Consideration of nuclear safety begins on or before the first day of a pro­posed project; this chapter is devoted entirely to a description of this aspect of plant justification. At the same time it must be recognized that all of the earlier considerations lead up to safety in actual operation — the plant is safe in the sense of radiological risk until its nuclear fuel materials arrive on site. From that day until the day that the licence of the plant is finally transferred to a second licensee or until the need for a radiation-related — licence is no longer required, it is the operating organization that is ulti­mately responsible for its safety, within the scope of its operating licence and in accordance with national standards and regulations.