The chapter contains a description of Safety Parameters Display Systems (SPDS) implemented at NPP units WWER-1000 of Ukraine. These systems were designed by Westinghouse Electric Corporation (USA). LLC “Westron” (Ukraine) took development and implementation of these systems. These systems were provided at 11 NPP units in the framework of the International Nuclear Safety Program with the support of DOE (USA). The general purpose of SPDS is to provide support for operators, when abnormality of NPP unit operational conditions must be determined rapidly. The chapter considers the purpose and the functions of these systems, specific features of the displaying information about the state of the functions, which are critical for NPP unit safety, and the structure of systems. Implementation of SPDS project at 11 units of Ukrainian NPPs is a good example of USA and Ukraine collaboration in the nuclear area. Organization of this large-scale modernization is described.
TopPurpose And Functions
The goal of SPDS introduction was improvement of safety, reliability and efficiency of operation of nuclear power plant units by offering information support to main control room personnel and other technical personnel of NPP in evaluating the safety state in the unit by virtue of continuous monitoring of important parameters of the unit or calculating variables, which represent the safety condition of the unit. The main purpose of the SPDS is to offer assistance to the operator in quickly determining deviations in unit operation.
In this case the SPDS can be used to analyze and diagnose causes of the onset of disturbances in operation of the generating unit, and to identify corrective actions.
The SPDS offers information support to the operator during normal operation of the nuclear power plant and during emergencies:
- 1.
To evaluate the ongoing condition of nuclear power plant safety;
- 2.
To evaluate safety margins and conditions of operation before triggering reactor protection system;
- 3.
To evaluate the state of limits and safety conditions of operation after initiation of protection and other safety systems;
- 4.
To evaluate effectiveness of the operation of protection and other safety systems;
- 5.
To evaluate the need for corrective actions, which are aimed at prevention and alleviating design and accidents.
The advantages of presenting information in the SPDS are the following: information distributed to the modular control panel is presented in concentrated form and in a single system; the operator can use associative thinking, and not complex computing operations and analysis to make decisions in stressful situations; the SPDS directly presents to the operator values of safety margins for changing parameters up to the emergency protection initiating settings; it concentrates a large amount of information, using special techniques of image displays, thereby making the information perception process simpler and quicker.
Because of significant differences of the limits for normal and safe operating conditions before and after shutdown of a reactor, the SPDS employs three upper level polarographic video frames.
The polarographic video frame “narrow range” is intended to monitor deviations in the production process from normal operation and to evaluate safety and integrity of protective barriers from radioactive releases of the reactor unit in full power operating modes. The video frame offers assistance to the operator in eliminating the reason of a normal operation deviation.
The polarographic video frame “wide range” is used to monitor safety and integrity of protective barriers from radioactive releases in all modes after shutdown of the reactor unit. The video frame helps the operator in preventing worsening of normal operational deviation.