Dismantling a Nuclear Reactor

nuclear reactor Mühleberg. 75,000 metric tons of nuclear waste

PATRICIA REMY – It hasn’t been done in Canada yet, but in Europe the nuclear reactors of the first generation have reached the end of their shelf-life and are being dismantled.  At some point in the not-too-distant future, very probably within the next twenty years, and despite attempts to refurbish them, the same fate awaits the Bruce Power reactor cluster and those in Pickering and Darlington.

My information is based on reports (i) on the nuclear reactor in Muehleberg (built in 1972), Canton Bern, in Switzerland, where the dismantling had in the spring of 2019 just begun and (ii) on a research reactor near Karlsruhe in Germany (erected in 1965), where the process of eliminating the complex completely is further along. 

On December 20, 2019 the nuclear reactor in Muehleberg was shut down.  The parent company decided in 2013 that refurbishing the complex was not a viable financial option.  The entire process of dismantling the buildings will take 15 years.  The difficult disposal of the remains follows.  The work will take place in several stages.  During the first few years the danger of a meltdown will still exist.

The first task is to remove the fuel rods.  These will be placed in basins of water and allowed to cool.  Sometime in 2021 they will be transported piece by piece to an interim storage site.  This will take 3 years.  By the end of 2024 all the fuel rods should have reached the storage site safely.  98% of their radioactivity will have dispersed.

In the meantime the mechanical and control centre will have been emptied and set up as the site for cleaning those components which have become radioactive by virtue of having been in contact with the live part of the reactor.  Each gram of material will be examined to ensure that nothing which exceeds the limits of what is considered safe [by whom, one asks] is released.  

In Karlsruhe the workers had to sign a waiver, before they were allowed into the reactor space:  No open wounds, not pregnant, take in nothing to eat or drink, and no electronic devices.  Their reactor, active 1965-1984, and much smaller than Muehleberg, was a pioneer work in every sense of the word: the construction, the operation, and the dismantling.  Others should profit from their experience.  The fuel rod container, the core of the reactor, relatively small at 7.6 x 4.6 meters and weighing 400 tons, had to be pulled out by crane and cut into 300 kg manageable pieces.  It and the steam pressure chamber had to be washed with water, which would bind still active neutrons and dust.  Metal and steel were chipped and scraped away with a custom-designed excavator.   Two-meter thick walls of rebar and the steel shell had to be broken down, each screw and nut pulled out, the metal then sorted out from the concrete with large magnets.  All radioactive materials were then enclosed and sealed in a special glass mixture.

Meanwhile, in Muehleberg, the concrete used in the housing of the reactor has already been broken down into five by five centimeter squares and examined with a Geiger counter.  Material successfully cleansed will be disposed of as normal garbage or recycled for other use.  (Remark of the author, for what, pray tell?)

By 2025 the whole complex will have been torn down.  By the end of 2030 the entire area should be free of radioactivity.  The site can now be used for other purposes.  Buildings which do not conform to the repurposing of the site will be demolished.  By 2034 the site can be used for a new industrial endeavour or left to return to nature.

Dismantling Muehleberg will cost three billion Swiss francs, four billion dollars.  At present 80% of the financing is planned.  The reactor produced electricity for 47 years and provided Switzerland with five percent of its electricity.  It will take a hundred years to pay off the costs completely.  The permanent disposal of the radioactive materials remains an unsolved problem.

Dismantling a Nuclear Reactor © 2020 by Patricia Remy in The Greenzine is licensed under CC BY-NC-ND 4.0