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and to make contact with persons outside the plant The emergency support facilities are designed to provide the following functions.

(5) The relevant personnel can safely stay in the facilities for a long time.

  1. Information is collected and provided to exactly and promptly grasp the accident condition, without assistance of the control room operators.

  2. Multiple contact lines, including at least one exclusive line, are provided to make contact with persons outside the plant

  1. Process Instrumentation System

  1. Primary system

Besides the above mentioned reactor control system, control systems are provided for other subsystems of the primary system such as, for the primary cooling system, the chemical and volume control system, the residual heat removal system and the radioactive waste treatment system. Each control system employs either analog or digital controllers to control parameters such as the temperature, pressure, water level, flow rate and so on.

  1. Secondary system

The control system of the secondary system mainly consists of the following four controllers.

(D Main turbine controller

Its function is to provide control for turbine speed up, turbine speed governing, turbine load, etc.

  1. Feedwater pump turbine controller

Its function is to provide control for the feedwater pump turbine speed up, turbine speed governing, etc.

  1. Moisture separator and heater controller

Its function is to control the inlet temperature increase rate of the steam flow to the low pressure turbine within the allowable range by regulating the heating steam flow (obtained from the main steam line) through the heating steam control valve, in order to reduce the thermal stresses developed in the low pressure turbine and the moisture separator and heater during the plant startup and shutdown.

  1. Turbine plant remote controller

Its function is to control the turbine plant auxiliary equipment, for example, to control the net positive suction head (NPSH) of the feedwater pumps during a rapid load reduction. Both analog and digital controllers are employed in the above mentioned control systems; however, analog controllers are gradually being replaced by computerized digital confrollers.

  1. Radiation Monitoring System

The radiation monitoring system consists of the process and area radiation monitors which monitor the radiation level at selected locations inside the plant, and the off site radiation monitors which monitor the environmental radiation levels around the plant site.

  1. Process radiation monitors

The process radiation monitors provide continuous and on-line measurements of the radiation level in various process flows to confirm the integrity of the plant systems and components and to manage the controlled discharge of radioactive materials to the environment. The functions of the system are as follows.

(D Continuous monitoring of the radioactive wastes discharged from the plant

(2) Early detection and alarm generation for any abnormal radioactivity level in each plant system, and execution of radioactive

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NSRA, Japan