THE CRITICALITY ACCIDENT IN SAROV INTERNATIONAL ATOMIC ENERGY AGENCY THE CRITICALITY ACCIDENT IN SAROV The following States are Members of the International Atomic Energy Agency: AFGHANISTAN GUATEMALA PANAMA ALBANIA HAITI PARAGUAY ALGERIA HOLY SEE PERU ANGOLA HUNGARY PHILIPPINES ARGENTINA ICELAND POLAND ARMENIA INDIA PORTUGAL AUSTRALIA INDONESIA QATAR AUSTRIA IRAN, ISLAMIC REPUBLIC OF REPUBLIC OF MOLDOVA BANGLADESH IRAQ ROMANIA BELARUS IRELAND RUSSIAN FEDERATION BELGIUM ISRAEL SAUDI ARABIA BENIN ITALY SENEGAL BOLIVIA JAMAICA SIERRA LEONE BOSNIA AND HERZEGOVINA JAPAN SINGAPORE BRAZIL JORDAN SLOVAKIA BULGARIA KAZAKHSTAN SLOVENIA BURKINA FASO KENYA SOUTH AFRICA CAMBODIA KOREA, REPUBLIC OF SPAIN CAMEROON KUWAIT SRI LANKA CANADA LATVIA SUDAN CHILE LEBANON SWEDEN CHINA LIBERIA SWITZERLAND COLOMBIA LIBYAN ARAB JAMAHIRIYA SYRIAN ARAB REPUBLIC COSTA RICA LIECHTENSTEIN THAILAND COTE D’IVOIRE LITHUANIA THE FORMER YUGOSLAV CROATIA LUXEMBOURG REPUBLIC OF MACEDONIA CUBA MADAGASCAR TUNISIA CYPRUS MALAYSIA TURKEY CZECH REPUBLIC MALI UGANDA DEMOCRATIC REPUBLIC MALTA UKRAINE OF THE CONGO MARSHALL ISLANDS UNITED ARAB EMIRATES DENMARK MAURITIUS UNITED KINGDOM OF DOMINICAN REPUBLIC MEXICO GREAT BRITAIN AND ECUADOR MONACO NORTHERN IRELAND EGYPT MONGOLIA UNITED REPUBLIC EL SALVADOR MOROCCO OF TANZANIA ESTONIA MYANMAR UNITED STATES OF AMERICA ETHIOPIA NAMIBIA URUGUAY FINLAND NETHERLANDS UZBEKISTAN FRANCE NEW ZEALAND VENEZUELA GABON NICARAGUA VIET NAM GEORGIA NIGER YEMEN GERMANY NIGERIA YUGOSLAVIA GHANA NORWAY ZAMBIA GREECE PAKISTAN ZIMBABWE The Agency’s Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of the Agency are situated in Vienna. Its principal objective is “to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world’’. © IAEA, 2001 Permission to reproduce or translate the information contained in this publication may be obtained by writing to the International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, Austria. Printed by the IAEA in Austria February 2001 STI/PUB/1106 THE CRITICALITY ACCIDENT IN SAROV INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 2001 VIC Library Cataloguing in Publication Data The criticality accident in Sarov. — Vienna : International Atomic Energy Agency, 2001. p. ; 24 cm. STI/PUB/1106 ISBN 92–0–100101–0 Includes bibliographical references. 1. Nuclear industry — Russia (Federation) — Accidents. 2. Radiological Accident, Sarov, Russia (Federation), 1997. I. International Atomic Energy Agency. VICL 00–00257 FOREWORD On 17 June 1997 a physicist working as a senior technician at the Nuclear Centre, Sarov, in the Russian Federation, was severely exposed as a result of a criticality accident with an assembly of high enriched uranium. The exposure, which caused a high neutron radiation dose, led to death within three days despite prompt medical attention. The Russian authorities requested urgent assistance from the IAEA under the terms of the 1986 Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency to provide the Clinical Department of the Institute of Biophysics of the Ministry of Health in Moscow with specialized medicines and other diagnostical supplies in the attempt to save the patient’s life. Information on the circumstances of the accident and the medical management of the patient was provided to the IAEA. This is the first of two criticality accidents (the other being the accident at Tokaimura in Japan in 1999) on which the IAEA has now issued reports, and it is intended that the reports will contribute to preventing such accidents in the future. The IAEA wishes to express its gratitude to the Russian authorities for their forthcoming and helpful attitude, which will enable other Member States to benefit from the lessons that can be drawn from the accident. The IAEA also wishes to acknowledge the contributions of physicians, dosimetrists and radiation safety specialists from the Russian Federation and other countries to the drafting and review of this report. The IAEA officer responsible for the preparation of this publication was I. Turai of the Division of Radiation and Waste Safety. EDITORIAL NOTE This report is based on information made available to the IAEA by or through the authorities of the Russian Federation. Neither the IAEA nor its Member States assume any responsibility for consequences which may arise from its use. The report does not address questions of responsibility, legal or otherwise, for acts or omissions on the part of any person. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA. CONTENTS 1. INTRODUCTION . 1 1.1. Background . 1 1.2. Objective . 1 1.3. Scope . 2 1.4. Structure . 2 2. RADIATION PROTECTION AND REGULATORY CONTROL IN THE RUSSIAN FEDERATION . 2 3. THE SITE OF THE ACCIDENT . 6 3.1. The Russian Federal Nuclear Centre . 6 3.2. The critical assembly . 7 4. CIRCUMSTANCES OF THE ACCIDENT . 10 5. RESPONSE TO THE ACCIDENT . 11 6. DOSIMETRIC ANALYSIS . 14 6.1. Evaluation of radiation fields during the criticality event . 14 6.2. Dose estimates obtained by physical means . 17 6.3. Dose estimates obtained by biological dosimetry . 22 6.4. Dose estimates obtained by retrospective dosimetry . 23 7. MEDICAL TREATMENT OF THE PATIENT . 25 7.1. Introduction . 25 7.2. Medical response at Sarov . 25 7.3. Specialized hospital treatment in Moscow . 26 8. FINDINGS OF THE POST-MORTEM INVESTIGATION (AUTOPSY) . 33 8.1. Internal organs . 33 8.2. Arms after amputation . 35 9. FINDINGS AND LESSONS TO BE LEARNED . 36 9.1. Operating organizations . 36 9.2. The medical community . 39 REFERENCES . 42 CONTRIBUTORS TO DRAFTING AND REVIEW . 45 1. INTRODUCTION 1.1. BACKGROUND In the course of the development and application of atomic energy and nuclear technologies, a number of radiation accidents have occurred, many of which have been documented in the scientific and medical literature. Some of these accidents have resulted in significant health effects and, occasionally, in fatal outcomes. Very few such accidents, however, have been criticality accidents (such as, for example, a self-sustaining uncontrolled chain reaction in an experimental reactor, in an assembly of fissile material or in fissile materials in a chemical process). One function of the IAEA since 1987 has been the investigation of the causes and consequences of serious radiation accidents. Accidents that occurred over the period 1940 to 1969 have been discussed in the course of conferences and symposia held by the IAEA [1–3] and included serious criticality accidents in the United States of America and in Belgium [4–7]. Over the period 1970 to 1989 three further criticality accidents were documented, two in the former Soviet Union and one in Argentina, although the information available on both of these is limited [8, 9]. In recent years the IAEA has directed its attention to a number of radiation accidents that have occurred in the industrial and medical use of radioactive sources. IAEA reports have highlighted issues relating to regulatory control, safety procedures and training. Reports on radiation accidents such as those that occurred in Goiânia in Brazil, El Salvador in San Salvador, Hanoi in Viet Nam, Nesvizh in Belarus, Tammiku in Estonia and San José in Costa Rica [10–17] have considered the causes and consequences of the accidents and the clinical course and medical management of severely overexposed persons, and derived lessons to be learned. On 17 June 1997 a criticality accident occurred at the Russian Federal Nuclear Centre (formerly known as Arzamas 16) in the town of Sarov, near Nizhnij Novgorod, about 400 km east of Moscow. The accident happened in a routine manipulation of the components of a critical assembly. The overexposed man, a skilled technician, died 66 h later from the effects of his exposure, despite prompt and intensive medical management. This was thus a very rare type of fatality. 1.2. OBJECTIVE The objective of this report is to provide information to national authorities and regulatory organizations, emergency planners, research workers in the field of nuclear physics, and a broad range of specialists, including physicists, technicians and medical specialists, and people responsible for nuclear safety and radiation 1 protection. In particular, the report concludes with lessons to be learned so that steps can be taken to avoid such accidents in the future and to minimize the consequences of any such accidents that do occur. 1.3. SCOPE The report describes the immediate response to the emergency, including the actions taken to return the facility to a safe condition. It describes various technical aspects of the accident, response and medical management of the patient, and gives lessons to be learned. It does not consider the direct causes of the accident or the reasons or responsibility for actions or omissions on the part of any person. 1.4. STRUCTURE The report gives a brief description of the relevant regulatory arrangements in the Russian Federation (Section 2). It then describes the facility in which the accident occurred (Section 3), the circumstances of the accident itself (Section 4) and the measures taken to make the facility safe (Section 5). It gives an account of the physical