Definitely. The government has not attempted to block access to any popular torrenting sites such as The Pirate Bay. This implies that you can torrent using a Bulgarian IP address.
It is, nevertheless, a good idea to use a VPN when downloading. A VPN shields you against IP address leaks by other users, which protects you from cyberattacks and hacking. You may use torrents without worrying about your ISP detecting them since VPNs also let you stay private by preventing your ISP from determining which torrents you download.