Machine implemented system for determining compliance of a complex process plant with technical specifications
First Claim
1. A machine implemented method of determining operating limitation compliance for a complex process plant having a plurality of interrelated components and systems, the method comprising the steps of:
- generating operability trees having cutsets representing various combinations of events associated with the state of operability of said components and systems and the status of said operating limitations, which cutsets taken separately and in sequence with other cutsets, result in an indication of non-compliance with said operating limitations;
generating in a digital computer a data base including a cutset table which includes an event attribute for identifying each event associated with a cutset and a top level event attribute identifying a higher level event activated by the cutset;
selecting a given event; and
operating said digital computer to;
(a) search the event attributes of said cutset table for the selected event to identify as activated all cutsets for which the selected event activates a top event as indicated by the top event attribute;
(b) as to each such activated cutset, repeat step (a) using the associated activated top event attribute as the selected event;
(c) repeating step (b) until the top level event activated by a cutset does not appear as an event attribute in the cutset table and identifying such top event as an ultimate activated top event; and
(d) generate an output identifying each ultimate top event activated by said given event.
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Abstract
Components and systems which impact technical specifications (tech specs) in a nuclear power plant are modeled in a set of cascading operability trees which represent the various combinations of component, system and parameter statuses which can result in non-compliance with the tech specs. Cutsets for the operability trees are entered into a cutset table in the data base of a digital computer which tracks the effect of a selected event up through the trees by repetitively searching the cutset table using the top event activated by the selected event as the selected event for the next search, until an activated top event is reached which is not entered in the cutset table as an event. A separate cutset evaluation table is used to assure that all the members of a multiple event cutset have been activated before the associated top event is activated. The base events which resulted in activation of a top event, such as non-compliance with a tech spec, can be identified by reversing the search process down through the cutsets in the cutset table.
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Citations
18 Claims
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1. A machine implemented method of determining operating limitation compliance for a complex process plant having a plurality of interrelated components and systems, the method comprising the steps of:
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generating operability trees having cutsets representing various combinations of events associated with the state of operability of said components and systems and the status of said operating limitations, which cutsets taken separately and in sequence with other cutsets, result in an indication of non-compliance with said operating limitations; generating in a digital computer a data base including a cutset table which includes an event attribute for identifying each event associated with a cutset and a top level event attribute identifying a higher level event activated by the cutset; selecting a given event; and operating said digital computer to; (a) search the event attributes of said cutset table for the selected event to identify as activated all cutsets for which the selected event activates a top event as indicated by the top event attribute; (b) as to each such activated cutset, repeat step (a) using the associated activated top event attribute as the selected event; (c) repeating step (b) until the top level event activated by a cutset does not appear as an event attribute in the cutset table and identifying such top event as an ultimate activated top event; and (d) generate an output identifying each ultimate top event activated by said given event. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A machine implemented method of determining limiting conditions of operation compliance and system operability in a nuclear power plant having a number of interrelated components and systems, said method comprising the steps of:
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generating operability trees having cutsets representing various combinations of events associated with the state of operability of said components and systems and the status of said limiting conditions of operation, which cutsets, taken separately and in sequence with other cutsets, result in indications of non-compliance with said operating limitations, and inoperability of said systems some of said cutsets being multiple event cutsets requiring more than one event to indicate non-compliance with a limiting condition of operation and inoperability of a system; generating in a digital computer a data base including a cutset table having an entry for each cutset which includes an event identifier attribute, a top event identifier attribute identifying a higher level event activated by the cutset, a top event status attribute indicating the status of the top event when activated;
an event status attribute indicating the status of the event required to activate the top event, a cutset type attribute identifying single event and multiple event cutsets, and a cutset identifier attribute, said cutset table including a separate entry for each event in a multiple event cutset with each such separate entry for a multiple event cutset having a common cutset identifier;selecting a given status for a given event; and operating the digital computer to; (a) search the event attributes and event status attributes of the cutset table to identify cutsets in which the event status attribute matches the selected status for the selected event; (b) determine the cutset type of each identified cutset from the cutset state attribute; (c) as to each identified single event cutset repeat steps (a) and (b) using the top event attribute from the identified cutset as the event attribute; (d) as to multiple event identified cutsets, generate a cutset evaluation table having an entry for each multiple event cutset which includes a top event identifier attribute for the multiple event cutset and a multiple event counter attribute which counts the number of events in said multiple event cutset which have been selected, identify a multiple event cutset as activated when said count attribute reaches a value indicating that all of the events associated with a multiple event cutset have been activated, and repeat the steps a, b and c using the top event identifier attribute of a multiple event cutset identified as activated as the event attribute; (e) repeat the above steps until the top event activated by a cutset does not appear as an event attribute in the cutset table and identifying this activated top event as the top event in the associated operability tree; and (f) generate an output identifying each top event in an operability tree activated by the given status of the given event. - View Dependent Claims (10, 11, 12)
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13. In combination:
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(A) a complex process plant having a plurality of interrelated components and systems; (B) means for selecting an event representing the inoperability of at least one of said components and systems; (C) a digital computer programmed to determine compliance of said complex process plant with a set of technical specifications and operability of certain of said systems and components; and
including;(1) means for storing a data base including a cutset table having an entry for each cutset in each of a plurality of operability trees, each cutset representing a different combination of events associated with the state of operability of said components and systems and the status of the technical specifications, which cutsets when taken separately and in sequence with other cutsets result in an indication of non-compliance with a technical specification or inoperability of a system, each said entry in the cutset table including an event attribute indicating the event which activates the cutset, and a top event attribute indicating the top event activated by that cutset; and (2) processing means responsive to said input means and including means for; (a) searching said cutset table to identify all entries in which the event attribute matches the selected event, (b) as to each such entry repeating (a) using the top event attribute of the identified entry of the cutset table as the selected event, (c) repeating (b) until the top event of each identified entry is not found in the cutset table; and (D) means for displaying indications of such top events as activated top events at the top of an operability tree. - View Dependent Claims (14)
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15. A machine implemented method of determining activation of a top event in a decision tree comprising the steps of:
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generating cutsets representing the various combinations of events in the decision tree, which when taken separately and in sequence with other cutsets, result in activation of the top event; generating in a digital computer a data base including a cutset table which includes an event attribute for identifying each event associated with a cutset and a top level event attribute identifying a higher level event activated by the cutset; selecting a given event; and operating said digital computer to; (a) search the event attributes of said cutset table for the selected event to identify as activated all cutsets for which the selected event activates a top event as indicated by the top event attribute; (b) as to each such activated cutset, repeat step (a) using the associated activated top event attribute as the selected event; (c) repeating step (b) until the top level event activated by a cutset does not appear as an event attribute in the cutset table and identifying such top event as an ultimate activated top event; and (d) generate an output identifying each ultimate top event activated by said given event. - View Dependent Claims (16, 17, 18)
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Specification