Chapter 5 State of the art in different countries

Nuclear emergency management: taking the right decisions with uncertain modelsCatrinel Turcanu, Johan Camps & Benny Carl

cturcanu@sckcen.be / jcamps@sckcen.be

Society and Policy SupportInstitute Environment, Health and SafetyBelgian Nuclear Research Centre

Workshop All models are wrong, Groningen, 14-16/03/2011#Copyright 2010 - SCKCEN - This is a copyright protected publication (2009). No part of this publication may be reproduced and/or made public without the express written consent ofSCKCEN. OutlineContextNuclear emergency model uncertaintiesConclusions

Model for evaluation of nuclear emergencies for the Doel NPP site#Copyright 2010 - SCKCEN - This is a copyright protected publication (2009). No part of this publication may be reproduced and/or made public without the express written consent ofSCKCEN. Nuclear emergencies & modelsAtmospheric transport and dispersion models (concentrations, deposition)Dose models (dose adults, children, thyroid, .)Food models (concentrations, dose)

Use of models for the protectionof peoplein emergency situations&preparednessphase:

#Copyright 2010 - SCKCEN - This is a copyright protected publication (2009). No part of this publication may be reproduced and/or made public without the express written consent ofSCKCEN.

rainWash-out

Irradiation shieldingIngestionIrradiationInhalationDry deposition

Inversion layerPlume riseHeight-dependent wind velocityAtmospheric turbulenceThe modelling problem:#Copyright 2010 - SCKCEN - This is a copyright protected publication (2009). No part of this publication may be reproduced and/or made public without the express written consent ofSCKCEN. How are decisions taken?LegislationReference band of dose values calculated based on model predictions (or measurements or both)Action levels on specific actions (Belgian levels)

New recommendations: 20-100 mSv/y, all pathwaysRange uncertainty !

#UncertaintiesModelling assumptionsSimplifications of realityParameter uncertaintyCalibration of model parametersInput dataMeteorologySource term

#Source models: Torben Mikkelsen, Ris

Average plumeMeandering plumeFluctuating plumeUncertainties from modelling assumptionssimplecomplexBest estimateConservative calculation#7Afsnit 3.2 (MN)Copyright 2010 - SCKCEN - This is a copyright protected publication (2009). No part of this publication may be reproduced and/or made public without the express written consent ofSCKCEN. Model intercomparison Standard conditions

Experimentally validated: factor 2-3 within experiments#Model intercomparisonVery specific conditions

#Model intercomparisonrealistic scenario

Noodplan Doel JRODOS Rimpuff (ARGOS)

TIC [Bq s/m3] same color scale#11Potential problems related to the resolution of the calculation gridFor the same scenario:Inner grid cell: 1 km Inner grid cell: 100m no sheltering sheltering

>1km#Source: Florian GeringParameter uncertainty:Cs-137 in milk

days after deposition#Copyright 2010 - SCKCEN - This is a copyright protected publication (2009). No part of this publication may be reproduced and/or made public without the express written consent ofSCKCEN. Model uncertainties in radiological assessments

Malcolm Crick, IAEASource: Malcolm Crick#

Source: Marc de CortUncertainties in input data (1): meteorology#Copyright 2010 - SCKCEN - This is a copyright protected publication (2009). No part of this publication may be reproduced and/or made public without the express written consent ofSCKCEN.

with on-site single rain gauge data with multiple rain gauge data With rain-radar dataUncertainties in the input data (2)

Example: Input data precipitation#Effect of conservative approach for treatment of rain

#

Example: conservative approachTihange, core melt, rupture primary circuitStandard weather conditions

#

Example: conservative approachTihange, partial core melt, rupture primary circuitStandard weather conditions

#

Example: conservative approachTihange, core melt, rupture primary circuitunstable weather conditions

#ConclusionsComplex problemOften models extended beyond validated rangeDifficult to obtain realistic uncertainties on calculations Even more difficult to communicate these uncertainties to decision-makersBest estimate often replaced by conservative approachBut conservative estimates may lead to unfeasible countermeasures#Document in ABR_SFRP

14/03/2011

ActionIndicative ranges for intervention

(dose mSv)

General sheltering

(up to 24h)5-15 (effective dose)

Stable iodine prophylaxis10-50 (thyroid equivalent dose)

General evacuation50-150 (effective dose integrated 1 week)

1 of 1