Handl, 31, said he had tried for months to set up a nuclear reactor at home and kept a blog about his experiments, describing how he created a small meltdown on his stove.
Only later did he realise it might not be legal and sent a question to Sweden’s Radiation Authority, which answered by sending the police.
“I have always been interested in physics and chemistry,” Handl said, adding he just wanted to “see if it’s possible to split atoms at home”.
The police raid took place in late July, but police have refused to comment. If convicted, Handl could face fines or up to two years in prison.