Intermediate and late phases emergency radiation monitoring
In the intermediate and late phases of a nuclear accident, major efforts in emergency radiation monitoring concentrate on foodstuffs and drinking water. The objective is to ensure that the supplied food and water are safe for public consumption. Most of the foodstuffs in Hong Kong are imported from mainland and more than 70% of the drinking water is supplied from Guangdong. Monitoring of imported food and drinking water are conducted primarily at the boundary control points. Food imported from within 50 km of the nuclear power stations is of primary concern. Those from farms near the power stations or affected by the plume are monitored more frequently. Random screening is also applied to foodstuffs at wholesale and retail markets in Hong Kong, and drinking water in reservoirs, inlets and outlets of water treatment works, water catchment areas and consumer taps.
The above three monitoring systems are high purity germanium based or sodium iodide based to monitor the activity concentrations of the radionuclides in foodstuffs or drinking water rapidly. Samples exceeding pre-determined screening levels will be further analysed by the Government Laboratory. All monitoring results will be transmitted to the HKO Headquarters for assessing nuclear accident consequences and considering necessary countermeasures.
Intermediate and late phase emergency radiation monitoring