Speaking of that - Dyatlov was one of the several men who were held responsible for the disaster (he was a deputy chief engineer on the power plant). I studied many materials about the disaster and, though I'm not in the position to judge since I have not seen all the documents, from what I studied I can conclude that personnel (Dyatlov included) made many mistakes that day and generally it was due to human intervention that the reactor blew up, it was not due to poor design (the main alternative version) or technical malfunction. Dyatlov claims that they were not aware of the positive reactivity that occurs at certain modes of operation but they deliberately put the reactor in the condition it was not designed to operate in violation of all operating instructions and regulations. As one of the RBMK constructors said -- it's a very good and reliable reactor unless you blow it up deliberately.

When you read his book (a very interesting reading, by the way) don't set your head to stone with his version of the disaster alone.