Abstract
Original language  English 

Awarding Institution 

Supervisors/Advisors 

Place of Publication  Espoo 
Publisher  
Print ISBNs  9513850498 
Publication status  Published  1997 
MoE publication type  G5 Doctoral dissertation (article) 
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Keywords
 probability theory
 decision theory
 reliability
 safety factor
 safety engineering
 risk analysis
 utilization
 mathematical models
 operations research
 theses
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Probabilistic safety assessment and optimal control of hazardous technological systems : A marked point process approach: Dissertation. / Holmberg, Jan.
Espoo : VTT Technical Research Centre of Finland, 1997. 32 p.Research output: Thesis › Dissertation › Collection of Articles
TY  THES
T1  Probabilistic safety assessment and optimal control of hazardous technological systems
T2  A marked point process approach: Dissertation
AU  Holmberg, Jan
PY  1997
Y1  1997
N2  Probabilistic safety assessment (PSA) and decision analysis are methods used for supporting risk management of hazards arising from technological systems. These methods are applied more often also in operational risk management, for instance, in the nuclear safety field. Operational risk management sets new requirements for modelling of systems and problems, since the context is dynamic compared with the static decisionmaking situation assumed in conventional risk and decision analysis approaches. This thesis applies a marked point process approach to represent dynamically the hazards of a technological process. The approach is applied here to risk followup and the problem of optimal control. Risk followup by PSA provides a systematic method for analysing incidents. In a retrospective risk assessment, operational events can turn out to be important in several respects. In order to highlight such differences, several alternative approaches should be used in parallel, as presented in this thesis. A period of actual operating history from a Finnish nuclear power plant is analysed. The thesis models risk management as an optimal control problem for a stochastic process. The approach classes the decisions made by management into three categories according to the control methods of a point process: (1) planned process lifetime, (2) modification of the design, and (3) operational decisions. The approach is used for optimization of plant shutdown criteria and surveillance test strategies of a hypothetical nuclear power plant. The thesis promotes use of the utility function as the objective function in optimization of risk management strategies. Compared with present approaches based on e.g. probabilistic safety criteria and ALARP principle (As Low As Reasonably Practicable), the utility theory would increase coherence in the analysis of different problems. The choice of utility function is here related to the problem of risk acceptance, i.e. probabilistic safety criteria are analysed using a utility function model. Conditions for a utility function satisfying the risk acceptance criterion are derived.
AB  Probabilistic safety assessment (PSA) and decision analysis are methods used for supporting risk management of hazards arising from technological systems. These methods are applied more often also in operational risk management, for instance, in the nuclear safety field. Operational risk management sets new requirements for modelling of systems and problems, since the context is dynamic compared with the static decisionmaking situation assumed in conventional risk and decision analysis approaches. This thesis applies a marked point process approach to represent dynamically the hazards of a technological process. The approach is applied here to risk followup and the problem of optimal control. Risk followup by PSA provides a systematic method for analysing incidents. In a retrospective risk assessment, operational events can turn out to be important in several respects. In order to highlight such differences, several alternative approaches should be used in parallel, as presented in this thesis. A period of actual operating history from a Finnish nuclear power plant is analysed. The thesis models risk management as an optimal control problem for a stochastic process. The approach classes the decisions made by management into three categories according to the control methods of a point process: (1) planned process lifetime, (2) modification of the design, and (3) operational decisions. The approach is used for optimization of plant shutdown criteria and surveillance test strategies of a hypothetical nuclear power plant. The thesis promotes use of the utility function as the objective function in optimization of risk management strategies. Compared with present approaches based on e.g. probabilistic safety criteria and ALARP principle (As Low As Reasonably Practicable), the utility theory would increase coherence in the analysis of different problems. The choice of utility function is here related to the problem of risk acceptance, i.e. probabilistic safety criteria are analysed using a utility function model. Conditions for a utility function satisfying the risk acceptance criterion are derived.
KW  probability theory
KW  decision theory
KW  reliability
KW  safety factor
KW  safety engineering
KW  risk analysis
KW  utilization
KW  mathematical models
KW  operations research
KW  theses
M3  Dissertation
SN  9513850498
T3  VTT Publications
PB  VTT Technical Research Centre of Finland
CY  Espoo
ER 