Jülich pilot reactor vessel removed

Tuesday, 10 February 2015

Mammoet has removed the reactor vessel from a pilot nuclear reactor in Jülich, Germany, marking an important milestone in the decommissioning of the facility.

A purpose-built lifting and skidding system moves the reactor vessel out of the opened reactor building towards its support frame (Image: Mammoet)

Mammoet is a privately held Dutch company specializing in the hoisting and transporting of heavy objects.

The reactor was a prototype pebble bed reactor constructed in the 1960s to demonstrate the feasibility and viability of a gas-cooled, graphite-moderated high temperature reactor. It was shut down in 1988 after 20 years of operation. The facility is being decommissioned by AVR GmbH.

Before decommissioning could begin, a large building, a so-called material lock, was constructed over the existing reactor building. This allowed the reactor building to be opened in a protected environment for removal of the reactor vessel.

Mammoet custom-designed the skidding and lifting equipment to move the reactor vessel from the reactor building into the material lock. The vessel weighs 2000 tonnes, is 26 meters high and has a diameter of 7.6 meters. It was lifted from its former position in the reactor building, moved and then placed into a custom-built support frame.

Later this year the reactor vessel will be lifted out of its support frame and moved from its current vertical position into a horizontal position. It will then be placed in a transport frame, and transported on self-propelled modular trailers to a purpose-built storage building where it will rest for the next 40-60 years until final storage is available in Germany.

Brunsbüttel waste

In another development in Germany’s decommissioning work, Vattenfall and the country's nuclear supervisory authority expect to complete the process of removing low- and intermediate-level radioactive waste from containers stored in caverns at the Brunsbüttel nuclear power plant by the first half of 2018.

The plant, which is near Hamburg, Germany has six caverns containing about 630 containers of radioactive waste. The caverns are in a shielded area of the plant and are intended for temporary storage pending commissioning of the Konrad nationwide repository for radioactive waste, which is not expected to be completed before 2022.

The Swedish state-owned utility inspected the containers for signs of corrosion in 2013 using a special camera. The containers contain waste from wastewater treatment or from process circuits. They include filter resins, evaporator concentrates or mixed waste including cloth and construction debris. The waste is to be emptied from the containers into new containers, which are cast-iron GNS yellow boxes.

Researched and written
by World Nuclear News