Re: 3) & 4), Uranium seawater extraction does exist, and it is cheap, easy, and requires very little energy. I toured PNNL and viewed their uranium extraction

Re: 3) & 4), Uranium seawater extraction does exist, and it is cheap, easy, and requires very little energy. I toured PNNL and viewed their uranium extraction project in person. It utilizes thin, high surface area fibers of plastic impregnated with a molecule that binds uranium and other heavy metals. A rinse with a dilute acid (acetic, citric, etc) releases the metals. The substrate can then be reused indefinitely. The deployed system is fully passive - basically fake floating kelp beds, anchored to the sea floor, deployed in high current areas. They would be hauled in every 3 months or so, rinsed off on the boat, and then redeployed. Everything could be done using standard bivalve farming methods, but with lower impact on the environment. They are now looking at a way to use the same material to post-filter desalination brine. https://www.pnnl.gov/news/release.aspx?id=4514 https://www.pnnl.gov/news/release.aspx?id=4514 https://www.youtube.com/watch?v=bCF3k_EbGiU https://www.youtube.com/watch?v=bCF3k_EbGiU