AN emergency drill will be carried out at the Daya Bay nuclear power plant today as the countdown begins for the installation of uranium fuel rods. It is understood Hongkong officials have been invited to take part as observers to gather information for the territory's own contingency plans in case of a nuclear accident at the plant, which is just 50 kilometres from Hongkong. The one-day exercise is a curtain-raiser for a larger one early next month when a team of 15 safety inspectors from the International Atomic Energy Agency (IAEA) arrive. They are expected to visit Daya Bay on May 3 and stay for two weeks while conducting the review. Approval of the plant's operations is needed before plant engineers can begin loading the nuclear fuel, according to sources. Once the rods are in place, engineers must test them up to 60 times to ensure they ''respect the safety criteria'' set by the IAEA. Testing is expected to take up to three weeks. Meanwhile, Hongkong officials from the Security Branch and the Royal Observatory have engaged in their own exercises. Each was based on the IAEA's standards for countries affected by a nuclear accident. Officials are still working on the details of the territory's emergency plan, a spokesman for the Security Branch said. ''The Hongkong Government is working with the Daya Bay company and China and it is a process of going through all the possibilities,'' he said. Officials from both sides of the border conduct monthly meetings to discuss the plans. The next meeting is likely to cover meteorological conditions and their effects on any nuclear leak. An emergency plan for the plant is almost complete, sources said. IAEA officials were present in February when more than 400 people were evacuated from the station as part of an exercise. Another evacuation is planned for mid-May after the international inspection team arrives. The team is expected to present a public report on their findings. The reactor's fuel assemblies are made up of uranium rod bundles. The assemblies have been on site since November. They are harmless until activated inside the reactor. The reactor will undergo its first critical test in July. A second reactor will begin operation in September or October. The $3.7 billion Daya Bay plant is the largest commercial nuclear power plant in China and is seen as a model operation for future reactors.