nuclear disaster: crossword puzzle

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Across
  1. 4. the last name of the two communist spies
  2. 5. the first name of the trainee
  3. 6. the country where chernobyl is in
  4. 7. "the first ___________ bomb was detonated in 1962"
Down
  1. 1. the name of the disaster
  2. 2. the first name of the scientist
  3. 3. the first name of the chief engineer
  4. 5. the first name of the code breaker