Risk-informed decisions

Risk-informed regulation by the USNRC has gained momentum in the last few years and has produced 

USNRC s policy for implementing risk-informed regulation was expressed in the 1995 policy statement on the use of probabilistic risk assessment (PRA) methods in nuclear regulatory activities. The policy statement says The use of PRA technology should be increased in all regulatory matters to the extent supported by the state-of-the-art in PRA methods and data and in a manner that complements the NRC s deterministic approach and supports the NRC s traditional defence-in-depth philosophy. 

Since adequate protection is presumably provided by existing regulations, the NRC has determined 

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National Research Council. (1996) Understanding Risk Informing Decisions In a Democratic Society. Washington, National Academy Press. 

National Research Conned. 1996. Understanding risk informing decisions in a democratic society. Washington (DC) National Academy Press. 

A. Amendola, Recent Paradigms for Risk Informed Decision Making, Safety Science, 2001, 40, 17. 

NRC, 1998b) NRC,RG 1.176 An Approach for Plant-Specific, Risk-Informed Decision-making Graded... 

Re-schedule the preventive maintenance of some systems. The comparison of the aggregate risk from a given maintenance activity serves as the basis for risk-informed decisions concerning the operational state (including full power operation) during which scheduled maintenance should be performed. 

The purpose of categorizing radioactive sources is to provide an internationally harmonized basis for risk informed decision making. It is envisaged that the categorization system will be used by national authorities in... 

AR443 1.174 An approach for using probabilistic risk assessment in risk-informed decisions on... 

AR444 1.175 An approach for plant-specific, risk-informed decision-making In-service testing... 

AR447 1.178 An approach for plant-specific risk-informed decision-making for in-service inspection... 

Integrated risk management and risk-informed decision-making... 

Adapted principles of risk-informed decision-making for new nuclear power plants... 

The paper presents ie adapted principles of risk-informed decision-making for new nuclear power plants. The adapted principles prevent large increase of risk measures due to plant specific changes in new nuclear power plants, which could be allowed, if current principles would be used for future plants. 

While both of those risk measures are expected to be smaller in the case of new nuclear power plants for orders of magnitude, there is a need to update the risk-informed decision-making principles, which have been determined with the methods summarized inRG 1.174. 

Cepin M. 2004, Development of Criteria for Risk-Informed Decision-Making, NECE2004, Portoroi. 

RG-1.174, 2002, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, US NRC, Rev. 1. TR-105396, 1995, PSA Applications Guide, Electric Power Research Institute - EPW. 

Addressing uncertainties in risk-informed decision-making of changes to nuclear power plant technical specifications... 

To make a risk-informed decision based on quantitative arguments, the numerical results of the PRA, including their associated uncertainty, must be compared with the appropriate decision guidehnes. 

NUREG 1855, 2007. Guidance on the Treatment of Uncertainties Associated with PRAs in Risk-Informed Decision Making, USNRC. 

Reinert, J.M., Apostolakis, G.E., 2006. Including model uncertainty in risk-informed decision making. Annals of Nuclear Energy, 33, 354-369. 

Istad, M. K., Nordgard, D. E., Gjerde, O., Catrinu, M. D., Nybo, A. Birkeland, B. E. (2008). Risk Informed Decision Support for Reinvestments in Distribution Systems. PMAPS - Probabilistic Methods applied to Power Systems, Rincon, Puerto Rico. 

Borgonovo, E. and G.-E. Apostolalds (2001). A new importance measure for risk-informed decision making. Reliability Engineering and System Safety 72(2), 193-212. 

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