Table of contents:

1. Introduction
2. General Bibliography
3. Hot Particles
4. Chernobyl Plume: Country-by-Country Summary:

• The following section of our website has been translated into Italian by Humus - Progetto.  (The Humus Project: The effects of Chernobyl contamination on the soil.)
• Austria, Bangladesh, Black Sea, Bulgaria, Canada, Czechoslovakia, Denmark, Estonia, Finland, France, Germany, Greece, Greenland, Italy, Japan, Monaco, Netherlands, Norway, Poland, Portugal, Romania, Russia and former USSR, Scotland, Spain, Sweden, Switzerland, Turkey, United Kingdom, Yugoslavia

• U.S.A.: Maine, Maryland, New Jersey, New York, Oregon, Tennessee, Vermont, Washington

 

1. Introduction

As a preview to the annotated citations pertaining to Chernobyl-derived fallout, the editor of RADNET offers the following comments and observations:

• Nuclear safety experts had not anticipated that a nuclear accident would release this large an inventory of radionuclides.
• These nuclides were dispersed further, more erratically, and in much greater quantities than had been anticipated prior to the accident.
• At the time the accident was occurring, and during the weeks and months that followed, there was a widespread lack of accurate information about the seriousness and the radiological impact (deposition levels) of the accident.
• During and after the accident, official information sources ranged from unreliable (Russian and French government sources) to inaccurate (IAEA, National Radiological Protection Board, etc.). Political considerations and partisan prejudice in favor of nuclear energy production combined with the lack of environmental monitoring information and skewed objective accident analysis with the result that the impact of the accident was and continues to be minimized.
• This underestimation of the extent of the Chernobyl accident continues today in most official versions in terms of where and in what quantity deposition from the accident occurred.
• Only a few locations were equipped with sufficient instrumentation to make accurate real-time nuclide-specific measurements of the passage of the fallout cloud and its erratic rainfall-associated deposition.
• Rainfall events were the fundamental mechanism responsible for the extremely high deposition levels in some locations, including areas located thousands of kilometers from the accident site. Dry deposition played a lesser role in the spread of Chernobyl fallout than in weapons testing fallout events.
• Only a minimum of information has been collected about the actual levels of the dietary intake of Chernobyl-derived radionuclides for persons living in areas with high fallout - greater than 1 Ci/km² (37,000 Bq/m²).
• The failure to measure accurately the dietary intake of specific population groups in the most affected areas and the general tendency to average dose equivalents over large population groups (including estimating projected deaths as a percentage of hemispheric death rates) are particularly reprehensible.
• A reconsideration of the accident ten years later can only conclude that accurate information is still unavailable about actual deposition levels over vast areas of the Northern Hemisphere where millions of residents do not have access to accurate radiological monitoring data (Turkey, Iran, Iraq, North Africa, etc.).
• Even in countries with modest to excellent radiological monitoring capabilities, accurate information about the impact of the accident was not available in a timely manner and, in some cases, has never been made available.
• The United States serves as an example of the problem of freedom of information. While most areas of the United States received only a minimum of Chernobyl-derived fallout, some locations (See Dibbs, Maryland) received fallout which exceeded weapons testing deposition. The radiological surveillance data collected by the EML (Environmental Measurements Laboratory) and the EPA were either limited to a very small number of locations or, in the case of the EPA, did not include ground deposition data (Bq/m²) or accurate air concentrations expressed in µBq/m³ (microbecquerels).
• Extensive data collected by the National Reconnaissance Office pertaining to the Chernobyl accident is not yet available to the general public.
• We welcome your comments on our editorial opinions. We also solicit additional citations pertaining to Chernobyl fallout.
• Articles cited in this section but not annotated were not present at hand for review.
• We will add citations and data to RADNET as they become available.
• This section of RADNET combines some editorial content with the data citations.

Aarkrog, A. (1994). Source terms and inventories of anthropogenic radionuclides. Riso National Laboratory, Roskilde, Denmark.
 

• This incomplete source term release will be updated with a more complete description of the total nuclide inventories released from the Chernobyl accident if and when the tenth anniversary report of the Chernobyl accident listing the revised release estimates is received from the OECD/NEA. The current estimates listed above derive from a world health organization report in 1989 which may underestimate the actual release activity during the accident. Many earlier reports contain even larger underestimations of the actual release during the accident, and, in fact, an exact source term estimate for all radionuclides released in the Chernobyl accident may never be possible. For a more detailed analysis of the release dynamics of the Chernobyl accident and the many mysteries surrounding exactly what transpired during the accident, see the publications of Alexander Sich, 1994 etc., which are reviewed in the following pages. It has taken almost a decade for an accurate analysis of the accident dynamics to emerge from the official evasions and misinformation which characterized the early reports on Chernobyl.

Aarkrog, A., Tsaturov, Y. and Polikarpov, G.G. (1993). Sources to environmental radioactive contamination in the former USSR. Riso National Laboratory, Roskilde, Denmark.
 

• The Chernobyl accident, if contaminated areas outside the USSR are included, resulted in the deposition of long-lived radionuclides in excess of 37,000 Bq/m² (1 Ci/km²) on +/- 200,000 km² of the world's surface. Areas impacted by iodine-131, ruthenium-103, tellurium-132, barium-140, and other short-lived isotopes (1/2 T = 1 week to 1 yr.), along with the longer-lived isotopes, to levels exceeding 37,000 Bq/m², may have exceeded 1,000,000 km² in the weeks after the accident.
• The primitive maps reproduced in this publication show extensive contamination not only in Byelorussia, but also throughout central Russia. With each passing year, our knowledge of the extent of the deposition from the Chernobyl accident grows larger as more information is collected and collated and the parameters of Chernobyl-derived deposition in excess of one curie per square kilometer are expanded.
• An accurate radiometric survey of the hemispheric impact of the Chernobyl accident would probably reveal significant additional contamination in locations such as Turkey, Iran, Iraq, North Africa, and possibly even areas in the Far East and in North America.
• The National Reconnaissance Office has extensive additional radiological surveillance data pertaining to the Chernobyl accident which is not available to the general public because it is classified.
• The USSR contamination estimates were republished by Aarkrog, et al, 1993, in the above citation from a UNSCEAR publication which was citing a Russian source (Israel, Y.A., Tsaturov Y.S., et al., 1991).

• The Black Sea was more impacted by the Chernobyl accident than the other Mediterranean sea basins; it was still showing the cumulative effects of the accident in 1990.
• The data was collected by a number of countries adjacent to the Mediterranean Sea, and is an extensive summary of the mean values, with a sea-by-sea survey of the major Mediterranean basins.

• "Transfer factors are strongly influenced by seasonal and geographical distributions. For example, if 1,000 Bq of 137 per m² are deposited over a barley field three months before harvest, the concentration in the mature grain will be 1 Bq ¹³⁷Cs/kg. If on the other hand contamination, with the same deposition, occurs one month before harvest, the mature grain will contain approximately 100 Bq ¹³⁷Cs/kg." (pg.155).
• "The mean concentration in Danish grain in 1962-74 was 7.1 Bq ¹³⁷Cs/kg. In 1986 the mean level was 3.3 Bq." (pg. 157) This illustrates the efficiency and uniformity of stratospheric fallout contamination compared to the erratic distribution patterns of Chernobyl-derived radiocesium, which did not significantly affect Denmark during the growing season.

• "The URGENT computer model developed at Riso has shown that as much as 89% of the dose to urban populations came from contamination on the soil surface in open areas such as gardens and parks." (pg. 183).
• Cesium remained strongly bound in the topmost 2 cm of soil associated with a mineral fraction; ruthenium was associated with an organic fraction; external exposure is the primary exposure pathway four years after the initial deposition.

Anspaugh, L.R., Catlin, R.J. and Goldman, M. (1988). The global impact of the Chernobyl reactor accident. Science. 242. pg. 1513-1519.

• "By means of an integration of the environmental data, it is estimated that ~100 petabecquerels of cesium-137 (1PBq = 10¹⁵ Bq) were released during and subsequent to the accident." (pg. 1513).

• "Localized peaks of wet deposition (in excess of 100 kilobecquerels per square meter) occurred in parts of Central Scandinavia." (pg. 18).
• "Deposition of the most important long-lived nuclide, ¹³⁷Cs, did not decrease smoothly with travel distance but was enhanced when rain or snow interrupted the plume." (pg. 18).
• The estimate for plume transport atmospheric height ranged from 4 km to 10 km. (pg. 19).

• Long range atmospheric dispersion model, MESOS, was used to provide a preliminary estimate of the accident source term release; 15-20% of iodine, tellurium and cesium and 1% or less of ruthenium and other isotopes was the estimated release.
• Relatively low airborne concentrations of Chernobyl-derived radionuclides were observed in comparison to ground deposition levels noted by other researchers (See EML-460).
• This is another in a series of early underestimations of the severity of the Chernobyl accident and the extent of the erratic fallout patterns which characterized the plume pulse pathway.

• "Geneva--radiation scientists now accept that the large increase in childhood thyroid cancers, particularly in Belarus and Ukraine, is the result of radiation released by the Chernobyl nuclear accident. The new focus is on trying to explain why the cancer epidemic is so virulent." (abstract).

Beskorovajnyj, V.P., et. al. (1995). Radiation effects of collapse of structural elements of the sarcophagus. Sarcophagus Safety '94: Proceedings of an International Conference, Zeleny Mys, Chernobyl, Ukraine, March 14-18, 1994. OECD/NEA, Paris. pg. 196-202.

• This publication also includes the following titles:
• "Hydrogeological Effects of the Principal Radioactive Waste Burial Sites Adjacent to the Chernobyl NPP."
• "The Current State of the Regulations on the Safety of Unit 4 at the Chernobyl NPP."
• "Hypothetical Accidents in the Sarcophagus."
• "Design of a Shelter - Experience of Planning and Construction in 1986."
• "Current State of the Sarcophagus and Safety Problems."

• "One of the highest atmospheric air concentrations recorded outside the Eastern Bloc, was in Stockholm, where a level of 5,130 pCi (190,000,000 micro becquerels) of ¹³¹I per cubic meter of air was found." (pg. 187).

Beninson, D. and Lindell, B. (1986). Chernobyl reactor accident: Report of a consultation, 6 May 1986. Report No. ICP/CEH. World Health Organization, Copenhagen, Denmark.

• While this report contains little or no data, it does have a list of remedial actions and a preliminary review of some precautions taken by a number of countries affected by the Chernobyl accident. (Fig. 10, pg. 30).

• The second in a series of articles in Nuclear Safety by A.R. Sich and, in their totality, the best summary of the Chernobyl accident available in the literature.
• "Approximately 135 tonnes of the 190.3-tonne initial core fuel load (~71%) at Chernobyl Unit 4 melted and flowed into the lower regions of the reactor building to form various kinds of the now-solidified lava-like fuel-containing materials (LFCMs) or corium." (pg. 1).
• Excellent descriptions and photographs of the sarcophagus which was built over the ruined reactor after the accident, with a detailed analysis of the location of the melted and resolidified fuel in the lower regions of the reactor building.
• "Investigations conducted during 1986 to 1989 showed that previous notions concerning the extent of damage within Unit 4 as a result of the accident in most cases did not correspond to the actual state of the destroyed reactor." (pg. 8).
• Contents of the sarcophagus are listed as including the following: "1,270 and 1,350 tonnes of fuel-containing materials (FCMs) (material containing ~ 10.5% of partially "burned" nuclear fuel), 64,000 m³ of other radioactive material (concrete, building metal, etc.), approximately 10,000 tonnes of construction metal, and 800 to 1,000 tonnes of contaminated water are located within the sarcophagus." (pg. 15).
• "A considerable amount of ¹³⁷Cs (35%) remains within the solidified remnants of the core....significantly higher than that retained at TMI-2 in the molten ceramic lower plenum debris (average of 3% retained) or in the upper plenum debris (average of 19% retained)." (pg. 29).

Buzulukov, Y.P. and Dobrynin, Y.L. (1993). Release of radionuclides during the Chernobyl accident. In: The Chernobyl Papers. Merwin, S. E. and Balonov, M.I., (eds.) Research Enterprises, Richland, WA. 1. pg. 321.

Cambrai, R.S. et. al. (1987). Observations on radioactivity from the Chernobyl accident. Nuclear Energy. 26. pg 77.

Devell, L. et. al. The Chenobyl reactor accident source term: Development of a consensus view. CSNI Report in preparation. OECD/NEA, Paris.

Dickerson, M.H. and Sullivan, T.J. (1986). ARAC response to the Chernobyl reactor accident. (Under U.S. Department of Energy Contract W-7405-Eng-48). Lawrence Livermore National Laboratory, Livermore, CA.

• This report illustrates the lack of centralized facility in the US for accurate "real-time" analysis of radioactive contamination and the failure of existing computer models to predict accurately the erratic ground deposition of Chernobyl fallout patterns.
• Deposition levels in Europe were grossly underestimated.
• "Detection of BA-140 and Zr-95 in Sweden implied a significant meltdown." (pg. 12).
• "An amount of 9000 pCi/l was estimated as the maximum expected I-131 concentration in milk for the U.S..." (pg. 13). (No contamination levels of this magnitude inside the U.S. were noted in the citations reviewed to date for RADNET.)

• "According to one IAEA official... on the basis of a study of 30,000 people living in the (Chernobyl) area, no adverse health effects on the general population had been attributed to the radiation." (pg. 285).
• "Although there are still a few hot spots, most of the area within 10-30 km from the reactor has returned to normal levels of activity." (pg. 285).
• Extraordinary misinformation from one of the most preeminent scientific journals; this IAEA editorial rhetoric is completely contradicted by other reports and data.

• This news summary is the paradigm of misinformation and selective interpretation of inadequate data and is an example of the biased reporting that characterized much of the Chernobyl-related editorial content of Nature in the first few months after the Chernobyl accident. This biased editorial reporting contrasts with the many objective scientific reports and papers which Nature published after the Chernobyl accident.

Gittus, J.H., Hicks, D., Bonell, P.G., Clough, P.N., Dunbar, I.H., Egan, M.J., Hall, A.N., Hayns, M.R., Nixon, W., Bulloch, R.S., Luckhurst, D.P., Maccabee, A.R., Edens, D.J. (1988). The Chernobyl accident and its consequences. Report No. NOR 4200. United Kingdom Atomic Energy Authority, London.

• Extensive discussion of how the accident happened.
• Little specific fallout data.
• Gross underestimation of radiological impact of the accident: inaccurate and overly generalized radiation dispersion maps.

• Global fatal cancers estimated at 39,000, most of them outside the Soviet Union.

• Radiocesium release was calculated to be 2.4 million curies (US DOE).
• Global fatal cancer ratio assessment of up to 28,000 deaths.
• This is one of many fluctuating estimates of deaths resulting from Chernobyl, none of which will allegedly have a statistically significant impact on the overall cancer rate.
• The New York Times (1995, date unavailable) has reported a sharp drop in the life expectancy of the Russian population since the Chernobyl accident. What role Chernobyl played in the drop is unknown.

Gudiksen, P.H. and Lange, R. (1986). Atmospheric dispersion modeling of radioactivity releases from the Chernobyl event. Report No. UCRL- 95363, Preprint. Lawrence Livermore National Laboratory, Livermore, CA.

• This report illustrates the unreliability of computer models in estimating atmospheric dispersion from a nuclear accident, particularly in the early stages of an accident with limited data availability.
• Neither the calculated nor the measured deposition levels seem to match data collected by other researchers.

• "In Konstanz the current ground activity of cesium-137 is estimated at 8,000-12,000 Bq/m², whereas the global weapons-testing fallout peak in West Germany was 800 Bq/m² in 1963." (pg. 36).
• "During passage of the cloud peak air radionuclide concentrations reached 100,000 times background levels in Poland and as high as 10,000 times background in Scotland." (One million times background equals 2,000 Bq/m³.) (pg. 35).

• "Ground level air concentrations... of ¹³⁷Cs in autumn 1986 were 100 times fallout values in 1985, and decreased by the end of 1987 to only 30 times the weapon fallout level. This very slow rate of decrease was not expected." (pg. 158).

• These preliminary source term estimates are for a core inventory with a cooling time of one hour. Total released activity is estimated at 1.58 x 10⁸ Ci (158,000,000 Ci) including the noble gases. (pg. 73).
• "The Soviets distinguish between 4 phases in the main release which lasted 9 days." (pg.71).
• Phase One: April 26: Mechanical dispersion of slightly enriched fuel (2.2 x 10⁷ Ci).
• Phase Two: April 27-May 1: Falling release level; diminishing graphite fire (2.2 x 10⁷ Ci).
• Phase Three: May 2-5: The core heats to a temperature exceeding 2000 degrees centigrade. Reactions occur between ²O and graphite, fission product aerosols combine with graphite particles (2.7 x 10⁷ Ci).
• Phase Four: May 5-6: Rapid falloff in fission product emission due to halting of the fission process. (1 x 10⁵ Ci).
• "Discharge of radioactive products into the atmosphere continued through the end of August at the rate of a few curies per day." (pg. 1).
• This revised early report still underestimates the source term release but is more accurate and comprehensive than the other reports presented at the IAEA conference at Vienna on August 25-29, 1986.

• This report is full of errors, incorrect descriptions of how the accident happened and incomplete or inaccurate information about the impact of the accident.
• A major blow to the credibility of the International Atomic Energy Agency and a graphic illustration of the unavailablility of accurate information about the Chernobyl accident in the months after it occurred; much of the contents of this report can no longer be relied on to provide accurate information about the Chernobyl accident.

International Atomic Energy Agency. (1991). The International Chernobyl Project, surface contamination maps. IAEA, Vienna.

International Atomic Energy Agency. (1991). The International Chernobyl Project, technical report. IAEA, Vienna.

Ilyin, L.A. and Pavlovskij, A.O. (1987). Radiological consequences of the Chernobyl accident in the Soviet Union and measures taken to mitigate their impact. IAEA Bulletin 4.

International Nuclear Safety Advisory Group. (1986). INSAG summary report on the post-accident review meeting on the Chernobyl accident (INSAG report to International Atomic Energy Agency general conference, Vienna, Austria, August 1986). Vienna. IAEA translation.

• This report includes the core inventory of radionuclides provided by Soviet authorities to the International Atomic Energy Agency at this conference and reprinted in RADNET under Warman, E.A. (1987) in this section.
• The core inventory of plutonium-239 at Chernobyl at the time of the accident is listed as 23,000 curies. For comparison with plutonium inventories at both U.S. nuclear power facilities and at U.S. DOE plutonium production facilities, RADNET readers are urged to refer to RADNET, Section 11: Anthropogenic Radioactivity: Major Plume Source Points: U.S. Military Source Points, Plutonium the first 50 years, and the annotations which follow this citation.

Kirchner, G. and Noack, C.C. (1988). Core history and nuclide inventory of the Chernobyl core at the time of the accident. Nuclear Safety, 29(1). pg. 1-5.

• "Any calculation of the radionuclide inventory of the Chernobyl core at the time of the accident... requires the specification of burnup and detailed irradiation history of the reactor core prior to the accident - data not accessible as yet." (pg. 1).
• The reactor vessel inventory of nuclides in this report is listed in Table 2 and is the calculated concentrations of selected nuclides per ton of initial heavy metal at the time of the accident. A note at the bottom of the table lists fuel loading of the Chernobyl core at 192 tons.
• The calculated concentration of ¹³⁷Cs is listed as 1.6 x 10¹⁵ Bq/ton; ²³⁹Pu is calculated at 4.7 x 10¹² Bq/ton; 28 other nuclide concentrations are calculated in this table. (pg. 4).

Krey, P.W. (1986). International data exchange and cooperative research. In: Environmental Measurements Laboratory: A compendium of the environmental measurements laboratory's research projects related to the Chernobyl nuclear accident: October 1, 1986. Report No. EML-460. U.S. Department of Energy, New York, NY. pg. 259-264.

• Chernobyl fallout conclusions (pg. 259-260):

• "The dose and subsequent health risk to the population of Western Europe are minimal."
• "Although fallout levels in Russia and Eastern Europe are not now known, circumstances would have been much worse had there been rain immediately following the accident."
• "There was evidence of several pulses of Chernobyl fallout in Western Europe."
• "The relative amount of gaseous ¹³¹I was large and variable... deposited ¹³¹I was distilled out of the soil back into the atmosphere during daylight hours."

Likhtarev, L.A. et. al. (1989). Radioactive contamination of water ecosystems and sources of drinking water. Medical Aspects of the Chernobyl Accident. TECDOC 516. IAEA, Vienna.

Morrey, M., Brown, J., Williams, J.A., Crick, M.J., Simmonds, J.R. and Hill, M.D. (1987). A preliminary assessment of the radiological impact of the Chernobyl reactor accident on the population of the European community. (Report from Health and Safety Directorate No. V/E/1 funded under CEC contract number 86 398). Commission of the European Communities, Luxembourg.
 

May 1986	S. Germany	Ground deposition	131I	240,000 Bq/m2
May 1986	S. Germany	Milk	131I	17,000 Bq/l

• 17,000 Bq/l = 1,020,000 pCi/liter.
• This report contains detailed media specific Chernobyl-derived activity levels for many European countries as well as an interesting evaluation of the availability of environmental monitoring data at the time of this study (See Table B-2, pg. 40).
• This report comes in two sections. Section one contains dose assessments. Section two contains the appendices with all the environmental monitoring data, as well as additional dose estimates. Section two also contains information about countermeasures taken in each country.

OECD. (1987). The radiological impact of the Chernobyl accident in OECD countries. Organization for Economic Cooperation and Development, Paris.

• This is a lengthy and detailed review of the Chernobyl accident and its impact throughout the northern hemisphere. At first glance it would seem to be the definitive summary of the radiological impact of the Chernobyl accident, particularly in view of the polychrome radiometric maps which appear to document the fallout patterns in a number of countries (not all of the maps are in color, but the ones that are look very impressive). A close comparison of the maps with many of the papers and the data they contain cited in RADNET illustrate the continued underreporting of the actual radiological impact of the Chernobyl accident.
• The gross underestimation of fallout in the United Kingdom, much of which was initially estimated by unreliable surface fallout measurements, is a paradigm for how inaccurate even the most professional analysis of a nuclear accident can be.
• Data within many articles annotated in this website indicate that actual fallout levels are neither as low as generally indicated in this publication, nor as uniform as shown on many of the fallout maps.

OECD, NRC and IAEA. (May 1995). Sarcophagus safety '94 the state of the Chernobyl Nuclear Power Plant Unit 4. 66-95-10-1. ISBN 92-64-14437-4. Organization for Economic Cooperation and Development, Paris.

• "Nine years after the Chernobyl disaster, scientific data for remedial and recovery programmes still need to be assembled and evaluated. Many questions must be addressed before the site can be radiologically stabilized and environmental remediations can be found. Can the nuclear and radiation safety conditions of the site be assured? What is the state of integrity of the 'sarcophagus'? What is the nature and degree of the radioactive contamination?" (abstract).

• This report is available on the Internet at URL: http://www.nea.fr/html/rp/chernobyl/chernobyl.html
• This report is an update on the Chernobyl accident with a particular emphasis on the radiological and health impact; the bibliography of this report cites a large number of research projects pertaining to this subject and is probably the largest single compilation of health physics related data-derived from the Chernobyl accident available in one location.
• This report also includes the accident source term release as well as interesting maps denoting the "main spots" of ¹³⁷Cs contamination within the former Soviet Union. It is interesting to note that "main spots" are defined as those areas with a ground deposition greater than 555,000 becquerels/m² (555 kBq/m²)(Fig. 5). The report notes that large areas of Ukraine and Belarus had ground deposition of ¹³⁷Cs over 40,000 becquerels/m² (40 kBq/m²).
• "The most highly contaminated area was the 30-km zone surrounding the reactor where ¹³⁷Cs ground depositions generally exceeded 1,500 kBq/m² ... the ground depositions of ¹³⁷Cs in the most highly contaminated areas ... (The Bryansk-Belarus spot, centered 200 km to the North-northeast of the reactor) ... reached 5,000 kBq/m² " (5 million Bq/m² ).
• Minimal information is given about contamination outside the former Soviet Union.
• Figure 6 gives a graphic illustration of satellite-derived data of the areas covered by the main body of the radioactive cloud on various days during the release, as provided by the ARAC (Atmospheric Release Advisory Capability), Lawrence Livermore Laboratory, Livermore, CA. These satellite-derived photographs provide an excellent overview of contamination dissemination but are not helpful in accurately describing actual ground deposition levels. The photographs in this report first appeared in a 1986 ARAC report: see Dickerson (1986) also in this section of RADNET.
• The remainder of this report is primarily concerned with:
• (III) reactions of national authorities
• (IV) dose estimates
• (V) health impact
• (VI) agricultural and environmental impacts (containing the above-mentioned maps)
• (VII) potential residual risks
• (VIII) lessons learned

OECD. (1996). The Chernobyl reactor accident source term. Report No. OCDE/GD(96)12. Organization for Economic Cooperation and Development, Paris.

• The OECD Nuclear Energy Agency (NEA) is in the process of issuing an updated report on the Chernobyl accident and its radiological and health impact which will be issued on the occasion of the tenth anniversary of the accident. This OECD report on the reactor accident source term is one component of the larger report. It summarizes the research pertaining to the inventory of reactor nuclides and the percentage of these inventories released to the environment during the accident.
• This report contains an extensive bibliography which includes many publications pertaining to the reactor vessel inventories and source term releases, only a few of which are cited in RADNET.
• Reactor inventories for ¹³⁷Cs are estimated at between 2.2 x 10¹⁷ Bq and 2.9 x 10¹⁷ Bq; seven different reactor inventory estimates are included in this report.
• The percentage of the reactor inventory of cesium-137 estimated to have been released (source term release) is 33 + 10, indicating that, out of 6.95 x 10⁶ to 7.84 x 10⁶ curies of radiocesium, approximately 40% was released to the environment.

Powers, D.A., Kress, T.S. and Jankowski, M.W. (1987). The Chernobyl source term. Nuclear Safety. 28(1). pg. 10-28.

• "The prolonged second stage of the release is not... well understood. Physical and chemical processes not likely to develop during LWR accidents may be responsible for the release during this stage of the accident." (pg. 27).
• Another of the early misinterpretations of the extent of the Chernobyl source term release.

Scheid, W., et. al. (1993). Chromosome aberrations in human lymphocytes apparently induced by Chernobyl fallout. ???? 64(5). pg. 531-534.

Scheid, W., Weber, J. and Traut, H. (1993). Chromosome aberrations induced in the lymphocytes of pilots and stewardesses. Naturwissenschaften. 80. pg. 528-530.

Shcherbak, Y. (April 1996). Ten years of the Chernobyl era. Scientific American.

Sich, A.R. (1994). Chernobyl accident management actions. Nuclear Safety. 35(1).

• The first in an important series of articles exploring what actually occurred during the release phase of the Chernobyl accident (April 26 through May 5).
• Startling information about the contradictions, misrepresentations and ineffectiveness of the accident management actions during and after the accident.
• The first clear analysis of the ineffectiveness of helicopter dropped materials and the flooding of the core with liquid (?) nitrogen in halting the accident.
• Excellent photographs and graphics give stark emphasis to the bizarre events which transpired during the accident.
• "71% of the initial 190.3 ton UO₂ fuel load was exposed to a high temperature oxidizing environment." (pg. 1).
• A frightening indictment of the inaccuracy of Soviet, IAEA and other early descriptions of the Chernobyl accident and an illustration of how long it can take to obtain accurate information about a serious nuclear accident and how it occurred.
• Mandatory reading for anyone trying to understand what really happened at Chernobyl, this is the first in a series of three articles by Sich in the Oak Ridge National Laboratory publication Nuclear Safety.

Sich, A.R. (1995). The Chernobyl accident revisited, part II: The state of the nuclear fuel located within the Chernobyl sarcophagus phase. Nuclear Safety. 36(1). pg. 1-32.

• See Borovoi and Sich (1995) above, for a review of this citation.

• Appraisal of (inaccurate) Soviet release data is followed by an evaluation of new release data and a consideration of the active phase release dynamics.
• The source term release estimate (lower-bound activity releases for eight volatile isotopes) is followed by a reconstruction of events during the active phase and serves as a summary of Sich's accident release dynamic studies. Also see Sich (1996) Nuclear Engineering International for our RADNET citation summarizing Sich's accident analysis.
• Sich makes the following general observations at the beginning of this article:
• "....iodine, cesium, and (to some extent) tellurium are considered to be the most important fission products in the early stages of a severe accident because they exhibit similar high volatility's and diffusion properties." (pg. 195).
• "The less-volatile species may be divided broadly into three groups: the semivolatiles (tellurium and antimony), the low volatiles (strontium, barium, and europium), and the refractories (molybdenum, ruthenium, zirconium, cerium, neptunium, etc.)." (pg. 195).
• "What complicates time-dependent source term release analyses (especially for the case of Chernobyl's 10-day active phase) is that the longer lived fission products continue to decay until a stable product is formed. The physical and chemical states of the intermediate species in a given decay chain are important because their volatilities span the entire range noted previouisly." (pg. 196).
• Sich gives the release estimate for the eight most significant volatile isotopes as 92 MCi. "...substantially more than a total release of 50 MCi (excluding noble gases) claimed by the Soviets in Vienna in August 1986....if the contributions of all other longer lived radioisotopes are added, the total release may approach 150 MCi. In fact, if Np-239 (half-life 2.355 d) is considered and if it was released at the 3.2% fraction claimed by the Soviets, its contribution to the releases over the period of the active phase alone could reach 30 Mci." (pg. 208).

• Detailed analysis of the release dynamics of the accident; as the graphite component of the core (corium) burned, it allowed the remaining fuel to eat away the lower biological shield (LBS) and flow into the lower regions of the reactor building. (pg. 23).
• After nine days, the corium quickly solidified and the accident stopped without direct human intervention (helicopter dropped materials were ineffective). The decay heat dropped due to the uptake of surrounding materials (the stainless steel and serpentine components of the LBS) combined with rapid spreading of the melted fuel up to 40 m from the epicenter of the melted corium. (pg. 23).
• "A reconvergence of volatile and non-volatile behavior and a large release around 7.5-8.5 days may indicate when the LBS melted through." (pg. 25).
• The solidified, ceramic-like corium indicates this rapid cooling once the corium penetrated the lower biological shield and flowed into the lower regions of the reactor building.
• 65% of the radiocesium was released; the Soviet report of a 13% release was as unreliable as other early reports about the accident.

• "He found research in the Zone to be poorly organized, encumbered with ideology, hampered by layer upon layer of bureaucracy and conducted in an atmosphere of conflict and mutual suspicion. " (pg. 26).
• "The manner in which some international organizations have dealt with the accident over the past ten years has strengthened in me the conviction that, sadly, scientific inquiry and politics are inextricably linked..." (pg. 26).

• A number of articles from this special issue are cited in this section of RADNET, particularly under the subheading "Russia and former USSR."

U. S. Department Of Energy. (1987). Health and environmental consequences of the Chernobyl Nuclear Power Plant accident. Report No. DOE/ER-0332. Committee on the Assessment of Health Consequences in Exposed Populations, U. S. Department of Energy, Washington, D.C.

• A compendium of the misinformation and underestimations within many of the early reports on the Chernobyl accident, this report includes the initial inaccurate source term release activities, a lack of media specific data, and summaries and conclusions based upon the inaccurate computer models of the time.
• The generalized conclusions about the health consequences of the Chernobyl accident in this and many other reports are simply speculation without a firm basis in an understanding of the radiological impact of the accident on specific population groups most affected by the erratic fallout patterns of the Chernobyl disaster.

• This report contains very little media specific data on Chernobyl fallout. Radionuclide deposition for Chester, NJ (5/6/86-6/2/86) is reported as (pCi/m²): ¹³¹I: 2,380; ¹³⁷Cs: 650; ¹³⁴Cs: 290; ¹⁰³Ru 720. (pg. 8-3).
• A detailed description of how the accident happened and of the design and construction of the reactor.

• This is a general summary of Chernobyl fallout data in the United States and in Sweden, with thirteen separate articles, the most important of which are cited in this website. See especially Hardy, et. al. (1986) in this Volume, Section 4, Sweden and Krey (1986) in this section.
• A bizarre documentation of the impact of the Chernobyl accident.

• One of the earliest reports to question the inaccurate source term reported by the Soviets.
• "Approximately 30-60% of the available radiocesium and at least 40-60% of the available radioiodine appear to have been released to the atmosphere from the accident." (pg. 1).
• "The radionuclide compositions observed outside the Soviet Union differ substantially from the Soviet source-term estimate, e.g., much more radioiodine and less nonvolatile radionuclides were observed in Europe than were estimated to have been released by the Soviets." (pg. 4).
• This is the first report to identify a second phase in the accident characterized by increased release of ¹³²Te, ¹⁰³Ru and ¹⁴⁰Ba.
• Warman's revision of the inaccurate Soviet source term release estimates were based upon a number of "far field" measurements taken after the accident in Finland (2), West Germany, Hungary and Greece, and summarized in chart form at the end of this report. Close inspection of isotopic ratios present in ground depositions and air samples led Warman to question, correctly, as it turned out, the inaccurate Soviet data.
• This is one of the few reports to include a core inventory of radionuclides at Chernobyl at the time of the accident (Taken by Warman from the International Safety Advisory Group (1986) report listed above):

Webb, G.A.M., Simmonds, J.R. and Wilkins, B.T. (1986). Radiation levels in Eastern Europe. Nature. 321. pg. 821-822.
 

29-30 April	Poland	Milk	131I	2,000 Bq/l
1-4 May	Hungary	Milk	131I	2,600 Bq/l

Williams, D. (1994). Chernobyl, eight years on. Nature. 371. pg. 556.

Wirth, E., van Egmond, N.D. and Suess, M.J. (1986). Assessment of radiation dose commitment in Europe due to the Chernobyl accident: Report on a WHO meeting: Bilthoven, 25-27 June 1986. Report No. ISH-HEFT 108. Institut fur Strahlenhygiene des Bundesgesundheitsamtes, Munchen.

• Cumulative deposition of iodine-131 in soil to May 8:
• Byelorussia: 1,000,000 Bq/m² +
• S. Germany: 130,000 Bq/m² pv
• Austria: 150,000 Bq/m² pv
• This report uses two computer models (MESOS and GRID) for calculating deposition activity levels. These models appear to grossly underestimate Chernobyl fallout data in areas where comprehensive radiometric surveys are available.

• "Six... pathways are possible by which exposure may occur following a nuclear accident..." (pg. 4).

External:  Ground shine Cloud shine Deposition on skin and clothing

Internal:  Ingestion Inhalation Absorption from skin

• "... root uptake of cesium will be substantially higher for acid soils with a low clay and a high organic matter content and may continue for many years in some soil conditions.... the external and internal doses will be roughly the same for the fifty year period after the accident." (pg. 8-9).
• "Direct exposure from deposited radionuclides together with the ingestion pathway was estimated to be three orders of magnitude greater than that from inhalation or exposure to airborne radionuclides (cloud shine)." (pg. 23).

• Large scale computerized dispersion models (MESOS and GRID) were used to reconstruct deposition patterns over Europe; these isolated areas of very high local deposition were located in the Ukraine, Central Scandinavia and Central Europe.
• "Exposure of the population occurs through three main pathways: inhalation of airborne material, external irradiation from material deposited on the ground and ingestion of contaminated foodstuff." (pg. 2).

• This publication contains no media specific data on the Chernobyl-derived radioactive fallout. It is a general survey of the pathways, radiological impact and risk assessment of radiocesium.