EXECUTIVE SUMMARY
Following the decision to construct a nuclear power station at Daya Bay in the People's Republic of China there is a need for the Government of Hong Kong to prepare a contingency plan to deal with potential consequences in Hong Kong following a major nuclear reactor accident at the Daya Bay site.
A major accident, resulting in a large release of radioactive material, is extremely unlikely. This is due to the defence in depth safety philosophy used in the design of modern nuclear reactors such as the Daya Bay reactors. Redundancy and diversity are designed into the reactor safety systems. At least four barriers prevent the escape of radioactive material from the fuel, the last barrier being a very strong containment building design to withstand any credible event. There are however a number of accident scenarios which could result in the release of some radioactive material into the atmosphere. Although these events are highly unlikely it is nevertheless prudent to prepare contingency plans.
In order to set the scene for the detailed contingency planning advice, information is given in the early chapters of this report on how nuclear reactors operate, radiation and a general discussion on reactor accidents. These chapters are included to give readers who may be unfamiliar with these topics some background information which should help them to understand the principles and practices being recommended in the more detailed chapters on contingency planning.
The need for contingency planning is discussed and a summary is given of emergency planning arrangements in
other countries.
The basic radiological protection principles to be applied in the event of a major reactor accident are given. These principles are then developed into practical advice.
Hong Kong is at least 25 km from the site of the Daya Bay reactors, and the very densely populated areas of Hong Kong island and Kowloon are some 50 km away. At these distances planning for evacuation is not required, however planning for the possible introduction of certain other countermeasures, particularly those designed to prevent the consumption of contaminated food, is recommended. In order to achieve this it is necessary to have an organisation in existence which will be able to monitor and assess any release of radioactivity, decide on any necessary countermeasures, action those countermeasures and keep the public informed about the situation.
In Hong Kong an emergency organisation is already in existence for dealing with potential disasters such as typhoons, landslips, aircraft crashes, etc. Advice is given on the structure, staffing and equipping of the emergency organisation needed to deal with major radiological incidents. Wherever practical this radiological emergency organisation utilises the extant emergency organisation. Where new sections of the emergency organisation are recommended use has been made of existing expertise within Hong Kong. For example, it is recommended that the centre which will co-ordinate emergency radiological monitoring and assessments should be based at the Royal Observatory who already have some experience and expertise in this field. In addition to the main structure of the emergency organisation, roles for a number of supporting organisations are identified and discussed. Advice on alerting procedures is also given.
Advice is given on the methods by which the radiological consequences of a release may be assessed. This assessment will be carried out in a number of stages. Initially very little data will be available and decisions will need to be based upon a number of prejudgements and conservative assumptions. Later, as more radiological data becomes available, the assessment will be refined. As a result of this assessment decisions may be taken about which, if
any, countermeasures need to be introduced, and in which areas.
The required emergency monitoring programme is discussed. This includes the equipment necessary to detect any plume of radioactivity entering Hong Kong and also the monitoring and sampling programme required to assess
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