emras ii, theme 3 wg tritium develop dynamic tritium model tentative working group leader: dan...
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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
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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