Transcript EMRAS II, Theme 3 - International Atomic Energy Agency

EMRAS II, Theme 3
WG 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
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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)
Pasture contamination
NO steady state model can be
adapted, as uptake and loss rate
differs strongly - HTO visa OBT
and environmental factor are
depending on site conditions
T concentration (Bq/kgfw)
1.E+08
1.E+07
hto
1.E+06
obt
1.E+05
1.E+04
1.E+03
1.E+02
1.E+01
1.E+00
150
200
250
300
time (d)
1.E+06
concentration (Bq/kg)
Veal, just weaned at
Accident time, on pasture until
Age 300 d, clean food after until
Sacrifice (500 kg)
OBT predominate in meat
muscle_conc
viscera_conc
1.E+05
mustotalT
1.E+04
1.E+03
1.E+02
150
250
350
450
time (d)
550
650
Using knowledge on
Plant growth processes
Testing with C experiments
simulation
experiment
We can fix some
Processes influencing
T transfer and
OBT formation
SARTANI
SARTANI
0.05
0.05
0.04
SAR
SAR
0.04
0.03
0.02
0.03
0.02
0.01
0.01
0
-60
-40
-20
0
DRA
20
40
60
0
-60
-40
-20
0
DRA
20
40
60
Simplification
latter, considering
robustness in final
dose and cost-benefit
No production near
exclusion zone
(except wine grapes)
Town nearfew local production
Not flat terrain
Building effect
Moderate capacity for
Improved ATM and
meteorological sensors
Operational model is site specific
Framework will be given with
specification on lost in dose
assessment robustness
Potential participants now in VIC are kindly
asked to complete their contact forms
and to disseminate our intentions and
needs of help
We are only at the begin and future depends
ON YOUR INVOVMENT AND POWER OF
PERSUASION AT HOME