Dry cask storage is a method of storing high-level

radioactive waste Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapon ...

, such as

spent nuclear fuel Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant). It is no longer useful in sustaining a nuclear reaction in an ordinary thermal reactor and ...

that has already been cooled in the

spent fuel pool Spent fuel pools (SFP) are storage pools (or "ponds" in the United Kingdom) for spent fuel from nuclear reactors. They are typically 40 or more feet (12 m) deep, with the bottom 14 feet (4.3 m) equipped with storage racks designed to hold ...

for at least one year and often as much as ten years.

Cask A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, u ...

s are typically

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistan ...

cylinders that are either

welded Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as braz ...

or bolted closed. The fuel rods inside are surrounded by

inert gas An inert gas is a gas that does not readily undergo chemical reactions with other chemical substances and therefore does not readily form chemical compounds. The noble gases often do not react with many substances and were historically referred to ...

. Ideally, the steel cylinder provides leak-tight containment of the spent fuel. Each cylinder is surrounded by additional steel,

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

, or other material to provide radiation shielding to workers and members of the public. There are various dry storage cask system designs. With some designs, the steel cylinders containing the fuel are placed vertically in a concrete vault; other designs orient the cylinders horizontally. The concrete vaults provide the radiation shielding. Other cask designs orient the steel cylinder vertically on a concrete pad at a dry cask storage site and use both metal and concrete outer cylinders for radiation shielding. As of 2021 there is no long term permanent storage facility anywhere in the world; dry cask storage is designed as an interim safer solution than spent fuel pool storage. Some of the cask designs can be used for both storage and transportation. Three companies – Holtec International, NAC International and Areva-Transnuclear NUHOMS – are marketing Independent Spent Fuel Storage Installations (ISFSI) based upon an unshielded multi-purpose canister which is transported and stored in on-site vertical or horizontal shielded storage modules constructed of steel and concrete.

Usage

During the 2000s, dry cask storage was used in the United States, Canada, Germany, Switzerland, Spain, Belgium, the United Kingdom, Japan, Armenia, Argentina, Bulgaria, Czech Republic, Hungary, South Korea, Romania, Slovakia, Ukraine and Lithuania. A similar system is also being implemented in Russia. However, it is based on 'storage compartments' in a single structure, rather than individual casks. In 2017 France's

Areva Areva S.A. is a French multinational group specializing in nuclear power headquartered in Courbevoie, France. Before its 2016 corporate restructuring, Areva was majority-owned by the French state through the French Alternative Energies and Atom ...

launched the NUHOMS Matrix advanced used nuclear fuel storage overpack, a high-density system for storing multiple spent fuel rods in canisters.

United States

In the late 1970s and early 1980s, the need for alternative storage in the United States began to grow when pools at many nuclear reactors began to fill up with stored spent fuel. As there was not a national nuclear storage facility in operation at the time, utilities began looking at options for storing spent fuel. Dry cask storage was determined to be a practical option for storage of spent fuel and preferable to leaving large concentrations of spent fuel in cooling tanks. The first dry storage installation in the US was licensed by the

Nuclear Regulatory Commission The Nuclear Regulatory Commission (NRC) is an independent agency of the United States government tasked with protecting public health and safety related to nuclear energy. Established by the Energy Reorganization Act of 1974, the NRC began opera ...

(NRC) in 1986 at the

Surry Nuclear Power Plant Surry Power Station is a nuclear power plant located in Surry County in southeastern Virginia, in the South Atlantic United States. The power station lies on an site adjacent to the James River across from Jamestown, slightly upriver from Sm ...

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth are ...

. Spent fuel is currently stored in dry cask systems at a growing number of power plant sites, and at an interim facility located at the

Idaho National Laboratory Idaho National Laboratory (INL) is one of the national laboratories of the United States Department of Energy and is managed by the Battelle Energy Alliance. While the laboratory does other research, historically it has been involved with nu ...

near

Idaho Falls, Idaho Idaho Falls (Shoshoni language, Shoshoni: Dembimbosaage) is a city in and the county seat of Bonneville County, Idaho, Bonneville County, Idaho, United States. It is the state's largest city outside the Boise metropolitan area. As of the 2020 Un ...

. The Nuclear Regulatory Commission estimates that many of the nuclear power plants in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

will be out of room in their spent fuel pools by 2015, most likely requiring the use of temporary storage of some kind. Yucca Mountain was expected to open in 2017. However, on March 5, 2009, Energy Secretary

Steven Chu Steven ChuYucca Mountain site was no longer considered an option for storing reactor waste. The 2008 NRC guideline calls for fuels to have spent at least five years in a storage pool before being moved to dry casks. The industry norm is about 10 years. The NRC describes the dry casks used in the US as "designed to resist floods, tornadoes, projectiles, temperature extremes, and other unusual scenarios." As of the end of 2009, 13,856 metric tons of commercial spent fuel – or about 22 percent – were stored in dry casks. In the 1990s, the NRC had to “take repeated actions to address defective welds on dry casks that led to cracks and quality assurance problems; helium had leaked into some casks, increasing temperatures and causing accelerated fuel corrosion”. With the zeroing of the budget for

Yucca Mountain nuclear waste repository The Yucca Mountain Nuclear Waste Repository, as designated by the Nuclear Waste Policy Act amendments of 1987, is a proposed deep geological repository storage facility within Yucca Mountain for spent nuclear fuel and other high-level radio ...

in Nevada, more

nuclear waste Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons ...

is being loaded into sealed metal casks filled with inert gas. Many of these casks will be stored in coastal or lakeside regions where a salt air environment exists, and the Massachusetts Institute of Technology is studying how such dry casks perform in salt environments. Some hope that the casks can be used for 100 years, but cracking related to corrosion could occur in 30 years or less. Company videos, covering the processes and remote handling, from the initial fuel loading to the removal and eventual dry-cask storage, are viewable on various video hosting domains.

Canada

In Canada, above-ground dry storage has been used.

Ontario Power Generation Ontario Power Generation Inc. (OPG) is a Crown corporation and "government business enterprise" that is responsible for approximately half of the electricity generation in the province of Ontario, Canada. It is wholly owned by the government ...

is in the process of constructing a Dry Storage Cask storage facility on its

Darlington Darlington is a market town in the Borough of Darlington, County Durham, England. The River Skerne flows through the town; it is a tributary of the River Tees. The Tees itself flows south of the town. In the 19th century, Darlington underw ...

site, which will be similar in many respects to existing facilities at Pickering Nuclear Generating Station and

Bruce Nuclear Generating Station Bruce Nuclear Generating Station is a nuclear power station located on the eastern shore of Lake Huron in Ontario, Canada. It occupies 932 ha (2300 acres) of land. The facility derives its name from Bruce Township, the local municipality wh ...

. NB Power's

Point Lepreau Nuclear Generating Station Point Lepreau Nuclear Generating Station is a nuclear power station located 2 km northeast of Point Lepreau, New Brunswick, Canada. The facility was constructed between 1975 and 1983 by NB Power, the provincially owned public utility. ...

and Hydro-Québec's Gentilly Nuclear Generating Station also both operate dry storage facilities.

Germany

A centralized storage facility using dry casks is located at Ahaus. As of 2011, it housed 311 casks: 305 from the

Thorium High Temperature Reactor The THTR-300 was a thorium cycle high-temperature nuclear reactor rated at 300 MW electric (THTR-300) in Hamm-Uentrop, Germany. It started operating in 1983, synchronized with the grid in 1985, operated at full power in February 1987 and was shut ...

, 3 from the Neckarwestheim Nuclear Power Plant, and 3 from the

Gundremmingen Nuclear Power Plant The Gundremmingen Nuclear Power Plant is a nuclear power station in Germany. It is located in Gundremmingen, district of Günzburg, Bavaria. It is operated by Kernkraftwerk Gundremmingen GmbH, a joint operation of RWE Power AG (75%) and Preuss ...

. The transport from Gundremmingen to the Ahaus site met with considerable public protest and the power plant operators and the government later agreed to locate such casks at the powerplants. ''CASTOR'' (''ca''sk for ''s''torage and ''t''ransport ''o''f ''r''adioactive material) is a trademarked brand of dry casks used to store

(a type of

). CASTORs are manufactured by

Gesellschaft für Nuklear-Service The Gesellschaft für Nuklear-Service mbH (GNS) carries out services in the field of radioactive waste disposal and decommissioning of nuclear facilities and operates through several subsidiaries interim storage depots for spent fuel and radioactiv ...

(GNS), a German provider of nuclear services. ''CONSTOR'' is a cask used for transport and long-term storage of spent fuel and high-level waste also manufactured by GNS. Its inner and outer layers are steel, enclosing a layer of

. A 9-meter

drop test A drop test is a method of testing the in-flight characteristics of prototype or experimental aircraft and spacecraft by raising the test vehicle to a specific altitude and then releasing it. Test flights involving powered aircraft, particularl ...

of the V/TC model was conducted in 2004; the results conformed to expectations.

Bulgaria

In 2008, officials at the

Kozloduy Nuclear Power Plant The Kozloduy Nuclear Power Plant is a nuclear power plant in Bulgaria situated north of Sofia and east of Kozloduy, a town on the Danube river, near the border with Romania. It is the country's only nuclear power plant and the largest in the ...

announced their intention to use 34 CONSTOR casks at the Kozloduy NPP site before the end of 2010.

Lithuania

Spent fuel from the now-closed

Ignalina Nuclear Power Plant The Ignalina Nuclear Power Plant ( lt, Ignalinos atominė elektrinė, IAE) is a decommissioned two-unit RBMK-1500 nuclear power station in Visaginas Municipality, Lithuania. It was named after the nearby city of Ignalina. Due to the plant's sim ...

was placed in CASTOR and CONSTOR storage casks during the 2000s.

Russia

The Russian dry storage facility for spent nuclear fuel, the HOT-2 at Mining Chemical Combine in

Zheleznogorsk, Krasnoyarsk Krai Zheleznogorsk (russian: Железного́рск), is a closed town in Krasnoyarsk Krai, Russia, with a developed nuclear industry. The town has a population of History The town was formerly known as Krasnoyarsk-26 (). It was established in ...

in Siberia, is not a 'cask' facility per se, as it is designed to accommodate the spent nuclear fuel (both

VVER The water-water energetic reactor (WWER), or VVER (from russian: водо-водяной энергетический реактор; transliterates as ; ''water-water power reactor'') is a series of pressurized water reactor designs originally de ...

and

RBMK The RBMK (russian: реактор большой мощности канальный, РБМК; ''reaktor bolshoy moshchnosti kanalnyy'', "high-power channel-type reactor") is a class of graphite-moderated nuclear power reactor designed and buil ...

) in a series of compartments. The structure of the facility is made up of monolithic reinforced concrete walls and top and bottom slabs, with the actual storage compartments formed by reinforced concrete partitions. The fuel is to be cooled by natural convection of air. The design capacity of the facility is 37,785 tonnes of uranium. It is now under construction and commissioning.

Ukraine

In Ukraine, a dry storage facility has been accepting spent fuel from the six-unit Zaporizhzhia Nuclear Power Plant (

VVER-1000 The water-water energetic reactor (WWER), or VVER (from russian: водо-водяной энергетический реактор; transliterates as ; ''water-water power reactor'') is a series of pressurized water reactor designs originally de ...

reactors) since 2001, making it the longest-serving such facility in the former Soviet Union. The system was designed by the now-defunct Duke Engineering of the United States, with the storage casks being manufactured locally. Another project is underway with Holtec International (again of the USA) to build a dry spent fuel storage facility at the 1986-accident-infamous

Chernobyl Nuclear Power Plant The Chernobyl Nuclear Power Plant (ChNPP; ; ), is a nuclear power plant undergoing decommissioning. ChNPP is located near the abandoned city of Pripyat in northern Ukraine northwest of the city of Chernobyl, from the Belarus–Ukraine borde ...

( RBMK-1000 reactors). The project was initially started with Framatome (currently

AREVA Areva S.A. is a French multinational group specializing in nuclear power headquartered in Courbevoie, France. Before its 2016 corporate restructuring, Areva was majority-owned by the French state through the French Alternative Energies and Atom ...

) of France, later suspended and terminated due to technical difficulties. Holtec was originally brought on board as a subcontractor to dehydrate the spent fuel, eventually taking over the entire project.

References

External links

NRC: Dry Cask StorageUnited States Nuclear Waste Technical Review Board, ''Evaluation of the Technical Basis for Extended Dry Storage and Transportation of Used Nuclear Fuel '' 2010Locations of Independent Spent Fuel Storage Installations
{{DEFAULTSORT:Dry Cask Storage Radioactive waste Waste treatment technology Nuclear power plant components