Under UK law (the Health and Safety at Work etc. Act 1974) employers are responsible for ensuring the safety of their workers and the public, and this is just as true for a nuclear site as for any other. This responsibility is reinforced for Nuclear Installations Act 1965 (NIA), as amended. Under the relevant statutory provisions of the NIA, a site cannot have nuclear plant on it unless the user has been granted a site licence by the Health and Safety Executive (HSE).
The NIA stipulates that only a corporate body, or in other words, a legally united body that can act as one individual, such as a registered company or a public body, can hold such a licence. This licensing function is administrated on HSE's behalf by its Nuclear Directorate (ND). The legal regime is complemented by the Ionising radiations and by the generality of health and safety regulation which the ND also enforces on nuclear sites.
ND, acting for HSE, sets out in conditions attached to a site licence the general safety requirements to deal with the risks on a nuclear site. Licensees comply with these in different ways; such as, with a safety case to meet a stage in the plant's life, or with arrangements and procedures to meet licence condition. Guidance is also set out in the Safe assessment principals, which ND has developed for its own use, and made available to the public.
ND seeks to keep up and improve safety standards for work with ionising radiations at licensed nuclear installations. It does so through its licensing powers by assessing safety cases and inspecting sites for licence compliance. it sets national regulatory standards and helps to develop international nuclear safety standards.