TOKYO - Nuclear safety officials say the first radiation measurements taken inside two reactor buildings at Japan's crisis-stricken nuclear plant show a harsh environment but not one that will be impossible for humans to work in.

Related readings: Japan to fix leakage in 9 months  TEPCO announces plan to end Japan nuke crisis

Nuclear safety agency official Hidehiko Nishiyama said Monday the measurements taken by two robots sent in to units 1 and 3 of the tsunami-wrecked Fukushima Dai-ichi nuclear plant mean that workers trying to restore plant systems will only be able to stay for short intervals inside the reactor buildings.

He said the radiation would not delay progress toward achieving a cold shutdown of the plant within nine months.