First off, I'm no nuclear physicist or have any type of expertise in this field, but my gut feeling (assumption!) is that neither do you.
First off, no nuclear waste is not a problem.
That's a blanket statement that just seems untrue. Nuclear waste as is being produced currently and in the past is highly radioactive and therefore harmful to life and our environment, ergo, a problem.
Second, Gen 4 doesn't usually produce radioactive waste that needs to be stored for centuries. There is a lot of information on the internet about this.
Just had a quick glance at Wikipedia, but I noticed two things while doing so:
1. No Gen 4 facilities exist or are expected to exist in the coming years.
2. Not even a clear DEFINITION of Gen 4 nuclear reactors exists.
So presenting it as some end-all solution seems a bit precarious to me and a weird hill to die on.
Not to mention that it is quite a stretch to assume that Apple, a consumer-electronics company, can somehow just churn out speculative nuclear technology.