General Information

  • What is spent/used nuclear fuel?

    The terms used nuclear fuel and spent nuclear fuel are both used to describe nuclear fuel that has been used in a nuclear reactor. There is no liquid in used nuclear fuel. Used nuclear fuel is a solid material, in the form of ceramic pellets. Each pellet is about the size of a pencil eraser. The pellets are stacked inside long metal zirconium tubes approximately 12 feet long, which are sealed on each end to form a fuel rod. Between 100 and 300 fuel rods are arranged in a square pattern to form a fuel assembly. Depending on the design, a reactor core may have between 120 and 800 fuel assemblies. A used fuel storage cask may contain up to 89 fuel assemblies. Learn more about nuclear fuel by watching this Nuclear Energy Institute video.

  • How is nuclear fuel stored?

    A single nuclear fuel assembly spends around five years in the reactor of a nuclear plant, creating heat that is then turned into electricity. Typically, every 18 to 24 months, a nuclear plant stops generating electricity to replace a third of the fuel assemblies in the reactor with fresh ones. The assemblies removed from the reactor are then stored in a large body of water inside the nuclear plant, called the spent fuel pool, where they cool over time. The water also shields the workers from the radiation that comes from the fuel assemblies. Due to the use of water, this storage method is also often referred to as “wet storage”.

    After the used fuel assemblies have cooled for at least one year, they may be moved from the pool to canisters made from stainless steel filled with an ‘inert gas,’ i.e. a gas that does not chemically react and prevents corrosion of the content of the canister, such as Helium. The steel canisters are strength welded closed in order to provide a leak-tight containment of the used nuclear fuel and are placed inside large robust casks made of steel and concrete.

    The steel and concrete casks surrounding the canister provide radiation shielding to workers and the public from the stored used nuclear fuel, and physical protection of the fuel. The casks are then initially stored at the site of the nuclear plant. Since this storage method does not require any water, it is often referred to as “dry storage”. It also does not use any fans for cooling and electric power is not required.

Background and History

  • What is the history of used nuclear fuel storage?

    The Nuclear Waste Policy Act of 1982 (NWPA) codified the U.S. Department of Energy’s responsibility for developing a geologic repository for used nuclear fuel. In 2002, the president and Congress approved Yucca Mountain in Nevada as the site for this repository. In 2010, however, the DOE shut down the Yucca Mountain project without citing any technical or safety issues. In contrast, decades of scientific study had consistently concluded that the proposed repository could safely protect future generations. At the time, $12 billion had already been spent on Yucca Mountain and 65,000 metric tons of spent fuel were in temporary storage across 39 states. In 2014, a federal court ordered the U.S. Nuclear Regulatory Commission to complete safety and environmental reviews of the site. While these reviews have since concluded that Yucca Mountain complies with all regulations, a final decision awaits an extensive formal hearing. That hearing can’t happen until Congress funds it.

    In response, the industry began responding through what is known as interim/temporary fuel storage. Title 10, Part 51.23(a), Code of Federal Regulations. § 51.23 Temporary storage of spent fuel after cessation of reactor operation–generic determination of no significant environmental impact. (a) The Commission has made a generic determination that, if necessary, spent fuel generated in any reactor can be stored safely and without significant environmental impacts for at least 30 years beyond the licensed life for operation (which may include the term of a revised or renewed license) of that reactor at its spent fuel storage basin or at either onsite or offsite independent spent fuel storage installations. Further, the Commission believes there is reasonable assurance that at least one mined geologic repository will be available within the first quarter of the twenty-first century, and sufficient repository capacity will be available within 30 years beyond the licensed life for operation of any reactor to dispose of the commercial high-level waste and spent fuel originating in such reactor and generated up to that time.

  • Why do we need Consolidated Interim Storage?

    Every nuclear plant stores used fuel on site as the industry awaits the completion of either a consolidated interim storage site or permanent disposal repository by the federal government. Taxpayers are assessed $800 million annually ($2.2 million per day) because of the federal government’s failure to meet its obligation to dispose of used fuel that currently resides at nuclear plants across the country creating a liability that has cost American taxpayers $6.9 billion through 2017.

    By their own estimates, the DOE indicates that their total liability is estimated at $34.1 billion. If the government does not find a way to begin satisfying their obligations by 2022. the DOE estimates that the liability will increase by approximately $500 million per year This money is paid out of the U.S. Treasury’s Judgement Fund – a source funded by all taxpayers, regardless of their source of energy, not through an appropriations process or from utility ratepayers.

    On-site storage of used nuclear fuel at nuclear power plants was never intended to be permanent. Spent nuclear fuel is being stored at 121 different facilities in 39 states. Each facility has its own security, operations, and maintenance requirements. A single facility would be beneficial because it would consolidate security, operations, and maintenance resources. Also, at some nuclear plant sites, all that remains following the decommissioning and dismantlement of the reactor and other buildings, is the used nuclear fuel. These communities cannot redevelop these former plant sites, resulting in the loss of millions in tax revenue every year.


  • What is the HI-STORE CISF?

    Holtec International launched the licensing of an autonomous consolidated interim storage facility (CISF) in southeastern New Mexico on land owned by Eddy-Lea Energy Alliance (ELEA), LLC. The facility, named HI-STORE CISF, will provide a significant step on the path to the Federal Government’s long standing obligation for disposition of used nuclear fuel by providing a safe, secure, temporary, retrievable, and centralized facility for storage of used nuclear fuel and high-level radioactive waste until such time that a permanent solution is available. The HI-STORE CISF provides a site to aggregate the used nuclear fuel canisters presently stored across the country at independent used fuel storage installations into one secure location.

    The license application for the HI-STORE CISF was submitted to the USNRC on March 31, 2017 and accepted by the USNRC in February 2018 (USNRC Docket No. 72-1051). It is anticipated that the HI-STORE CISF  license will be issued in early 2022. The HI-STORE CISF will utilize Holtec’s licensed HI-STORM UMAX, an underground dry storage system engineered and sized to hold all currently licensed dry spent fuel storage canisters throughout the U.S.

    The initial application for the HI-STORE facility includes storage of up to 8,680 metric tons of uranium in commercial used fuel (500 canisters) with future amendments for additional canisters up to 10,000 storage locations. The U.S. currently has more than 80,000 metric tons of used nuclear fuel in storage and more is being generated every day at a rate of 2,000 metric-tons per year.

  • What is HI-STORM UMAX?

    HI-STORE will employ Holtec’s HI-STORM UMAX used fuel storage system, the most secure and safest technology licensed by the USNRC, which will store the canisters bearing the used fuel in a dry, below-grade configuration with unrestricted capability to retrieve and move the canisters at any time during the facility’s life. The HI-STORM UMAX technology was first licensed by the USNRC in 2015 (USNRC Docket No 72-1040). Already in use in the U.S., the HI-STORM UMAX is a system that provides the utmost protection to the environment and superior radiation shielding for workers and the public by storing the canisters in below-grade steel enclosures covered by heavy lids, where each enclosure contains one canister in a vertical orientation.

  • Is the HI-STORE CISF the permanent solution for storage of used nuclear fuel?

    No. HI-STORE CISF is temporary storage, complementary to a permanent deep repository. Under federal law, DOE has the undivided responsibility to perform construction of and transport the fuel to the repository.

  • How long will the Holtec dry storage system last?

    The life expectancy of the stainless-steel canister, which is the primary containment of the spent nuclear fuel, varies based on the environment. Conservative estimates put the life expectancy of the canister at hundreds of years. As part of the aging management program, there are regular inspections of canisters that will check the entire surface of a single canister, or part of the surface of multiple canisters. If these inspections would ever indicate an imperfection or crack, canisters would be re-packaged before a crack could propagate and a leak occur. There is sufficient time to re-package the canister since it would take many years for a crack to develop into a leak.


  • What financial assurance does Holtec International need to provide for this project?

    Under federal law, a decommissioning fund is established to cover the cost of demolition and remediation of the facility once it reaches the end of its life.

  • Who is responsible for decommissioning and restoring the HI-STORE site once the fuel is finally removed?

    Holtec will be responsible for decommissioning and restoring the HI-STORE site once the fuel is finally removed. Like an operating nuclear plant, Holtec will be required by the NRC to establish a decommissioning trust fund and maintain certain funding levels that would allow decommissioning to proceed when needed. The local community does not bear any responsibility for funding the trust fund nor decommissioning.

  • Does the Price Anderson Act apply to transporting fuel to and from HI-STORE?

    Yes, the Price Anderson Act does apply. Operating and non-operating nuclear plants as well as some other facilities are covered under the Price Anderson Act. The act includes transportation of nuclear fuel to and from a covered facility.


  • Will there be security at the HI-STORE CISF?

    Yes. Robust security measures are required by law at facilities regulated by the U.S. NRC. Beginning with Holtec’s storage technology, the HI-STORM UMAX is an inherently secure, robust structure below grade made of concrete with silos where the canister containing the used fuel will reside. The HI-STORM UMAX is built to withstand hurricanes, tornadoes and earthquakes. Storing the strength-welded canister containing the used fuel completely below grade removes any target that an airplane or missile could hit. The specific security capabilities required by the U.S. NRC are compartmented, and not available to the general public. It can be said that the measures will include a well-trained and armed security force, physical barriers, proper lighting, and intrusion detection and surveillance systems. Holtec will also coordinate security with Local, State, and Federal Agencies. Because the HI-STORM UMAX is a very low-profile storage system (less than 3 feet from the ground) a security guard can see from one side of the storage facility to the other with no obstructions.

  • Will an airplane or other missile damage the used nuclear fuel?

    An airplane or other missile will not damage the used nuclear fuel. The HI-STORM UMAX, the used fuel storage system to be used at the HI-STORE CISF, is an inherently secure and robust structure. The silos where the canister containing the used fuel will reside are below grade and made of steel surrounded by concrete. The HI-STORM UMAX is built to withstand hurricanes, tornadoes and earthquakes. Storing the strength-welded canister containing the used fuel completely below grade removes any target that an airplane or missile could hit.

  • Can a saboteur cause a radioactivity release accident by blocking the air flow vents in the storage system?

    No, not possible.

    To meet the transport constraints, the heat load of each canister at HI-STORE will be less than 60% of the NRC-certified value for on-site storage. Thus, the heat generation rate in any canister stored at HI STORE CISF will be well below the thermal capacity of the storage system when it is first installed and then continuously decline from that point in accordance with the natural law of radioactive decay. The reduced heat load at the HI-STORE CISF ensures that a canister’s failure causing radiological release is not possible even if a saboteur were to miraculously evade the security forces and intrusion sensors, and have possession of the specially-engineered hardware that would be needed to block the air flow.

  • Should a fuel pool be available for re-packaging of fuel?

    The basic concept of the canister-based used fuel storage system is that fuel is packaged once, in a strength-welded canister. Hence, there is no need for re-packaging fuel at the HI-STORE CISF.

  • Does Holtec have a strong safety record?

    Yes, Holtec International has, for over the past three decades, undergone rigorous inspections by the U.S. Nuclear Regulatory Commission, its clients, and nuclear industry organizations, passing every inspection since its inception, no exceptions. Holtec International has an impeccable safety record. None of Holtec’s equipment has ever experienced a safety issue, leaked or caused any injury.

  • Are there damaged Holtec canisters in California?

    No, there are no damaged, cracked or gouged canisters in California or any nuclear plant using Holtec’s used fuel storage systems. The Holtec canisters are designed to meet or exceed the standards set forth by the NRC. The materials, fabrication procedures, and personnel qualifications are closely controlled to ensure high and reproducible quality. Using these tenants, the NRC approved and certified our technology. The canisters themselves are subjected to multiple tests in the factory including radiography and leak testing before the canisters are sent to a nuclear plant for use. In the field (at the plant), after the used nuclear fuel is loaded into the canister, the canister lid is welded to the canister body and is subjected to multiple tests including liquid penetrant and helium leak testing. Canisters are required to pass all tests prior to being placed into storage. Some time ago, Holtec voluntarily inspected two canisters. No abnormalities in the canisters were found. These inspections, although not required, lent credence to Holtec’s fabrication standards and practices. In the future, aging management programs, mandated and approved by the U.S. Nuclear Regulatory Commission, will provide assurance the canisters do not develop cracks or leaks over the many years that the canisters will be in use.


  • Are the casks too heavy for the rail lines?

    No, they are not too heavy. Weight capacity of rail systems is specified as weight per axle of the rail car. A rail car with 8 or 12 axles can carry a cask without exceeding any limitation. A locomotive easily weighs 400,000 pounds, similar to a cask. So, weights such as that are nothing unusual for the rail system.

  • Will transporting the waste twice double the risks?

    The final repository will most likely be in the western U.S. So, we will actually be transporting it one time to the western destination with a temporary stop over while waiting for the repository to be completed. There will be very little difference in the distance traveled, and thus, the risk calculations change very little.

  • The used nuclear fuel in the casks contains plutonium, similar to a nuclear bomb. Could an accident with a cask create a nuclear explosion?

    No, absolutely not. While it is correct that used nuclear fuel contains plutonium, it is in a state and configuration that makes a nuclear explosion physically impossible.

Radiological and Environmental

  • What prevents water and debris from entering the underground storage cavity?

    The HI-STORM UMAX lid is designed to direct storm water and, in northern climates, snow/ice melt-off away from the lid where the air passages are located. The concrete pad is sloped to direct water away from the lid. Moreover, any minor amount of moisture that may intrude into the storage cavity due to wind-driven rain will evaporate in a short period of time due to the continuous movement of heated air in the storage cavity. Also, all inlets and outlets are equipped with screens that prevent any significant debris from entering the vaults.

  • What impact would a brush fire have on the HI-STORE CISF?

    A brush fire would not have any impact on HI-STORE. The HI-STORM UMAX system is designed to resist natural and manmade events like fire, earthquakes, projectiles, tornados, floods and other extremes. As part of the final safety analysis report for HI-STORM UMAX, the NRC previously concluded the design basis fire accident does not affect the safe operation of the HI-system. If a brush fire were to occur near the HI-STORE facility, the potential of the fire spreading to the site is also extremely remote since combustible materials are not allowed to be stored in the area. The NRC will further examine this issue as part of its final safety evaluation report for HI-STORE.

  • What dose could I receive from a train transporting used nuclear fuel?

    If you were to stand at a rail road crossing and a train with 10 spent fuel casks would slowly roll past you (at 3 miles per hour) you would receive less than 0.03 mrem of radiation. This amount of radiation is not measurable compared to background radiation levels. This is less than 1/10,000th of the typical annual dose from the background radiation that every person experiences in the US, which is about 360 mrem. This is also less than 1/10th of what a person receives during just 1 hour traveling by plane, which is about 0.5 mrem. Hence the dose rate from rail transport of used nuclear fuel casks, even at close distance, is negligible compared to other radiation sources that are part of everyday life.

  • What dose could I receive if I were to stand at the boundary of the HI-STORE CISF?

    If you were to stand at the site boundary of the HI-STORE CISF for 24 hours, you would receive less than 0.03 mrem of radiation. This amount of radiation is not measurable compared to background radiation levels. This is less than 1/10,000th of the typical annual dose from the background radiation that every person experiences in the US, which is about 360 mrem. This is also less than 1/10th of what a person receives during just 1 hour traveling by plane, which is about 0.5 mrem. Hence the dose rate from the facility, even at close distance, is negligible compared to other radiation sources that are part of everyday life.

  • Will the UMAX storage system cause a large increase in the ground load underneath the storage cavities?

    No. The ground load will remain substantially unchanged after the subterranean storage system is installed and placed in service with loaded multi- purpose canisters. This is because the mass of the earth  removed to make the canister storage cavity approximates  the combined mass of the constructed storage cavity and its stored multi-purpose canister. Therefore, long-term settlement of the site caused by a large increase in the load overburden is not possible.

  • What is the risk of radiological release from a transport accident involving a ​​​loaded ​Holtec transport cask traveling over the railroads to the HI-STORE CIS ​​​site?

    Holtec’s NRC-certified transport casks carry the used fuel inside an all-welded stainless-steel vessel known as multi-purpose canisters (MPCs). The MPC is, however, optional for transporting used fuel in a transport cask. The transport cask is designed to carry “bare” fuel without any MPC inside it. The transport cask, certified by the USNRC, must be demonstrated to maintain the radiological matter contained in the used fuel’s rods inside the cask’s internal space under a set of punishing accidents such as free fall simulating a hard collision, fire, and deep submersion. In other words, the transport casks are licensed by the NRC to serve as an autonomously leak-tight fortress capable of preventing leakage of its internal gaseous matter to the environment under a series of bounding accidents without any reliance on a leak-tight MPC which may be inside it. For the HI-STORE CIS facility, adopting an even more stringent posture of safety, Holtec has mandated that a shipment of used fuel can occur only after the fuel has been packaged in an MPC. This voluntary measure amounts to sequestering the used fuel inside the welded Canister which is itself sequestered from the environment by the corpus of the transport cask. Together, the MPC and the transport cask reduce the probability of a radiological release to the environment to several orders of magnitude below what is considered “non-credible” under USNRC’s definition.

    In fact, the MPC has been recognized as an exceedingly stout barrier against leakage able to withstand deceleration loads in the wake of a postulated accident so severe that it would totally demolish the transport car and its associated structures! The railroad cars are restricted from traveling at a speed limit that is substantially below the level for which the cask is qualified. A Holtec paper, “MPC: A bulwark of safety in the post-9/11 age,” provides additional technical information on the invulnerability of the MPC to severe accidents here.

    To summarize, the maximum impact load that can conceivably develop from a transport accident is well below the structural capacity of the cask to maintain leak-tightness and an order of magnitude below the capacity of its enclosed MPC to maintain radiological confinement. Therefore, the risk of radiological release from an MPC bearing the HI-STAR model cask subject to the most severe transport accident contemplated in the NRC regulations (which bound those possible in practice) is essentially zero.

    Furthermore, the assessment of a cask encountering a severe transport accident has been estimated by the authorities to be “non-credible.” Industry experience with millions of miles of cask transports over the past four decades bear out the above estimate.

    Thus, the occurrence of a radiological release from a Holtec cask must overcome three non-credible independent probabilities that are stacked against it. First, the occurrence of a transport accident would be a complete departure from the industry experience, and then if the transport accident is (counter-factually) assumed, two non-credible occurrences of failure of the transport cask’s containment boundary, and failure of the MPC confinement structure both must occur as a result of the accident to produce a release. Because of the above-described cascade of non-credible possibilities, the scenario of a radiological release from a Holtec transport cask is best termed as “impossible.”

Regulatory Compliance

  • What regulations and oversight apply to the HI-STORE CISF?

    At the federal government level, the U.S. Nuclear Regulatory Commission must approve the license application submitted by Holtec International. Regulatory requirements would be imposed on all aspects of the operation, including security and liability. Oversight would include periodic inspections and audits conducted by regional inspectors. All of this occurs at operating interim storage facilities across the country today. Construction and environmental permits will be approved at the state and local levels.