As they examined the data, the physicists discerned the broad sweep of events that led up to the accident: the reactor running at low power; the withdrawal of almost every one of the control rods from the core; muffled voices, a shout of “Press the button!”, and the activation of the AZ-5 emergency system. Finally, they saw the pen trace lines showing reactor power beginning a steep ascent until suddenly they rose vertically and ran off the top of the page.
