The CIL Nuclear Law and Policy Team is joined in conversation by Dr Charles D Ferguson, Director of Nuclear and Radiation Studies Board at the National Academies of Sciences, Engineering and Medicine and former President of the Federation of American Scientists. In this episode, key concepts relevant to understanding nuclear safety, security and safeguards including the difference between nuclear energy and nuclear power, ionising radiation and the nuclear fuel cycle are discussed. This is the first of a four-part series on the fundamentals of nuclear safety, security and safeguards and their interrelationships.