Henning wrote: This needs special handling on the launch site, when maintenace crew needs to service the craft.
Nope. You’ve confused the FF unit with a fission reactor.
A fission unit is a neutron source whether it’s on or off.
An FF unit is just a pile of machinery when it’s turned off. When even an unshielded FF unit is not operating there won’t be a neutron problem for the maintenance crew to worry about.
And be advised that attempts at describing “near-term” FF-powered launchers are an interesting mental exercise but should not even be considered in a real-world context of near-term FF power plants and then ships etc etc.
