" Peythieu added that the cost of SWU contained in LEU+ material may be just a step-change higher than for current <5% LEU, whereas higher enriched HALEU pricing would probably be very different."
Yep, LEU+ is certainly a direction that some fuel manufacturers are taking right now!
https://atompeace.org/haleu-going-beyond-5/
going Beyond 5%
By Anna Bryndza|August 19th, 2020|Research|0 Comments
Commercial light water reactors (LWRs) use fuel that does not exceed the 5% 235U weight-percent (w/o) enrichment level. However, the last few years have seen increasing interest in exceeding the 5% limit, also known as high-assay low enriched uranium (HALEU), recently culminating in a flurry of notable developments. Thus, for the first time, there is a concerted effort to clear the path towards establishing a nuclear fuel supply chain to ensure the availability of HALEU. This essay examines the drivers behind the latest HALEU developments, current global efforts to build a commercially viable HALEU supply chain, as well as challenges yet to be overcome.
What Is HALEU and Who Needs It
HALEU is a broad term that describes LEU enriched above 5% 235U, but below 20% 235U. Enrichment above 20% 235U is not commercially allowed due to nonproliferation reasons as anything above this threshold is considered high enriched or weapons-grade. The desired HALEU enrichment levels vary depending on the application, but most fall into three separate ranges: 6-7% (LEU+); 13-16%, and just below 20% (~19.75%). As a result, it is important to begin by understanding what the projected uses for HALEU are.
Existing LWRs Seeking Improved Economics
Staying below the 5% enrichment level for existing LWRs limits nuclear power plant operators as they seek to improve the operational efficiency of their fuel designs. According to a study carried out by Electric Power Research Institute (EPRI), 99% of efficiency variations in LWRs is attributable to enrichment and burnup. Figure 1 illustrates the relationship between these factors. Indeed, operators of some existing nuclear power plants are seriously considering switching to LEU+. Having studied the proposal for decades, Russia, is quite advanced in its studies of using LEU+ for VVER-1000 and VVER-1200 reactors.
Figure 1. Fuel Burnup / Enrichment Impact
Source: EPRI
Accident Tolerant Fuels (ATFs) are a promising direction currently being explored and tested in the U.S. These solutions, beyond their inherent safety benefits, could also provide the operating nuclear fleeting with substantial cost efficiencies. However, many ATF solutions, particularly those that are more revolutionary, long-term designs, translate into higher neutron absorption penalties as new cladding materials are envisioned. This, in turn, requires compensation by higher enrichments to allow for higher burnups. As such, further progress in commercial implementation of ATFs is closely connected with the production and utilization of LEU+.
Advanced Reactors
There are a number of advanced nuclear technologies in various stages of development. Notable among these are small modular reactor (SMR) and advanced reactor technologies based on gas-cooled, liquid metal, or molten salt designs. Many of these advanced reactors will require HALEU in the highest enrichment category of just short of 20%. Utilizing higher enrichment fuel allows these next generation reactor technologies to achieve improved efficiencies and longer core lifetimes.
Research Reactors
HALEU is already commonly utilized in research reactors. A global effort led by the U.S. has resulted in many of the world’s research reactors converting their reactors to use HALEU from HEU to help meet nonproliferation objectives. High performance research reactors in the U.S. and Europe have yet to be converted, however. These reactors require new high-density fuels currently under development, which will result in a larger increase in HALEU demand.
Medical Isotope Production
Using HALEU to produce medical isotopes, particularly molybdenum-99 (Mo-99), is critical for diagnostic medical imaging. Historically, Mo-99 production has been done using HEU targets, but the U.S. has supported an initiative to convert HEU production processes to HALEU targets. Although the needed quantities are small, the HALEU inputs are critical to maintain the medical isotope industry.
HALEU Fuel Cycle
The development of a robust HALEU fuel cycle is complicated by the varying enrichment levels classified as HALEU fuel. The LEU+ fuel cycle for existing LWRs utilizing UO2 / zircaloy fuels would primarily rely on the existing centrifuge-based enrichment infrastructure, although it will require additional licensing and some modifications.
Figure 2. HALEU Nuclear Fuel Cycle
Source: URENCO
Russia’s HALEU Activities
Russia has long been a proponent of LEU+. The country also has several advanced reactor projects and existing capabilities to produce and utilize HALEU. As such, it comes as no surprise that even though the U.S. is now seen as a hotbed of various HALEU-focused initiatives, it is actually Russia that has the most advanced studies, benchmarking, economic justifications, infrastructure, and regulatory environment for HALEU’s introduction.
TVEL has already carried out substantial work related to LEU+, which has focused on increasing the fuel cycle of VVER-1000 units to 18 months and VVER-1200 reactors to 24 months. For each of these, two enrichment levels have been considered: slightly below and slightly above 5%. Separately, TVEL’s studies of ATF for VVER-1200 reactors are based on an average enrichment level of 5.74% (maximum enrichment level of 6.06%).
LEU+ (up to 5.37%) is also considered for reprocessed uranium (RepU) fuel to be used in VVER-type reactors to compensate for the penalties of enriched reprocessed uranium (ERU). The enrichment level of fuel depends on the 236U concentration of ERU. Today, Russia utilizes its RepU in the RBMK-type reactors, which are able to use lower enrichment levels. As the country is phasing out its RBMK fleet, Russia is shifting its attention to use ERU in its VVER fleet. The final decision on the enrichment level of ERU to be used in VVER-type reactors is yet to be made.
In terms of infrastructure, Russia is well advanced, as the country can produce HALEU of varying enrichment levels from its existing enrichment plants, also in addition to production via a blending method. Both of Russia’s fuel fabrication plants already produce nuclear fuel of varying enrichment levels, including for LWRs, SMRs, fast neutron, and research reactors.
In 2018, TVEL hosted the IAEA Technical Meeting on LWR fuel enrichment beyond the 5% limit, facilitating an international discussion regarding the economics and safety aspects LEU+. There is no doubt that Russia is the most likely to be the first to exceed the 5% enrichment limit for LWR fuel.
When it comes to higher enrichment HALEU, there is no doubt that Russia would also be fully capable of becoming a supplier of such fuel and would be very interested in serving this emerging market. It appears clear, however, that this emerging market requires government support at this early stage, with the U.S. recently stepping up its backing and involvement in the HALEU sector. For various reasons, ranging from ranging from trade to geopolitical concerns, among others, breaking into this emerging western market will likely be challenging for Russia.
U.S. HALEU Initiatives
The U.S. government has recently increased its interest and support in the development a domestic HALEU supply chain, taking a dual approach towards meeting projected industry needs via projects with INL and Centrus. In the near-term, the government is prepared to meet the industry’s limited HALEU needs through its domestic stockpile, but the availability of government material is limited and should be considered a stopgap measure until a steady supply of HALEU is manufactured commercially in the U.S.
U.S. DOE Clears Path for HALEU Fabrication at INL
On January 17, the U.S. Department of Energy (DOE) determined that using DOE-owned HALEU stored at Idaho National Laboratory (INL) will not have a significant impact on the environment and is an important tool for advancing safe, economical, low carbon nuclear energy.
With the finding of no significant impact, the U.S. government will fabricate HALEU nuclear fuel at INL from the lab’s HALEU feedstock. The volumes in question are limited – approximately 10 metric tons (MT). Most of the HALEU to be used for fuel fabrication results from the processing and treatment of used fuel from the decommissioned EBR-II reactor at INL. Fabrication will take place at INL’s Materials and Fuels Complex (MFC) and potentially at the Idaho Nuclear Technology and Engineering Center (INTEC).
According to INL, this effort will support the near-term RD&D needs of private-sector developers and government agencies, including advanced reactor developers. INL stated that HALEU would have limited applications for specific advanced reactor designs, and is one of several efforts undertaken by DOE to help ensure the availability of HALEU in support of the U.S. nuclear power industry.
INL’s supply of HALEU is a temporary measure and is recognized as such by all parties involved. This measure is indeed a bridge allowing the industry itself to create the necessary infrastructure in time.
DOE’s choice of INL as the location for the HALEU program is not surprising since the site currently stores the HALEU to be used in fabrication. Although some have pointed to INL being the future site of the NuScale demonstration small modular reactor (SMR), this reactor design is intended to use conventional LEU nuclear fuel.
U.S. DOE Selects Centrus for HALEU Project
On May 31, U.S. DOE announced a sole source award to a Centrus subsidiary American Centrifuge Operating LLC for the demonstration of HALEU production. The demonstration program has two primary goals:
- Deployment of a cascade of 16 HALEU AC-100M gas centrifuges by June 2022 capable of producing 19.75% 235U enriched product.
- Demonstration of the capability to produce HALEU with existing U.S. origin enrichment technology and provide DOE with a small quantity of HALEU beginning in 2022 for use in its research and development activities.
Centrus will modify its AC-100 centrifuge design to run a small cascade. The company previously operated a 120-centrifuge demonstration cascade of AC-100s before ending the program in 2015. This cascade is understood to have been fully dismantled and decommissioned. Although the centrifuges themselves have been decommissioned, Centrus is understood to have retained the supporting infrastructure, including the buildings, along with the U.S. Nuclear Regulatory Commission (NRC) license for the demonstration facility. The new cascade will only have 15 machines, which will use an optimized, upgraded version of the AC-100. It is reasonable to assume that Centrus continues to seek ways to prove technological reliability of its centrifuge design as the company’s long-term goals are ultimately to rejoin the group of primary enrichers.
Figure 3. U.S. HALEU Demonstration Enrichment Project
Source: U.S. DOE
U.S. government’s preference for Centrus despite the fact it has no existing enrichment plant appears to also be tied to its efforts to create a domestic source of enriched uranium to support tritium production for its nuclear weapons stockpile. In his May 2018 statement before Congress, Edward McGinnis, Deputy Assistant Secretary for Nuclear Energy at DOE, stated that the National Nuclear Security Administration’s domestic uranium enrichment program “has synergies with efforts for a HALEU enrichment capability in the longer run,” adding that the NE and the NNSA “intend to continue our production collaborations on HALEU in the future.”
Opposition to DOE’s Centrus Award
Wyoming Senator and Chair of the Senate Environment and Public Works Commit-tee John Barrasso opposed DOE awarding the $115 million contract to Centrus. Barrasso issued DOE Secretary Rick Perry a letter on January 23 that was critical of the Centrus contract, questioning whether the money would end up supporting Russia’s TENEX, from which Centrus buys enriched uranium. “This contract appears to use American taxpayer funding to bailout Centrus, an unsuccessful business that relies on commercial relationships with Russian state-owned corporations to stay in business,” Barrasso wrote. “Congress did not authorize or fund this project.”
Meanwhile, URENCO has the support of Senator Martin Heinrich (D-NM), who has continued his efforts to make URENCO a contender in the HALEU market. Senator Heinrich has also publicly questioned the sole-source award to Centrus.
Centrus’ Partnership with X-energy
Of note here is Centrus’ advanced reactors initiative with X-energy. The companies signed a services contract to proceed with the preliminary design of a facility to fabricate advanced nuclear fuel for the X-energy Xe-100 high temperature gas-cooled reactor, which is designed to use HALEU TRISO fuel.
NEI’s Role in Promoting Government Action on HALEU
The Nuclear Energy Institute (NEI) has played an important role advocating for the U.S. government to take steps towards ensuring HALEU supply for future needs. In July 2018, NEI sent a letter to U.S. Secretary of Energy Rick Perry, requesting the DOE to provide an interim supply of HALEU. NEI pointed out that DOE already has material that could be used for this interim supply: both an inventory of HEU that could be downblended to HALEU and spent high-enriched fuel that could be processed and converted to HALEU.
In a response to the DOE’s announcement of the pilot HALEU program, NEI’s CEO Maria Korsnick said, “The Department of Energy’s high-assay low-enriched uranium (HALEU) pilot program demonstrates continued confidence in the success of the next generation of advanced nuclear reactors and for new fuel options for the existing fleet. DOE’s investment is a significant starting point in the HALEU fuel infrastructure. We appreciate Secretary Perry’s attention to this urgent matter and look forward to working with DOE and Congress to ensure the U.S. can compete globally to design and deploy advanced reactor technology.”
Legislative Support for HALEU Infrastructure
This March, a bipartisan group of U.S. Senators led by Senate Energy and Natural Resources Chairman Lisa Murkowski (R-AK) reintroduced the Nuclear Energy Leadership Act (NELA) 1 aimed at boosting U.S. nuclear energy innovation. NELA instructs the DOE to make available the following quantities of HALEU:
“(A) by December 31, 2022, high-assay, low-enriched uranium containing not less than 2 metric tons of the uranium-235 isotope; and
(B) by December 31, 2025, high-assay, low-enriched uranium containing not less than 10 metric tons of the uranium-235 isotope (as determined including the quantities of the uranium-235 isotope made available before December 31, 2022).”
Additionally, the proposed legislation requires the DOE to establish an RD&D program for the development of NRC-licensed HALEU transport packages.
URENCO Seeks to Become HALEU Supplier
URENCO has also been actively looking at opportunities in the area of HALEU production.
URENCO Announces HALEU Capabilities
In February 2019, URENCO’s U.S. subsidiary announced the launching of a new program that covers the production of HALEU. The company said that its advanced gas centrifuge technology can produce a “full range of LEU enrichments, including HALEU.”
Currently, several URENCO enrichment facilities are licensed to produce enrichments above 5% 235U. The company said it is exploring the construction of a dedicated HALEU unit at the URENCO USA facility in Eunice, New Mexico, along with design engineering and related licensing activities to support the initiative. Furthermore, URENCO USA is working to support the near-term delivery of slightly greater than 5% 235U enrichments for existing LWRs seeking higher burnups and/or extended operating cycles.
“This work falls within the core expertise and technology of URENCO as a leader in the civil nuclear power industry for nearly 50 years, providing enrichment services for customers and meeting 100% of our deliveries,” said former URENCO CEO Thomas Haeberle. “We have proven enrichment technology which benefits from modular deployment. This was successfully demonstrated when we built the USA’s world scale commercial enrichment plant which can suitably accommodate a HALEU facility.”
URENCO Explores Construction of Dedicated HALEU Unit
Getting URENCO into the game is not an easy task since it is not a U.S. owned company. The DOE’s sole-source award to Centrus was based in large part on the fact that the company is the only U.S.-owned and controlled entity with an existing NRC license. Both the international treaties and U.S. policy forbid the use of foreign technology for national security reasons, although there are no treaty considerations or restrictions regarding production of HALEU to be used in the commercial nuclear fuel cycle.
What URENCO does have going for it is the fact that unlike Centrus, the company already has a proven enrichment technology and an operating enrichment facility in the United States. URENCO’s David Fletcher emphasized this point in April during the World Nuclear Fuel Cycle (WNFC) conference in Miami, Florida, noting that the company’s gas centrifuges are capable of producing a full array of HALEU enrichments without further development or testing.
The company’s recent announcements point to the fact that URENCO is considering creating a dedicated HALEU enrichment unit. Speaking before a House Energy and Commerce subcommittee in 2018, Melissa Mann, President of URENCO USA Inc., said that the company would only need an amended NRC license to support such a HALEU enrichment module. Mann further stated that “if detailed design, site permitting and contractor selections were undertaken during the NRC review process, we could construct, commission and start-up such a module within 24 months of NRC licensing.”
In December 2018, URENCO’s Stephen Cowne said that URENCO USA could submit an amendment request by April 30 to increase the enrichment level of the facility’s license to 5.5% while a license to increase the enrichment limit to 6% could be ready by June 30. Cowne noted in his presentation that the creation of a “complete and sustainable HALEU fuel cycle” covers three capabilities, of which enrichment is the initial one. The site would also need to develop capabilities to convert HALEU into metal, oxide, or salts along with fuel fabrication facility to manufacture specific fuel designs.
URENCO is currently exploring construction of a dedicated HALEU unit in its U.S. enrichment plant, with additional activity at URENCO USA underway to support near-term delivery of LEU slightly above 5% to support the operating LWRs looking to increase the burnup rates or extend operating cycles.
Interestingly, most of URENCO’s activities in the area of HALEU appear to be centered on the U.S. and its UUSA plant although there is likely feasibility to produce HALEU at all three of its European sites if the market interest materializes.
Orano’s Work on HALEU
According to a speech at the 46th Annual Meeting of the World Nuclear Fuel Market, (WNFM) in June 2019 in Lisbon, Portugal by Jacques Peythieu, Orano’s Senior Executive Vice President, Chemistry Enrichment Business Unit, his company is also currently working on a number of areas related to HALEU. Orano has been looking at the feasibility and commercial desirability of producing various HALEU products from its Georges Besse II (GBII) in France. According to Peythieu, Orano has discovered no major technical obstacles to increasing enrichment levels up to 20% at GBII. However, the French nuclear regulator ASN will need to approve any increase beyond the current limit of 5% enrichment, and such a license is expected to take at least two years to acquire. Peythieu indicated that while HALEU production is not seen as very difficult, the advanced fuel designs that are being contemplated involving uranium metal would be more challenging. Notably, Orano’s French compatriot Framatome is currently working on a joint venture with Lightbridge on a zirconium-uranium metallic fuel design through a 50-50 joint venture company called Enfission. The Enfission fuel concept is expected to require LEU+ material in metallic form.
Challenges to Going Beyond the 5% Enrichment Limit
According to all information and statements by the enrichers, technically producing EUP with enrichment levels beyond 5% is the easy part. Everything else, however, requires overcoming many hurdles. Several of these obstacles are discussed below.
Regulatory and Licensing Issues
There are several regulatory issues that must be overcome for HALEU production to commence in earnest. The first step would be attaining regulatory approval to modify the existing enrichment plant license, which would require new criticality benchmarking for the gas centrifuges. According to Orano and URENCO, this process could be completed in around two years once an application is submitted.
Fuel fabrication facilities would also need to obtain license amendments to produce HALEU fuel. The licensing process would be complex, in part due to increased security requirements along with the engineering and design changes, and potentially the need to build a separate HALEU fuel fabrication complex. None of the three major commercial fuel fabrication facilities in the U.S. – Framatome’s Richland, WA plant, GNF-A’s Wilmington, NC plant, and Westinghouse’s Columbia, SC plant – are currently licensed to handle material above 5%.
In the U.S., there are two fuel fabrication facilities – Nuclear Fuel Services (NFS) in Erwin, TN and the BWXT Nuclear Operations Group plant in Lynchburg, VA – that work with HALEU and HEU fuel, including for U.S. nuclear navy fuel and research reactor fuel. These two facilities could manufacture HALEU fuel without major (if any) license amendments.
Physical protection issues along with material control and accounting for HALEU facilities would also need to be addressed.
Transportation and Packaging Issues
Transportation is a critical part of the nuclear fuel cycle. After all, without transportation solutions, having the ability to produce HALEU is meaningless as it cannot be delivered to fabricators and customers.
To date, shipments of uranium above 5% enrichment have been very small. The transportation packages currently used for these smaller shipments are not suitable for commercial-scale operations, and thus would be uneconomical. Therefore, one of the gaps that must be addressed before growing the HALEU fuel cycle is the development and certification of an appropriate transportation cylinder.
Figure 4. Existing UF
6 Cylinders for Higher Assays
Source: URENCO
Funding Issues
Another issue to consider is funding, particularly to support U.S. HALEU initiatives. The DOE plans to allocate $35 million from the fuel cycle research and development program and from prior year unobligated balances in DOE’s NE to the HALEU project in Fiscal Year (FY) 2019, which ends September 30, 2019. Funding for the program in FY 2020 and FY 2021 is contingent on receiving congressional appropriations.
For FY 2020, the administration proposed to increase funding for HALEU production to $30 million to $40 million. The budget justification states that the demonstration project is to last three years, with the total federal contribution not to exceed $115 million.
Economics of LEU+
In any initiative, the key question is of course economics. Any change is costly and must be justified compared to continued use of UO2/zirconium alloy fuel. Whether LEU+ is utilized depends on the assessment of economic feasibility of its utilization.
Considering ATFs, for example, from the utility perspective, economics is the biggest driver – after all, accident tolerance is currently deemed to be sufficient and increasing it will not matter if it is not economically feasible. Fuel fabrication vendors have acknowledged the fact that the ATF will be more expensive for different reasons. Increasing enrichment levels, for example, necessarily increases the cost, although the historically low enrichment prices today alleviate some of these concerns. On the other hand, evaluating the benefits has not been easy given the lack of operating experience at this point. Some of the potential benefits include lower maintenance costs as a result of lower safety risks and the ability to reclassify certain equipment as being less critical to safety. Some regulatory simplification as a result of reduced risks is also expected. Some view the need to utilize LEU+ as a major challenge to the ATF program and a factor in the ongoing cost-benefit analysis.
A recent study by EPRI estimated the economic benefits of higher enrichment / higher burnups focusing on the U.S. nuclear fleet both in PWRs and BWRs. The economics were based on the difference in the fuel management results between the reference and high enrichment cases. The results for the reload fuel cases are summarized in Figure 5 below based on project fuel component costs in 2030. As is apparent, enrichment expenses increase for all cases while most of the savings come from fabrication, which is to be expected as there is a reduced number of fuel assemblies per each reload. Smaller savings would come from uranium and conversion. EPRI has concluded that the economics is not sensitive to the future uranium feed or enrichment market prices.
Figure 5. Annual Fuel Component Cost Saving
Source: EPRI
Figure 6. Savings & Estimated Distribution of Benefits, High Burnup PWR and New BWR Fuel Design
Source: EPRI
Given the absence of a commercial market for HALEU, the question arises as to how such material would be priced. This remains an open question at the moment, although in a 2018 presentation, URENCO made a case that valuation of HALEU requires moving “from ‘commodity’ to ‘value-added’ pricing.”
Figure 7. SWU Required to Produce LEU+ and HALEU
Source: URENCO
Ultimately, it is clear that questions about the pricing of HALEU cannot be fully answered at this time given that a market for any of these products on a broader commercial basis is yet to exist.
Spent Fuel Management Issues
Using nuclear fuel with higher enrichment and burnups necessarily will have an impact on the back-end of the nuclear fuel cycle. This will involve wet and dry storage, transportation, and final disposal of spent fuel. Some of the issues with spent HALEU-based fuel involve higher decay heat, higher specific activity, and degraded cladding mechanical properties, etc., which would clearly necessitate the relicensing of existing dry cask systems. At the same time, decreasing the volume of high-level radioactive waste is expected to result in savings. While higher burnups has received some attention recently, additional studies related to the impact of HALEU on the back-end of the nuclear fuel cycle are clearly necessary.
Forecasting Demand for HALEU: When & How Much?
Focusing on HALEU specifically (as opposed to LEU+), one of the biggest challenges is understanding market demand going forward. The key questions to be answered include:
- How much HALEU is needed?
- When is it needed?
- In what form will it be needed?
In a 2018 survey, NEI estimated annual requirements for HALEU to 2030, showing growing requirements towards the end of the period. Figure 8 below provides these estimates. These self-assessed needs by the U.S. industry reflect the expectation that advanced reactors will be commercialized in the second half of the next decade. Until then, the annual quantities are projected to remain small.
Figure 8. NEI Estimated Annual Requirements for HALEU to 2030 (MTU/yr)
Source: Nuclear Energy Institute
Figure 9. Graphic of Estimated Annual Requirements for HALEU to 2030 (MTU/yr)
Source: Nuclear Energy Institute
The U.S. government’s HALEU needs are not included in the NEI estimate, but DOE has estimated that it is able to cover its requirements for research reactors and Mo-99 production through the mid-2030s. By 2040, the current HEU available for downblending will be exhausted and annual requirements will be ~9.7-10.7 MT 19.75% HALEU. These estimates are highly uncertain, but do provide some indication regarding the U.S. government’s current coverage and future needs. In any case, the government’s HALEU needs should remain a relatively small part of future demand.
1 https://www.congress.gov/bill/116th-congress/senate-bill/903
Anna Bryndza
+ posts
Anna (Anya) Bryndza joined UxC, LLC (UxC) in 2008 and currently holds the position of Executive Vice President, International. In this capacity, she is responsible for analyzing government policies as they relate to the nuclear fuel markets worldwide. In this capacity, she manages UxC's Policy Watch service. Ms. Bryndza is recognized as the industry's leading expert on nuclear power and fuel developments in Eastern Europe and Central Asia, with a comprehensive understanding of the current state, ongoing trends, and prospects for Russia's vast nuclear power complex. She has presented at the nuclear industry's key international forums, including the World Nuclear Association's Symposium (London), ATOMEXPO (Moscow), and NEI's Nuclear Fuel Supply Forum (Washington), among others. Ms. Bryndza has been interviewed by worldwide press publications, including a number of Eurasian media outlets. She is trilingual (English, Russian, and Ukrainian) and holds a dual degree of Bachelor of Science and Arts in Economics and Political Science from the College of Charleston and a Master of Arts in International Trade and Investment Policy from the George Washington University.
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