Abstract Recent events in the nuclear industry have blamed a declining safety culture both on the utility and regulatory side as the major responsible. Confidence in the nuclear industry can be dramatically affected by such events. In this context, the present paper analyses a recent crisis event that involved a research reactor. It shows the time history of the event and how its escalation brought to a temporary shut down of the reactor. In-depth analysis of the event pointed out safety culture deficiencies within the organization. The paper presents the key elements in the ensuing organizational change process and describes the different phases (short and long term approaches), players and measures involved in the process that the organisation set up to address deficiencies and improve safety culture. The case represents an interesting example from which important lessons can be learnt. In particular, staff motivation in terms of involvement in improvement activities is considered central in managing safety.