Deep Isolation Technology
What is the Deep Isolation concept, in simple terms?
Deep Isolation will emplace nuclear waste in corrosion-resistant canisters (typically 9 to 13 inches in diameter and 14 feet long) deep into horizontal drillholes, in rock that has been stable for tens to hundreds of millions of years.
A Deep Isolation drillhole begins with a vertical “access” section that goes down from a few thousand feet to a few miles, depending on the geology. The drillhole then gradually curves, over a distance of typically 1000 feet, until the hole is near horizontal. (We give it a slight upward tilt for additional safety.) This (nearly) horizontal part we refer to as the “disposal” section.
Once the waste is in place, the vertical access section of the drillhole and the beginning of its horizontal disposal section are sealed using rock, bentonite and other materials.
Virtually all committees of scientists convened to study the disposition of nuclear waste have concluded that deep geologic burial (1000 feet or more) is the best disposal solution. Most previous approaches have assumed this requires large excavated tunnels for emplacement of the waste.
The key advantages of the Deep Isolation method are the depth of burial and the fact that the waste is stored in a suitable geologic formation far below the water table, in rock that is saturated with brine that has no commercial value and has been virtually stagnant for millions of years. In addition, the small diameter drillholes require less disturbance of the rock than a mined repository.
The horizontal drilling technology that will be used is highly developed and can be implemented at a relatively low cost. It can be modular, thus minimizing transportation concerns by allowing disposal at or near the generation site. Cost and safety are also improved by the fact that no person needs to go underground during construction.
The horizontal disposal section could be up to 2 miles long. With horizontal disposal sections this long, it would take 300 such horizontal drillholes to dispose of 80,000 tons of commercial spent nuclear fuel.
For an illustration of a Deep Isolation drillhole, see Figure 1.
Can you really put three miles of continuous steel liner (a “casing”) down the drillhole (1 mile of vertical access and 2 miles of horizontal storage)? How does it get around the curved section?
Do you pick sites that are suitable for natural resource recovery?
Why didn’t someone think of this before?
Didn’t the Department of Energy try this and why didn’t it work?
Why is the horizontal section of the Deep Isolation concept necessary?
What keeps the radioactivity from reaching the surface?
Why a mile deep?
How do you put the fuel down there?
Does the fuel assembly have to be repackaged to fit in the canisters?
How can a vertical drillhole bend to allow horizontal storage?
Has this drilling technology been tested?
The Deep Isolation solution was also successfully tested at a commercial drilling facility where a prototype canister was successfully lowered 2200 ft. (670 meters) into an existing drillhole using a wireline cable and then pushed over 400 ft. (122 meters) using an underground “tractor” into a long horizontal storage section. The canister was released and the tractor and cable withdrawn. Several hours later, the tractor was placed back in the hole, where it latched and retrieved the canister, bringing it back to the surface.
Can the waste be retrieved?
What if a canister gets stuck in a hole?
How will you monitor the waste in the drillhole?
Would the drilling cause earthquakes?
Will you be utilizing long-haul transportation of waste as part of your solution?
What kind of steel will be used and how thick?
Won’t the canisters and casings quickly rust?
How soon can you dispose of existing waste?
Would you be a competitor to Yucca Mountain?
Is your solution ready for market and which markets do you intend to sell to?
Nuclear Waste Innovation Act
What does the act say, in simple words?
Would disposal by a private company be safe?
How can a company maintain liability for thousands of years?
What companies might apply for licenses?
Who benefits from the Nuclear Waste Innovation Act?
How could private companies do better than the US government?
Would the passage of the Nuclear Waste Innovation Act slow progress on the Yucca Mountain facility?
Nuclear Waste 101
Why should I care about nuclear waste?
According to the International Atomic Energy Agency, there are approximately 370,000 tons of radioactive spent fuel that is being temporarily stored in pools and dry casks at hundreds of sites around the world. No spent nuclear fuel anywhere in the world has yet been placed in a permanent repository.
In the United States, there are over 80,000 tons of spent nuclear fuel currently stored on site at the nuclear reactors that produced it, including nuclear plants that have recently stopped operating and decommissioned nuclear plants. Most of the waste is being stored in water pools for cooling in buildings near the reactors. Some have been transferred to dry casks that are sitting on concrete pads or slightly below grade within a secured area on the site. See Figure 2.
The reason we believe one should care is that it has always been the plan to dispose of this waste in a deep geological environment. But for decades the plans for doing so have not proved workable and so it remains in pools or casks – a situation that was neither envisioned nor advised by the experts.
What is spent nuclear fuel?
What is the difference between nuclear waste, radioactive waste and spent nuclear fuel?
What is the current plan for nuclear waste?
What do experts say is the best way to dispose of nuclear waste?
Community and Public Support
Wouldn’t communities reject disposal in their backyards?
About 1/3 of U.S. citizens already live within 50 miles of a place where nuclear waste is stored above ground in cooling pools or dry casks. Deep Isolation would take that waste and put it thousands of feet underground, protected by over a billion tons of rock. This would make the waste safer and more secure than the status quo.
Deep Isolation has talked with people in many affected communities and in 2018 engaged the highly respected firm GfK Global to survey the opinions of people living in over 20 states. On average 82% of those surveyed prefer deep burial on-site rather than transportation over local roads to distant storage facilities. They do not want waste brought in to their communities from outside, nor do they want waste transported across their state. Read the results.
Deep Isolation will only work with communities and states that give their support for the permanent isolation of nuclear waste in their community and state. If a community and state are not interested in our permanent disposal method, they can still advocate for the waste to be shipped to an interim site, or a different disposal facility when one becomes available.
The decision process as to whether a community and state would prefer to transport waste to another location or dispose of it nearby is a complex one. Potential benefits of permanent isolation in their community and state include a timely solution that improves safety, minimizes transportation, adds jobs, and provides new fees for the use of land. Only if the community and state decide the benefits make it worthwhile would a site be selected there.
Deep Isolation will work with communities and states to help them make an informed decision about which option is the best fit for them. With over 60 locations in the United States that are currently storing nuclear waste in pools or dry casks, we have indications that at least a few of them are interested in exploring the option of a Deep Isolation facility.
What kind of consent is required from the local community?
What will happen if the community is not interested?
Why would a community consider a Deep Isolation disposal solution?
Does the public think that the U.S. government is the only appropriate organization to solve the waste problem?
Would there be jobs for the local communities?
How much radioactivity will be emitted by the spent fuel before the repository is sealed? How much after the drillhole is sealed?
Nuclear radiation is emitted by the canisters whether above or below ground. Virtually all of this consists of “gamma rays,” which are like high-energy X-rays. To assure safety, there will be shielding between the canisters and any workers. Once underground, the rock will provide shielding and safety for the environment and human health.
At all times, the drillhole will be in compliance with regulations for the release of radioactive isotopes and radioactive dose to the public. The release of radioactive isotopes has been specified by law and regulation. These laws and regulations are written in highly technical language, but generally speaking, they assure that no human-harmful levels of radioactivity will reach the surface for tens of thousands to millions of years. The geologic formations chosen for the Deep Isolation drillholes will have been stable for tens to hundreds of millions of years. Ultimately, it is the geology that provides long-term confinement.
How will workers and the environment be protected during insertion?
Will you be removing waste from dry casks and if so what are the process and safety issues?
Will the encased spent fuel be as safe as dry casks?
Is it safeguarded from terrorists?
Can Deep Isolation meet the NRC standard that a member of the public be exposed to no more than 15 mrem per year?
What does a Deep Isolation repository cost?
The drilling costs are low, since drilling is a mature and competitive industry. A two-mile-long repository can be constructed for under $10M, and hold 300 tons of waste, so the cost is under $130,000 per ton. Contrast this with the cost of a tunnel facility. The US OMB estimates completion of Yucca will cost $96B to hold 70,000 tons of waste, at a cost of $1.4M per ton, over 10x higher than the cost of the Deep Isolation solution.
How could multiple drilled repositories a mile deep be less expensive than a second tunnel repository that is only 1000 feet deep?
The lower cost for Deep Isolation directly reflects the fact that our drillholes have much less volume. Drilled repositories make much more efficient use of space. The Yucca repository will have 40 miles of tunnel, typically 18-25 feet in diameter; the waste occupies less than 0.4% of the volume. For a drilled repository, the waste occupies about 20% of the volume, making it much more space efficient. The lower volume of rock removed, compared to tunnel disposal methods, also minimizes the disruption to the rock.
Would US government financial support be required?
It is anticipated that all the costs could be carried by the applicant companies and their investors. Upon completion, the companies would be paid from the Nuclear Waste Fund.
Figure 1 (below). The Deep Isolation drillhole waste repository concept. The horizontal section of the drillhole will be 18 inches wide, which will fit the 9 to 13 inch diameter of the disposal canister.
Figure 2 (below). A typical nuclear fuel assembly. The one shown below is a common design for a Boiling Water Reactor (BWR). The fuel pellets for Pressurized Water Reactors are the same size but are placed in somewhat larger fuel assemblies that contain more rods. The fuel assembly would be placed in canisters that fit conveniently down drillholes.