I have written and researched about nuclear power before, and in one of my previous posts I mentioned wanting to visit COVRA, as it is the only nuclear waste storage facility of the Netherlands. A year after that post I read on the website that tours were available again, and half a year later - last tuesday - it was finally time to visit one of the most secure places in the Netherlands.
If you want, it is possible to schedule a private tour with a group, but as a minimum of 10 people are required per group we were combined with two other groups; A couple of high-schoolers doing a paper on nuclear energy and a company on a company trip.
Our tour of more than 3 hours started with a 3D video about how COVRA was founded and the processes involved, followed by a lengthy Q&A. We were than led to the on-site cloud chamber of a similar size of the one at CERN (I guess I didn’t share the pictures of my trip down the ATLAS building there, a post about it will follow soon), but a lot bigger than the one I built, where the concept of radiation and the different kinds of radiation were explained.
After everyone went through the security gates with their personal visitor card and each group was provided a dosimeter - I brought my own Geiger counter - we went outside. Our first stop: the low- and medium-level waste building. Once inside, we were greeted by this nice warning;
Once past the series of locked doors we were inside the big hall where the barrels of low and medium level radioactive materials are stored.
Each barrel is filled in a particular way: A customer like a hospital pays COVRA a set price to store their nuclear waste indefinitely. To simplify a bit; the customer fills a barrel with nuclear waste, that barrel gets compressed and the height of the compressed barrel determines the price that customer has to pay.
A bunch of these compressed barrels with the same level of radioactivity are put together in another barrel, this time surrounded by concrete. That combination of compressed barrels and concrete is what makes up almost half of this storage hall. A letter “A”, “B”, “C”, or “D” determines the level of radiation. Highly radioactive barrels are surrounded by a concrete cylinder.
Even though the walls here are made up of almost 2 meters of concrete, huge efforts are put into strategically placing the barrels in such a way that as little radiation as possible is affecting employees or the outside world. In the picture above, you can see the more radioactive center of the hall, while the picture below was taken closer to one of the outside wall.
These “D” level barrels are emitting lower levels of radiation themselves, but their material also shields the outside world of the radiation of the barrels in the inner level. What you can’t see in this picture is the second level of “D” barrels behind them offset a half their right and a half upwards to cover the geometry that is not shielded because the barrels are cylindrical and not square.
I only took a bunch of measurements here as I was kind of bothered by my Geiger counter. In several places the radiation levels of above 9μsv/h, and my Geiger counter has an alarm functionality that can’t be turned off and that has a maximum threshold of that value. The average value was about 1μsv/h across the walkable section of the warehouse, based on the measurements I took until I took the batteries out;
Once a bunch of questions were answered we went to the high-level storage facility. This is the iconic orange building (which gets repainted a bit lighter every 20 years to signify the decreased level of radioactivity this building houses).
Security here was on a whole other level, with multiple levels of security doors we had to go through. After climbing some stairs, we ended up in the security room with a view of the control chamber. The orange window in the back has a direct view of the room where the radioactive barrels are handled and which we would soon enter. The orange color is because of the lead infused in the very thick window. Even though this room looks empty, there is somebody here 24-7, but the people in here were hiding for the 20-some people in our group.
After manoeuvring a couple more doors and alleys, we ended up in a room with this very heavy concrete-filled steel door closing of the handling chamber. This door only opens when it is safe to do so based on the several Geiger counters measuring the radiation constantly.
And finally we were in the main storage facility. But surprisingly: even though under most of the grey covers there are 5 barrels of highly radioactive barrels cooled by a breeze of outside air, and the background radiation in this part of the netherlands is around 0.09μsv/h, the radiation inside this room was lower: 0.08μsv/h!
Did you get interested? You can sign up for your own visit on the COVRA website! (Our tour was scheduled 4 months in advanced, so be patient)