Windscale renamed itself Sellafield after a little tiny, nothing to worry about, nothing to see here, reactor explosion.

Plan B, after the next incident, is to rename it Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch

Here's some humour help. Looks like your third attempt is almost Welsh.

How about: Windscale renamed itself Sellafield after their reactor exploded. I hear they're going to try "Blaidd Drwg" next.

Llanfair.... is a famous (for very small values of famous) welsh railway station with the longest name in the world. People go there to take pictures of the sign.

However having a name longer than a tweet is likely to limit your fame in the internet age!

Mae'n ddrwg gennyf am y camddeall. Yr wyf yn sefyll gywiro.