the emras (environmental modelling for radiation safety...
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The EMRAS (Environmental
Modelling for Radiation Safety)
programme - IAEA
Cristina Nuccetelli
Dipartimento tecnologie e Salute
Istituto Superiore di Sanità
Introduction
The general aim of the EMRAS II Programme is to improve capabilities in the
field of environmental radiation dose assessment by means of:
• acquisition of improved data for model testing
• comparison
• reaching consensus on modelling philosophies, approaches and parameter
values, development of improved methods
• exchange of information.
The activities of the EMRAS II Programme emphasize on improvement of
environmental transfer models for reducing associated uncertainties or
developing new approaches to strengthen the evaluation of the radiological
impact to man, as well as to flora and fauna, arising from radionuclides in the
environment.
EMRAS II continues some of the work of previous international exercises in the
field of radioecological modelling and focuses on areas where uncertainties
remain in the predictive capability of environmental models.
Previous international exercises:
• BIOMOVS (BIOspheric Model Validation Study) and
• BIOMOVS II (Swedish Radiation Authority in 1985)
• VAMP (Validation of Model Predictions, 1988-1996)- IAEA
• BIOMASS (BIOsphere Modelling and ASSessment, 1996-2001) - IAEA
• EMRAS which ran from 2003 to 2007 - IAEA
Introduction (cont.)
All data and pictures are from IAEA official EMRAS and EMRAS II sites.
Objectives
The objectives of EMRAS in environmental modelling are:
• to enhance the capabilities of Member States to simulate radionuclide
transfer in the environment and, thereby
• to assess exposure levels of the public and in the environment, associated
with radionuclide releases and from existing radionuclides in the
environment.
Specific objectives in the areas of radioactive release assessment, restoration
of sites with radioactive residues, and environmental protection are:
• to test the performance of models developed for assessing the transfer of
radionuclides in the environment and radiological impact to man and
environment
• to develop and improve models for particular environments and, where
appropriate, to agree on data sets that are generally applicable in
environmental transfer models
• to provide an international forum for the exchange of experience, ideas
and research information
Organization of the EMRAS II Programme
The EMRAS II Programme will be run to 2011.
It was launched at IAEA's headquarters in Vienna in January 2009.
Other two Technical Meetings
25-29 January 2010
24-28 January 2011.
45 Countries 120 participants 3 Themes 9 Working Groups
Two types of meetings:
•The annual Technical Meeting, generally held at the IAEA’s headquarters in
Vienna during the first quarter of each year. During the week long Technical
Meeting, typically Plenary Sessions will be held on the first and last days and,
the remaining three days will be used for the Working Group Meetings.
•The interim Working Group Meetings, which take place in the second or
third quarter of each year.
EMRAS II Working Groups
Reference Approaches for Human Dose Assessment
Working Group 1 - Reference Methodologies for "Controlling Discharges" of Routine Releases
Working Group 2 - Reference Approaches to Modelling for Management and Remediation at "NORM and
Legacy Sites"
Working Group 3 - Reference Models for "Waste Disposal"
Reference Approaches for Biota Dose Assessment
Working Group 4 - "Biota Modelling"
Working Group 5 - "Wildlife Transfer Coefficient" Handbook
Working Group 6 - Biota "Dose Effects Modelling"
Approaches for Assessing Emergency Situations
Working Group 7 - "Tritium" Accidents
Working Group 8 - "Environmental Sensitivity"
Working Group 9 - "Urban" Areas
Methodologies to set up reference models for assessing radiological
impacts
• from planned releases
• in existing exposure situations.
Wide range of scenarios (e.g. Ottawa River from Chalk River Labs; Sizewell, releases
to marine envir.)
The aim is to develop standardized and harmonized models for
assessing radiological impacts to people and the environment.
WG1 - Reference Methodologies for Controlling
Discharges of Routine Releases
WG3 - Reference Models
for Waste Disposal
• Environmental changes
– climate
– changes in landscape
– groundwater and sea levels
– changed land use by humans.
• Processes at the transition zone between the geosphere and
the biosphere
– identified a variety of potentially relevant geosphere-biosphere
interfaces
– details will be site specific.
• Important migration and accumulation processes within the
biosphere, which in many cases are radionuclide and/or site
specific.
WG4-Biota Modelling
The aim of the work is to improve Member States' capabilities for
protection of the environment by comparing and validating
models being used, or developed, for biota dose assessment (that
may be used) as part of regulatory process of licensing and
compliance monitoring of authorised releases of radionuclides.
Beaverlodge uranium mine - CanadaLittle Forest Burial Ground-waste disposal
Australia
WG5 - Wildlife Transfer Coefficient Handbook
The aim of the Working Group is to contribute to the development and
implementation of an online Wildlife Transfer Parameter Database which
will be applied in the production of a Technical Reports Series (TRS)
Handbook on Wildlife Transfer Coefficients.
In parallel a core group was established by the IAEA in cooperation with
International Union of Radioecology (IUR) to develop an online
concentration ratio database, initially populated with the ERICA data, to
provide data tables for the Handbook.
A further objective of the Working Group is to provide a peer review of the
text of the above mentioned Handbook.
WG6 - Biota Dose Effects Modelling
The Working Group works with 5 subgroups to derive relationships
between exposures to ionizing radiation and effects on flora and fauna.
1. Update Data Base
2. Dose Response Curves and species sensitivity curves
3. Population Models and Alternative Methods
4. Multiples Stressors
5. Canadian Benthic Data
All subgroups contribute to Reports and Guidance Documents
WG7-Tritium Accidents
The Working Group focuses on the
development of a dynamic reference
model to estimate exposure to tritium
subsequent to accidental releases.
The processes involved in the transfer
of tritium in the environment will be
analysed in dependence on the
environmental conditions, season and
time of the day.
A main issue is the integration of
actual weather data to enable reliable
estimation of the tritium behaviour.
The Cardiff case
WG8 - Environmental Sensitivity
environmental sensitivity: rural and semi-natural
environments within the framework of assessments after an
emergency situation.
a) formulate the concept of environmental sensitivity;
b) compile a list of sensitivity factors;
c) design scenarios;
– Agricultural (Europe and Canada)
– Alpine (Central Europe)
–Temperate forest (Europe and Canada)
–Arctic (Europe and Canada)
–Freshwater aquatic environment
–Coastal marine environment
d) carry out modelling exercises
WG 9 – Urban areas
urban situations: dispersion and retention of radionuclides in urban
environments
(a) Atmospheric dispersion, short-range;
b) Atmospheric dispersion, mid-range;
c) Contaminant transport and countermeasures.
8 participants
5 participants
The aim of the Working Group is to assess
• the environmental impacts and risks
• the effect of remediation measures
The work concentrates on the areas affected by
residues of the mining industry (phosphorus, uranium,
metals, etc.) and on contaminations due to past
activities.
WG2 - Reference Approaches to Modelling for
Management and Remediation at "NORM and
Legacy Sites"
WG2-Models
Model
name
Model
type
Application Transport processes
modelled
Endpoints calculated
CROM Gaussian
plume module,compartmental
model
Screening Gaseous and liquid discharge;
Atmospheric dispersion ofradionuclides (Gaussian
plume) and transfer through
terrestrial food-chains
External, inhalation and
ingestion Dose .(Activities in soil,
sediment and water ?)
PC-CREAM(Set of
modules)
1.PLUME:atmospheric
dispersion
2. DORIS:marine (coast)
dispersion
3. FARMLAND:food chaincalculations
4. GRANIS:gamma radiationfrom ground
5. RESUS:resuspendedmaterial
6. ASSESSOR:results from other
modules and
calculates annual doses
Routine continuous
releases toatmosphere, river,
estuarine, marineenvironments;
detailed committedeffective dose
assessment,collective dose
assessment;
screeningassessment
available within theriver model.
Atmospheric dispersion
Transfer through the terrestrial environment: wet deposition,
resuspension, migration in soil,
transfer to plants and in animals,external irradiation due to surface
deposition;
Estuary models
Marine model – MARINA II –
water movement, sediments,
sediment/water interaction,
exposure pathways – exposure
pathways from ingestion of seafood
and from sediments;
River models – simple dilution,
hydraulic models, dynamic models
– simple screening;
1. PLUME average
radioactivity conc. in air.
2. DORIS rad conc in
seawater and sediments.
3. FARMLAND - annual
average
rad conc in the most popular
foodstuffs.
4. GRANIS external gamma
exposure to anindividual from
deposited radioactivity in soil.
5. RESUS annual average
radconc in air due to the
resuspension of
previously deposited activity.
6. ASSESSOR - individual
or collective doses
WG2-Models (cont.)
Model
name
Model
type
Application Transport processes
modelled
Endpoints
calculated
RESRAD
ONSITE
OFFSITE
Suite of modules, e.g.
guassian Plume for atmospheric
discharges,
semi-empirical models for sediment-water
interactions (Kds) and transfer through food
chains (transferfactors) etc
Detailed Solid
waste-near surface
disposal,
surface disposal,landfill –
screeningor detailed
assessment, sitecharacterisation
Surface, near surface Multi soil
compartments with one primarycontaminated soil layer and
secondary contaminated
zone.Time-dependent soil processes: leaching, erosion
and ground water transport.Equilibrium approach for
external irradiation, ingestionand inhalation pathways.
Total annual
effective dose, doseconcentrations from
individual pathways,
activity concentrations in air,
soil and water, etc.
IAEA SRS-19
The SRS models have distinct models for
considering thedispersion of nuclides
following
(i) atmosphericrelease (guassian
plume)(ii) river
(iii) small lake(iv) large lake
(v) estuary
(vi) coastal
Generic-screening
assessment. Routine
release situations
(long operationtimes for
installationsdischarging liquid
radioactivematerial) -
equilibrium
Gaseous and liquid discharge;Atmospheric dispersion of
radionuclides (Gaussian plume)and transfer through terrestrial
food-chains.
Activity concentrations in
soil (atmosphericmodel) water
(aquatic models).
Concentrations insediment, plants and
animals may be appropriately
derived using Kdsand concentration
factors
and others...
1rst scenario:
Gela phosphogypsum landfill
55 hectares, 1 km from the sea
Available data:
• Radionuclide concentration in
phosphogypsum, leachate
• Meteorological, hydrological
Modelling
– Three models (RESRAD, DOSDIM, ReCLAIM)– Model-model intercomparison
– Modeller-modeller intercomparison (RESRAD)– Validation against measurements
WG2-Scenarios
WG2-Scenarios (cont.)
Notwithstanding the WG2 focus on NORM scenarios,
the approaches, methodologies and models (e.g.
RESRAD) can be easily transposed to any situation
with large “source term” in contact with environment.
This is true for the most part of the EMRAS II WG issues.
WG2- methodology and applicability
EMRAS II programme, like EMRAS, is an important opportunity to develop methodologies and compare results but, more
interesting, it is the frame where different approaches and points
of view can be shared.
This is the reason why IAEA will continue to promote this kind of
international exercise after the EMRAS II end (January 2012)
EMRAS III (?) will probably start in 2012.
EMRAS is really open to any researcher who wants to contribute
and it is possible to join a WG in any moment.
http://www-ns.iaea.org/projects/emras/
http://www-ns.iaea.org/projects/emras/emras2/default.asp?s=8&l=63
Conclusions
