Workshop on Tritium and Carbon - EMRASBucharest May 2007 TRITIUM MODEL IN RODOS SYSTEM Dan Slavnicu D.Galeriu, D.Gheorghiu, A.Melintescu National Institute

Workshop on Tritium and Carbon - EMRAS Bucharest May 2007

TRITIUM MODEL IN RODOS SYSTEM

Dan SlavnicuD.Galeriu, D.Gheorghiu, A.Melintescu

National Institute of R&D for Physics and Nuclear EngineeringIFIN - HH ROMANIA


Experience gained after the Chernobyl accident clearly demonstrated the importance of improving administrative, organisational and technical emergency management arrangements in Europe.

Under the auspices of its RTD (Research and Technological Development) Framework Programmes, the European Commission has supported the development of the RODOS (Real-time On-line DecisiOn Support) system for off-site emergency management.

Tritium in RODOS System


The main objectives of the RODOS project were :

• to develop a comprehensive and integrated decision support system that is generally applicable across Europe,

• to provide a common framework for incorporating the best features of existing decision support systems and future developments,

• to provide greater transparency in the decision process as one input to improving public understanding and acceptance of off-site emergency measures,

• to facilitate improved communication between countries of monitoring data, predictions of consequences, etc., in the event of any future accident,

• to promote, through the development and use of the system, a more coherent, consistent and harmonised response to any future accident that may affect Europe.



Participation and geographical coverage increased progressively during the 3rd and 4th European Commission Framework Programmes. By the end of the 4th Framework Programme, some 40 institutes from about 20 countries in the Union and in Eastern Europe were actively involved in the project.

The development of the RODOS system continued during 5th and 6th Framework. The RODOS PV6.0 is in preparation for the final version.

The EC project EURANOS (European Approach to Nuclear and Radiological Emergency Management and Rehabilitation Strategies) has as one of the key strategies the further enhance advanced decision support system, in particular RODOS, through feedback from their operational use.



The RODOS system can provide decision support at four distinct levels:

• Level 0: acquisition and checking of radiological data and their presentation, directly or with minimal analysis, to decision makers, along with geographical and demographic information.

• Level 1: analysis and prediction of the current and future radiological situation (i.e., the distribution over space and time in the absence of countermeasures) based upon information on the source term, monitoring data, meteorological data and models.

• Level 2: simulation of potential countermeasures (e.g., sheltering, evacuation, issue of iodine tablets, relocation, decontamination and food-bans), in particular, determination of their feasibility and quantification of their benefits and disadvantages.

• Level 3: evaluation and ranking of alternative countermeasure strategies by balancing their respective benefits and disadvantages (e.g., costs, averted dose, stress reduction, social and political acceptability) taking account of societal preferences as perceived by decision makers.



The conceptual RODOS architecture is split into three distinct subsystems which are denoted by Analysing Subsystem (ASY), Countermeasure Subsystem (CSY) and Evaluating Subsystem (ESY).

ASY analysing subsystem

CSY countermeasure subsystem

ESY evaluating subsystem

data base

OSYoperatingsubsystem

communication interface

users with different capabilities



The transfer of radionuclides from the plume to terrestrial foods, as well as the resulting radiation exposure, are modelled in the Terrestrial Food Chain and Dose Module, FDMT, which comprises the Deposition Module, the Food Chain Modules, and the Dose Modules.

An additional specialised radioecological model has been developed for semi-natural (forest) pathways, FDMF. It considers transfer of radionuclides to mushrooms, berries and game and quantifies the internal and external exposure from contaminated forests.

After reviewing the present status of tritium modelling for emergency response purposes, a dedicated module describing the transfer of tritium through foodchains, FDMH, has also been developed. The dose combination module, DCM, combines results from these and the FDMT food chain and dose modules.

Atmospheric Dispersion Module

Terrestrial Food Chain

Module

Aquatic

Food Chain

Module

Forest Food Chain

and Dose

Module

Tritium

Food Chain

and Dose

Module

Terrestrial Dose

Module

Aquatic

Dose

Module

Countermeasure Subsystem CSY

Dose Combination Module

FDMH FDMF FDMA FDMT

Hydrological Module



The main results of FDMH are:• Maps of the specific activities in a chosen plant or animal product.

The results can be given for both OBT and HTO• Time dependency plots of specific activities in a chosen plant or

animal product. The results can be given for both OBT and HTO• Maps of individual doses. The results are given for one of 7

populations groups, for different time steps and for both OBT and HTO.

• Time dependency plots of individual doses for different time steps and for both OBT and HTO.



HTO in Cow’s milk distribution



OBT in Cow’s milk distribution



ConvEX-3 Exercise

In May, 2005, the International Atomic Energy Agency of the United Nations has conducted a comprehensive nuclear alert exercise code-named ConvEX 3.

More than 20 countries in Europe and off its shores were actively participating, in an attempt to verify the capability of assessment and reaction to a significant abnormal event in a nuclear facility.



ConvEX-3 Exercise

The choice of the nuclear power reactor (A CANDU type) at the Cernavoda Nuclear Power Plant, Romania, as the target for a disruptive scenario entailing significant radioactive releases and off site consequences has placed special responsibilities on both the Romanian authorities, paramountly including the National Commission for Nuclear Activity Control (CNCAN), the Civil Defense system and the expert assistance pool normally on standby in several research institutes, including NIPNE.



Assessment of the tritium dose from inhalation



Assessment of the tritium dose from ingestion



RODOS - HYDRO: Hydrological model chain

The individual models cover the relevant transfer processes in the hydrosphere, such as :

RETRACE-1 and RETRACE-2 run-off of radionuclides from watersheds following deposition from the atmosphere for small and large watersheds;

RIVTOX transport of radionuclides in river network;

The resulting contamination of water and fish is input to the Aquatic Food Chain and Dose Module FDMA, which simulates the transfer of radionuclides from contaminated water and fish to man and the resulting radiation exposure.



In the case of tritium, the release from CANDU NPP could be directly in the Danube River or due to run-off processes of radionuclide from watersheds, following an atmospheric deposition and transport of tritium in river system.

More recently we developed AQUATRIT, a dynamic model for the transfer of tritium (including organic forms) in the aquatic food chain.




Processing flow:

Transfer to ARCGIS 9.3: thematic maps generation for

different time intervals

RODOS HYDRO: RIVTOX used for simulating the

transport of tritium.

AQUATRIT: assessment of the tritium transfer in

environment


Tritium propagation downstream Danube:


5 Days after the emission

10 days after the emission

12 h after the emission

8 days after the emission


Graph of GALATI

phytoplancton

zooplancton

zoobentos

moluscus

non-predatory fish

predatory fish

bentic alge

prey fish

Bq/

kg days

0.00001

0.0001

0.001

0.01

0.1

1

10

100

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99

2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98100

Time evolution of OBT for different biological species


Documents

Workshop on Tritium and Carbon - EMRASBucharest May 2007 TRITIUM MODEL IN RODOS SYSTEM Dan Slavnicu D.Galeriu, D.Gheorghiu, A.Melintescu National Institute