Plant emergencies operation under normal conditions

The reactor unit of a land-based ABV nuclear power plant (see Fig. V-6 and V-7) includes the steam-generating unit, the biological shielding, and equipment of the main and auxiliary systems providing heat removal from the reactor and safe reactor operation under normal and emergency conditions. 

The deficiencies in the design of the main control room and the emergency control room increase the potential incidence of human errors. These situations are possible under normal operating conditions as well as under DBA and beyond DBA conditions and could become a major contribution to the total plant risk. 

Under normal plant operating conditions, heat release is determined by the cyclo-hexanol/cyclohexanone mix flow, which is instrument-controlled in order to keep the correct mix-to-nitiic acid ratio. By cutting off the KA oil feed, the reaction stops and heat release ceases. In most industrial reactors, the water cooling system inside the reactor is regulated by the temperature of the reaction mix. Redimdant alarms and emergency stops are installed to automatically cut off the flow of the cyclo-hexanol/cyclohexanone mix in case of a malfunction. Some of the conditions and chains of events that could lead to potentially dangerous situations include ... 

The objective of the VK-300 safety design is to assure radio nuclide confinement in the fuel under normal operating and emergency conditions so that radiation exposure of personnel and radiation in the area of the nuclear power plant site are maintained within the limits prescribed by regulations. 

Sufficient and reliable means of commnnication should be provided to enable information and instructions to be transmitted between locations to support the operator actions during normal operation and recovery following accidents. This would include communications between the main or emergency control rooms and operating personnel at remote locations who may have to take actions affecting the state of the plant, and with off-site organizations in accident situations. The means of communication should be available under all relevant accident conditions and should not interfere with the plant protection system. 

Oral communications between the main control room, the supplementary control rooms, other suitable plant locations and ofif-site emergency services are important to safety, particularly under conditions of anticipated operational occurrences or design basis accidents. Such conunuiucations should normally be provided with two, preferably diverse communication Unks and should be electromagneticaUy compatible with the I C systems (self-powered telephones, battery operated telephones, hand held portable radios). These communication links should be routed in such a way that fires, failures of electrical systems or other applicable PlEs cannot incapacitate both systems simultaneously. 

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