Table Of ContentTHE INTERNATIONAL
CHERNOBYL PROJECT
AN OVERVIEW
ASSESSMENT OF RADIOLOGICAL CONSEQUENCES
AND EVALUATION OF PROTECTIVE MEASURES
REPORT BY AN INTERNATIONAL ADVISORY COMMITTEE
THE INTERNATIONAL CHERNOBYL PROJECT
AN OVERVIEW
Assessment of Radiological Consequences
and Evaluation of Protective Measures
Report by an International Advisory Committee
ST1/PUB/884
ISBN 92-0-129091-8
Printed by the IAEA in Vienna
© IAEA, 1991
THE INTERNATIONAL CHERNOBYL PROJECT
AN OVERVIEW
Assessment of Radiological Consequences
and Evaluation of Protective Measures
Report by an International Advisory Committee
Acknowledgements
The International Advisory Committee wishes to thank the large number of people who were involved in so
many different ways in the International Chernobyl Project — the governments, institutions and organizations who
donated the time of their staff and the many individuals who gave of their own time for this important work. Gratitude
is expressed to the governments and commercial companies which provided equipment and supplies, without which
some major parts of the work could not have been carried out. The complete acknowledgement list is included in
the Technical Report.
It is impossible to overestimate the value of the assistance and contribution of the many authorities at the Ail-
Union and Republic levels, and the scientists, experts, technical and administrative staff and members of the public
who co-operated with the visiting Project teams. Thanks are also due to the population and the authorities (including
physicians, nurses and other staff of hospitals and polyclinics) in the settlements visited.
A considerable debt of gratitude is due to the IAEA Secretariat, who overcame the many difficulties inherent
in an effort of such complexity.
Preface
by the Chairman of the
International Advisory Committee
It was my privilege to act as Chairman of the International Advisory Committee (IAC), which was composed
of prominent experts in different fields. They were called together by the various participating organizations of the
United Nations system and the Commission of the European Communities. The IAC approved the work plan for the
International Chernobyl Project described in the present Overview and monitored its implementation. The aims of
the Project were to examine assessments of the radiological and health situation in areas of the USSR affected by
the Chernobyl accident and to evaluate measures to protect the population.
The task assigned to the IAC was a formidable one. There were unavoidable constraints on the time, man-
power and funds available for the assignment. The Project was centred on questions of continuing mass relocation
of people and sought to provide sound scientific bases for decisions yet to be made.
The Project teams applied their collective expertise and experience to sort facts from misconceptions and
radiation effects from effects not related to radiation exposure. They obtained and examined vast quantities of data
in their task to understand the present situation and to draw conclusions on the further steps that might be taken
to alleviate the consequences of the Chernobyl accident.
The IAC set out to conduct an independent, scientifically authoritative study and to provide a readily under-
standable report that could assist the authorities in deciding how to proceed. Only time will show the significance
of our contribution.
My profound thanks go to all those who contributed to this work: the members of the Committee; the
consultants; the task leaders; the team leaders and all the experts who participated; the secretariat of the Project;
and the many officials of the USSR, the BSSR, the RSFSR and the UkrSSR who gave their time and efforts to assist
the Project.
Itsuzo Shigematsu
Radiation Effects Research Foundation
Hiroshima, Japan
Editorial Note
This Overview presents the conclusions and recommendations of the International Advisory Committee which
directed the project on the Radiological Consequences in the USSR from the Chernobyl Accident: Assessment of
Health and Environmental Effects and Evaluation of Protective Measures (hereinafter referred to as 'the International
Chernobyl Project'). For a more detailed scientific account, the reader is referred to the full Technical Report, in which
the various technical chapters have been written by the relevant task leaders of the Project. It is the primary authorita-
tive document of the Project. While the wording of the conclusions and recommendations presented in the Overview
has been agreed upon by the members of the Committee, the additional parts of the document were compiled from
the Technical Report and provide a summary of the evidence on which the conclusions and recommendations are
based.
CONTENTS
Chapter One: The International Chernobyl Project 1
Chapter Two: Environmental Contamination 10
Chapter Three: Radiation Exposure of the Population 19
Chapter Four: Health Impact 27
Chapter Five: Protective Measures 36
Appendix: Historical Portrayal 47
Epilogue 55
International Advisory Committee 57
Chapter One:
The International Chernobyl Project
Introduction tives of the USSR, the BSSR, the UkrSSR and the IAEA
took part in discussions on the goals of the Project and
The accident at the Chernobyl power plant occurred the methods to be used in achieving them.
on 26 April 1986. A brief chronology of some relevant
events up to the inception of the International Chernobyl The Government of the USSR had already benefited
Project is given overleaf and a more extensive account from international assistance with this problem. The
is presented in the Appendix. WHO sent a team of experts in June 1989, as did the
In October 1989, the Government of the USSR for- League of Red Cross and Red Crescent Societies in early
mally requested the International Atomic Energy 1990. The final report of the WHO group concluded
Agency (IAEA) to carry out: inter alia that: "... scientists who are not well versed
in radiation effects have attributed various biological and
"... an international experts' assessment of the health effects to radiation exposure. These changes
concept which the USSR has evolved to enable the cannot be attributed to radiation exposure, especially
population to live safely in areas affected by radio- when the normal incidence is unknown, and are much
active contamination following the Chernobyl more likely to be due to psychological factors and stress.
accident, and an evaluation of the effectiveness of the Attributing these effects to radiation not only increases
steps taken in these areas to safeguard the health of the psychological pressure in the population and pro-
the population." vokes additional stress related health problems, it also
undermines confidence in the competence of the radia-
The response was a proposal for a multinational team to tion specialist." The Report of the League of Red Cross
undertake an assessment of the radiological situation in and Red Crescent Societies indicated inter alia that:
the three affected Soviet Republics — the Ukrainian "Among the health problems reported it was felt that
Soviet Socialist Republic (UkrSSR), the Byelorussian many of these, though perceived as radiation effects both
Soviet Socialist Republic (BSSR) and the Russian Soviet by the public and by some doctors, were unrelated to
Federated Socialist Republic (RSFSR). The Interna- radiation exposure. Little recognition appears to have
tional Chernobyl Project was thus arranged, with the been given to factors such as improved screening of the
participation of the Commission of the European Com- population and changed patterns of living and of dietary
munities (CEC), the Food and Agriculture Organization habits. In particular, psychological stress and anxiety,
of the United Nations (FAO), the International Labour understandable in the current situation, cause physical
Office (ILO), the United Nations Scientific Committee symptoms and affect health in a variety of ways."
on the Effects of Atomic Radiation (UNSCEAR), the It was clear that the assessment of the Chernobyl acci-
World Health Organization (WHO) and the World dent had already involved extensive efforts and it would
Meteorological Organization (WMO). The Project was not be necessary for the Project to undertake a totally
formalized at a February 1990 meeting in Moscow at the new, comprehensive assessment of the situation. Rather,
headquarters of the USSR State Committee on the Utili- the task would be to assess the quality and correctness
zation of Atomic Energy. Some twenty-five representa- of the existing results. Secondly, to be manageable, the
1
Chapter One: The International Chernobyl Project
CHRONOLOGY OF MAJOR EVENTS
26 April 1986 Accident occurs 01:23. Governmen- April 1987 Completion of the work begun in
tal Commission formed May 1986 for protecting the water
system
27 April 1986 Evacuation of Pripyat takes place
6 May 1986 End of 10 days of atmospheric December 1987 Revision of the 'temporary per-
release of radioactive material from missible levels' established 31 May
the core 1986
6 May 1986 Introduction of 'temporary permissi- _
'Temporary dose limits' for the
ble levels' for drinking water and
population reduced to 25 mSv annual
foodstuffs total dose
6 May 1986 Evacuation of the population within
September 1988 Council of Ministers of USSR adopts
the prohibited zone completed
the 350 mSv lifetime dose for
31 May 1986 Revision of 'temporary permissible
relocation to be implemented as of
levels'
1 January 1990
May 1986 'Temporary dose limits' for the
March 1989 Contamination maps officially pub-
population set at 100 mSv (internal
lished in the three Republics
and external) annual total dose
July 1986 First summarized contamination map April 1989 BSSR Academy of Sciences registers
(not published until 1989) disagreement with the 350 mSv life-
time dose concept and makes new
November 1986 •Completion of the 'sarcophagus'
proposals
construction
- 1987 - 'Temporary dose limits' for the October 1989 USSR requests the IAEA to organize
population reduced to 30 mSv annual an international assessment of the
total dose (subsequently lowered to consequences of the accident and the
25 mSv for 1988) protective measures taken
international assessment would have to focus on the key Supreme Soviet, travelled on a fact finding mission
issues of concern to the population and policy makers, through the affected Republics over the period
namely: the true extent of the contamination; the past, 25-30 March 1990. Their visit enabled them to learn
current and future radiation exposure of the population; first hand about the requirements of the Project. The
the actual and potential health effects; and the adequacy group met with officials in Moscow and the Republic
of measures being taken to protect the public. capitals and with representatives of scientific organiza-
The work of recommending an approach for examin- tions, hospitals, clinics and agricultural centres in the
ing these issues was given to a group of ten scientists, affected areas and in the cities of Kiev, Gomel and
who, accompanied by two members of the USSR Moscow.
