Radiation levels just after the disaster were so high that human workers were unable to work longer than 40 seconds so these robots were developed to try and do the hub. For the most part they simply weren't up to it. The high radiation levels destroyed the electronic parts very quickly, so the human Liquidators were sent back in. Most of the robots are still very radioactive 24 years on.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/26781577@N07">Clay Gilliland</a>
CC BY-SA 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/26781577@N07/11384369646/">Robots used during the Chernobyl cleanup</a>