Cutting begins at Unterweser as GNS prepares for dismantling

Experience gained on domestic German projects will be used to target dismantling and decommissioning projects overseas.

The GNS group says cutting work has begun at Unterweser as it prepares for dismantling of the reactor pressure vessels (RPVs) of PreussenElektra’s (PEL) entire nuclear power fleet following a second tender win.

The latest project comprises the complete dismantling and packaging of the six pressure vessels, each weighing between 400 and 500 tons, for final disposal, and is expected to last 10 years. The six plants are Brokdorf, Grafenrheinfeld, Grohnde, Isar (1 & 2), and Unterweser.

Höfer & Bechtel GmbH, in which the GNS Group has held a majority stake since last year, will be responsible for the dismantling of the RPVs, while GNS will be responsible for the project management and packaging of the dismantled components for final disposal. The two companies are supported by the GNS subsidiary WTI Wissenschaftlich-Technische Ingenieurberatung GmbH. GNS is partly owned by PEL.

“The dismantling work will be carried out serially starting with Unterweser,” Jörg Viermann, Head of Department Sales Waste Management GNS, told Nuclear Energy Insider.

“GNS and Höfer & Bechtel will manufacture two sets of equipment. Working at two sites in parallel will therefore also be possible but is currently not planned. We have formed an integrated team to prepare for and execute the RPV segmentation. The team was already able to show during the tendering phase that it harmonizes very well.”

Dismantling work in the reactor pressure vessel has begun at Unterweser. Image: PEL

Cutting begins

Two years ago, a consortium led by GNS, and including Westinghouse, was awarded the contract for dismantling and packaging the reactor pressure vessel internals of the six PEL nuclear power plants.

Viermann adds that while that project started two years ago, actual cutting started at Unterweser just a few weeks ago.

“After 25 months of planning, including the preparation of licensing documents, both for the cutting and packaging work on site as for the disposal of the resulting packages in the Konrad repository, the first cut was executed during the week commencing 27 January,” explained Viermann.

“The first component to be cut was a control rod guiding tube. It was cut with a circular saw designed by our partner Westinghouse Sweden AB.”

GNS has been working with Westinghouse and additional partners for the dismantling of activated components at EnBW’s Neckarwestheim (GKN I) and Philippsburg (KKP 1) plants. The segmentation of core internals at GKN I was completed in June 2019, and RPV segmentation will follow in 2020.

GNS staff at Unterweser will proceed from packaging the RPV-internals on to the segments of the RPV itself. Viermann says this will offer lots of synergies concerning staff and equipment, because GNS workers already know the plant, and the plant staff. In addition, GNS equipment for packaging is already inside the plant.

Just like Westinghouse for the internals, GNS will use various saws to cut the RPVs. Viermann says that though cutting times may be a little longer than for thermal technologies, this does not lead to a significantly longer total duration of the project which is mainly influenced by handling of the cut pieces rather than by the cutting speed.

Höfer & Bechtel specializes in equipment for spent fuel and high dose rate items in the pool (sipping, cutting, drying, etc.). The company also delivered equipment for previous projects for dismantling of RPV internals and RPV which was then operated by others.

Timeline of expenditure by German private companies
(excluding disposal). Total approx. €34 billion

Westinghouse has also been active in the M&A market, completing the acquisition of Rolls-Royce's Civil Nuclear Systems and Services business in North America and in select sites in Europe at the end of January 2020.

This was viewed as a strategic investment in expanding the company's nuclear products and services offerings, particularly through enhanced operating plant services capabilities and technologies.

The sites acquired by Westinghouse support plant automation and monitoring systems to maximize performance, cost effectiveness and support life extension of nuclear plants.

The German government has committed to close its six operational nuclear power plants, with three shutting down at the end of 2021 and the final three by the end of 2022. GNS says this is an opportunity for the company to develop and export its operations.

Scott Birch