system
Given the following post, respond as if you're commenting on Reddit:
human
Why is the Chernobyl New Safe Confinement dome only good for 100 years?

Is it only needed for 100 years, or will something occur to it to make it inoperable? And what is it actually made out of?
gpt
100 years is the reference lifespan for the structure. I.e. engineering decisions and safety margins were developed around the expectation that the probability of failure before 100 years should be below some determined amount. In all likelihood, it could exceed 100 years of useful life.