Most of the best traps can only be sprung once, or at most a few times. So you get the first trespasser, but everyone after that just walks over it.

And honestly, Indiana Jones style traps would never survive 10 years of deferred maintenance, much less 10,000 years. Even simple traps like weak floors over spike filled pits would tend to rot and collapse over the years, especially if you need to build it lightly enough that a single person can trigger it unknowingly.

The only Egyptian tombs that survived to the modern era were the ones so well hidden that nobody had managed to stumble across them.

Also not having a pile of gold at the end of the tunnel might help.

Then again, we can't really know if the future civilization will consider out spent nuclear fuel as a pretty good store of value.

the radiation is the death trap

I was thinking the same. However, the problem is not to avoid people from getting in and causing harm to themselves, but them getting the dangerous stuff out and causing harm to others who actually heeded the warnings. You'd need extremely strong radiation

If you're talking about 10,000 years in the future it may not matter so much since the radioactivity would be much less after so many half lives.

Exactly. You can't rely on the radiation itself as a deterrent.