Ah, didn't realize what was being referred to happened 32 years ago and right before Chernobyl. Based on what (little) I've read about this reactor in particular, safety was just one of the concerns. The other was the expense. It took 13 years to build, was dramatically over budget and more expensive to run than anticipated. In addition, according to the report I read, the reactor had design flaws in common with Chernobyl which is one of the major reasons it ended up never being brought online. A similar reactor design in France (Superphenix) was also shut down due to the same safety and budget concerns. It seems like every single fast breeder reactor experiment around the world was an economic failure.

My source seemed relatively neutral if not friendly to the idea of nuclear power, so I don't think it's just a biased source, but would be happy to read about other analysis of the situation.

https://publikationen.bibliothek.kit.edu/270037170/3813531

https://energypost.eu/slow-death-fast-reactors/

> Fast reactors aren’t becoming mainstream. One country after another has abandoned the technology. Nuclear physicist Thomas Cochran summarises the history: “Fast reactor development programs failed in the: 1) United States; 2) France; 3) United Kingdom; 4) Germany; 5) Japan; 6) Italy; 7) Soviet Union/Russia 8) U.S. Navy and 9) the Soviet Navy. The program in India is showing no signs of success and the program in China is only at a very early stage of development.”