This article relates the findings of an ethnographically informed study conducted at a Swedish Nuclear Power Plant. It describes a set of events while the plant was shut down for a short non-productive outage. In order to understand better how high-reliability organizations successfully manage the conflict between bureaucratic planning and flexibility we provide a description of simultaneous levels of control that dissolve the conflict. Instead of merely describing actions as planned, or improvised, the present work illustrates that no clear-cut distinctions can be drawn between what is improvisation and what is not. Understanding planning as a control activity as well, enables us to grasp the different values of the canonical activity of planning. © 2005 Elsevier Ltd. All rights reserved.