Nuclear engineer here. I did a similar write-up (gratuitously leveraging GNU Units) since most people don't seem to know this fact about fission breeder reactors. I added some other references at the bottom of people pointing this out throughout nuclear fission's history.

https://whatisnuclear.com/nuclear-sustainability.html

In addition to the OP, it's also worth mentioning that you can breed with slow (aka 'thermal') neutrons as well as fast ones, you just have to use the Thorium-Uranium fuel cycle to do so.