Reactors, which are needed for the production of electricity, are found at power plants all over the world. You may be most familiar with the term "nuclear reactor." That is exactly the thing which powers a nuclear power plant. In order for reactions to occur in a reactor, something called a "catalyst" is required to get the reaction going and to speed it up.
Someone has to go inside those things in order to clean them. It seems like that must be dangerous work. To an extent, it is but it still must be done for the safety of all concerned. These are specially trained cleaning and repair technicians who specialize in reactor care only. This means they have the seasoned level of training required to deal with such sensitive and volatile equipment.
There are companies that deal with reactor cleaning and repair. These repair crews will also handle blending, vacuuming, and screening of catalysts as well as catalyst loading and care for any catalyst unloading system. All of these tasks are necessary for proper reactor function. As far as keeping the reactors clean, these very same steps need to be attended to.
Catalyst handling is important. Without the catalyst, reactions would not occur and then the heat to boil the water to run the turbines would not be there either. No electricity would be the result and then, what is the point of having a nuclear power plant then? The whole idea was to produce massive amounts of cheap power.
As long as reactors are maintained well and catalysts are handled properly, the reactors should make it for a very long time. The care and repair these have seen over the years marks how long they will exist into the future. If you are in charge of hiring reactor cleaning and repair crews, look for the best in the area and hire a good team right away.