Since nuclear plants generally operate at full capacity all the time you won't get changes in how much energy is produced. The linked graphs above are how much the market price is at specific locations, not how much energy get produced.
The European energy market price is determined by changes in supply (wind and solar being the main contributors for fluctuations, followed by water supplies), demand for energy, and prices for fossil fuel. If gas prices goes up, the price for energy on the market goes up. If cheap wind is flooding the market, prices goes down. As can be read by the graphs, since the European energy market is connected those changes occur simultanious in both Germany and France. However, there is an additional transport cost and thus prices can be a bit different. The negative energy prices also seems to effect those more closely to the plants with excess energy, rather than transporting the excess energy across the European continent.
The actually cost at any specific location is then determined by the energy market price (see above) and transport distance between the energy production point and energy consumption point.
A graph over nuclear waste would have no correlation with the market price. At most one would see a slightly more volatile market price when nuclear energy production is low, and a slightly more stable market price when the production is high, but one would need to have a pretty fancy graphical design in order to confer that knowledge in a graph.