Patent Number: 053533151
Section: claims

1. An alarm system for alerting the operator of a nuclear power plant of abnormal operating conditions, each abnormal operating condition resulting from an abnormal processor component parameter signal falling within one of a preestablished set of at least two priority of importance categories, comprising: an alarm display means including a screen area for displaying the images of a plurality of alarm tiles in a normal state and, upon the occurrence of an abnormal parameter signal, in an activated state that includes a concise descriptor within the activated tile image of the abnormal operating condition resulting from the abnormal parameter's signal;  means for associating a priority category with each abnormal parameter signal for which a tile image is displayed in an activated state;  means for displaying with the descriptor of each activated tile, a preestablished, distinctly shaped coded image indicative of the priority of category of the abnormal operating condition that resulted from the abnormal parameter.  a monitoring display means distinct from said alarm display device, for generating images descriptive of plant components and processes;  means for determining which plant components and processes have deviated abnormally such that an abnormal parameter signal is generated and alarm tile is activated;  means for communicating to the monitoring display device, the priority category of the parameter signal associated with abnormally deviated component or process; and  means communicating with the monitoring display device for generating a shape coded image at the descriptor image of the components and processes involved in the abnormal condition for which an alarm tile is activated.  means for flashing each descriptor on an activated tile which has not been acknowledged;  means for presenting the ,descriptor in one color when the alarm represents an abnormal condition whether or not acknowledged and in another color when the alarm represents a normal condition whether or not acknowledged.  activating at least two of a multiplicity of alarm tiles on an alarm tile array such that each activated tile presents an activated descriptor of the source of an abnormal condition in the plant;  for one of said activated tiles, presenting a shape coded indication that the associated source requires attention with high priority;  for the other of said activated tiles, presenting a shape coded indication that the associated source requires attention with a low priority;  wherein the operator can respond to each activated alarm tile so each tile is in one of four statuses consisting of,  a new alarm associated with an abnormal condition and unacknowledged tile,  an existing alarm associated with an abnormal condition and acknowledged tile,  a cleared alarm associated with a normal condition and unacknowledged tile, and  a reset alarm condition associated with a normal condition of an acknowledged alarm;  generating a first, momentary audible tone upon the activation of a new alarm;  generating a second, momentary audible tone upon the occurrence of a cleared alarm; and  generating a third, periodically repeating audible tone during a new alarm and a cleared alarm.  flashing the descriptor of a new alarm and a cleared alarm at a first rate,  flashing the descriptor of a cleared alarm at a second rate that is slower than that of said first rate,  illuminating the descriptor of an existing alarm without flashing, and presenting the descriptor of a reset alarm without illumination and without flashing.  activating a particular tile to indicate a low priority alarm with low priority shape coding,  upon the occurrence of a high priority abnormal source condition for said particular tile, automatically clearing the lower priority shape coding without a reset tone or slow flash rate,  automatically substituting the high priority shape code for said alarm tile,  upon the improvement of the alarm condition from high priority to low priority, automatically clearing only the high priority alarm,  manually acknowledging the clearing of the high priority alarm, and  automatically presenting the lower priority of alarm shape coding in an acknowledged state. 2. The alarm system of claim 1, wherein the system has three priority categories and the shape coding comprises a respective three distinct variations of a common shape outline. 3. The alarm system of claim 2, wherein said common shape outline comprises a border surrounding said concise descriptor and the shape coding includes a respective three variations of the border. 4. The alarm system of claim 3, wherein said three variations include no border for the highest priority, a solid line border for the middle priority, and a broken line border for the lowest priority. 5. The alarm system of claim 2, wherein the shape coding of an activated tile is retained while the color of the shape is changed to indicate that the abnormal condition has returned to normal but the activated tile has not been acknowledged. 6. The alarm system of claim 1, wherein said system includes, 7. The alarm system of claim 6, wherein the monitoring display means includes a plurality of screens situated substantially at eye level of the operator when seated at a respective plurality of control panels, and a single overview display board situated behind the screens and visible by the operator when seated at any panel. 8. The alarm system of claim 1, including 9. The alarm system of claim 8, including means for generating a first type of audible tone upon the activation of a tile to indicate the occurrence of an abnormality, and a second type of audible tone to indicate that an activated alarm has not been acknowledged. 10. A method of controlling the presentation of abnormal condition alarms in an alarm system for use by an operator of a nuclear power plant, comprising: 11. The method of claim 10, wherein the first and second tones have a duration of about one second every other second and the third tone repeats with a duration of about one second every minute. 12. The method of claim 10, further including the steps of, 13. The method of claim 12, including the step of optionally suppressing the flashing of previously activated new and cleared alarms, without suppressing the generation of said third, periodically repeating audible tone for the alarms that have been suppressed. 14. The method of claim 10, wherein at least some tiles can be activated by more than one abnormal source condition and wherein the method includes the steps of,