Presenting Uncertain Information in Radiological Emergencies University of Warwick, Public Health England, Met Office 20 th September 2016, 9.30am 12.30pm
Accident scenario example Presentation of theoretical accident scenario and output examples Objective: to explore possible means of communication of uncertain information, to decision makers, particularly geographical uncertainty All scenarios and data are completely fictitious and used for this example only
Example information flow in decision making Local Response Local Public National Public National Response Police, fire fighters, ambulance, site operator, local government, representatives of national government Media Ministers and senior civil servants from relevant ministries* Scientific advisers Eg Met Office, public health, radiation modellers, nuclear regulators, operators Teams at National expert agencies eg Met Office, PHE, ONR* International Liaison: EU, IAEA, governments * In the UK SAGE (the Scientific Advisory Group for Emergencies) advises COBR the national/ministerial decision making body
Emergency assessments (atmospheric release) Inputs to assessments Accidental release Measurements Site data Estimated source term Dose modelling Assessments Contamination pattern Doses Weather Environmental modelling Dispersion & deposition modelling Countermeasures advice sheltering stable iodine evacuation etc 4
Emergency assessments (atmospheric release) Accidental release Measurements All components contain uncertainties, and calculations are approximations Site data Estimated source term Dose modelling Assessments Contamination pattern Doses Weather Environmental modelling Dispersion & deposition modelling Countermeasures advice sheltering stable iodine evacuation etc 5
Emergency assessments (atmospheric release) Accidental release Measurements All components contain uncertainties, and calculations are approximations Site data Estimated source term Dose modelling Assessments Contamination pattern Doses Weather Environmental modelling Dispersion & deposition modelling Countermeasures advice sheltering stable iodine evacuation etc 6
Immediate response in threat and release phases Possible actions advising the public to shelter evacuating some of the public most at risk distributing stable iodine tablets In the UK, there are Emergency Reference Levels (ERLs) which guide decisionmaking: Countermeasure Body or organ dose Averted dose (msv) Lower Upper Sheltering Whole body 3 30 Evacuation Whole body 30 300 Stable iodine Thyroid 30 300
Background Information
Pagham Nuclear Power Plant Pagham Nuclear Power Plant is a fictitious site located on the south coast of the UK East of Havant South of Chichester South west of Bognor Regis. To the north of Pagham Nuclear Power Plant is an area of predominantly agricultural land
Hypothetical Reactor Location
Key Locations
Population Density
Pagham Nuclear Power Station emergency plan: Specified plant conditions and monitoring results (on site & off site) trigger its emergency plan Bands and sectors around the plant are used to define specific actions When the plan is triggered, the site operator will: Inform the local police, fire service, ambulance service, local authority, and national authorities. Advise all residents within 3km to take pre distributed stable iodine tablets Advise the local police to evacuate all residents within 3 km Advise all residents in some or all sectors in band 3 5 km to shelter
Example scenario
Friday August 14 th 2016 09:30 10:00 the nuclear power plant at Pagham reports an engineering fault which has the potential to become more serious a very low level release of radionuclides is detected it is not sufficient to trigger the emergency plan however, the nuclear power plant takes the decision to inform government of the potential for the situation to escalate Met Office and PHE are informed and begin a range of preliminary modelling runs, so that they are ready if it does become an emergency
Friday August 14 th 2016 11.00 a moderate release of radionuclides is detected the full local emergency plan is followed with evacuation, iodine and sheltering begun in the planned areas The Met Office and PHE begin full modelling a still larger release is thought possible, starting between 13:00 and 14:00 to complicate matters a weather front will pass through around this time causing a rapid change in wind direction
Weather Forecast for South East England Headline: A windy and cloudy day with rain Today: A windy, cloudy start for all with a wet start in the west of the region. Rain will spread across to the east of the region by late evening. Continuing to feel cooler than average. Maximum temperature 19C Tonight: Staying mostly cloudy with rain becoming light and patchy. Winds will ease overnight. Minimum temperature 13C Saturday: Saturday will be a mostly cloudy day with some bright spells in the west. It will remain dry but cool for the time of year 1200 Fri 1200 Fri
Local forecast for Pagham provided by Met Office at 12:00 Weather in Pagham is currently cloudy and dry with wind blowing from the south Rain is expected to reach Pagham vicinity between 13:00 and 14:00 At the same time the wind direction will change moving from the south to the south west and then, later, from the west There is some uncertainty in the timing of the arrival of the rain and change in wind direction
Any thoughts? At this point in the UK workshop we asked people to reflect on their first thoughts at this point If they had responsibility to give advice, what factors would seem most important? What additional information would they request (recognising it may not be possible to get it in the near future)?
Some predictions At 12.00, modelling results are available for a number of bounding scenarios from a wider set All scenarios include the early release starting at 11.00 (approximately 1 10 14 Bq of iodine 131 over 1 hour) Scenario 1 : The release at 11.00 only Scenario 3: The release at 11.00 followed from 14.00 to 16.00 by a large release with a change in weather conditions as a result of the arrival of the front occuring midway through the release (approximately 4 10 14 Bq of Cs 137 and 1 10 16 Bq of I 131 over 2 hours) Scenario 5: The release at 11.00 followed from 14.00 to 16.00 by a large release following a change in weather conditions as a result of the arrival of the front (approximately 4 10 14 Bq of Cs 137 and 1 10 16 Bq of I 131 over 2 hours) Scenario 6: The release at 11.00 followed from 14.00 to 16.00 by a very large release with a change in weather conditions as a result of the arrival of the front occuring midway through the release (approximately 2 10 15 Bq of Cs 137 and 4 10 16 Bq of I 131 over 2 hours four times greater than the large release)
Presentations of alternative outcomes time integrated air concentrations of I-131 1 3 5 6 21
Presentations of alternative outcomes effective dose 0 2 days 1 3 5 6 22
Presentations of alternative outcomes effective dose > 3 msv (lower ERL for sheltering) 1 3 5 6 23 NB shaded zones display areas where the effective dose is greater than 3mSv, but the actual area sheltered may be larger than this since it is assumed that anyone advised to take stable iodine (following slide) will also be advised to shelter.
Presentations of alternative outcomes thyroid dose > 30 msv (lower ERL for stable iodine) 1 3 5 6 24
Discussion For ease of reference you have the figures on paper for you to be able to consult. We will now move to the discussion part of the workshop to be led by Simon.