EMRAS II, Theme 3WG tritium

Develop Dynamic Tritium Model

Tentative Working Group Leader:

Dan Galeriu

Assisted by S.L. Chouhan and P. Guetat

Canada-France-Romania (CFR)

Aim and Objectives• To develop a standard conceptual dynamic model for

tritium dose assessment for acute releases to atmosphere and water bodies

• To focus on only starting the new model from the given air or water concentrations (HT or HTO) and the duration of the exposure

• To agree on common sub-models, based on understanding of the processes and agreed key parameters (interdisciplinary approach)

• To define the framework for an operational model• To obtain quality assured sub-models and harmonize

approaches in order to get confidence in the predictions (moderate conservatism)

• To have capability to assimilate real data from measurements

Justifications for an Improved Model

• Licensing and accident preparedness specific for utilities with large tritium inventory and tritium transport

• Uncertainties in the existing models are high.• Models must incorporate new knowledge for

credibility• OBT (organically bound tritium) models need

improvements (e.g. night time release are not well understood)

• Processes for tritium transfer and conversion under precipitation conditions need better understanding

• The dynamics of OBT and 14C concentrations were generally poorly reproduced in scenarios involving short-term releases EMRAS I-TRITIUM &14C

Interested Participants• Romania ( IFIN-HH, SNN) >2• Canada (AECL, CNSC, Health Canada, COG) 4• France (CEA, EDF, IRSN, ?) >4• Slovakia (VUJE Inc) 1• Czech Republic (NRPI) 1• Mongolia (Nuclear Research Centre) 1• Germany (KFK, to be confirmed) >1 W Raskob need financing• Ukraine (NIIEP) 1• More participants are welcome (Hopefully more participant may join

the next meeting)• Questionnaire on our needs will be spread

ITER: to be requested; Japan Russia and USA

Immediate Provisional Working Plan (up to the next meeting)

• To check if TRS-364 can be partially used (do an example calculations for an acute release using a routine release model)

• To make available the existing models (i.e. ETMOD, UFOTRI, OURSON, RODOS and GAZAXI) to understand a way forward

• To establish a tritium modelling knowledge base (seek EMRAS-II website to host web page)

• To compile tritium experimental datasets (especially for transfer from air/soil/water to plants)

• To define the framework for linking from operational model (e.g. atmospheric dispersion model and site specific data) to the new conceptual tritium model

• Identify financial support• Tentative WG meeting, September France

Long Term Provisional Working Plan

• To update the documentation in RODOS research for the new tritium model

• To use current research regarding animals model to construct a simple but robust new tritium model

• To collect data for constructing new plant model• To gain knowledge from other experts (i.e. life

scientists) regarding photosynthesis and water cycle in plants

• To optimize existing soil plant transfer model for tritium

End Result

• A new document covering acute release tritium model (Jan 2012)

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NO steady state model can be adapted, as uptake and loss ratediffers strongly - HTO visa OBTand environmental factor aredepending on site conditions

Pasture contamination

Veal, just weaned at Accident time, on pasture until Age 300 d, clean food after until Sacrifice (500 kg)OBT predominate in meat

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Using knowledge onPlant growth processes

Testing with C experiments

experiment simulation

We can fix some Processes influencingT transfer and OBT formation

Simplificationlatter, consideringrobustness in finaldose and cost-benefit

No production near exclusion zone (except wine grapes)Town near-few local productionNot flat terrainBuilding effectModerate capacity forImproved ATM and meteorological sensors

Operational model is site specificFramework will be given withspecification on lost in dose assessment robustness

Potential participants now in VIC are kindly asked to complete their contact formsand to disseminate our intentions andneeds of helpWe are only at the begin and future dependsON YOUR INVOVMENT AND POWER OF PERSUASION AT HOME