The paper looks at the outcomes of nuclear technology policies in five advanced Western industrialised countries which have developed major nuclear construction industries. The genesis, development and dissemination of thermal nuclear reactors is examined and found to be influenced by a range of non-technical factors. Various concepts of ‘political styles’ are explored. Different styles of technological development are identified with reference to the networks of actors relevant to the development of thermal reactor technology, taking particular account of the resources of different actors and their interrelationship. Three distinctive styles are found, associated with three different technological outcomes, two of which are associated with policy success. We conclude that political styles do make a difference, but that their applicability to the explanation of outcomes of technology policy is dependent on the resources of individual actors and the specific demands set by the technological, economic and political context.