The conversion is not direct, and involves the initial formation of thorium-233, which decays rapidly to protactinium-233, and then to uranium-233 over a period of about a month.
FORBES: Thorium Nuclear Power -- A Lesson From Norway
2.
Although not fissile itself, Th-232 will absorb slow neutrons to produce uranium-233 (U-233)a, which is fissile (and long-lived).
FORBES: Is Thorium the Biggest Energy Breakthrough Since Fire? Possibly.
3.
Thorium can be used as a nuclear fuel through breeding to fissile uranium-233.
FORBES: Is Thorium the Biggest Energy Breakthrough Since Fire? Possibly.