Damage to multiple reactors at the Japanese plant left fire fighters struggling to regain control.
"Fire preparedness is the biggest lesson to be learned from Fukushima," wrote Jan Hanberg at the Swedish Radiation Security Authority in a press release.
The assessment was made public today after Sweden's reactors were put through several stress test following the accident in Fukushima.
It also concluded the reactors did not meet the government's safety requirements in the event of an earthquake.
Sweden's nuclear reactors are well prepared for a serious crisis - but not if more than one are affected at once.