Generating an integrated graphic display of the safety status of a complex process plant

A method of generating on a visual display device a real time display indicative of the safety status of a nuclear power plant at the current operating level as represented by the status of selected operating parameters, said method comprising the steps of:

• generating status signals representative of the value of said selected operating parameters measured on a real time basis,
• generating on a real time basis reference signals for each of said operating parameters representative of the target signal level for each of said status signals for the current operating level of the nuclear power plant, at least some of which real time reference signals vary in magnitude with changes in said operating level,
• generating on a real time basis limit signals for each parameter signal representative of a limiting value for each status signal for the current operating level of the nuclear plant, at least some of which limit signals may vary in magnitude with changes in the operating level,
• normalizing each status signal to its associated reference signal in such a manner that the normalized status signal has a first fixed, preselected magnitude when the status signal equals the associated reference signal regardless of the magnitude of the reference signal and has a second fixed magnitude when the magnitude of the status signal equals the magnitude of the limit signal, regardless of the magnitude of the limit signal, and
• generating from said normalized status signals a display on the visual display device in the form of a polygon with the magnitude of at least one of the normalized status signals determining the distance of each vertice from a common origin, and with all of the vertices being displayed at a first fixed distance from the common origin to form a regular polygon when all of the selected operating parameters are at the target values, a vertice being displayed at a second fixed distance from the common origin when the corresponding parameter is at its limit value, and a vertice being displayed between the first and second fixed distances on a variable scaled determined by the difference between the current values of the associated reference signal and limit signal when the value of the parameter is between the reference and limit value.

Apparatus for generating a display representing the real time safety status of a nuclear power plant at the current operating level as represented by the status of selected operating parameters comprising;

• means for measuring selected parameters on a real time basis and for generating status signals representative thereof;
• means for generating reference signals representative of a target value for each of the status signals at the current operating value of the nuclear plant;
• means for generating a limit signal for each parameter representative of a limiting value for each of said status signals;
• processing means for normalizing each status signal to its associated reference signal on a fractional scale defined by the ratio of the difference between the current magnitudes of the status signal and reference signal to the difference between the current magnitudes of the reference signal and the limit signal in such a manner that the normalized status signal has a first fixed preselected magnitude when the status signal equals the magnitude of the reference signal regardless of the magnitude of the reference signal, and has a second fixed magnitude when the magnitude of the status signal equals the magnitude of the limit signal, regardless of the magnitude of the limit signal;
• and
• means for generating from said normalized status signals a display on a visual display device in the form of a polygon with the distance of each vertice of the polygon from a common origin being determined by the magnitude of a normalized status signal with all of the vertices being at a first fixed distance from the common origin to form a regular polygon when all of the selected operating paramters are at the target values, with a vertice being at a second fixed distance from the origin when the normalized status signal equals the limit signal, and with a vertice being displayed between said first and second fixed distances on said fractional scale when the status signal is between the reference signal and the limit signal.