METHOD FOR DETERMINISTIC SAFETY ANALYSIS IN NON-STATIONARY HIGH RISK SYSTEM, CONTROL METHOD AND CONTROL SYSTEM USING THEREOF

• US 20080288121A1
• Filed: 11/20/2007
• Published: 11/20/2008
• Est. Priority Date: 05/20/2005
• Status: Active Grant

• Current Assignee: Diakont Advanced Technologies, Inc.
• Original Assignee: Diakont Advanced Technologies, Inc.
• Inventors: Fedosovskiy, Mikhail Evgenievich, Dunaev, Vadim Igorevich, Kopiev, Yurii Vladimirovich, Sherstobitov, Alexander Evgenievich
• Granted Patent: US 8,566,139 B2
• Time in Patent Office: Days
• US Class Current: 700/292
• CPC Class Codes: G05B 23/0243 model based detection method, e.g. first-principles knowledge model
• CPC Class Codes: G05B 23/0291 Switching into safety or degraded mode, e.g. protection and supervision after failure
• CPC Class Codes: G06F 2111/08 Probabilistic or stochastic CAD
• CPC Class Codes: G06F 30/00 Computer-aided design [CAD]
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
• CPC Class Codes: G06Q 10/0635 Risk analysis of enterprise or organisation activities

Abstract

A method and systems of safety analysis of engineering processes for safety analysis of nuclear power stations are disclosed. A distribution of risk factors is analysed on different stages of the engineering process, and safety intervals are determined where safety conditions remain invariable. The method further includes analysis of failure transitions from one safety interval into another by means of cause-effect analysis. Based on the results of this analysis, deterministic safety models are created for possible scenarios of transition of failures from one safety interval into another. The method and systems provide quantitative safety analysis and evaluation for engineering processes in variable safety conditions and enable creating valid safety requirements to perform optimisation of an engineering processes control system.

Claims

1. A computer-implemented method of safety analysis of a high risk engineering process, wherein the process comprises a series of stages involving one or more non-stationary objects characterized by at least one variable risk factor, wherein the method comprises:

dividing the high risk engineering process into a plurality of safety intervals, wherein each safety interval comprises a series of process stages where a combination of risk factors remains invariable for all stages of the series;

for each safety interval, creating a safety model; and

for each safety interval, performing qualitative and quantitative safety analysis.

2. A method of claim 1, further comprising, prior to dividing the engineering process, collecting process-specific data.

3. A method of claim 1, wherein the safety interval comprises a series of consecutive process stages.

4. A method of claim 1, wherein the method comprises, prior to dividing the engineering process, creating a computer readable representation of the high risk engineering process.

5. A method of claim 1, wherein creating the safety model comprises creating a deterministic safety model.

6. A method of claim 1, wherein performing the qualitative and quantitative safety analysis comprises calculating probabilities of risk factors.

7. A method of claim 1, wherein, for each variable process parameter, a maximum permissible value P_imax is defined in accordance with safety requirements for the associated engineering process.

8. A method of claim 6, wherein the risk factors comprise engineering process and operation parameter failures, which may result in at least one overrun of a maximum safe operation parameter.

9. A method of claim 6, wherein a distribution analysis of the risk factors throughout different stages of the engineering process is performed using a process representation in computer readable form.

10. A method of claim 1, further comprising performing a distribution analysis, wherein sequential transition of failures of the engineering process and operation parameters from one safety interval to another are analysed using cause-effect analysis.

11. A method of claim 1, further comprising constructing at least one deterministic safety model based on the results of an analysis of possible scenarios of sequential transitions of engineering process failures from one safety interval to another safety interval.

12. A method of claim 1, wherein the engineering process comprises safety intervals, wherein a risk factor is associated with each stage or part of the engineering process for each safety parameter.

13. A computer-implemented method of safety evaluation of a high risk engineering process of a nuclear core loading, wherein the method comprises:

defining safety criteria as maximum safe operation parameters, wherein said operation parameters include process parameters or forces acting upon objects involved in the process;

comparing actual measured operation parameters with the safe operation parameters to determine risk factors, which may result in overrun of the maximum safe operation parameters;

for each determined risk factor, defining a plurality of process stages, which are affected by the said risk factor;

determining one or more safety intervals, wherein the safety intervals each comprise a series of consecutive process stages wherein a combination of the risk factors remains invariable;

for each determined safety interval, creating a deterministic safety model and calculating probabilities of risk factors in the safety interval; and

modifying the system based upon the calculated probabilities to reach the required safety parameter of the whole system.

14. A method of claim 13, wherein defining the plurality of process stages comprises performing distribution analysis of the risk factors throughout different stages of the engineering process using a process representation in computer readable form.

15. A method of claim 13, further comprising performing a distribution analysis, wherein sequential transitions of risk factors from one safety interval to another safety interval are determined using cause-effect analysis.

16. A method of claim 13, further comprising constructing deterministic safety models based on analysis of possible scenarios of the determined sequential transitions of risk factors from one safety interval to another safety interval.

17. A method of claim 13, further comprising constructing one or more logical or logical-probabilistic models for at least one risk factor.

18. A method of claim 13, wherein the actual operation parameters for the current engineering process are obtained prior to comparing the measured and the safe operation parameters using measurement devices.

19. A method of claim 17, wherein said logical or logical-probabilistic models are constructed based upon analysis of risk factors, which separately or in combination, potentially result in run-over of the respective engineering process parameters.

20. A method of claim 13, wherein the objects involved in the process are non-stationary objects having safety parameters varying with time or allocation of the said object in a particular process stage.

21. A method of claim 20, wherein the said non-stationary object is selected from at least one of the following:

an engineering process, at least one stage or part of an engineering process, at least one product, at least one device, at least one unit, a combination thereof, wherein the safety conditions of the object vary depending on time and allocation of the object.

22. A method of claim 13, further comprising plotting diagrams of partitioning into safety intervals.

23. A method of claim 16, further comprising creating at least one deterministic-probabilistic safety model of the whole engineering process using the determined safety intervals.

24. A method of claim 17, further comprising creating at least one deterministic-probabilistic safety model of the whole engineering process using the logical-probabilistic models.

25. A method of claim 17, further comprising creating at least one deterministic-probabilistic safety model of the whole engineering process using the determined safety intervals and the logical-probabilistic models.

26. A method of claim 13, further comprising performing analysis of failure transitions in the engineering process based on cause-effect relations of a combination of parameters selected from risk factors, possible failures in engineering process, and malfunction of protectors or locks on each stage of the engineering process.

27. A method of claim 13, wherein performing analysis of risk factors distribution is performed by considering each separate stage of the engineering process to determine a particular risk factor, which could result in overrun of any one acceptable operation parameter.

28. A method of claim 13, further comprising creating logical-probabilistic models using probabilistic coefficients for each event of the model.

29. A method of claim 13, further comprising separating the engineering process into safety intervals with account of each risk factor in each stage or part of the engineering process for each safety parameter.

30. A method of claim 13, further comprising performing quantitative analysis of safety.

31. A method of claim 13, further comprising determining necessary and sufficient number of protectors and locks.

32. A method as recited in claim 13, further comprising optimizing the structure of a control system of said engineering process.

33. A method as recited in claim 13, comprising determining valid safety parameters of equipment reliability to provide safety parameters of the process.

34. A system for safety analysis of a high risk engineering process, wherein the process comprises a series of stages involving non-stationary objects characterized by at least one variable risk factor, wherein the system comprises:

a central processor configured to perform the safety analysis;

means for storing data;

means for modeling the engineering process;

means for calculating probabilistic safety parameters;

means for analyzing risk factors distribution areas;

means for partitioning the engineering process into a plurality of safety intervals, wherein each safety interval comprises a series of at least one process stage, for which safety conditions comprise a combination of risk factors, which remain invariable for all stages of the series.

35. A system of claim 34, wherein the means for storing is configured to store at least one of the following:

process-specific data for analysis of safety regulations;

a list of safety criteria, and a list of maximum safe operation parameters overruns.

36. A system of claim 34, wherein the system further comprises means for analyzing transitions of engineering process failures from one safety interval to another safety interval using cause-effect analysis.

37. A system of claim 34, wherein the means for modeling comprises means for creating deterministic safety models taking into consideration possible scenarios of transitions of engineering process failures from one safety interval to another safety interval.

38. A system of claim 34, wherein the system further comprises means for performing qualitative and quantitative safety analysis.

39. A system of claim 34, wherein the system comprises means for creating a deterministic-probabilistic model.

40. A system of claim 34, configured to compute safety parameters, which characterize contribution of individual technological operations and individual protectors and locks into a general safety parameter of the overall engineering process of nuclear fuel reloading.

41. A system of claim 34, wherein the system comprises means for creating at least one failure propagation scenario using a database for storing statistical information on probabilities of occurrence of various events in the engineering process.

42. A system of claim 34, wherein the system further comprises:

means for creating an engineering process flowchart;

means for creating a matrix of safety criteria;

means for creating a matrix of engineering process failures;

a matrix of initial events; and

a matrix of protectors and locks.

44. A system of claim 39, wherein the modeling means comprises means for creating deterministic safety models taking into consideration possible scenarios of transitions of engineering process failures from one safety interval to another safety interval.

45. A system of claim 39, further comprising means for performing qualitative and quantitative safety analysis.

46. A system of claim 39, further comprising means for creating a deterministic-probabilistic model.

43. A control system configured to control a high risk engineering process of a nuclear core loading, wherein the system comprises:

means for detecting at least one process parameter acting upon one or more objects involved in the engineering process;

means for storing maximum safe operations parameters;

means for comparing the actual detected at least one process parameter with the stored maximum safe operating parameter to determine risk factors;

means for creating a matrix of distributions of risk factors within a plurality of process stages, indicating those process stages which are affected by the risk factor, and determining one or more safety intervals, wherein each safety interval comprises a series of consecutive process stages wherein a combination of the risk factors remains invariable;

modeling means for creating a deterministic safety model for each safety interval, and for calculating probabilities of risk factors;

means for modifying the system based upon the calculated probabilities to reach the required safety parameter of the whole system.

47. A medium comprising computer readable code, which, when executed causes the computer to perform a method of safety analysis of a high risk engineering process, wherein the process comprises a series of stages involving one or more non-stationary objects characterized by at least one variable risk factor, wherein the method comprises:

dividing the high risk engineering process into a plurality of safety intervals, wherein each safety interval comprises a series of process stages, and wherein a combination of risk factors remains invariable for all stages of the series; and

for each safety interval, creating a safety model and performing qualitative and quantitative safety analysis.