grade used by LWRs, and TRISO fuel fabrication is more challenging to monitor than LWR fuel fabrication. Also, it is difficult to accurately account for nuclear material at pebble-bed HTGRs because fuel is continually fed into and removed from the reactor as it operates. On the other hand, it may be more difficult for a proliferator to reprocess TRISO spent fuel than LWR spent fuel to extract fissile material because the required chemical processes are less mature.

Molten Salt-Fueled Reactors

Safety and Security Risk: MSR advocates point to the fact that this type of reactor cannot melt down—the fuel is already molten. However, this simplistic argument belies the fact that MSR fuels pose unique safety issues. Not only is the hot liquid fuel highly corrosive, but it is also difficult to model its complex behavior as it flows through a reactor system. If cooling is interrupted, the fuel can heat up and destroy an MSR in a matter of minutes. Perhaps the most serious safety flaw is that, in contrast to solid-fueled reactors, MSRs routinely release large quantities of gaseous fission products, which must be trapped and stored. Some released gases quickly decay into troublesome radionuclides such as cesium-137— the highly radioactive isotope that caused persistent and extensive environmental contamination following the Chernobyl and Fukushima nuclear accidents.

Sustainability: A main argument for MSRs is that they are more flexible and can operate more sustainably than reactors using solid fuel. In theory, some MSRs would be able to use natural resources more efficiently than LWRs and generate lower amounts of long-lived nuclear waste. However, the actual sustainability improvements for a range of thermal and fast MSR designs are too small, even with optimistic performance assumptions, to justify their high safety and security risks.

Nuclear Proliferation/Terrorism: MSRs present unique challenges for nuclear security because it would be very difficult to account for nuclear material accurately as the liquid fuel flows through the reactor. In addition, some designs require on-site, continuously operating fuel reprocessing plants that could provide additional pathways for diverting or stealing nuclear-weapon-usable materials.

MSRs could also endanger global nuclear security by interfering with the worldwide network of radionuclide monitors put into place to verify compliance with the Comprehensive Nuclear Test Ban Treaty after it enters into force.5 MSRs release vast quantities of the same radioactive xenon isotopes that are signatures of clandestine nuclear explosions—an issue that MSR developers do not appear to have addressed. It is unclear whether it would be feasible or affordable to trap and store these isotopes at MSRs to the degree necessary to avoid degrading the effectiveness of the monitoring system to detect treaty violations.

Safely Commercializing NLWRs: Timelines and Costs

Can NLWRs be deployed quickly enough to play a significant role in reducing carbon emissions and avoiding the worst effects of climate change? The 2018 special report of the UN’s Intergovernmental Panel on Climate Change identified 85 energy supply pathways to 2050 capable of achieving the Paris Agreement target of limiting global mean temperature rise to 1.5°C. The median capacity of nuclear power in 2050 across those pathways is about 150 percent over the 2020 level. Taking into account planned retirements, this corresponds to the equivalent of at least two dozen 1,000 MWe reactors coming online globally each year between now and 2050— five times the recent global rate of new LWR construction. If the world must wait decades for NLWRs to be commercially available, they would have to be built even faster to fill the gap by 2050.

Some developers of NLWRs say that they will be able to meet this challenge by deploying their reactors commercially as soon as the late 2020s. However, such aggressive timelines are inconsistent with the recent experience of new reactors such as the Westinghouse AP1000, an evolutionary LWR. Although the AP1000 has some novel features, its designers leveraged many decades of LWR operating data. Even so, it took more than 30 years of research, development, and construction before the first AP1000—the Sanmen Unit 1 reactor in China—began to produce power in 2018.

How, then, could less-mature NLWR reactors be commercialized so much faster than the AP1000? At a minimum, commercial deployment in the 2020s would require bypassing two developmental stages that are critical for assuring safety and reliability: the demonstration of prototype reactors at reduced scale and at full scale. Prototype reactors are typically needed for demonstrating performance and conducting safety and fuel testing to address knowledge gaps in new reactor designs. Prototypes also may have additional safety features and instrumentation not included in the basic design, as well as limits on operation that would not apply to commercial units.

By a 2017 report, the DOE asserted that SFRs and HTGRs were mature enough for commercial demonstrations without the need for additional prototype testing. For either of these types, the DOE estimated it would cost approximately $4 billion and take 13 to 15 years to complete a first commercial demonstration unit, assuming that reactor construction and startup testing take seven years. After five years of operating the demonstration unit, additional commercial units could follow in the mid-2030s.

In contrast, for MSRs and other lower-maturity designs, the DOE report judged that both reduced-scale and full-scale prototypes (which the report referred to as “engineering” and “performance” demonstrations, respectively) would be needed before a commercial demonstration reactor could be built. These additional stages could add $2 billion to $4 billion to the cost and 20 years to the development timeline. The subsequent commercial demonstration would not begin until 2040; reactors would not be available for sale until the mid-2040s or even the 2050s.

In May 2020, after receiving $160 million in initial congressional funding for the new Advanced Reactor Demonstration Program (ARDP), the DOE issued a solicitation for two “advanced” commercial demonstration reactors. In October 2020, the DOE chose SFR and HTGR designs—as one might expect given its 2017 technology assessment. The DOE estimates that these projects will cost up to $3.2 billion each (with the vendors contributing 50 percent) for the reactors and their supporting fuel facilities. The department is requiring that the reactors be operational within seven years, a timeline—including NRC licensing, construction, fuel production, and startup testing—that it acknowledges is very aggressive.

However, even if this deadline can be met and the reactors work reliably, subsequent commercial units likely would not be ordered before the early 2030s. Moreover, it is far from certain that the two designs the DOE selected for the ARDP are mature enough for commercial demonstration. Past demonstrations of both SFRs and HTGRs have encountered safety and reliability problems. Additionally, for both reactor types, the DOE has chosen designs that differ significantly from past demonstration reactors.

In the 1990s, the NRC concluded that it would require information from representative prototype testing prior to licensing either of these reactor types—but no prototypes were ever built. More recently, in a letter to the NRC, the agency’s independent Advisory Committee on Reactor Safeguards reaffirmed the importance of prototypes in new reactor development. Nevertheless, the NRC—a far weaker regulator today—has apparently changed its position and may proceed with licensing the ARDP demonstration reactors without requiring prototype testing first. But by skipping prototype testing and proceeding directly to commercial units, these projects may run not only the risk of experincing unanticipated reliability problems, but also the risk of suffering serious accidents that could endanger public health and safety.

An additional challenge for NLWR demonstrations and subsequent commercial deployment is the availability of fuels for those reactors, which would differ significantly from the fuel that today’s LWRs use. Even a single small reactor could require a few tons of HALEU per year—far more than the 900 kilograms per year projected to be available over the next several years from a DOE-funded pilot enrichment plant that Centrus Energy Corporation is building in Piketon, Ohio. It is far from clear whether that pilot will succeed and can be scaled up in time to support the two NLWR demonstrations by 2027, not to mention the numerous other HALEU-fueled reactor projects that have been proposed……. https://ucsusa.org/resources/advanced-isnt-always-better#read-online-content

Conclusions and recommendations of safety assessment of advanced nuclear reactors – non-light-water ones

May 3, 2021

Assessing the Safety, Security, and Environmental Impacts of Non-Light-Water Nuclear Reactors,Union of Concerned Scientists, Edwin Lyman Mar 18, 2021  “Advanced” Isn’t Always Better  

”……….Conclusions of the Assessment

The non-light-water nuclear reactor landscape is vast and complex, and it is beyond the scope of this report to survey the entire field in depth. Nevertheless, enough is clear even at this stage to draw some general conclusions regarding the safety and security of NLWRs and their prospects for rapid deployment.

Based on the available evidence, the NLWR designs currently under consideration (except possibly once-through, breed-and-burn reactors) do not offer obvious improvements over LWRs significant enough to justify their many risks. Regulators and other policymakers would be wise to look more closely at the nuclear power programs under way to make sure they prioritize safety and security. Future appropriations for NLWR technology research, development, and deployment should be guided by realistic assessments of the likely societal benefits that would result from the investment of billions of taxpayer dollars.

Little evidence supports claims that NLWRs will be significantly safer than today’s LWRs. While some NLWR designs offer some safety advantages, all have novel characteristics that could render them less safe.

All NLWR designs introduce new safety issues that will require substantial analysis and testing to fully understand and address—and it may not be possible to resolve them fully. To determine whether any NLWR concept will be significantly safer than LWRs, the reactor must achieve an advanced stage of technical maturity, undergo complete comprehensive safety testing and analysis, and acquire significant operating experience under realistic conditions.

The claim that any nuclear reactor system can “burn” or “consume” nuclear waste is a misleading oversimplification. Reactors can actually use only a fraction of spent nuclear fuel as new fuel, and separating that fraction increases the risks of nuclear proliferation and terrorism.

No nuclear reactor can use spent nuclear fuel directly as fresh fuel. Instead, spent fuel has to be “reprocessed”—chemically treated to extract plutonium and other TRU elements, which must then be refabricated into new fuel. This introduces a grave danger: plutonium and other TRU elements can be used in nuclear weapons. Reprocessing and recycling render these materials vulnerable to diversion or theft and increases the risks of nuclear proliferation and terrorism—risks that are costly to address and that technical and institutional measures cannot fully mitigate. Any fuel cycle that requires reprocessing poses inherently greater proliferation and terrorism risks than the “once-through” cycle with direct disposal of spent fuel in a geologic repository.

Some NLWRs have the potential for greater sustainability than LWRs, but the improvements appear to be too small to justify their proliferation and safety risks.

Although some NLWR systems could use uranium more efficiently and generate smaller quantities of long-lived TRU isotopes in nuclear waste, for most designs these benefits could be achieved only by repeatedly reprocessing spent fuel to separate out these isotopes and recycle them in new fuel—and that presents unacceptable proliferation and security risks. In addition, reprocessing plants and other associated fuel cycle facilities are costly to build and operate, and they increase the environmental and safety impacts compared with the LWR once-through cycle. Moreover, the sustainability increases in practice would not be significant in a reasonably foreseeable time frame.

Once-through, breed-and-burn reactors have the potential to use uranium more efficiently without reprocessing, but many technical challenges remain.

One type of NLWR system that could in principle be more sustainable than the LWR without increasing proliferation and terrorism risks is the once-through, breed-and-burn reactor. Concepts such as TerraPower’s traveling-wave reactor could enable the use of depleted uranium waste stockpiles as fuel, which would increase the efficiency of uranium use. Although there is no economic motivation to develop more uranium-efficient reactors at a time when uranium is cheap and abundant, reducing uranium mining may be beneficial for other reasons, and such reactors may be useful for the future. However, many technical challenges would have to be overcome to achieve breed-and-burn operation, including the development of very-high-burnup fuels. The fact that TerraPower suspended its project after more than a decade of development to pursue a more conventional and far less uranium-efficient SFR, the Natrium, suggests that these challenges have proven too great.

High-assay low enriched uranium (HALEU) fuel, which is needed for many NLWR designs, poses higher nuclear proliferation and nuclear terrorism risks than the lower-assay LEU used by the operating LWR fleet.

Many NLWR designs require uranium enriched to higher levels than the 5 percent U-235 typical of LWR fuel. Although uranium enriched to between 10 and 20 percent U-235 (defined here as HALEU) is considered impractical for direct use in nuclear weapons, it is more attractive for weapons use—and requires more stringent security—than the lower-assay enriched uranium in current LWRs.

The significant time and resources needed to safely commercialize any NLWR design should not be underestimated.

It will likely take decades and many billions of dollars to develop and commercially deploy any NLWR design, together with its associated fuel cycle facilities and other support activities. Such development programs would come with a significant risk of delay or failure and require long-term stewardship and funding commitments. And even if a commercially workable design were demonstrated, it would take many more years after that to deploy a large number of units and operate them safely and reliably.

Vendors that claim their NLWRs could be commercialized much more quickly typically assume that their designs will not require full-scale performance demonstrations and extensive safety testing, which could add well over a decade to the development timeline. However, current designs for sodium-cooled fast reactors and high-temperature gas-cooled reactors differ enough from past reactor demonstrations that they cannot afford to bypass additional full-scale prototype testing before licensing and commercial deployment. Molten salt–fueled reactors have only had small-scale demonstrations and thus are even less mature. NLWRs deployed commercially at premature stages of development run a high risk of poor performance and unexpected safety problems.

Recommendations

The DOE should suspend the advanced reactor demonstration program pending a finding by the NRC whether it will require full-scale prototype testing before licensing the two chosen designs as commercial power reactors.

The DOE has selected two NLWR designs, the Natrium SFR and the Xe-100 pebble-bed HTGR, for demonstration of full-scale commercial operation by 2027. However, the NRC has yet to evaluate whether these designs are mature enough that it can license them without first obtaining data from full-scale prototype plants to demonstrate novel safety features, validate computer codes, and qualify new types of fuel in representative environments. Without such an evaluation, the NRC will likely lack the information necessary to ensure safe, secure operation of these reactors. The DOE should suspend the Advanced Reactor Demonstration Program until the NRC—in consultation with the agency’s Advisory Committee on Reactor Safeguards and external experts—has determined whether prototypes will be needed first.

Congress should require that an independent, transparent, peer-review panel direct all DOE R&D on new nuclear concepts, including the construction of additional test or demonstration reactors.

Given the long time and high cost required to commercialize NLWR designs, the DOE should provide funding for NLWR R&D judiciously and only for reactor concepts that offer a strong possibility of significantly increasing safety and security—and do not increase proliferation risks. Moreover, unlike the process for selecting the two reactor designs for the Advanced Reactor Demonstration Program, decision-making should be transparent.6 Congress should require that the DOE convene an independent, public commission to thoroughly review the technical merits of all NLWR designs proposed for development and demonstration, including those already selected for the ARDP. The commission, whose members should represent a broad range of expertise and perspectives, would recommend funding only for designs that are highly likely to be commercialized successfully while achieving clearly greater safety and security than current-generation LWRs.

The DOE and other agencies should thoroughly assess the implications for proliferation and nuclear terrorism of the greatly expanded production, processing, and transport of the high-assay low-enriched uranium (HALEU) required to support the widespread deployment of NLWRs.

Large-scale deployment of NLWRs that use HALEU fuel will require establishing a new industrial infrastructure for producing and transporting the material. The DOE is actively promoting the development of HALEU-fueled reactor designs for export. Given that HALEU is a material of higher security concern than lower-assay LEU, Congress should require that the DOE immediately assess the proliferation and nuclear terrorism implications of transitioning to the widespread use of HALEU worldwide. This assessment should also address the resource requirements for the security and safeguards measures needed to ensure that such a transition can occur without an unacceptable increase in risk.

The United States should make all new reactors and associated fuel facilities eligible for IAEA safeguards and provide that agency with the necessary resources for carrying out verification activities.

The IAEA, which is responsible for verifying that civilian nuclear facilities around the world are not being misused to produce materials for nuclear weapons, has limited or no experience in safeguarding many types of NLWRs and their associated fuel cycle facilities. NLWR projects being considered for deployment in the United States, such as the Natrium SFR and the Xe-100 pebble-bed HTGR, would provide ideal test beds for the IAEA to develop safeguards approaches. However, as a nuclear-weapon state, the United States is not obligated to give the IAEA access to its nuclear facilities. To set a good example and advance the cause of nonproliferation, the United States should immediately provide the IAEA with permission and funding to apply safeguards on all new US nuclear facilities, beginning at the design phase. This would help to identify safeguard challenges early and give the IAEA experience in verifying similar facilities if they are deployed in other countries.

The DOE and Congress should consider focusing nuclear energy R&D on improving the safety and security of LWRs, rather than on commercializing immature NLWR designs.

LWR technology benefits from a vast trove of information resulting from many decades of acquiring experimental data, analysis, and operating experience—far more than that available for any NLWR. This gives the LWR a significant advantage over other nuclear technologies. The DOE and Congress should do a more thorough evaluation of the benefits of focusing R&D funding on addressing the outstanding safety, security, and cost issues of LWRs rather than attempting to commercialize less mature reactor concepts. If the objective is to expand nuclear power to help deal with the climate crisis over the next few decades, improving LWRs could be a less risky bet.

Endnotes………

This is a condensed, online version of the executive summary. For all figures, references, and the full text, please download the PDF.  https://ucsusa.org/resources/advanced-isnt-always-better#read-online-content

Nuclear reactors – “Advanced” Isn’t Always Better” – Non-Light-Water Nuclear Reactors

May 3, 2021

Assessing the Safety, Security, and Environmental Impacts of Non-Light-Water Nuclear Reactors,Union of Concerned Scientists, Edwin Lyman Mar 18, 2021  “Advanced” Isn’t Always Better  ”……………………….Key Questions for Assessing NLWR Technologies

It is critical that policymakers, regulators, and private investors fully vet the claims that the developers of NLWRs are making and accurately assess the prospects for both successful development_ and_ safe, secure, and cost-effective deployment. Given the urgency of the climate crisis, rigorous evaluation of these technologies will help our nation and others avoid wasting time or resources in the pursuit of high-risk concepts that would be only slightly better— or perhaps worse—than LWRs.

Key questions to consider are the following:

  • What are the benefits and risks of NLWRs and their fuel cycles compared with those of LWRs?
  • Do the likely overall benefits of NLWRs outweigh the risks and justify the substantial public and private investments needed to commercialize them?
  • Can NLWRs be safely and securely commercialized in time to contribute significantly to averting the climate crisis?

To help inform policy decisions on these questions, the Union of Concerned Scientists (UCS) has evaluated certain claims about the principal types of NLWRs. In particular, this report compares several classes of NLWRs to LWRs with regard to safety and security, the risks of nuclear proliferation and nuclear terrorism, and “sustainability”—a term that in this context includes the often-claimed ability of some NLWRs to “recycle” nuclear waste and use mined uranium more efficiently. The report also considers the potential for certain NLWRs to operate in a once-through, “breed-and-burn” mode that would, in theory, make them more uranium-efficient without the need to recycle nuclear waste—a dangerous process that has significant nuclear proliferation and terrorism risks.

Non-Light-Water Reactor Technologies

UCS considered these principal classes of NLWRs:

Sodium-cooled fast reactors (SFRs): These reactors are known as “fast reactors” because, unlike LWRs or other reactors that use lower-energy (or “thermal”) neutrons, the liquid sodium coolant does not moderate (slow down) the high-energy (or “fast”) neutrons produced when nuclear fuel undergoes fission. The characteristics and design features of these reactors differ significantly from those of LWRs, stemming from the properties of fast neutrons and the chemical nature of liquid sodium.

High-temperature gas–cooled reactors (HTGRs): These reactors are cooled by a pressurized gas such as helium and operate at temperatures up to 800ºC, compared with around 300ºC for LWRs. HTGR designers developed a special fuel called TRISO (tristructural isotropic) to withstand this high operating temperature. HTGRs typically contain graphite as a moderator to slow down neutrons. There are two main variants of HTGR. A prismatic-block HTGR uses conventional nuclear fuel elements that are stationary; in a pebble-bed HTGR, moving fuel elements circulate continuously through the reactor core.

Molten salt–fueled reactors (MSRs): In contrast to conventional reactors that use fuel in a solid form, these use liquid fuel dissolved in a molten salt at a temperature of at least 650ºC. The fuel, which is pumped through the reactor, also serves as the coolant. MSRs can be either thermal reactors that use a moderator such as graphite or fast reactors without a moderator. All MSRs chemically treat the fuel to varying extents while the reactor operates to remove radio-active isotopes that affect reactor performance. Therefore, unlike other reactors, MSRs generally require on-site chemical plants to process their fuel. MSRs also need elaborate systems to capture and treat large volumes of highly radioactive gaseous byproducts.

The Fuels for Non-Light-Water Reactors

Today’s LWRs use uranium-based nuclear fuel containing less than 5 percent of the isotope uranium-235. This fuel is produced from natural (mined) uranium, which has a uranium-235 content of less than 1 percent, in a complex industrial process called uranium enrichment. Fuel enriched to less than 20 percent U-235 is called “low-enriched uranium” (LEU). Experts consider it a far less attractive material for nuclear weapons development than “highly enriched uranium” (HEU), with a U-235 content of at least 20 percent.

The fuel for most NLWRs differs from that of LWRs. . Some proposed NLWRs would use LEU enriched to between 10 and 20 percent uranium-235; this is known as “high-assay low enriched uranium” (HALEU).2 While HALEU is considered impractical for direct use in a nuclear weapon, it is more attractive for nuclear weapons development than the LEU used in LWRs. Other types of NLWRs would use plutonium separated from spent nuclear fuel through a chemical process called reprocessing. Still others would utilize the isotope uranium-233 obtained by irradiating the element thorium. Both plutonium and uranium-233 are highly attractive for use in nuclear weapons.

Typically, the chemical forms of NLWR fuels also differ from those of conventional LWR fuel, which is a ceramic material composed of uranium oxide. Fast reactors can use oxides, but they can also use fuels made of metal alloys or chemical compounds such as nitrides. The TRISO fuel in HTGRs consists of tiny kernels of uranium oxide (or other uranium compounds) surrounded by several layers of carbon-based materials. MSR fuels are complex mixtures of fluoride or chloride salt compounds.

The deployment of NLWRs also would require new industrial facilities and other infrastructure to produce and transport their different types of fuel, as well as to manage spent fuel and other nuclear wastes. These facilities may use new technologies that themselves would require significant R&D. They also may present different risks related to safety, security, and nuclear proliferation than do LWR fuel cycle facilities—important considerations for evaluating the whole system.

Non-Light-Water Reactors: Past and Present

In the mid-20th century, the Atomic Energy Commission (AEC)—the predecessor of today’s Department of Energy (DOE) and the NRC—devoted considerable time and resources to developing a variety of NLWR technologies, supporting demonstration plants at various scales at sites around the United States. Owners of several of these reactors abandoned them after the reactors experienced operational problems (for example, the Fort St. Vrain HTGR in Colorado) or even serious accidents (the Fermi-1 SFR in Michigan).

Despite these negative experiences, the DOE continued R&D on various types of NLWR and their fuel cycles. In the 1990s, the DOE initiated the Generation IV program, with the goal of “developing and demonstrating advanced nuclear energy systems that meet future needs for safe, sustainable, environmentally responsible, economical, proliferation-resistant, and physically secure energy.” Although Generation IV identified six families of advanced reactor technology, the DOE has given most of its subsequent support to SFRs and HTGRs.

Today, a number of NLWR projects at various stages of development are under way, funded by both public and private sources (Table 1). With support from Congress, the DOE is pursuing several new NLWR test and demonstration reactors. It is proceeding with the design and construction of the Versatile Test Reactor (VTR), an SFR that it hopes to begin operating in the 2026–2031 timeframe. The VTR would not generate electricity but would be used to test fuels and materials for developing other reactors. In October 2020, the DOE selected two NLWR designs for demonstrating commercial power generation by 2027: the Xe-100, a small pebble-bed HTGR that would generate about 76 megawatts of electricity (MWe), and the 345 MWe Natrium, an SFR that is essentially a larger version of the VTR with a power production unit. The DOE is also providing funding for two smaller-scale projects to demonstrate molten salt technologies. In addition, the DOE, the Department of Defense (DOD), and a private company, Oklo, Inc., are pursuing demonstrations of so-called micro-reactors—very small NLWRs with capacities from 1 MWe to 20 MWe—and project that these will begin operating in the next few years. A number of universities also have expressed interest in building small NLWRs for research.

Congress would need to provide sufficient and sustained funding for any of these projects to come to fruition. This is far from assured—for example, funding for the VTR to date has fallen far short of what the DOE has requested, all but guaranteeing the project will be delayed.

The Goals of New Reactor Development

If nuclear power is to play an expanded global role to help mitigate climate change, new reactor designs should be demonstrably safer and more secure—and more economical—than the existing reactor fleet. Today’s LWRs remain far too vulnerable to Fukushima-like accidents, and the uranium enrichment plants that provide their LEU fuel can be misused to produce HEU for nuclear weapons. However, developing new designs that are clearly superior to LWRs overall is a formidable challenge, as improvements in one respect can create or exacerbate problems in others. For example, increasing the physical size of a reactor core while keeping its power generation rate constant could make the reactor easier to cool in an accident, but it could also increase cost.

Moreover, the problems of nuclear power cannot be fixed through better reactor design alone. Also critical is the regulatory framework governing the licensing, construction, and operation of nuclear plants and their associated fuel cycle infrastructure. Inadequate licensing standards and oversight activities can compromise the safety of improved designs. A key consideration is the extent to which regulators require extra levels of safety—known as “defense-in-depth”—to compensate for uncertainties in new reactor designs for which there is little or no operating experience………

This is a condensed, online version of the executive summary. For all figures, references, and the full text, please download the PDF.         https://ucsusa.org/resources/advanced-isnt-always-better#read-online-content

Assessing types of non-lightwater nuclear reactors

April 5, 2021

Assessing the Safety, Security, and Environmental Impacts of Non-Light-Water Nuclear Reactors, Union of Concerned Scientists, Edwin Lyman,  Mar 18, 2021

“Advanced” Isn’t Always Better

”………………..Assessments of NLWR Types

UCS has reviewed hundreds of documents in the available literature to assess the comparative risks and benefits of the three major categories of NLWR with respect to the three evaluation criteria (Table 2).

Sodium-Cooled Fast Reactors

Safety and Security Risk: SFRs have numerous safety problems that are not issues for LWRs. Sodium coolant can burn if exposed to air or water, and an SFR can experience rapid power increases that may be hard to control. It is even possible that an SFR core could explode like a small nuclear bomb under severe accident conditions. Of particular concern is the potential for a runaway power excursion: if the fuel overheats and the sodium coolant boils, an SFR’s power will typically increase rapidly rather than decrease, resulting in a positive feedback loop that could cause core damage if not quickly controlled.

Chernobyl Unit 4 in the former Soviet Union, although not a fast reactor, had a similar design flaw—known as a “positive void coefficient.” It was a major reason for the reactor’s catastrophic explosion in 1986. A positive void coefficient is decidedly not a passive safety feature—and it cannot be fully eliminated by design in commercial-scale SFRs. To mitigate these and other risks, fast reactors should have additional engineered safety systems that LWRs do not need, which increases capital cost.

Sustainability: Because of the properties of fast neutrons, fast reactors do offer, in theory, the potential to be more sustainable than LWRs by either using uranium more efficiently or reducing the quantity of TRU elements present in the reactor and its fuel cycle. This is the only clear advantage of fast reactors compared with LWRs. However once-through fast reactors such as the Natrium being developed by TerraPower, a company founded and supported by Bill Gates, would be less uranium-efficient than LWRs. To significantly increase sustainability, most fast reactors would require spent fuel reprocessing and recycling, and the reactors and associated fuel cycle facilities would need to operate continuously at extremely high levels of performance for many hundreds or even thousands of years. Neither government nor industry can guarantee that future generations will continue to operate and replace these facilities indefinitely. The enormous capital investment needed today to build such a system would only result in minor sustainability benefits over a reasonable timeframe.

Nuclear Proliferation/Terrorism: Historically, fast reactors have required plutonium or HEU-based fuels, both of which could be readily used in nuclear weapons and therefore entail unacceptable risks of nuclear proliferation and nuclear terrorism. Some SFR concepts being developed today utilize HALEU instead of plutonium and could operate on a once-through cycle. These reactors would pose lower proliferation and security risks than would plutonium-fueled fast reactors with reprocessing, but they would have many of the same safety risks as other SFRs. And, as pointed out, most once-through SFRs would actually be less sustainable than LWRs and thus unable to realize the SFR’s main benefit. For this reason, these once-through SFRs are likely to be “gateway” reactors that would eventually transition to SFRs with reprocessing and recycling. The only exceptions—if technically feasible—are once-through fast reactors operating in breed-and-burn mode. However, the only breed-and-burn reactor that has undergone significant R&D, TerraPower’s “traveling-wave reactor,” was recently suspended after more than a decade of work, suggesting that its technical challenges proved too great.

High-Temperature Gas-Cooled Reactors

Safety and Security Risk: HTGRs have some attractive safety features but also a number of drawbacks. Their safety is rooted in the integrity of TRISO fuel, which has been designed to function at the high normal operating temperature of an HTGR (up to 800ºC) and can retain radioactive fission products up to about 1,600ºC if a loss-of-coolant accident occurs. However, if the fuel heats up above that temperature—as it could in the Xe-100—its release of fission products speeds up significantly. So, while TRISO has some safety benefits, the fuel is far from meltdown-proof, as some claim. Indeed, a recent TRISO fuel irradiation test in the Advanced Test Reactor in Idaho had to be terminated prematurely when the fuel began to release fission products at a rate high enough to challenge off-site radiation dose limits.

The performance of TRISO fuel also depends critically on the ability to consistently manufacture fuel to exacting specifications, which has not been demonstrated. HTGRs are also vulnerable to accidents in which air or water leaks into the reactor; this is much less of a concern for LWRs. And the moving fuel in pebble-bed HTGRs introduces novel safety issues.

Despite these unknowns, HTGRs are being designed without the conventional leak-tight containments that LWRs have—potentially cancelling out any inherent safety benefits provided by the design and fuel. Given the uncertainties, much more testing and analysis are necessary to determine conclusively if HTGRs would be significantly safer than LWRs.

Sustainability: HTGRs are less sustainable than LWRs overall. They use uranium no more efficiently due to their use of HALEU, and they generate a much larger volume of highly radioactive waste. Although pebble-bed HTGRs are somewhat more flexible and uranium-efficient than prismatic-block HTGRs, the difference is not enough to overcome the penalty from using HALEU fuel.

Nuclear Proliferation/Terrorism: HTGRs raise additional proliferation issues compared with LWRs. Current HTGR designs use HALEU, which poses a greater security risk than the LEU grade used by LWRs, and TRISO fuel fabrication is more challenging to monitor than LWR fuel fabrication. Also, it is difficult to accurately account for nuclear material at pebble-bed HTGRs because fuel is continually fed into and removed from the reactor as it operates. On the other hand, it may be more difficult for a proliferator to reprocess TRISO spent fuel than LWR spent fuel to extract fissile material because the required chemical processes are less mature.

Molten Salt-Fueled Reactors

Safety and Security Risk: MSR advocates point to the fact that this type of reactor cannot melt down—the fuel is already molten. However, this simplistic argument belies the fact that MSR fuels pose unique safety issues. Not only is the hot liquid fuel highly corrosive, but it is also difficult to model its complex behavior as it flows through a reactor system. If cooling is interrupted, the fuel can heat up and destroy an MSR in a matter of minutes. Perhaps the most serious safety flaw is that, in contrast to solid-fueled reactors, MSRs routinely release large quantities of gaseous fission products, which must be trapped and stored. Some released gases quickly decay into troublesome radionuclides such as cesium-137— the highly radioactive isotope that caused persistent and extensive environmental contamination following the Chernobyl and Fukushima nuclear accidents.

Sustainability: A main argument for MSRs is that they are more flexible and can operate more sustainably than reactors using solid fuel. In theory, some MSRs would be able to use natural resources more efficiently than LWRs and generate lower amounts of long-lived nuclear waste. However, the actual sustainability improvements for a range of thermal and fast MSR designs are too small, even with optimistic performance assumptions, to justify their high safety and security risks.

Nuclear Proliferation/Terrorism: MSRs present unique challenges for nuclear security because it would be very difficult to account for nuclear material accurately as the liquid fuel flows through the reactor. In addition, some designs require on-site, continuously operating fuel reprocessing plants that could provide additional pathways for diverting or stealing nuclear-weapon-usable materials.

MSRs could also endanger global nuclear security by interfering with the worldwide network of radionuclide monitors put into place to verify compliance with the Comprehensive Nuclear Test Ban Treaty after it enters into force.5 MSRs release vast quantities of the same radioactive xenon isotopes that are signatures of clandestine nuclear explosions—an issue that MSR developers do not appear to have addressed. It is unclear whether it would be feasible or affordable to trap and store these isotopes at MSRs to the degree necessary to avoid degrading the effectiveness of the monitoring system to detect treaty violations.

Safely Commercializing NLWRs: Timelines and Costs

Can NLWRs be deployed quickly enough to play a significant role in reducing carbon emissions and avoiding the worst effects of climate change? The 2018 special report of the UN’s Intergovernmental Panel on Climate Change identified 85 energy supply pathways to 2050 capable of achieving the Paris Agreement target of limiting global mean temperature rise to 1.5°C. The median capacity of nuclear power in 2050 across those pathways is about 150 percent over the 2020 level. Taking into account planned retirements, this corresponds to the equivalent of at least two dozen 1,000 MWe reactors coming online globally each year between now and 2050— five times the recent global rate of new LWR construction. If the world must wait decades for NLWRs to be commercially available, they would have to be built even faster to fill the gap by 2050.

Some developers of NLWRs say that they will be able to meet this challenge by deploying their reactors commercially as soon as the late 2020s. However, such aggressive timelines are inconsistent with the recent experience of new reactors such as the Westinghouse AP1000, an evolutionary LWR. Although the AP1000 has some novel features, its designers leveraged many decades of LWR operating data. Even so, it took more than 30 years of research, development, and construction before the first AP1000—the Sanmen Unit 1 reactor in China—began to produce power in 2018.

How, then, could less-mature NLWR reactors be commercialized so much faster than the AP1000? At a minimum, commercial deployment in the 2020s would require bypassing two developmental stages that are critical for assuring safety and reliability: the demonstration of prototype reactors at reduced scale and at full scale. Prototype reactors are typically needed for demonstrating performance and conducting safety and fuel testing to address knowledge gaps in new reactor designs. Prototypes also may have additional safety features and instrumentation not included in the basic design, as well as limits on operation that would not apply to commercial units.

By a 2017 report, the DOE asserted that SFRs and HTGRs were mature enough for commercial demonstrations without the need for additional prototype testing. For either of these types, the DOE estimated it would cost approximately $4 billion and take 13 to 15 years to complete a first commercial demonstration unit, assuming that reactor construction and startup testing take seven years. After five years of operating the demonstration unit, additional commercial units could follow in the mid-2030s.

In contrast, for MSRs and other lower-maturity designs, the DOE report judged that both reduced-scale and full-scale prototypes (which the report referred to as “engineering” and “performance” demonstrations, respectively) would be needed before a commercial demonstration reactor could be built. These additional stages could add $2 billion to $4 billion to the cost and 20 years to the development timeline. The subsequent commercial demonstration would not begin until 2040; reactors would not be available for sale until the mid-2040s or even the 2050s.

In May 2020, after receiving $160 million in initial congressional funding for the new Advanced Reactor Demonstration Program (ARDP), the DOE issued a solicitation for two “advanced” commercial demonstration reactors. In October 2020, the DOE chose SFR and HTGR designs—as one might expect given its 2017 technology assessment. The DOE estimates that these projects will cost up to $3.2 billion each (with the vendors contributing 50 percent) for the reactors and their supporting fuel facilities. The department is requiring that the reactors be operational within seven years, a timeline—including NRC licensing, construction, fuel production, and startup testing—that it acknowledges is very aggressive.

However, even if this deadline can be met and the reactors work reliably, subsequent commercial units likely would not be ordered before the early 2030s. Moreover, it is far from certain that the two designs the DOE selected for the ARDP are mature enough for commercial demonstration. Past demonstrations of both SFRs and HTGRs have encountered safety and reliability problems. Additionally, for both reactor types, the DOE has chosen designs that differ significantly from past demonstration reactors.

In the 1990s, the NRC concluded that it would require information from representative prototype testing prior to licensing either of these reactor types—but no prototypes were ever built. More recently, in a letter to the NRC, the agency’s independent Advisory Committee on Reactor Safeguards reaffirmed the importance of prototypes in new reactor development. Nevertheless, the NRC—a far weaker regulator today—has apparently changed its position and may proceed with licensing the ARDP demonstration reactors without requiring prototype testing first. But by skipping prototype testing and proceeding directly to commercial units, these projects may run not only the risk of experincing unanticipated reliability problems, but also the risk of suffering serious accidents that could endanger public health and safety.

An additional challenge for NLWR demonstrations and subsequent commercial deployment is the availability of fuels for those reactors, which would differ significantly from the fuel that today’s LWRs use. Even a single small reactor could require a few tons of HALEU per year—far more than the 900 kilograms per year projected to be available over the next several years from a DOE-funded pilot enrichment plant that Centrus Energy Corporation is building in Piketon, Ohio. It is far from clear whether that pilot will succeed and can be scaled up in time to support the two NLWR demonstrations by 2027, not to mention the numerous other HALEU-fueled reactor projects that have been proposed……. https://ucsusa.org/resources/advanced-isnt-always-better#read-online-content

Despite the problems, small nuclear reactor salesmen aggressively marketing: it’s make or break time for the nuclear industry.

April 5, 2021

Entrepreneurs Look to Small-Scale Nuclear Reactors,   The American Society of Mechanical Engineers,  Mar 2, 2021, by Michael Abrams  ‘‘……… even concepts that are predicated on being small, modular, and fast to build seem locked into decades-long development cycles.

The key to reviving the nuclear power industry  is building these small reactors not as projects, but as factory-made products. That’s easier said than done. “Usually, a bunch of nuclear engineers go in a room and then they come out after a year or two, and they have a design that doesn’t have a lot of foundation in realty, and nobody can make it, and the projects dies,” said Kurt Terrani, a senior staff scientist at Oak Ridge National Laboratory………..

In terms of reactor physics, the NuScale concept is fairly bog standard: low-enriched uranium, light-water cooling. In essence, their reactor is just a smaller version of the nuclear plants already in operation. That NuScale didn’t go with a more revolutionary design to mitigate waste or utilize an alternative fuel cycle is no accident. To do so would require the Nuclear Regulatory Commission to come up with an entirely new licensing framework, said José Reyes, cofounder and chief technology officer at NuScale.

“Pressurized water-cooled reactors have benefited from billions of dollars of research and development and millions of hours of operating experience over the past 50 year,” Reyes said. “NuScale went with a more traditional approach to assure a design that is cost-competitive and capable of near-term deployment.” …………. The containment vessel will also sit underground in a giant pool capable of absorbing radiation from a leak. Multiple reactors would share the same pool. Being underground, they are also earthquake- and airplane-resistant. [ Ed. no mention of what would happen in the case of flooding, or of an emergency requirinfpeople to quickly respond underground] The company believes that its design is robust enough that utilities could site the reactors much closer to population centers, rather than in remote locations surrounded by an emergency planning zone.

So far, the concept and design have been convincing enough to win funding from the DoE and to move NuScale farther along in the regulatory process than any of its would-be competitors. “NuScale’s small modular reactor technology is the world’s first and only to undergo design certification review by the U.S. Nuclear Regulatory Commission,”   NuScale set out to design a reactor that was small enough to transport to site, essentially complete. Not everyone agrees, however, that building out a power plant in 60-MW modules is optimal. “The whole idea of SMRs is that smaller is better,” said Jacopo Buongiorno, a professor of nuclear science and engineering at MIT and the director of the Center for Advanced Nuclear Energy Systems. “But within the class of small reactors, larger is still better.  If you can design a reactor that is still simple, that  is still passively safe, that can still be built in a factory, but that generates 300 megawatts, that for sure is going to be more economically attractive than the same thing that generates 60 megawatts.” Buongiorno points to GE’s BWRX-300 concept as a potentially better option. It, too, is a light-water reactor with fuel rods and passive cooling. But its larger size makes it a more of a plug-and-play replacement for coal plants…… Holtec’s SMR-160 is intended to be installed deep underground; the steel containment vessel is strong enough to keep the core covered during any conceivable disaster. “ …… Other SMR designs are dispensing with solid fuel altogether. These reactors would instead dissolve uranium in a molten salt. Some of these designs are miniaturized versions of the Molten Salt Reactor Experiment built by the Oak Ridge National Laboratory in the late 1960s………   The one downside to molten salt reactors is that the salts usually contain fluoride, which is extremely corrosive. Simplifying the mechanical design of the cooling system cuts down on the parts in danger of corroding, but the pins that will contain the fuel are still at risk…..

Make or Break for Nuclear

Moltex is aiming for build costs at around $2,000 per kW—more than wind or solar, but less than newly built coal or gas plants, let alone competing nuclear concepts. “We’ve believe we’ve come up with a concept that can radically reduce the cost of nuclear power,” ……   Other SMR companies are less aggressive with their cost estimates—NuScale has its scopes on a cost of around $3,600 per kW, while GE is aiming for less than $2,500—but still come in under conventional nuclear power. ……. Proof of whether those costs can be achieved will be actual construction and commissioning. “This decade will be very telling,” said Chicago’s Rosner. “It’s the make or break decade for nuclear.” Furthest along is NuScale, which in September 2020 announced its SMR design had been issued a standard design approval from the U.S. Nuclear Regulatory Commission. That means the design can be referenced in an application for a construction permit—a big step, and one that had not been before achieved by a small modular reactor design. In August 2020, the NRC had completed its Phase 6 review and issued a Final Safety Evaluation Report (FSER). The company also announced in November that it had uprated its Power Module to 77 MW, which should improve its economics by around 25 percent…. The key is getting the cost and scale right.  https://www.asme.org/topics-resources/content/entrepreneurs-look-to-small-scale-nuclear-reactors

Reality bats last-Small Nuclear Reactors just not economic for Australia (or anywhere else)

February 18, 2021
Small modular reactor rhetoric hits a hurdle  https://reneweconomy.com.au/small-modular-reactor-rhetoric-hits-a-hurdle-62196/    Jim Green, 23 June 2020, The promotion of ‘small modular reactors’ (SMRs) in Australia has been disrupted by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Australian Energy Market Operator (AEMO). The latest GenCost report produced by the two agencies estimates a hopelessly uneconomic construction cost of A$16,304 per kilowatt (kW) for SMRs.But it throws the nuclear lobby a bone by hypothesising a drastic reduction in costs over the next decade. The A$16,304 estimate has been furiously attacked by, amongst others, conservative politicians involved in a federal nuclear inquiry last year, and the Bright New World (BNW) nuclear lobby group. The estimate has its origins in a commissioned report written by engineering company GHD. GHD provides the estimate without clearly explaining its origins or basis. And the latest CSIRO/AEMO report does no better than to state that the origins of the estimate are “unclear”. Thus nuclear lobbyists have leapt on that muddle-headedness and filled the void with their own lowball estimates of SMR costs.
Real-world data
Obviously, the starting point for any serious discussion about SMR costs would be the cost of operational SMRs – ignored by CSIRO/AEMO and by lobbyists such as BNW. There is just one operational SMR, Russia’s floating plant. Its estimated cost is US$740 million for a 70 MW plant. That equates to A$15,200 per kW – similar to the CSIRO/AEMO estimate of A$16,304 per kW. Over the course of construction, the cost quadrupled and a 2016 OECD Nuclear Energy Agency report said that electricity produced by the Russian floating plant is expected to cost about US$200 (A$288) per megawatt-hour (MWh) with the high cost due to large staffing requirements, high fuel costs, and resources required to maintain the barge and coastal infrastructure. Figures on costs of SMRs under construction should also be considered – they are far more useful than the estimates of vendors and lobbyists, which invariably prove to be highly optimistic. The World Nuclear Association states that the cost of China’s high-temperature gas-cooled SMR (HTGR) is US$6,000 (A$8,600) per kW. Costs are reported to have nearly doubled, with increases arising from higher material and component costs, increases in labour costs, and increased costs associated with project delays. The CAREM SMR under construction in Argentina illustrates the gap between SMR rhetoric and reality. In 2004, when the reactor was in the planning stage, Argentina’s Bariloche Atomic Center estimated an overnight cost of USS$1,000 per kW for an integrated 300-MW plant (while acknowledging that to achieve such a cost would be a “very difficult task”). When construction began in 2014, the cost estimate was US$15,400 per kW (US$446 million / 29 MW). By April 2017, the cost estimate had increased US$21,900 (A$31,500) per kW (US$700 million / 32 MW). To the best of my knowledge, no other figures on SMR construction costs are publicly available. So the figures are: A$15,200 per kW for Russia’s light-water floating SMR A$8,600 per kW for China’s HTGR A$31,500 per kW for Argentina’s light-water SMR The average of those figures is A$18,400 per kW, which is higher than the CSIRO/AEMO figure of A$16,304 per kW and double BNW’s estimate of A$9,132 per kW. The CSIRO/AEMO report says that while there are SMRs under construction or nearing completion, “public cost data has not emerged from these early stage developments.” That simply isn’t true.
BNW’s imaginary reactor
BNW objects to CSIRO/AEMO basing their SMR cost estimate on a “hypothetical reactor”. But BNW does exactly the same, ignoring real-world cost estimates for SMRs under construction or in operation. BNW starts with the estimate of US company NuScale Power, which hopes to build SMRs but hasn’t yet begun construction of a single prototype. BNW adds a 50% ‘loading’ in recognition of past examples of nuclear reactor cost overruns. Thus BNW’s estimate for SMR construction costs is A$9,132 per kW. Two big problems: NuScale’s cost estimate is bollocks, and BNW’s proposed 50% loading doesn’t fit the recent pattern of nuclear costs increasing by far greater amounts. NuScale’s construction cost estimate of US$4,200 per kW is implausible. It is far lower than Lazard’s latest estimate of US$6,900-12,200 per kW for large reactors and far lower than the lowest estimate (US$12,300 per kW) of the cost of the two Vogtle AP1000 reactors under construction in Georgia (the only reactors under construction in the US). NuScale’s estimate (per kW) is just one-third of the cost of the Vogtle plant – despite the unavoidable diseconomies of scale with SMRs and despite the fact that independent assessmentsconclude that SMRs will be more expensive to build (per kW) than large reactors. Further, modular factory-line production techniques were trialled with the twin AP1000 Westinghouse reactor project in South Carolina – a project that was abandoned in 2017 after the expenditure of at least US$9 billion, bankrupting Westinghouse. Lazard estimates a levelised cost of US$118-192 per MWh for electricity from large nuclear plants. NuScale estimates a cost of US$65 per MWh for power from its first plant. Thus NuScale claims that its electricity will be 2-3 times cheaper than that from large nuclear plants, which is implausible. And even if NuScale achieved its cost estimate, it would still be higher than Lazard’s figures for wind power (US$28-54) and utility-scale solar (US$32-44). BNW claims that the CSIRO/AEMO levelised cost estimate of A$258-338 per MWh for SMRs is an “extreme overestimate”. But an analysis by WSP / Parsons Brinckerhoff, prepared for the SA Nuclear Fuel Cycle Royal Commission, estimated a cost of A$225 per MWh for a reactor based on the NuScale design, which is far closer to the CSIRO/AEMO estimate than it is to BNW’s estimate of A$123-128 per MWh with the potential to fall as low as A$60.
Cost overruns
BNW proposes adding a 50% ‘loading’ to NuScale’s cost estimate in recognition of past examples of reactor cost overruns, and claims that it is basing its calculations on “a first-of-a-kind vendor estimate [NuScale’s] with the maximum uncertainly associated with the Class of the estimate.” Huh? The general pattern is that early vendor estimates underestimate true costs by an order of magnitude, while estimates around the time of initial construction underestimate true costs by a factor of 2-4. Here are some recent examples of vastly greater cost increases than BNW allows for: * The estimated cost of the HTGR under construction in China has nearly doubled. The cost of Russia’s floating SMR quadrupled. * The estimated cost of Argentina’s SMR has increased 22-fold above early, speculative estimates and the cost increased by 66% from 2014, when construction began, to 2017. * The cost estimate for the Vogtle project in US state of Georgia (two AP1000 reactors) has doubled to more than US$13.5 billion per reactor and will increase further. In 2006, Westinghouse said it could build an AP1000 reactor for as little as US1.4 billion – 10 times lower than the current estimate for Vogtle. * The estimated combined cost of the two EPR reactors under construction in the UK, including finance costs, is £26.7 billion (the EU’s 2014 estimate of £24.5 billion plus a £2.2 billion increase announced in July 2017). In the mid-2000s, the estimated construction cost for one EPR reactor in the UK was £2 billion, almost seven times lower than the current estimate. * The estimated cost of about €12.4 billion for the only reactor under construction in France is 3.8 times greater than the original €3.3 billion estimate. * The estimated cost of about €11 billion for the only reactor under construction in Finland is 3.7 times greater than the original €3 billion estimate.
Timelines
BNW notes that timelines for deployment and construction are “extremely material” in terms of the application of learning rates to capital expenditure. BNW objected to the previous CSIRO/AEMO estimate of five years for construction of an SMR and proposed a “more probable” three-year estimate as well as an assumption that NuScale’s first reactor will begin generating power in 2026 even though construction has not yet begun. For reasons unexplained, CSIRO/AEMO also assume a three-year construction period in their latest report, and for reasons unexplained the operating life of an SMR is halved from 60 years to 30 years. None of the real-world evidence supports the arguments about construction timelines: * The construction period for the only operational SMR, Russia’s floating plant, was 12.5 years. * Argentina’s CAREM SMR was conceived in the 1980s, construction began in 2014, the 2017 start-up date was missed and subsequent start-up dates were missed. If the current schedule for a 2023 start-up is met it will be a nine-year construction project rather than the three years proposed by CSIRO/AEMO and BNW for construction of an SMR. Last year, work on the CAREM SMR was suspended, with Techint Engineering & Construction asking Argentina’s National Atomic Energy Commission to take urgent measures to mitigate the project’s serious financial breakdown. In April 2020, Argentina’s energy minister announced that work on CAREM would resume. * Construction of China’s HTGR SMR began in 2012, the 2017 start-up date was missed, and if the targeted late-2020 start-up is met it will be an eight-year construction project. * NuScale Power has been trying to progress its SMR ambitions for over a decade and hasn’t yet begun construction of a single prototype reactor. * The two large reactors under construction in the US are 5.5 years behind schedule and those under construction in France and Finland are 10 years behind schedule. * In 2007, EDF boasted that Britons would be using electricity from an EPR reactor at Hinkley Point to cook their Christmas turkeys in December 2017 – but construction didn’t even begin until December 2018.
Learning rates
In response to relentless attacks from far-right politicians and lobby groups such as BNW, the latest CSIRO/AEMO GenCost report makes the heroic assumption that SMR costs will fall from A$16,304 per kW to as little as A$7,140 per kW in 2030, with the levelised cost anywhere between A$129 and A$336 per MWh. The report states that SMRs were assigned a “higher learning rate (more consistent with an emerging technology) rather than being included in a broad nuclear category, with a low learning rate consistent with more mature large scale nuclear.” But there’s no empirical basis, nor any logical basis, for the learning rate assumed in the report. The cost reduction assumes that large numbers of SMRs will be built, and that costs will come down as efficiencies are found, production capacity is scaled up, etc. Large numbers of SMRs being built? Not according to expert opinion. A 2017 Lloyd’s Register report was based on the insights of almost 600 professionals and experts from utilities, distributors, operators and equipment manufacturers, who predicted that SMRs have a “low likelihood of eventual take-up, and will have a minimal impact when they do arrive”. A 2014 report produced by Nuclear Energy Insider, drawing on interviews with more than 50 “leading specialists and decision makers”, noted a “pervasive sense of pessimism” about the future of SMRs. Last year, the North American Project Director for Nuclear Energy Insider said that there “is unprecedented growth in companies proposing design alternatives for the future of nuclear, but precious little progress in terms of market-ready solutions.” Will costs come down in the unlikely event that SMRs are built in significant numbers? For large nuclear reactors, the experience has been either a very slow learning rate with modest cost decreases, or a negative learning rate. If everything went astonishingly well for SMRs, it would take several rounds of learning to drastically cut costs to A$7,140 per kW. Several rounds of SMR construction by 2030, as assumed in the most optimistic scenario in the CSIRO/AEMO report? Obviously not. The report notes that it would take many years to achieve economies, but then ignores its own advice: “Constructing first-of-a-kind plant includes additional unforeseen costs associated with lack of experience in completing such projects on budget. SMR will not only be subject to first-of-a-kind costs in Australia but also the general engineering principle that building plant smaller leads to higher costs. SMRs may be able to overcome the scale problem by keeping the design of reactors constant and producing them in a series. This potential to modularise the technology is likely another source of lower cost estimates. However, even in the scenario where the industry reaches a scale where small modular reactors can be produced in series, this will take many years to achieve and therefore is not relevant to estimates of current costs (using our definition).” Even with heroic assumptions resulting in CSIRO/AEMO’s low-cost estimate of A$129 per MWh for SMRs in 2030, the cost is still far higher than the low-cost estimates for wind with two hours of battery storage (A$64), wind with six hours of pumped hydro storage (A$86), solar PV with two hours of battery storage (A$52) or solar PV with six hours of pumped hydro storage (A$84). And the CSIRO/AEMO high-cost estimate for SMRs in 2030 ($336 per MWh) is more than double the high estimates for solar PV or wind with 2-6 hours of storage (A$90-151).
Reality bats last
The economic claims of SMR enthusiasts are sharply contradicted by real-world data. And their propaganda campaign simply isn’t working – government funding and private-sector funding is pitiful when measured against the investments required to build SMR prototypes let alone fleets of SMRs and the infrastructure that would allow for mass production of SMR components. Wherever you look, there’s nothing to justify the hype of SMR enthusiasts. Argentina’s stalled SMR program is a joke. Plans for 18 additional HTGRs at the same site as the demonstration plant in China have been “dropped” according to the World Nuclear Association. Russia planned to have seven floating nuclear power plants by 2015, but only recently began operation of its first plant. South Korea won’t build any of its domestically-designed SMART SMRs in South Korea – “this is not practical or economic” according to the World Nuclear Association – and plans to establish an export market for SMART SMRs depend on a wing and a prayer … and on Saudi oil money which is currently in short supply. ‘Reality bats last’, nuclear advocate Barry Brook used to say a decade ago when a nuclear ‘renaissance’ was in full-swing. The reality is that the renaissance was short-lived, and global nuclear capacity fell by 0.6 gigawatts last year while renewable capacity increased by a record 201 gigawatts. Dr. Jim Green is the national nuclear campaigner with Friends of the Earth Australia and editor of the Nuclear Monitor newsletter.

Even a pro nuclear enthusiast admits that Small Nuclear Reactors cause toxic radioactive wastes

February 18, 2021

13 Feb 21 I was quite fascinated to note a paragraph in a long nuclear  propaganda article, (by Stikeman Elliott, in Mondaq) yesterday, in which this, hitherto rather hidden problem, gets a mention.

Of course, this pro nuclear writer is not really worried all that much about the actual problem.

Oh no –  his concern is about the public’s perception of it –  that public perception might hamper the develoment of the nuclear lobby’s newest gimmick. Can’t have that!

”…….efforts need to be made to address the perceived risks so as to establish confidence in the ability of SMRs to operate safely while proving to be a viable source of low-carbon energy. 

While SMRs produce less nuclear waste than traditional reactors, the issue of radioactive waste still exists. Nuclear waste needs to be safely stored and transported to secure facilities. SMRs have often been proposed as a solution for electricity generation in remote areas, but this proves problematic from a waste perspective as any nuclear waste would need to be transported over long distances. There is currently no permanent nuclear waste storage site in Canada……”

Dangers of plutonium fuelled, sodium cooled “Versatile Nuclear Reactor”

February 18, 2021

”Small Modular Reactors”’- governments are being sucked in by the ”billionaires’ nuclear club” 

February 18, 2021

SNC-Lavalin   Scandal-ridden SNC-Lavalin is playing a major role in the push for SMRs.

Terrestrial Energy…..  Terrestrial Energy’s advisory board includes Dr. Ernest Moniz, the former US Secretary of the Dept. of Energy (2013-2017) who provided more than $12 billion in loan guarantees to the nuclear industry. Moniz has been a key advisor to the Biden-Harris transition team, which has come out in favour of SMRs.

The “billionaires’ nuclear club”  …“As long as Bill Gates is wasting his own money or that of other billionaires, it is not so much of an issue. The problem is that he is lobbying hard for government investment.”

Going after the public purse

Bill Gates was apparently very busy during the 2015 Paris climate talks. He also went on stage during the talks to announce a collaboration among 24 countries and the EU on something called Mission Innovation – an attempt to “accelerate global clean energy innovation” and “increase government support” for the technologies.

Gates’ PR tactic is effective: provide a bit of capital to create an SMR “bandwagon,” with governments fearing their economies would be left behind unless they massively fund such innovations.

governments “are being suckers. Because if Wall Street and the banks will not finance this, why should it be the role of the government to engage in venture capitalism of this kind?”

It will take a Herculean effort from the public to defeat this NICE Future, but along with the Assembly of First Nations, three political parties – the NDP, the Bloc Quebecois, and the Green Party – have now come out against SMRs.