"Old" as in "we built it and discovered it's not wanted". The French basically gave up on the idea of fast reactors (as did the Japanese, although their fast reactor program appears to have been an excuse to obtain a stockpile of separated plutonium in case they need to make bombs). There's no market for them. The Russians have continued to try, but they're selling LWRs.

The big problem with fission is that it's too expensive. Fast reactors make that main problem worse. There is no economic margin to do fancy (and expensive) things to try to address the lesser issue of nuclear waste.