Upper ports

A very international effort

17 Jun 2019 - ITER Russia

The 18 upper ports of the ITER vacuum vessel are procured by Russia, manufactured in Germany, and mounted (in part) on the vessel sectors by contractors in Italy and Korea. Another example of how ITER would not be taking shape without globe-spanning collaboration.

The first upper port stub extension delivered by ITER Russia, PSE #12, was delivered to Korea in December, 2017. After site acceptance testing, it can now be welded on vacuum vessel sector #6. The 18-tonne component is made of ITER-grade stainless steel (316L(N)-IG).

On a cold night in December 2018, upper port stub extension #10 left the factory of MAN Energy Solutions in Deggendorf, Germany, on the back of a transport truck for a several-day drive to Italy.

It was an inaugural voyage—over the next two years, the Russian Domestic Agency will be shipping four other port stub extensions to European Domestic Agency contractors in Italy to be welded onto vacuum vessel sectors before they are shipped to ITER.

The vehicle was blocked unexpectedly in Austria for nearly one month by heavy snow, but all ended well: the component was delivered in January and four other expeditions to Italy—less eventful we hope—are planned before the end of the year. Two upper port stub extensions—including the first production unit #12—have also been successfully transported by sea to Hyundai Heavy Industries in Korea and two others are expected.

Procured by Russia, built in Germany from material sourced in Europe, welded to the vacuum vessel sectors in Korea or Europe ... the upper ports are a very international effort. Fabrication began in 2014.

Four ITER Domestic Agencies are participating in the fabrication of the ITER vacuum vessel, making it a very international venture: Korea (four main sectors, equatorial ports, lower ports, gravity supports); Europe (five main sectors); India (in-wall shielding); and Russia (upper ports).

Spaced in neat rows around the torus-shaped vacuum vessel at upper, equatorial and lower levels are 44 openings, or "ports" with a variety of service functions. From inside the plasma chamber, these access windows resemble the porthole of an airplane, only larger and with a variety of rectangular or trapezoidal shapes. From outside the vessel, the openings are completely hidden behind stub extensions and splice plates, connecting ducts and port stubs—everything needed to create a corridor of connection between the exterior wall of the vacuum vessel and the cryostat approximately six metres away.

"Ports" are the stainless steel structures that extend out from each opening in the vacuum vessel, creating corridors of access to the machine for maintenance, diagnostics, or heating, fuelling, and vacuum pumping systems. They are made of the same ITER-grade austenitic steel as the main sectors and are an integral part of the vacuum vessel confinement and safety boundary.

Like the vacuum vessel sectors, the ports are Safety Important Class components whose manufacturing requires strict quality assurance and close adherence to the nuclear code and regulations. Compliance to safety requirements at all fabrication stages is controlled by the Agreed Notified Body¹ (ANB Vinçotte, Belgium).

The ports will be manufactured and installed in two phases—the 3- to 7-metre-long port stub extensions will be shipped to sector manufacturers and welded directly onto the vacuum vessel sectors, while the second-phase port extensions will be delivered directly to the ITER site and installed after the magnets in the Tokamak assembly pit.

In Russia, the procurement of the 18 upper ports has been underway under the responsibility of main contractor NIIEFA (the Efremov Institute) since the signature of the Procurement Arrangement in 2009. NIIEFA has extensive experience in ITER standards and requirements, having led and coordinated R&D work undertaken by Russian laboratories for the modelling of high-vacuum and high-pressure components, in-vessel plasma-facing components, and the ITER divertor.

In advance of or in parallel to the manufacturing activities, which were launched in 2014, ITER Russia has developed quality assurance documents and had them agreed by the ITER Organization, completed drawings, procured material (over 1,000 tonnes of austenite steel procured in Europe), selected the primary manufacturing contractor (2012), certified welding procedures, and qualified welding and non-destructive testing personnel in accordance with French nuclear regulations. For the fabrication of upper port stub extension #12, more than 250 procedures/documents were prepared by the Russian Domestic Agency and its suppliers.

And there is more: at the completion of each component, factory acceptance tests are carried out by MAN Energy Solutions, with ITER Russia and ITER Organization observers, followed by site acceptance tests in Korea and Europe.

"Being part of the worldwide team to realize ITER has been a challenge as well as an opportunity," says Thomas Schiller, head of Energy & Physics at MAN Energy Solutions. "Engineering and manufacturing such a safety-important component, given the quality and the quantity demanded, has opened a new chapter for MAN ES Deggendorf."

¹An Agreed Notified Body (ANB) is a private company authorized by the French Nuclear Regulator ASN to assess the conformity of components in the pressure equipment category (ESPN).

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