May 19th Risø fuel production cleaned up

DD is well advanced in the clean-up and release of the facility where Risø produced fuel for the experimental reactors. Come on a tour of the building and read about the task of removing radioactive contamination from floors, walls and drains.

When theRisø Research Centre was in operation, part of the task was to produce our own fuel rods for the experimental reactors. This was done in the so-called Fuel fabrication plant, where uranium powder was pressed and rolled into fuel rods. During the winter, Danish Decommissioning removed or cleared a large part of the production facility at the Fuel fabrication plant, and the walls and floors were cleaned. Among other things, we have removed a two-metre wide melting furnace that was part of the early fuel production (up to the mid-1980s). The furnace is contaminated with uranium and has therefore been dismantled and packaged separately for disposal or melting.

Powder room
The first part of fuel production took place in the so-called powder room. Here Risø's laborers measured uranium in powder form and pressed it into solid pieces surrounded by aluminum. The powder was valuable and was carefully controlled, but it could not be avoided that uranium was swirled up or lost in small quantities. Therefore, the powder room and the associated ventilation system will be a greater challenge to clean of radioactive contamination. It will take place under a plastic tent, so dust with possible radioactivity is kept inside. The ventilation above the powder compartment is completely disconnected and the pipes have no connection to other ventilation in the building.

The rolling plant
When the uranium was pressed into pieces encased in aluminum, these were rolled into thin plates of about 70 x 10 cm. The rolling plant in the Fuel fabrication plant have been measured and the floor covering has been removed half a metre from the roller. There has been no free-floating uranium around the roller, so this was a somewhat simpler task than the powder room will be. The rolling plant and the hall in which it is in is released are released, and thus this part of the Danish Decommissioning Mission is complete.

The cleaning room
Once rolled out, the uranium plates were cleaned and degreased in, among other things, acid in the so-called cleaning room. Here we have removed the cleaning vessels and sanded the walls in a horizontal belt of 70 cm in height with the vessels. The floor covering has been removed and along with the plaster that has been sanded by the walls, it has been handled as radioactive waste. Our work in the cleaning room is complete and the room is released. This release takes place every time we complete a sub-task in a decommissioning project: all rooms and installations are carefully measured for radiation as they are cleaned. There are precise requirements for how much radioactivity may remain when a building or building part is released. The release measurements themselves are a rather slow procedure, as the measurement time for low levels of unirradiated uranium is long.

All in all, the dismantling and cleaning of the the Fuel fabrication plant well forward and follow the plan. The last part of the task will be to clean and measure the so-called powder room for release as well as the associated ventilation and drain system, which is a little cumbersome to get to. By the end of the year, we expect to be able to put an end to the work the Fuel fabrication plant . A final report must then be prepared, which must be approved by the nuclear DD can transfer the rooms for other use without restrictions.