Here is a collectible map for the Nuclear Waste. Please click on the image below to be taken to the full-sized map in 8192 x 8192 resolution!
The numbers on the map match up with the video. All of the nuclear waste is in the ocean. The first one is in the north-western part of the map, near the sonar docks.
These collectibles are not required for 100% Completion, but are required for the Waste Management achievement.
There are a total of 30 Nuclear Waste collectibles in GTA V. To collect them you need to buy the Sonar Collections Dock with any character. This property can be bought after completing the main story mission "The Merryweather Heist". The dock costs $250,000. You need to pick up the waste with the submarine, which always spawns at the dock.
Pretty much all of the Nuclear Waste is at the bottom of the ocean. Buying the docks will also give you a new app called "Trackify", which starts automatically when entering the submarine and provides a radar that points to the next collectible. The order in this video matches with the order of the Trackify app.
However, the app won't mark any of the waste on your in-game world map. Sometimes a piece of waste is miles away on a different part of the coast. The submarine is also very slow. If you collect everything in one run it will take about 2 hours.
On the bright side, getting all this stuff will help you uncover the ocean map further (required for San Andreas Sightseer
) and you will get a lot of money ($32,000 per piece of Nuclear Waste you find and a $250,000 bonus after finding the last one).