Does fission require many safety features making it expensive to build power plants?

This depends strongly on the reactor design (mostly the moderator material chosen) and the temperature coefficient of reactivity of the design (a positive coefficient is unsafe, a negative coefficient is safe).

Unfortunately most current reactor designs are not inherently safe and do need multiple expensive safety systems that could fail themselves. However many reactor designs that would be inherently safe and need only minimal additional safety systems have been examined, unfortunately almost no money has been made available for development of such reactors.