Background
Radium-226 (Ra-226) is a member of the uranium-238 (U-238) series decay chain and is found in minute quantities in a wide range of uranium-bearing rocks. Mining and processing of these rocks, for a wide range of industrial purposes, gives rise to waste containing elevated concentrations of Ra-226 relative to those normally found in nature. Radium-226 is also of particular interest in safety assessments for the geological disposal of spent nuclear fuel, where in-growth of U-238 daughters may lead to additional input to the biosphere (the surface environment normally accessed and used by humans) over long timeframes.
Radium-226 is of concern in risk assessments due to its long half-life (1,600 years), its high degree of radiotoxicity and its relative physical and biological mobility. As a trace element, the behaviour of Ra-226 in the environment is complex and affected by many biological and physicochemical factors. An interdisciplinary approach is therefore required in order to make appropriate predictions of long-term environmental impact of Ra-226, based on knowledge of the mechanisms ruling radium mobility and behaviour both in and between different ecosystem components.
Objectives
- To provide an open forum for presentation and discussion of environmental processes governing radium behaviour in the biosphere with a view to improving confidence in prospective long-term safety assessments of public radiation exposure.
- To develop recommendations for the direction of continuing research as input to long-term radiological assessment
Presentations were made on the following subjects:
Proposal for new best estimates of Kd and TF coefficient for Radium |
H. Vandenhove, SCK•CEN, Belgium |
Overview on the radiological effect of the use of phosphogypsum amendments in agriculture |
R. Garcia-Tenorio, Seville University, Spain |
Radium interactions with solid phase |
A. Abdelouas, Subatech, France |
Review of the radiological characteristics of the environment around a former uranium mine site in France : the case of the Saint Pierre site in the Cantal district of France |
M.-O. Gallerand, IRSN, France |
Estimation of soil-to-plant transfer factor of radium-226 |
K. Tagami, NIRS, Japan |
Uranium and its decay products in human food chain |
M. Jeambrun, IRSN, France |
Data requirements to determine effective distribution coefficients for radium in soils |
L. Duro, Amphos21, Spain |
Radium in Animals |
M. Thorne, MTA, UK |
Performance Assessment needs |
G. Smith, GMS Abingdon, UK |
Radium mobility and cycling in re-vegetated mining debris |
Y. Thiry, Andra, France |
Treatment of radium in the Andra biosphere impact assessment |
A. Albrecht, Andra, France |