International Advisory Committee (IAC) (1998), The Radiological Situation in the Atolls of Mururoa and Fangataufa, Main Report, Radiological Assessments Reports Series No. STI/PUB/1028 | 92-0-101198-9, International Atomic Energy Agency (IAEA), Vienna, 282 pp. [The members of Working Group 4 (Geosphere radionuclide transport) of Task Group B (Evaluation of potential long term radiological situation) who contributed to Section 6 of the Main Report were Fairhurst, C., de Marsily, G., Hadermann, J., Nitsche, H., Sastratenaya, A.S., and Townley, L.] The Main Report is available online.

Between 1966 and 1996, France conducted 193 'expériences nucléaires' (nuclear experiments - a term used by the French authorities to include the full testing of nuclear weapons and the conduct of certain safety trials) above and beneath the atolls of Mururoa and Fangataufa in the Tuamotu Archipelago of French Polynesia. All French testing ceased on 27 January 1996. Before the completion of the last series of tests the Government of France requested the International Atomic Energy Agency (IAEA) to conduct a study to assess the radiological impact of the tests.

The IAEA agreed to carry out a study - the Study of the Radiological Situation at the Atolls of Mururoa and Fangataufa - for the purpose of ascertaining whether, as a consequence of the tests, radiological hazards exist now or will exist in the future, and making recommendations on the form, scale and duration of any monitoring, remedial action or follow-up action that might be required. An International Advisory Committee (IAC) was convened by the Director General of the IAEA to provide scientific direction and guidance to the IAEA in the conduct of the Study and to prepare a report on the Study's findings, conclusions and recommendations.

The IAC's first formal meeting took place in Vienna on 13-14 April 1996 and its final one, also in Vienna, on 3-5 February 1998. This publication constitutes one of several reports of the IAC to the Director General describing the conduct of the Study and its findings, conclusions and recommendations.

The terms of reference of the Study called for an evaluation of the radiological situation at the atolls (and in other involved areas). It is important to emphasize that it is the radiological situation at the atolls, both as it is at present and as it might develop in the long term, including its consequences for human health, that the Study was required to address, and not any past radiological consequences of the French nuclear testing programme. This had two implications for the Study.

First, it was not within the terms of reference of the Study to attempt to assess retrospectively doses received by inhabitants of the region as a result of the atmospheric nuclear tests at the time when those tests were carried out. Those doses were due in part to short lived fallout - for example, radioactive iodine (especially ¹³¹I, which has a half-life of eight days). However, the Secretariat of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) did provide the IAC with the results of a review of such doses that had been received by people in the South Pacific region in the past. The IAC believes that readers will be interested in these results, and it has therefore included them in an annex to the Main Report on the Study. The results are accepted by the IAC as providing an objective and balanced view of the situation.

Second, the IAC felt that the most informative indicator of the radiological situation at the atolls would be the present and future individual annual effective doses that people (real and hypothetical) at the atolls and in other involved areas might receive as a consequence both of the radioactive material that is now in the accessible environment and of that which might be released into the accessible environment over time from underground. It should be noted that while UNSCEAR has invoked other dosimetric quantities - the 'effective dose commitment' and the 'collective effective dose commitment' - in assessing the global impact of nuclear weapon testing, the IAC did not consider it appropriate to use these quantities in any reports of the Study for the reasons discussed in Section 1 of the Main Report.

The French Government provided much of the information used in the Study. This information was independently evaluated by Study participants and, where practicable, validated. For example, to provide a basis for the evaluation of French environmental monitoring data, the IAEA carried out an environmental sampling and surveillance campaign to measure independently contemporary levels of radioactive material present in the environment of the atolls. Also, with the co-operation of French scientists, samples of underground water were collected by Study participants from two test cavity-chimneys beneath the rim of Mururoa, and from deep in the carbonate layer beneath the two lagoons. These samples were analysed for a number of radionuclides, and the results provided an independent check on the validity of assumptions made in some of the Study's calculations, for example of radionuclide concentrations in the cavity-chimney of each test. The French Government allowed complete access to the atolls for these surveys and provided the necessary logistic support.

In addition to the information provided by the French Government, a small amount of information had been published in the open literature on measured levels of certain radionuclides (⁶⁰Co, ⁹⁰Sr, ¹³⁷Cs and ^239+240Pu) in the environment of the atolls, and reports of three scientific missions to the atolls - the Tazieff Mission of June 1982, the Atkinson Mission of October 1983 and the Cousteau Mission of June 1987 - were in the public domain. Issues raised by these missions guided the IAC in the choice of certain topics to be addressed in the Study.

It is not possible to place reliable quantitative limits on the errors associated with the dose assessments carried out by the Study. The estimated upper limits to contemporary doses can be accepted with confidence as they are based on measurements of the concentrations of residual radioactive material at present in the environment of the atolls. However, considerable uncertainty is possible in the estimation of future doses because of the complexities of the physical processes involved in releases from underground sources and the limitations of the geological migration models used. Therefore, in the absence of definitive information, conservative assumptions have been made and the estimated future doses can be regarded as upper limit values. In any event, they are so small that large errors in the assumptions made would not affect the IAC's basic finding that possible radiation doses to people now, and potential doses at any time in the future, arising from the conditions at the atolls are a very small fraction of the doses people already receive from natural radiation sources.

The Main Report (which includes the Executive Summary) is a distillation of the large amount of scientific work carried out in the course of the Study, which is described in detail in the accompanying six-Volume Technical Report. The Summary Report presents a comprehensive summary of the Main Report, including its findings, conclusions and recommendations.