The operator of the crippled Fukushima No. 1 nuclear complex was on Tuesday forced to suspend an operation to examine the inside of reactor 1 with a self-propelled robot after experiencing camera trouble.

Tokyo Electric Power Company Holdings Inc. said the same day it was checking the cause of the problem and hoped to resume the survey on Wednesday.

It is its latest attempt to ascertain the condition of melted fuel debris inside in the reactor in order to extract it.