The requirement for licensees to obtain a site licence before the start of construction of nuclear installa­tions and the power to attach mandatory licence conditions at any time, form a powerful and effec­tive means of control for the regulatory authority. The licence is specifically granted for a particular site and, until it is issued, the Health and Safety Executive has no formal power over a particular site under the Nuclear Installations Act. It might appear, there­fore, that there is no statutory control in the initial siting, investigative, and informative design stages of a nuclear power plant. In practice, however, a licence would not be granted unless sufficient assurance had previously been given on the suitability of the pro­posed site and the installation as previously described. Therefore consultation between the CEGB and the Nil proceeds in parallel with the pre-site investigations by the CEGB, including consultation with other sta­tutory authorities who also need to obtain informal understanding in relation to a wide range of additional statutory consents at an early stage.

Such informal consultation and discussion between the CEGB and the Nil during the application stage is a necessary preview to the formal licensing procedure. As the civil nuclear power programme has been run­ning since 1955, a large amount of expertise and ex­perience has been accumulated on gas-cooled reactors by the CEGB and the Nil. If, therefore, a licence application is for a plant type which is produced fol­lowing a pattern of steady development and operational experience it is likely that this pre-licence examination would not be as extensive or detailed as it would be if the plant concerned was of a new type, or contained extensively different features from previous design. The safety report system would, of course, still be fol­lowed. If, however, as in the case of the Sizewell В proposals, the design is new it will be subjected to exhaustive, lengthy, and searching examination both by the CEGB and the NIL Once the Nil is satisfied that the proposed plant can be designed and built to the requirements for a specified nuclear site, the ap­plicant is informed that there are no objections to granting a licence. Subject to clearing other statutory obligations, the licence may be granted and the ap­plicant may then commence construction within the terms of the licence and the relevant conditions.

The licence document consists of the signed licence, authorised on behalf of the Health and Safety Exe­cutive by a Senior Officer in the Nil and includes three attached schedules. Part 1 of Schedule 1 pro­vides details of the site and Part 2 of Schedule 1 provides a brief description of the plant. The licence is granted subject to the conditions attached to it and these are contained in Schedule 2. The continuing valid consents, approvals and directions are included in Schedule 3. The Nil, acting on behalf of the Executive, provides itself with direct powers under the licence conditions of which there are three main types. These are consents, approvals and directions. The requirement for a consent prevents the licensee from carrying out a specific operation on the site unless the Nil is satisfied and gives formal agreement to its implementation. The approval procedure is invoked when the licensee is required by a licence condition to furnish its arrangements or procedure for carrying out a specific activity which requires the direct appro­val of the NIL A particular example of a direction in a. site licence is the one which requires the CEGB to provide operational records of its nuclear plant. Cer­tain directions are used very infrequently when the Nil wishes to direct the licensee to carry out a specific action it considers essential in the interests of safety. The initial licence is quite short and has only some 10 or 12 conditions. These cover the project up to the commissioning stage and include requirements on site security, laying of the foundations of the reac­tors, and bringing nuclear fuel onto the site. Require­ments on the furnishing of information on design, and evidence of supporting research and development pro­grammes in advance of specific stages of construction may also be included. Certain conditions may require the licensee to halt construction at specified points, until the Nil is satisfied with the information pro­vided. A further licence condition, which applied to previous nuclear stations, required the licensee to make arrangements for the examination and testing of speci­fied parts of the plant by suitably qualified people, and to ensure that the materials used in construction were suitable for the purpose for which they were intended and that the plant was properly constructed and installed. The arrangements which had to be approved covered the pressure vessel structures and foundations, the pressure vessel liners and penetrations and any other parts of plant designed to contain and control the cooling gas under pressure. On the concrete pressure vessel stations pre-stressing cables, anchorage devices, cooling systems, pressure vessel insulation, and installed instrumentation were also included. The li­cence issued for the Heysham 2 project, included a further requirement for quality assurance arrangements to be provided for all safety related items. This re­quirement will be extended to all future stations.

The licensee is required to set up a station com­missioning committee for the control of the plant, and to furnish the Health and Safety Executive with a commissioning programme and any documents re­lating to the commissioning of the plant. The com­missioning programme must be formally approved, and forms the means by which the nuclear reactors are taken through clearly defined and approved stages of commissioning up to full commercial operation. Each stage is defined in the programme which briefly describes the commissioning tests, associated safety features, and programme of work. At each commis­sioning stage it must be shown that the results ob­tained confirm the design safety intent and that no unexpected features have arisen which could adversely influence the safety of the plant. Following accept­ance of such evidence, approval is given by the Nil for the commissioning programme to continue to the following stage.

At some time before the first reactor becomes op­erational, which is usually when nuclear fuel is first brought to site, the original licence may either be re­voked and replaced by a new licence or the original licence may be varied by the addition of a new set of conditions. Whichever method is used the licence for the operational phase of the station comprises the following schedules:

• Schedule 1, description of the site and plant.

• Schedule 2, conditions attached to the licence.

• Schedule 3, continuing valid consents, approvals and

directions.

At this stage the licence is greatly expanded contain* ing some 33 conditions covering every safety related aspect of nuclear power station operation, including such matters as plant operating rules, operation and maintenance procedures, storage and consignment of nuclear fuel, storage and processing of radioactive waste, plant modification procedures and provision of emergency arrangements. A further most important requirement is the establishment of a safety committee which will consider any matter of relevance to the safety of the plant which may be placed before it, including modifications and additions. The safety committee is referred to in more detail later in this chapter.

Each of the CEGB’s nuclear stations has its own individual licence. In general all licences are basically the same, although there may be minor differences between specific licences. When the Nil is considering licensing changes these are discussed with the CEGB before implementation and will be included in the li­censing process, either by varying the licence through adding additional conditions, changing existing condi­tions or by re-issuing the licence.