Over the past decade, the BIOPROTA forum has undertaken a number of projects relating to the behaviour C-14 in the biosphere, both in terms of a review of the assessment models used, and the modelling of C-14 uptake in agricultural crops. To date, the model comparison studies undertaken in BIOPROTA for C-14 have used hypothetical release scenarios, with no data to support the results reported.
Independently of BIOPROTA studies, a number of waste management and research organisations have been further developing their in-house C-14 modelling capabilities, and testing their conceptual models against real world datasets. These have all focussed on modelling the uptake of C-14 into plants, and have utilised both laboratory and field data. The French Institute for Radioprotection and Nuclear Safety (IRSN) in particular, have used the application of their TOCATTA model to the La Hague field data [Les Dizès et al., 2012] to further develop their conceptual model, which is now referred to as TOCATTA-χ [Aulagnier et al., 2013].
The proposed work programme is therefore designed to provide participants with an opportunity to test and potentially validate their models of C-14 dynamics in terrestrial ecosystems using real world data.
The specific objective of this project is, based upon the interests of the participating organisations, to facilitate the validation of aspects of existing terrestrial biosphere models for C-14 using real world data. It may also provide participating organisations with the opportunity to undertake model development during this project, or in the future as a result of this study.
A follow-on project for model-data comparisons for C-14 is planned.
The International Atomic Energy Agency (IAEA) BIOMASS-6 report on reference biospheres for solid radioactive waste disposal was published in 2003 following an extensive international collaborative work program. The report sets out a structured approach for the assessment of impacts of radionuclide releases to the biosphere from radioactive waste disposal facilities. It also includes examples of the application of the methodology, called Example Reference Biospheres (ERBs) and associated results expressed in terms of radiation dose rates to humans for unit release rates of some relevant radionuclides.
With the focus of such assessments being on long-term future biosphere conditions, the methodology was intended to support the development of biosphere models as a measuring instrument, providing assessment results for comparison with protection objectives rather than a prediction of future conditions and exposures.
Given the significant developments in a wide range of factors including technical developments in models for radionuclide migration and accumulation, climate change model treatments and site investigation, characterisation methods and their interpretation, it is considered timely for the reference biospheres methodology to be internationally reviewed and enhanced to take account of this new knowledge and experience.
The first project meeting took place from in April 2016 in Brussels, Belgium (hosted by FANC) after the Annual BIOPROTA meeting.
The workshop report can be downloaded here.
The second workshop was held in conjunction with the first Technical Meeting of the IAEA MODARIA II programme, working group 6). The report from this meeting can be downloaded here. Other project reports on this work are being finalized and will be made available soon.
A third project workshop took place in Switzerland in May 2016, hosted by ENSI. The meeting report can be downloaded here.
Two workshops have been organised though BIOPROTA to consider the non-radiological post-disposal impacts of radioactive waste disposal. The first, held in Slovenia in 2013, addressed the scientific basis for long-term radiological and hazardous waste disposal assessments. Building on that discussion, a second workshop was held in Åsker, Norway in 2015, focussing more precisely on comparison of safety and environmental impact assessments for disposal of radioactive waste and hazardous waste. There it was noted that assessment of post-disposal non-radiological impacts of disposal of radioactive waste is nowadays commonly carried out for all types of radioactive waste, from high level to very low level. In assessing the non-radiological impacts, it has been natural to draw on the methods used to assess those impacts if the waste were not also radioactive. It has also been natural to develop an approach in which non-radioactive pollutants are treated using similar models to those adopted for radioactive materials.
Although assessment methods for radioactive and hazardous waste disposal include similar modelling techniques and other procedures, different protection objectives are applied, leading to different levels of protection. This, in turn, results in inconsistencies and challenges when identifying and applying optimum waste management strategies. Even where the same protection objectives are set, the bases for demonstrating compliance with the objectives, e.g. assessment methods and issues addressed, are often different.
This work aims to provide information that supports the development of a consensus on how to address the issues raised above, leading to the application of more coherent and consistent assessment methods.