PNNL-SA-108973 Risk-Informed Decision-Making: Basic Concepts Presentation to the State Energy Risk Assessment Workshop April 28-29, 2015 Presented by Steve Unwin, Ph.D. Pacific Northwest National Laboratory 1 Business Sensitive
Outline Risk Decisions Risk Models Risk Management Risk Perception Risk Guidance First Steps 2 Business Sensitive
Risk-Informed Decision-Making Decisions that take into account: Uncertain future events The impacts of those events The likelihoods of those events Structuring data, judgment, and system logic in a coherent framework for decision-making Risk-Informed versus Risk-Based decisions The reality of accounting for risk 3 Business Sensitive
Modeling Risk Hazard condition that poses threat: presence of flammables or toxics, natural phenomena, potential for market upsets, threat of malevolent acts, presence of physical energies, ... Scenario specific hypothetical sequence of events that would result in adverse consequences Risk a combination of the adverse consequences and likelihoods of a scenario set 4 Business Sensitive
Risk Models – What varies between them? Scope natural phenomena? terrorism? human factors? system boundaries? impact region of concern? ... Depth model resolution: e.g., industries vs. facilities vs. systems vs. components (how far into the weeds?) Precision full quantitative vs. order of magnitude vs. qualitative Risk types safety, environmental, production/outage, business, schedule, budget, public perception 5 Business Sensitive
Risk Type: Business – Risk (probability- weighted production loss) associated with forced outage of refinery units HYDROGEN PLANT SULFUR RECOVERY SOUR WATER STRIPPING VAPOR RECOVERY/GAS TREAT ALKYLATION OLEFIN TREATING FLUIDIC CAT CRACKING REFORMING GAS OIL HYDROTREATING DISTILLATE HYDROTREATING NAPHTHA HYDROTREATING DELAYED COKING VACUUM DISTILLATION CRUDE UNIT CRUDE BLENDING 0 200,000 400,000 600,000 800,000 1,000,000 1,200,000 1,400,000 Downtime $ risk per quarter 6 Business Sensitive 5/1/2015
Risk Type: Safety & Health – Frequency vs. number of individuals exceeding ERPG2 exposure due to presence of a selective catalytic reduction unit at a fossil plant 7 Business Sensitive 5/1/2015
Broadly Risk-Oriented: Representation of bulk power system interruption NERC, 2010 8 Business Sensitive
Structure of a Risk Model Models Mechanistic models natural phenomena engineered system behavior Logic models (event trees, fault trees, networks) logical relationships between events Evidence/likelihood models probabilistic other Consequence models health, exposure, financial, reputation, ... Input Hard data/statistical models Informed judgment 9 Business Sensitive
Example: Event tree that models fire risk in a research facility – Systematically defines scenarios Ignition Failure to Ignition was in a Failure to prevent END STATE immediately Cluster area propagation beyond extinguish room/cluster Ignition occurs Personnel unable to No fire suppression High combustibles / No fire suppression Failure of other fire Failure of extinguish system (sprinkler) in flammables load in (sprinkler) system in isolation system (fire emergency response immediately or no place, failure to actuate adjacent rooms place, or failure to wall) organization to extinguishers present locally, or system actuate globally, or respond effectively ineffective system ineffective P1: Annual Frequency P2: Probability (Yes) P3: Probability (Yes) P4: Indicator P5: Probability (Yes) P6: Probability (Yes) P7: Probability (Yes) P8: Probability (Yes) Yes Yes Yes Yes Yes Yes Yes 1. Building Cluster Damage 2. Local Cluster Damage No No 3. Local Cluster Damage No 4. Local Cluster Damage No 5. Local Cluster Damage No Yes Yes Yes Yes 6. Building Cluster Damage OK No No OK No OK No OK 7. Local Water Damage No Yes No OK No OK 10 Business Sensitive
Risk Management Doing what needs to be done to continually and economically reduce risks. Once we know where the greatest risks lie, effectively manage them. Where can resources be most effectively spent to reduce risk? Where might expenditures be reduced without significantly affecting risk? 11 Business Sensitive
The Elements of Risk Management Determining risks and Analysis uncertainties I dentifying risk and uncertainty drivers. Evaluation Assessing risk and uncertainty-reduction options Control Research Reducing the uncertainties Reducing and controlling the risks Communicating risks and Communication their management to stakeholders Ongoing Monitoring confirmation/revision of assumptions about risk 12 Business Sensitive
Risk-Informed Decision Portfolio Risk tolerance criteria/goals, limits/objectives numerical risk acceptance levels Risk-based prioritization/allocation risk importance metrics Cost/benefit analysis ALARP as low as reasonably practicable risk-based cost-benefit analysis 13 Business Sensitive
Risk objectives and limits. Risk acceptance criteria for public radiation exposure UK Health and Safety Executive Dose Tolerance 1.0E+01 1.0E+00 Greatest Annual Exceedence Frequency tolerable risk 1.0E-01 level Basic safety limit 1.0E-02 Targeted risk level 1.0E-03 1.0E-04 Basic safety objective 1.0E-05 1.0E-06 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 Maximum Individual Public Dose (mSv) 14 Business Sensitive
Risk-ranking for explosion damage in chemical process facility STRUCTURE RANK 2.8 6 Fermentation Building 3 Process 95 Building 2.9 2 Control Room A 2.9 5 Extraction Building 3.0 4 Laboratory Area 3.1 High rank = Vulnerable 3.3 7 Maintenance Building high Structures 10 Guard Shack 3.4 protection 6.2 9 Stores priority 8 Warehouse 6.9 X 1 Administration Offices SOURCE RANK Explosion 2.3 Fermentation Area VCE Sources Process 95 PVE 2.9 3.3 Extraction Area PVE Process 95 VCE 3.8 6.2 Extraction Area VCE High rank = Main Storage PVE 6.2 high Tank Farm B BLEVE 6.4 prevention Main Storage BLEVE 7.1 priority 8.0 Tank Farm B PVE 15 Business Sensitive
Cost-Benefit Criteria: Risk reduction / cost tradeoff USNRC: US$ 2,000/person-rem (radiological dose) averted UK HSE: UK£ 0.75 M per fatality averted Range inferred from a variety of organizations (1990s): $20K - $100M per fatality averted Cost-benefit acceptance Cost-beneficial threshold Assessing expenditure a risk- Risk- Reduction reduction Unwarranted option: expenditure Cost 16 Business Sensitive
ALARP: As Low (A Risk) As Reasonably Practicable Risk Intolerable Reduce Risk Regardless of Cost Follow Good Practice Tolerable if ALARP Consider Cost of Risk- Reduction De Minimis Risk Tolerable Risk 17 Business Sensitive
Risk Perception Perceived versus calculated Factors driving risk perception Personal controllability of exposure Dreadedness of potential consequences “Visibility” of exposure Fairness of risk and benefit distribution Peter Sandman’s Equation Risk = Hazard + Outrage 18 Business Sensitive
Risk Perception Factors Not Observable Unknown to Those Exposed Uncontrollable Effect Delayed Dread New Risk Global Catastrophic Risk Unknown to Science Consequences Fatal Not Equitable Catastrophic Factor 2 High Risk to Future Unknown risk Generations Not Easily Reduced Risk Increasing Involuntary Laetrile DNA Technology Microwave Ovens SST Electric Fields Water Fluoridation DES Nitrates Saccharin Hexachlorophene Nitrogen Fertilizers Water Chlorination Polyvinyl Coal Tar Hairdyes Chloride Cadmium Usage Radioactive Waste Oral Contraceptives Mirex Diagnostic 2,4,5-T Trichloroethylene X-Rays Nuclear Reactor Valium IUD Pesticides Uranium Mining Accidents Antibiotics Darvon Asbestos PCBs Nuclear Weapons Rubber Fallout Insulation Mfg. Satellite Crashes DDT Auto Lead Mercury Caffeine Fossil Fuels Lead Paint Factor 1 Aspirin Coal Burning (Pollution) Vaccines Dread risk Auto Exhaust (CO) LNG Storage & Skateboards Nerve Gas Accidents D-CON Transport Smoking (Disease) Coal Mining (Disease) Power Mowers Snowmobiles Large Dams Trampolines Tractors SkyScraper Fires Alcohol Nuclear Weapons (War) Chainsaws Underwater Elevators Home Swimming Pools Construction Electric Wir & Appl (Fires) Coal Mining Accidents Downhill Skiing Sport Parachutes Smoking Recreational Boating General Aviation Electric Wir & Appl (Shock) Motorcycles High Construction Bicycles Railroad Collisions Bridges Alcohol Commercial Aviation F rom: Fireworks Accidents Auto Racing Auto Accidents Slovic, P. (1987). Perception of risk. Science, 236, 280- Handguns 285. Dynamite 19 Business Sensitive
Risk Standards / Methodology Guides / Risk Acceptance Criteria / Review Guides 20 Business Sensitive
Risk reading: A few starting points - Quantifying and Controlling Catastrophic Risks, by B. John Garrick (Academic Press, 2008) U.S. Nuclear Regulatory Commission, A Proposed Risk Management Regulatory Framework , NUREG-2150, 2012 Guidelines for Chemical Process Quantitative Risk Analysis ( American Institute of Chemical Engineers, 2 nd Ed., 1999) NASA, Risk-Informed Decision Making Handbook , NASA/SP-2010-576, 2010 21 Business Sensitive
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