Handling systems for deep storage of spent nuclear fuel packages in Finland

In January 2020, STUK the Finnish nuclear authorities (French equivalent of ASN – Autorité de Sûreté Nucléaire), validated both the design and the industrialization plan for one of the three secured fuel handling machines that CNIM will supply at Olkiluoto, for the Finnish geological repository for spent nuclear fuel, currently under construction.

Key figures

3

Handling systems of nuclear packages

EN 13001

Latest EU standard for sizing handling systems

1
mm

Precise positioning to the nearest millimeter

Highly safe handling and precise positioning in a constraint environment: CNIM’s recognized know-how

Posiva Oy is the leading final disposal operator in the world, preparing to start the final disposal for spent nuclear fuel generated by its owners TVO and Fortum Power and Heat Oy in the ONKALO® facility that is going to be excavated deep in the bedrock in 2020’s.

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Deep storage_Olkiluoto Encapsulation Plant © POSIVA

Olkiluoto Encapsulation Plant © Posiva Oy.jpg

Olkiluoto Encapsulation Plant © Posiva Oy

Posiva Oy entrusted CNIM in January 2017 with the design, manufacturing and installation of three handling machines for Olkiluoto Encapsulation Plant:

  •   The "Transfer Cask Transfer Trolley", a trolley conveying the fuel assembly transportation casks to beneath the hot cell (PK.221 - see picture below)
  • The “Fuel Handling Machine”, for the transfer of spent fuel assemblies from the transportation casks into their copper canisters (PK.231)
  • The "Canister Trolley", transfer / maintenance / positioning / lifting / rotation system of the copper canisters through different stations for their finalization (welding, machining, inspection) before transfer to the deep storage areas. (PK.251).

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The Transfer Cask Transfer Trolley © Posiva Oy / CNIM

"The handled transportation casks and the copper canisters measure up to more than 5 m and must be positioned to the millimeter," said Gregory Ecalle, who participated to the project and is one of the design expert at CNIM Systèmes Industriels. For the “Canister Trolley”, for example, these extremely precise positioning performances are achieved thanks to a system of tri-directional cylinders, placed on a lower rotary plate. Our expertise in electromechanical systems for secure handling in a constraining environment allows us to find solutions that are both innovative and robust. "

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The Canister trolley (PK.251) is a  handling system for copper canisters which performs a whole series of precise operations © Posiva Oy / CNIM

 

EN 13001 standard & international nuclear design codes

Having already supplied the spent fuel cask transfer system on global scale, CNIM’s engineers have once again demonstrated their ability to design electromechanical systems for the nuclear sector, while applying the latest safety and dimensioning standards, on an international scale.

"We had to take into account the new Finnish regulations - the new YVL - for the design of the handling machines for the Olkiluoto site," explained Gregory Ecalle. “There was the EN 13001 standard. It is a recent European standard for the dimensioning of secure handling systems. It was the first time that it had been deployed on a project of this magnitude and our teams had to clarify its interpretation with the drafters of the standard themselves, said the design expert. Today we have gained skills and we continue to aim for projects for the secure handling of very sensitive and large packages for which precise positioning on the order of a millimeter must be achieved. "

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Operating environment of the "Cask Transfer Trolley" handling system © Posiva Oy / CNIM

 

More than a design, a validated industrialization plan

The Finnish authorities requires licensee (Posiva Oy) to provide them with not only design studies but a complete "Construction Plan" related to the safety parts of the machine, which are in CNIM’s scope of work.

The STUK thus formally validated in January 2020 the design of the "Canister Trolley", the prequalification of the materials and the precise description of its industrialization (in particular for welding operating procedures, tests and qualifications). The manufacturing of this handling system began in early 2020 in CNIM’s workshops in La Seyne-sur-Mer and will be completed in the summer of 2021.

The design of the “Transfer Cask Transfer Trolley” and its industrialization plan have been submitted and are in the process of being approved by the STUK. As for the “Fuel Handling Machine”, its design will be finished in spring 2020.

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Operational environment of the "Canister Trolley": passage through different stations to finalize the canisters before their transfer to the storage areas © Posiva Oy / CNIM