sorry if this has been answered but is there an atm at the airport when you arrive and if so is it wise and safe to use it

Can't help as far as Burgas Airport is concerned, there is certainly a Central Cooperative Bank ATM just after the baggage collection/Customs area in Varna Airport.

I can't really comment on its safety, as I have never used it - however it is in a heavily used part of the airport, so would (I imagine) present difficulties for anyone who wished to tamper with it.

Baldur