Measuring Radiation: Improved Models Help Correct Assessment

Measuring Radiation: Improved Models Help Correct Assessment

Caption: Participants at the Modelling and Data for Radiological Impact Assessment meeting held at the IAEA headquarters in Vienna. (Photo: J. Castillo/IAEA)

Measuring the level of radioactivity during the routine discharges of radionuclides in the environment is a prerequisite for the assessment and evaluation of radiological impacts. Participants at an IAEA Modelling and Data for Radiological Impact Assessment (MODARIA) workshop this week compared and evaluated methods to estimate the impact of radionuclide exposures on people and the environment.

“Assessment modelling tools, like MODARIA contribute to strengthening global efforts to control public exposure to radionuclides, which are or have been released into the environment,” said Peter Johnston, Director of the IAEA Division of Radiation, Transport and Waste Safety. “These tools are vital for decision makers to support swift action and respond rapidly to emergencies or other incidents from nuclear related applications.”

Radio-ecological models as discussed in the MODARIA programme are widely used. The results of such assessments help to evaluate the radiological relevance of routine or accidental radionuclides releases. The results are also an essential part of safety assessments, which is an integral part of licensing any operation of nuclear facilities to meet compliance with international safety standards.

Models are used – in combination with measurements – to assess exposure to people, when areas have been contaminated. This in turn, helps support Member States in planning and performing remediation work. “We have to demonstrate and take the necessary steps to adequately protect the people and the environment from radiation, which is the key to the Basic Safety Standards,” Johnston added.

Over 150 experts, including regulators, operators and scientists, from over 40 countries have come together to exchange ideas and experiences at the week-long meeting.

Participating experts are sharing scientific papers, progress in their work, as well as information on topics from other scientific meetings. “Sharing information helps in informing the public about the IAEA Safety Standards, which are developed to enhance safety for people and the environment when using nuclear applications,” said Jane R. Simmonds, the Chairperson of MODARIA and former Head of Environmental Assessments Department at the Centre for Radiation, Chemical and Environmental Hazards in the United Kingdom. It also generates transparency in the scientific community, which builds trust among researchers and decision makers, she added.

Data strengthens remediation strategies

Following nuclear power plant accidents like Chernobyl in 1986 and Fukushima Daiichi in 2011, scientists and regulators have developed newer methods to assess radiation levels. “Such analysis after a nuclear emergency can also enable decision makers to take careful and critical steps for effective remediation action,” highlighted Simmonds.

MODARIA is the latest of the several international modelling and assessment projects launched by the IAEA over the past 30 years to measure and examine radioactive levels.

Determining radiological impacts to humans and the environment requires an understanding of the complex interaction between the properties of the radionuclides involved, the environmental conditions, agricultural practices and human habits. “To characterize specific exposure situations, many model parameters are needed to quantify the transfer of radionuclides within an ecosystem,” explained Gerhard Proehl, Head of the Assessment and Management of Environmental Release Unit at the IAEA. “Radio-ecological models provide data for assessments so that Member States are in compliance with national and international regulatory standards, when applying nuclear techniques.”

MODARIA’s objective has been to further improve the methodologies for radiological impact assessment, strengthen remediation strategies for effective national planning and response, and to develop conceptual tailor-made solutions for Member States.

Next step

The current MODARIA project has 10 working groups that focus on a range of diverse but inter-related issues such as the routine discharges of radionuclides into the environment, the need for possible contingency measures; the special cases of contamination of urban environments and legacy sites; and the use of the radionuclide data that has been published in various IAEA reports.

The follow-up programme MODARIA II will continue to foster, develop and maintain capabilities to assess released radionuclides. Experienced assessors and those who are new in the field have expressed great interest in MODARIA-type modelling exercises, Proehl said.

“We need to develop a programme that assimilates science to address the regulator’s needs,” added Simmonds. “The development of long term global safety standards, involves continuous monitoring of radioactive releases and it is necessary for us to be alert and prepared for any kind of emergencies or incidents that can happen.”

MODARIA II is scheduled to take place in Vienna from 31 October to 4 November 2016. 

Radio-ecological models also provide data for assessments so that Member States are in compliance with national and international regulatory standards.
Gerhard Proelh, Head, IAEA Assessment and Management of Environmental Release Unit
Last update: 11 November 2015