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The Chornobyl Accident: A Comprehensive Risk Assessment
Annals of Nuclear Energy 28 (2001) 89±91 www.elsevier.com/locate/anucene
Book review The Chornobyl Accident: A Comprehensive Risk Assessment G.J. Vargo (Ed.); Battelle Press, Columbus, OH, USA, 2000 Use of the Ukrainian transliteration `Chornobyl' rather than the more familiar Russian transliteration `Chernobyl' reveals that this book is a Ukrainian account of the accident and its aftermath. It was written by a group of Ukrainian specialists who have been involved on a ®rst-hand basis for the last 13 years. Following a brief introduction, Chapter 2 provides a detailed account of the chronology and causes of the accident and of the radionuclide releases that occurred. A strong emphasis is placed on weaknesses in the design of RBMK reactors and in safety management systems that provided a context within which such a catastrophic accident could happen. The authors comment that the design included several substantial deviations from the safety requirements in force at the time and that the signi®cance of these deviations was never analysed. Furthermore, they note that almost all these design ¯aws were known before the accident as were the measures required to eliminate them. In their view, the main reason that the accident occurred was excessive reliance on administrative controls and human performance rather than engineered safety features and automatic control systems. Underlying this was a seriously ¯awed safety culture during both the construction and operational phases. Organisations concerned with the construction and operation of the plant were only responsible for their own work, and there was no single person or organisation with overall responsibility for safety. Various government ministries were the only entities with high-level decision-making authority and these were distant from plant construction and operations. Detailed information is provided on the nature of releases of radioactive materials from the plant. These included both volatile materials that became distributed on a continental scale and fuel particles that were distributed more locally, notably in a narrow plume stretching some 80 km to the west. Following the accident, a shelter was constructed to contain the destroyed reactor. The construction and durability of this shelter are the subject of Chapter 3. Originally, 18 dierent designs were proposed. The one selected was one of a group in which the walls and roof of the shelter were supported by the remains of the destroyed unit. Although the selected approach led to substantial savings in terms of cost and speed of construction, it resulted in a very large collective dose to the construction workers and limitations in the performance of the facility. Speci®cally, a large number of cracks and openings existed by which water could percolate into the structure, and ¯ows of concrete into the damaged building hindered or precluded inspection of many locations.
90
Book review / Annals of Nuclear Energy 28 (2001) 89±91
Safety evaluations of the shelter and its contents have indicated that there is a continuing potential for criticality events. However, of greater concern is the possibility of collapse leading to release of a plume of radioactive dust. The radiological consequences of such a collapse have been estimated. Committed eective doses from inhalation range from 2 Sv at 50 m to 50 mSv at 1800 m downwind. On this basis, it seems that collapse of the shelter would constitute a major, but not a catastrophic, radiation accident. It seems unlikely that acute radiation deaths would occur as a result. Chapter 4 deals with storage and disposal of radioactive wastes. After the accident, large quantities of soil, debris, wood, structural materials, equipment and other contaminated materials were isolated by burial in mounds and trenches within the 30 km exclusion zone. The quantities involved are detailed on a site-by-site basis and are quite staggering. For example, at the Rozoskha equipment holding facilities there is a collection of vehicles with surface contamination of up to 6.6 106 Bq mÿ2. These vehicles include 1193 transport trucks, 234 military vehicles, 119 tow trucks, 16 road construction vehicles and 59 cars and buses. Assessments indicate that these stores and disposals pose only a limited radiological risk compared with the widely spread environmental contamination that arose at the time of the accident and is the subject of Chapter 5. The review of environmental contamination addresses in detail issues of mapping and provides a great deal of data on the distribution and total inventory of the various radionuclides released during the accident. Patterns of contamination of the surface terrestrial environment, the Dneiper River system and groundwaters are covered in some detail. Information on transport of radionuclides in soils, contamination of agricultural products and the eectiveness of countermeasures is provided. Although a great deal of ground is covered in this chapter, the presentation is not very coherent and it will be used more as a compendium of useful details than as an overview of the current state of the environment. Chapter 6 deals with radiation doses received by individuals involved in accident remediation and by members of the public. Nearly 300,000 people were involved in remediation activities and the Ukrainian National Register, which was established following the accident, lists approximately 175,000 remediation personnel, of whom 126,000 participated in remediation eorts between 1986 and 1987, when levels of exposure were highest. These persons typically received 50 to 250 mGy, although a few received more than 500 mGy. The total collective dose to remediation personnel was probably somewhere in the range of 10,000 to 40,000 person-Gy. Assuming a linear, no-threshold dose±response relationship, as recommended by the International Commission on Radiological Protection, about 600 to 2400 excess cancer deaths might be expected to occur in this population as a result of their exposure. This raises the question of whether the approach to remediation was appropriate. Collective eective doses to members of the public were mainly to rural populations. Annual collective eective doses to rural Ukrainians fell from around 10,000 man-Sv in 1986 to 3000 man-Sv in 1990 and 1000 man-Sv in 1996. Doses are discussed for various groups including those evacuated during 1986 and those resettled since 1987. Although it is important to establish individual and collective doses to members of the public, it is widely recognised that the main eects of the accident have been associated with social disruption and associated health eects that are not directly
Book review / Annals of Nuclear Energy 28 (2001) 89±91
91
related to exposure to radiation. These matters are addressed in Chapter 7, where the authors comment that the psychological impact of the accident resulted primarily from a lack of public information, the stress and trauma of relocation, the breaking of social ties, and the fear that any radiation exposure would be damaging to health. They point out that it is understandable that people who were not told the truth for several years after the accident continue to be sceptical of ocial statements and to believe that illnesses of all kinds that now seem to be more prevalent must be due to radiation. A particularly interesting aspect of this chapter is the inclusion of results from a questionnaire survey of 1200 respondents relating to their health, welfare and general level of satisfaction with social conditions. It was found that residents in the mandatory and voluntary resettlement zones that had never been evacuated or resettled showed a higher overall level of social satisfaction than did resettled evacuees and residents of a `clean' area used as a control population. This is presumably because the residents had never experienced the stresses of relocation, but had received compensation as identi®ed `victims' of the accident. In addition to its impact on individual health and social well being, the accident has had an enormous economic impact at a time when Ukraine has been exposed to major changes for other reasons related to the break-up of the Soviet Union. Direct accident remediation costs were equivalent to about US $6109. Costs of social and medical programmes for those aected by the accident have been of a similar magnitude, as have resettlement costs. Indirect costs due to sterilisation of natural resources and loss of electrical production have been even larger. Overall, the economic impact on Ukraine is estimated at US $1.31011. A major continuing problem is the number of Ukrainian citizens declared as victims of the accident. As the authors note, under current Ukrainian law, the number of individuals requiring support as victims of the accident is increasing. This is imposing a heavy burden on the Ukrainian economy during a severe economic turndown. This raises the question of whether it would be possible to modify the law to achieve an allocation of resources that would be more eective in improving the health and social well being of all Ukrainians in the long term. Lessons from the accident are discussed in Chapter 9 and there is an extensive reference list. This is mainly of Russian and Ukrainian publications and will be a major resource to specialists working in the various areas covered. The book is completed by two useful brief appendices on radiation, radioactivity and radiation protection, and on medical consequences of the accident. There is also a useful index. Overall, this review is a substantial contribution to the literature on the Chornobyl accident. It is not an easy read and would have bene®ted from rather more authoritarian editing. Also, there are a number of minor errors, including some mistakes in units, that could cause confusion. Nevertheless, it is an important source book that I anticipate consulting regularly over the next few years. M.C. Thorne AEA Technology Ð Environment, UK 10 May 2000 0306-4549/01/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0306-4549(00)00056-6
Book review The Chornobyl Accident: A Comprehensive Risk Assessment G.J. Vargo (Ed.); Battelle Press, Columbus, OH, USA, 2000 Use of the Ukrainian transliteration `Chornobyl' rather than the more familiar Russian transliteration `Chernobyl' reveals that this book is a Ukrainian account of the accident and its aftermath. It was written by a group of Ukrainian specialists who have been involved on a ®rst-hand basis for the last 13 years. Following a brief introduction, Chapter 2 provides a detailed account of the chronology and causes of the accident and of the radionuclide releases that occurred. A strong emphasis is placed on weaknesses in the design of RBMK reactors and in safety management systems that provided a context within which such a catastrophic accident could happen. The authors comment that the design included several substantial deviations from the safety requirements in force at the time and that the signi®cance of these deviations was never analysed. Furthermore, they note that almost all these design ¯aws were known before the accident as were the measures required to eliminate them. In their view, the main reason that the accident occurred was excessive reliance on administrative controls and human performance rather than engineered safety features and automatic control systems. Underlying this was a seriously ¯awed safety culture during both the construction and operational phases. Organisations concerned with the construction and operation of the plant were only responsible for their own work, and there was no single person or organisation with overall responsibility for safety. Various government ministries were the only entities with high-level decision-making authority and these were distant from plant construction and operations. Detailed information is provided on the nature of releases of radioactive materials from the plant. These included both volatile materials that became distributed on a continental scale and fuel particles that were distributed more locally, notably in a narrow plume stretching some 80 km to the west. Following the accident, a shelter was constructed to contain the destroyed reactor. The construction and durability of this shelter are the subject of Chapter 3. Originally, 18 dierent designs were proposed. The one selected was one of a group in which the walls and roof of the shelter were supported by the remains of the destroyed unit. Although the selected approach led to substantial savings in terms of cost and speed of construction, it resulted in a very large collective dose to the construction workers and limitations in the performance of the facility. Speci®cally, a large number of cracks and openings existed by which water could percolate into the structure, and ¯ows of concrete into the damaged building hindered or precluded inspection of many locations.
90
Book review / Annals of Nuclear Energy 28 (2001) 89±91
Safety evaluations of the shelter and its contents have indicated that there is a continuing potential for criticality events. However, of greater concern is the possibility of collapse leading to release of a plume of radioactive dust. The radiological consequences of such a collapse have been estimated. Committed eective doses from inhalation range from 2 Sv at 50 m to 50 mSv at 1800 m downwind. On this basis, it seems that collapse of the shelter would constitute a major, but not a catastrophic, radiation accident. It seems unlikely that acute radiation deaths would occur as a result. Chapter 4 deals with storage and disposal of radioactive wastes. After the accident, large quantities of soil, debris, wood, structural materials, equipment and other contaminated materials were isolated by burial in mounds and trenches within the 30 km exclusion zone. The quantities involved are detailed on a site-by-site basis and are quite staggering. For example, at the Rozoskha equipment holding facilities there is a collection of vehicles with surface contamination of up to 6.6 106 Bq mÿ2. These vehicles include 1193 transport trucks, 234 military vehicles, 119 tow trucks, 16 road construction vehicles and 59 cars and buses. Assessments indicate that these stores and disposals pose only a limited radiological risk compared with the widely spread environmental contamination that arose at the time of the accident and is the subject of Chapter 5. The review of environmental contamination addresses in detail issues of mapping and provides a great deal of data on the distribution and total inventory of the various radionuclides released during the accident. Patterns of contamination of the surface terrestrial environment, the Dneiper River system and groundwaters are covered in some detail. Information on transport of radionuclides in soils, contamination of agricultural products and the eectiveness of countermeasures is provided. Although a great deal of ground is covered in this chapter, the presentation is not very coherent and it will be used more as a compendium of useful details than as an overview of the current state of the environment. Chapter 6 deals with radiation doses received by individuals involved in accident remediation and by members of the public. Nearly 300,000 people were involved in remediation activities and the Ukrainian National Register, which was established following the accident, lists approximately 175,000 remediation personnel, of whom 126,000 participated in remediation eorts between 1986 and 1987, when levels of exposure were highest. These persons typically received 50 to 250 mGy, although a few received more than 500 mGy. The total collective dose to remediation personnel was probably somewhere in the range of 10,000 to 40,000 person-Gy. Assuming a linear, no-threshold dose±response relationship, as recommended by the International Commission on Radiological Protection, about 600 to 2400 excess cancer deaths might be expected to occur in this population as a result of their exposure. This raises the question of whether the approach to remediation was appropriate. Collective eective doses to members of the public were mainly to rural populations. Annual collective eective doses to rural Ukrainians fell from around 10,000 man-Sv in 1986 to 3000 man-Sv in 1990 and 1000 man-Sv in 1996. Doses are discussed for various groups including those evacuated during 1986 and those resettled since 1987. Although it is important to establish individual and collective doses to members of the public, it is widely recognised that the main eects of the accident have been associated with social disruption and associated health eects that are not directly
Book review / Annals of Nuclear Energy 28 (2001) 89±91
91
related to exposure to radiation. These matters are addressed in Chapter 7, where the authors comment that the psychological impact of the accident resulted primarily from a lack of public information, the stress and trauma of relocation, the breaking of social ties, and the fear that any radiation exposure would be damaging to health. They point out that it is understandable that people who were not told the truth for several years after the accident continue to be sceptical of ocial statements and to believe that illnesses of all kinds that now seem to be more prevalent must be due to radiation. A particularly interesting aspect of this chapter is the inclusion of results from a questionnaire survey of 1200 respondents relating to their health, welfare and general level of satisfaction with social conditions. It was found that residents in the mandatory and voluntary resettlement zones that had never been evacuated or resettled showed a higher overall level of social satisfaction than did resettled evacuees and residents of a `clean' area used as a control population. This is presumably because the residents had never experienced the stresses of relocation, but had received compensation as identi®ed `victims' of the accident. In addition to its impact on individual health and social well being, the accident has had an enormous economic impact at a time when Ukraine has been exposed to major changes for other reasons related to the break-up of the Soviet Union. Direct accident remediation costs were equivalent to about US $6109. Costs of social and medical programmes for those aected by the accident have been of a similar magnitude, as have resettlement costs. Indirect costs due to sterilisation of natural resources and loss of electrical production have been even larger. Overall, the economic impact on Ukraine is estimated at US $1.31011. A major continuing problem is the number of Ukrainian citizens declared as victims of the accident. As the authors note, under current Ukrainian law, the number of individuals requiring support as victims of the accident is increasing. This is imposing a heavy burden on the Ukrainian economy during a severe economic turndown. This raises the question of whether it would be possible to modify the law to achieve an allocation of resources that would be more eective in improving the health and social well being of all Ukrainians in the long term. Lessons from the accident are discussed in Chapter 9 and there is an extensive reference list. This is mainly of Russian and Ukrainian publications and will be a major resource to specialists working in the various areas covered. The book is completed by two useful brief appendices on radiation, radioactivity and radiation protection, and on medical consequences of the accident. There is also a useful index. Overall, this review is a substantial contribution to the literature on the Chornobyl accident. It is not an easy read and would have bene®ted from rather more authoritarian editing. Also, there are a number of minor errors, including some mistakes in units, that could cause confusion. Nevertheless, it is an important source book that I anticipate consulting regularly over the next few years. M.C. Thorne AEA Technology Ð Environment, UK 10 May 2000 0306-4549/01/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0306-4549(00)00056-6