| Answer | Crossword Clue |
|---|---|
| CHAINREACTION | Self-sustaining sequence |
| permaculture | a system of self-sustaining natural agriculture |
| permacultures | PERMACULTURE, a system of self-sustaining natural agriculture |
| critical | (of a nuclear reactor or fuel) Maintaining a self-sustaining chain reaction |
| reactor | An apparatus or structure in which fissile material can be made to undergo a controlled, self-sustaining nuclear reaction with the consequent release of energy |
