S.T.A.L.K.E.R.: Can you explain in-game how do you "wear" an artifact and what the hell is an "artifact pocket" on an armor?

It's an obvious game design decision in the S.T.A.L.K.E.R. games to limit the usage of the "magic items" known as artifacts as having a negative side-effect (usually something harmful like radiation damage or increased vulnerability against burning) to compensate for some positive effect (like increased healing or endurance), but in all these games the player can carry a lot of artifacts in their backpack without any problems, and they have to "activate" an artifact to benefit from the positive and suffer from the negative effects. There's also a limit to the maximum number of active artifacts at a given time, defined by the worn armor's "artifact pocket" capability, which is another game design decision, allowing armor upgrades for example.

I'm looking for in-game ideas to explain what exactly means to "activate" and "deactivate" an artifact and to see if the armor's artifact pockets can make any sense.