Assertion: fission | /r/AtLocation | nature
Facets:
value: rarely
type: DEGREE
value: within a star
type: LOCATION
value: artificially in a nuclear reactor
type: MANNER
Source sentences:
text: Nuclear fusion and fission occur in nature, for example, within a star, and artificially, for example in a nuclear reactor.
text: Nuclear fission occurs rarely in nature, with the last known episode on Earth occurring some 2 billion years ago.