The Green Frontier: Key Considerations for Data Centers Adopting Nuclear SMRs
Luay Zayed
Environmental Project Manager | DesignBuild | Data Centres | Battery Assembly | Gigafactories | Semiconductor fabs | Green Hydrogen | Nuclear | Adv. Manufacturing | Mission Critical | EMEA | MENA | APAC | GLOBAL
With recent news announcements linking big players such as Google, Microsoft and Amazon to nuclear power deals. '??????????????' is the new buzz word in the world of power-hungry data centres.
?????????? ?????????????? ???????????????? (????????)?generate electricity through nuclear fission and are?considered?green?because?they?produce?virtually?no?greenhouse?gases?during?their operation albeit with minor emissions associated with the construction, fuel production, and decommissioning phases of the reactor lifecycle. Therefore, they are touted as a reliable, low-carbon energy option for ever increasing data centre power supply requirements.
While SMRs are currently subject to higher costs, ongoing research and development coupled with economies of scale are expected to reduce these costs over time. They also offer power outputs of up to 300MWe which distinguishes them from smaller 'Microreactors' typically used in remote locations and military bases. Meanwhile '???????????????? ?????????????? ????????????????' (????????) refer to SMRs that use advanced technologies beyond traditional designs, i.e. featuring innovations that boast higher efficiencies, improved safety systems, hybrid fuel usage, heat reuse in various applications, etc.
Let's take a look at some of the environmental challenges surrounding this technology.
Low-enriched uranium (LEU) is currently the primary fuel for SMRs and sourced via underground or open-pit mines - with many advanced reactor designs requiring high assay low enriched uranium fuel (HALEU) allowing for smaller designs, longer operating cycles and increased efficiency. Australia, Kazakhstan, and Canada hold 50% of the World’s Uranium Reserves, whilst continued advances in extraction technologies can extend the lifetime of these substantial reserves, especially if coupled with innovative uranium recycling from spent nuclear fuel plus fuel-efficient SMR design. Hybrid approaches can also be developed including the use of natural gas as a supplementary fuel to enhance the reliability and flexibility of the system.
Alternative fuel sources include 'thorium-based' nuclear reactors, commonly found in igneous rocks and heavy mineral sands, with India boasting the world's largest reserves - the metal is seen as a more abundant and efficient substitute for the current dominate nuclear fuel.
Uranium is also subject to strict regulations relating to its mining, transportation and disposal - including The Nuclear Safeguards (EU Exit) Regulations 2019 (legislation.gov.uk) in the UK and the EU's Radioactive?Waste?and?Spent?Fuel?Management?Directive?(2011/70/Euratom) requiring all member states to have national policies for managing spent fuel and radioactive waste.
The common perception is that traditional nuclear reactors generate reliable supplies of clean electricity whilst on the flip side generating radioactive waste that must be isolated from the environment for hundreds of thousands of years. SMRs were then seen as a way to reduce the CapEx of such installations whilst offering a reduction in radioactive byproducts compared to conventional large-scale reactors.
There is however some speculation in the scientific community that due to the differing design features and compact nature of SMRs - the volume of short-lived low and intermediate-level waste (LILW-SL) may actually be higher compared to larger reactors, depending on the specific system design, fuel cycle and waste management practices dealing with materials such as 'contaminated tools and clothing', 'filters and resins' and 'debris from reactor maintenance'.
On a positive note, because of its lower radioactivity and shorter half-life, LILW-SL can be managed and disposed of more easily compared to high-level waste (HLW), which remains hazardous for much longer periods. Examples of the latter include spent nuclear fuel and reactor components.
???? ??????????????, both types of waste need to be fully assessed and managed carefully to ensure safety and environmental protection. SMRs need to incorporate advanced waste management strategies to handle these different waste streams effectively.
A multi-step process is usually implemented that can include;
Innovative waste management approaches also include Partitioning?and?Transmutation?(P&T) which converts long-lived radioactive elements from spent fuel into short-lived, less hazardous forms. Reusable parts of spent fuel components can also be reprocessed, transmutated and recycled to minimise waste volumes (i.e. Uranium, Plutonium, Minor Actinides and fission products). Whilst advanced reactors should be designed in a way that reduces waste volume generation and radiotoxicity (making it easier to handle) plus promote higher 'burnup' and improved fuel cycles. Another important design challenge is mitigation of radiation leakage ('neutron leakage' - the?escape?of?neutrons?from?the?reactor?core?without?contributing?to the fission process) which can alter the amount and composition of waste streams in addition to the environmental, human health and economic impacts. SMR designs typically utilise three strategies to mitigate neutron leakage, including enriched fuel, neutron reflectors, or modified coolant types. Thus, it is vitally important to evaluate the effectiveness of the mitigation methods chosen.
When?selecting?sites?for?geologic?repositories,?radiotoxicity?is?crucial?because of:
Whilst the amount of spent nuclear fuel continues to grow, several countries are leading the development of permanent DGRs and have historically relied on interim wet or dry storage solutions scattered regionally at the surface or near-surface level. Finland appears to be ahead of the curve with their Onkalo spent nuclear fuel repository situated 400m below ground. It began construction in 2015 and recently completed the first stage of a trial run accepting used fuel from interim storage - highlighting the potential timeframes associated with building, commissioning and operating these kinds of facilities. The US's discontinued 'Yucca Mountain Project' also showcases the political, legal and regulatory challenges with establishing such facilities.
Historically, ocean disposal under the seabed was also an option to consider. However, this practice has since been discontinued due to environmental concerns and international regulations prohibiting ocean disposal of radioactive waste. It's interesting though to follow updates on Japan's gradual nuclear wastewater releases into the ocean (following the 2011 Fukushima tsunami incident) with approval from the International Atomic Energy Agency (IAEA) - a process that could take at least 30 years.
The delay in building permanent DGRs in the UK and Europe can be attributed to several factors including technical, operational and regulatory hurdles in addition to achieving the 'holy grail' of ???????????? ???????????????????? - the combined willingness of a host community (financial incentives included) plus a suitable host geology being critical success factors in the site selection process - a tough ask when faced with the prospect of potentially hot radioactive waste over the course of a 1,000 years, with prolonged radiological hazards in excess of 10,000 years. Requiring a robust storage solution that ultimately removes any likelihood of barrier system degradation, inadvertent intrusion, and contamination via air, soil and water pathways over the lifetime of the decontamination process. Operators also need to be mindful of nuclear liability conventions set up to compensate victims having suffered nuclear damage either at the installation level or during transportation. Another critical design criterion includes security, with measures for redundancy, diversity, and defense-in-depth to protect against potential threats, which includes cyber-attacks.
Proper evaluation of the potential environmental impacts and compliance with environmental regulations is critical - in addition to several important geological surveys to validate the feasibility of the prospective site(s). These include a seismic hazard assessment, soil and rock stability assessment, hydrogeological (groundwater condition)?survey, slope stability analysis plus infrastructure availability assessments (i.e. access roads and utilities) with a key focus on redundancy to ensure?continuous?and?reliable?operation.
In?the?UK,?the?construction,?installation,?operation,?and?decommissioning?of?SMRs?are governed by several?key?pieces?of?legislation?and?regulatory?frameworks:
One of the benefits of GDA is that it can reduce the overall time for deployment of a design at more than one site by assessing generic aspects only once and before site specific proposals come forward.
Step 1 – usually takes around a year – this is where the project is set up with the design company, defining the scope and forming an agreement on what information is required. The ONR/EA/NRW assessment team also learn about the design and offer advice to help in the preparation of the assessment.
Step 2 – usually takes around a year – here the fundamentals of the design are assessed – are the basics of the design correct, what’s missing? What are the intended functions of key systems? The key focus is on features of the design which protect the environment including how the design can be optimised to reduce the amount of radioactive waste produced and how that waste is managed and disposed of.
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More detailed information from the company is scrutinised and should concerns be raised it will be done via a formal process – be it an issue, observation or query.
Step 3 – usually takes around two years. The design is then assessed in greater detail to ensure that it sufficiently meets the key objectives and intended environmental protection functions. The design should use best available techniques to ensure that the radiation exposure of people and the environment are minimised and within statutory limits and guidelines, and that other environmental impacts are also minimised. Rolls Royce's UK SMR design has recently entered this phase.
Thus, in order to deploy SMRs quickly and efficiently, several strategies need to be implemented.
Parallel?Processes
Streamlined?Approvals
Factory?Fabrication
Government?Support
Once the Generic Design Assessment (GDA) process is approved and complete for a Small Modular Reactor (SMR) deployment, there are still additional approvals required before construction and operation can begin. Again, early engagement is critical to expedite the process. These include:
Established law firms such as Burges Salmon LLP, Castletown Law and Womble Bond Dickinson (UK) LLP have expertise in these requirements and can help navigate developers through the process.
Small?Modular?Reactors?(SMRs)?produce?waste?heat?as?a?byproduct?of?their?operations.?The amount of?waste?heat?produced?can?vary?depending?on?the?specific?reactor?design?and its efficiency. Whilst about 25% of industrial processes in the EU require heat that is above 400 degrees Celsius, which can be produced by SMRs. In the UK, this heat might be used to produce hydrogen, ammonia, and other sustainable synthetic fuels, as well as to directly absorb carbon dioxide from the air. Conversely, district heating systems could employ lower temperature "waste" steam to heat homes. In colder regions, a number of nations now use nuclear cogeneration for district heating; in China, SMRs are being constructed specifically for this purpose.
For hydrogen production, the waste heat can be harnessed via processes such as high-temperature steam electrolysis (HTSE) or sulfur-iodine (SI) cycles. As showcased by developers including NuScale and Rolls Royce.
Last month, it was announced in the UK that four companies (Westinghouse, GE-Hitachi Nuclear Energy (GEH), Holtec Britain, and Rolls-Royce) remain in the running to potentially deliver nuclear technology development contracts aimed at providing operational SMRs by the mid-2030s.
We look forward to following these developments further, whilst key selection criteria Biyat Energy & Environment Ltd would look out for include:
We hope you found this article useful!
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This article was written by Luay Zayed, founder of Biyat Energy & Environmental Ltd. A global energy and environmental consultancy specializing in turnkey engineering solutions that protect the environment and improve energy efficiency in the manufacturing & industrial sectors.
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1 个月Hi Luay, thank you for putting together a very comprehensive overview of this fast evolving area. Gexcon is proud to have evolved our expertise in safety and risk modelling within the traditional Nuclear industry to support one of the leaders in the SMR race. Whilst it goes without saying, any crack, weakness or stone left unturned relating to safety and risk management has the potential to significantly delay or derail the adoption of SMR’s. Whilst the GDA timescales look long, they seem appropriate given the complexity of the designs and the extent of the legislative and regulatory frameworks which they need to comply with.