Skip to main content

Global Dispersion Models for I-129 and C-14

Objective

The objective of this project is to provide up-to-date models for assessing the radiological impact arising from the global circulation of carbon-14 and iodine-129. These radionuclides are long-lived and mobile in the environment. This gives them the potential to deliver significant collective doses to the world's population over long timescales, if released either directly to the environment or from a geologic repository for solid radioactive waste. In this project the National Radiological Protection Board (NRPB) is collecting information on existing models and parameter values for the global circulation of carbon-14 and iodine-129, in order to develop up-to-date models. The influence of environmental changes over long timescales, for example, climatic changes, is also being considered. The final report will contain a description of the proposed models, their parameter values and example results.
The objective of this project is to provide up to date models for assessing the radiological impact arising from the global circulation of carbon-14 and iodine-129. These radionuclides are long lived and mobile in the environment. This gives them the potential to deliver significant collective doses to the world's population over long timescales, if released directly to the environment or from a geologic repository for solid radioactive waste. Information has been collected on existing models and parameter values for the global circulation of carbon-14 and iodine-129, in order to develop up to date models. The influence of environmental changes over long timescales, for example, climatic changes, is also being considered.

Several models for predicting the global circulation of stable carbon and carbon-14 have been identified. The models were solved using a matrix inversion method for solving systems of coupled linear first order differential equations. Predictions of stable carbon and carbon-14 distribution between the different environmental compartments were obtained for both models. Literature searches and consultations with individuals and organizations have revealed only two available models to predict the global circulation of iodine-129. Parameter values for the global circulation of iodine-129 have been examined by reviewing the concentrations of stable iodine in different parts of the environment. Information on the origin of iodine in soil is also being collated since some measurements indicate that the iodine in soil is derived from sedimentary rocks and not from the marine environment.
Work programme:

- Consultation and literature search to identify available models, their implementation on the NRPB computer and comparison of their results,

- Consultation and literature search for information on important processes in the global circulation of carbon and iodine and for parameter values for use in models identified,

- Review of models obtained in the light of information on important processes and parameters selected and construction of 'state of the art' models,

- Calculation of collective doses using the 'state of the art' models considering possible future climatic scenarios and quantification of possible ranges of results,

- Preparation of final report.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

NATIONAL RADIOLOGICAL PROTECTION BOARD
Address
Chilton
OX11 0RQ Didcot,harwell,chilton
United Kingdom