The first cask of the new type for Temelín NPP
20. 9. 2019
The first spent nuclear fuel cask of the new type, ŠKODA 1000/19, has left the Reactor Shop of ŠKODA JS a.s. in Pilsen for the Temelín nuclear power plant. The cask is intended for the transport and dry storage of spent nuclear fuel from the VVER 1000 pressure vessel type reactors at the Temelín NPP. The contract for the delivery of 60 casks, which should be supplied gradually by 2035, was concluded between ŠKODA JS and ČEZ in 2015. In the upcoming years, six casks should be supplied annually.
The first ŠKODA 1000/19 cask dispatched
ŠKODA JS has been manufacturing casks for spent nuclear fuel since 1995 and so far has supplied nuclear power plants and facilities in the Czech Republic, Germany, the USA, Switzerland, Lithuania and Bulgaria with more than 400 of them. The ŠKODA 1000/19 cask that was shipped today is the result of the company’s own development, works on which began at ŠKODA JS in 2012. In 2017, the cask received type approval from the State Office for Nuclear Safety. Apart from its development, work was underway on the design and delivery of accessory equipment necessary for clearing and handling the cask at the power plant.
“We focus not only on our participation in the construction of new nuclear units and maintenance and modernization activities in current nuclear operations,” stated Chairman of the Board of Directors and General Director of ŠKODA JS, Vladimír Poklop. “We also want to contribute to the safe and environmentally-friendly storage of spent nuclear fuel. Our contribution in this area is the long-term production program for the manufacture of casks for the storage of spent nuclear fuel, the new generation of which we are introducing today.”
“The cask that is being dispatched today is evidence of not only the technical advancement of our company. It also illustrates that just like a number of other Czech companies in this industry, we are capable of delivering a significant part of nuclear engineering projects,” he added. “These days, ŠKODA JS generates a larger part of its revenue in international markets; however, we are prepared to take a major part in projects of new nuclear sources in our country. At the current stage of the development of the power industry, we see no other alternative that would guarantee a sufficient amount of electricity in a 20–30-year time frame, and as a result not only the energy security of our country. That is also the message contained in an open letter addressed to the Prime Minister of the Czech Republic, which was sent recently on behalf of the Czech Power Industry Alliance.”
In 2021, the supply of casks for the Temelín NPP, which began today, will be followed by the supply of casks for the Dukovany NPP. In a contract concluded with ČEZ in 2016, ŠKODA JS undertook to produce 35 casks by the year 2031. If the nuclear power plant’s lifetime is extended, the supply of casks will continue until 2048. Just like the casks for the Temelín NPP, those for the Dukovany NPP will be the result of ŠKODA JS’s own development.
The ŠKODA 1000/19 cask
The first ŠKODA 1000/19 cask dispatched
The body of the ŠKODA 1000/19 cask consists of a cylinder of forged steel with an outer diameter of 2.3m and height of 5.6m in storage configuration. It weighs almost 105 tons empty and when filled to capacity with fuel assemblies, its weight is almost 119 tons. The thickness of the cask wall is 410 mm and it is impervious to gamma and neutron radiation. The cask leak-tightness is guaranteed for a minimum of 60 years.
The cask also meets requirements in terms of mechanical resistance to emergency situations, as required by international standards: e.g., resistance to a fall from a drop height of 9 meters onto a hard surface and a fall from a drop height of 1 meter onto a pointed object; resistance to hydrostatic pressure equivalent to the 200m vertical height of a water column; fire resistance of 30 minutes at 800°C, etc.
The inner surface of the cask is covered with a corrosion-resistant metal coating. In the cask wall, there are two rows of drill holes for moderator rods intended for neutron shielding. A load bearing basket is inserted in the body of the cask. The fuel basket is constructed of 19 hexagonal aluminum alloy tubes containing approx. 5% B4C (boron carbide), in which the nuclear fuel is placed.
At the Temelín NPP, nuclear fuel remains in the reactor core for a period of four years. Following its removal, it is placed in a special spent fuel pool for approximately ten years, where it cools down. Subsequently, fuel assemblies are then loaded into casks and transported to a spent fuel storage facility located on the premises of the nuclear power plant and managed by it.