SuperLAT™ drilling technology – enabling ultradeep nuclear waste repository systems

By Dr Henry Crichlow, NuclearSAFE

illustration: NuclearSAFE
illustration: NuclearSAFE

Today, “nuclear is the new green”. No other energy producing system in existence or under development is capable of producing the level of carbon free energy critical to meeting the increasing world energy demand while simultaneously mitigating the negative effects of climate warming emissions across the globe.

The future for nuclear energy is excellent, with one significant caveat. The nuclear energy industry currently exists as a bifurcated, disconnected enterprise. The “front-end” actively and profitably designs, builds, and provides the power generation systems. Meanwhile, he “back-end” is trying to find ways to get rid of or dispose of the accumulating spent nuclear fuel waste assemblies that are the by-products of power generation. These two systems are uncoupled. The “back end” has always taken a literal backseat in the process and has significantly lagged in investment and development.

Safety and environmental concerns
Today, most high-level radioactive waste (HLW) is stored on-site in cooling ponds or in massive surface containers at the power plants. These expensive short-term fixes are greatly increasing in costs beyond just the financial, as they come with major safety and environmental concerns as well. The waste disposal management effort is relegated to a series of agencies or other usually under-budgeted regulatory entities that have been striving un-successfully for decades to develop and manage a disposal system. After billions of dollars and decades of fruitless effort, that system has not yet been finalised. Without a long-term solution, the shortcomings of the aforementioned short-term fixes become more evident by the day. Negative public opinion adversely impacts the continued growth of nuclear energy, and likely will continue to do so until safe disposal of this accumulating toxic waste is successfully demonstrated.

Today it is possible to drill and complete a nuclear waste repository system in a deep zone at least 10,000 feet below the surface
Today it is possible to drill and complete a nuclear waste repository system in a deep zone at least 10,000 feet below the surface (illustration: NuclearSAFE)

In order to succeed, the industry must solve this waste problem. To date, the nuclear industry has focused collectively and single-mindedly on a near-surface “mine” or “tunnel” storage for the long-term disposal of HLW. In the US, Yucca Mountain starting in 1987; in Canada the Deep Geological Repository (DGR) starting in 2002; in Europe KBS type since 2010. After decades wasted and billions squandered, these systems all have been plagued by major, environmental, scientific, economic, and political problems. Some of these problems are insurmountable and today some researchers believe near surface disposal is not the answer. Technical analysis has shown migrating rainwater can and shall reach the storage zones in fewer than 50 years. The resultant problems in corrosion, and eventual waste capsule deterioration, risk contaminating the water supply, in addition to already known concerns with such failed efforts.

SuperLAT™ wellbore
However, there is an engineering solution to this seemingly intractable problem – the SuperLAT™ wellbore, patented technology by NuclearSAFE. This waste disposal technology was first researched, developed, and patented in the 1990s (US 5,850,614 (Crichlow)), and later presented at an international environmental Conference in Regina, Canada. This novel and extremely effective technology is the modified “brainchild” of the oilwell drilling industry, building on the learned experience of over two million wells drilled through hundreds of millions of feet of different rock formations.

A specialised type of very deep wellbore (borehole), it is drilled from the surface into a selected disposal zone and then turned horizontally (sideways) into the deep selected rock formation. Continued drilling further horizontally for several kilometres in the disposal zone makes a long empty cavity in the impermeable rock in which the nuclear waste is stored in steel capsules lying horizontally. Horizontal storage protects the capsules by minimising the increased weight and pressure that would result from vertical stacking.

Today, with more than 200,000,000 feet of horizontal wellbores drilled every year in the US alone, wellbore technology has been developed to a very high level. It is economic, rapidly deployable, and implementable at the volumes needed to store thousands of metric tons of HLW. Horizontal wellbores form the backbone of a massive industry that has continued to drill millions of feet of lateral wells in every conceivable natural environment, under the most demanding ecological conditions.

Today it is possible, with this new technology, to drill and “complete” a nuclear waste repository system in a deep zone at least 10,000 feet below the surface and successfully extend the wellbore laterally another 15,000 feet into the disposal formation for a total measured depth of 25,000 feet. This vertical depth places the HLW far below any surface waters, in a closed geologic basin that can be demonstrably shown by radioisotope dating to have been undisturbed for at least 10,000,000 years. Proposed solutions such as the Yucca Mt. disposal site in the US require “band-aid” solutions like “difficult-to-install titanium shield umbrellas” to protect the capsules from migrating surface waters, with other at or near-surface solutions requiring similar complex and expensive protections after-the-fact – problems overcome by the SuperLAT™ wellbore

Ultimate protection
Some technical personnel have argued that this new wellbore approach is incapable of storing the large volumes of waste contemplated by the industry. To the contrary. Some mistakenly believe HLW storage requires massive casks, extensive and costly capsules, and other extraneous materials to secure and protect the waste. However, with this new technology, the deep impermeable formation is considered to be the ultimate protection for the waste. The capsules are simply short term (10,000 year) devices to rapidly and safely transport and sequester the waste in the repository formation. The continued refrain that current waste forms are not amenable to wellbores is also fallacious.

Reactors such as the Canadian CANDU system are already suited to disposal in cylindrical wellbores with almost no further modifications. In the United States, both Boiling Water Reactor and Pressurised Water Reactor systems can be easily disassembled and functionally encapsulated to fit the cylindrical waste capsule systems designed for lateral wellbores. A similar approach is available for other spent nuclear fuel (SNF) assemblies in European operations.

Using the best available technology to locate closed basins that are amenable to nuclear waste sequestration
Using the best available technology to locate closed basins that are amenable to nuclear waste sequestration (illustration: NuclearSAFE)

Furthermore, the disposal of spent fuel assemblies in vertical boreholes, a concept originally proposed by some US National Labs, has two critical shortcomings: low capacity and high compressive forces. The vertical system relies on storage only in the limited bottom-most section of the borehole. The upper 80% or so of the wellbore is not used for storage of waste. In the preferred lateral wellbore technology, the full 15,000 feet or more of the lateral wellbore can be used for disposal. Additionally, vertical boreholes may cause massive compressive forces generated at the lowermost level of the well. With thousands of feet of very heavy SNF material positioned above the bottom capsules, collapse or burst may be inevitable. In the lateral system, the capsules rest horizontally just like in a warehouse on the surface, so no such vertical compressive force exists.

Capacity-wise, a single lateral wellbore with a nominal diameter of 12 to 14 inches may store 1,000,000 lbs of SNF, or a thousand SNF capsules across its 15,000-foot length. Multiple laterals may be drilled as needed to meet SNF requirements at a given operations site.

Versatile and dependable
A dominant feature of the deep lateral wellbore system technology is its speed, versatility, and economy. For less than USD 25 million, lateral wellbores can be drilled and completed within 100 days, not three or four decades as planned for some near surface multi-billion-dollar repositories. Furthermore, several lateral wellbores may be drilled from the same site or location by simply “walking” the drill rig over 200 feet and drilling another wellbore. Simultaneous operation and cost effectiveness are two critically important issues in this technology for SNF disposal.

Using this new technology, there is no need for a “town on the surface and a village underground” to manage the waste disposal operations. No substantial underground “mining” operations, no extensive power, no evacuation zones, and no personnel facilities either on-surface or below ground. No need for thousands of workers as one DGR proposal in Canada proposes. The drill rig crew used in this technology is minimal, less than 30 people. The disposal system is fully automatic and loading the “just in time” delivered waste capsules, which are prepared off-site, is robotically controlled on the surface, using what have been euphemistically called “iron-roughnecks” in the oil drilling industry.

This novel technology is safer, quicker, cheaper, more dependable and can be duplicated several times either sequentially or simultaneously at multiple existing power generating sites and make the nuclear power industry success a reality.

Dr Henry Crichlow, founder and CEO of NuclearSAFEDr Henry Crichlow, founder and CEO of NuclearSAFE, literally wrote the engineering book which transformed the oil and gas industry. A recognised expert in Oil and Gas, Energy and Nuclear Waste Engineering, he helped the Kuwaiti government in extinguishing oil wells set on fire during the Kuwait-Iraq war, and analysed the 2010 BP Macondo blowout in the Gulf of Mexico. Now, Dr Crichlow has turned his expertise to the problem of nuclear waste. His focus now is utilising his “brainchild”, a patented technology he developed in 1998 to utilise oil well drilling techniques as a cost-effective and scalable solution for nuclear waste disposal.