- To provide an overview of the accident at the FD (Fukushima Daiichi) reactor facilities, with a concise introduction to reporting units, background radiation levels, exposure guidelines and pathways, contamination levels of concern, historic contamination baseline data, a comparison of the FD disaster with the Chernobyl disaster, and a summary of the inventory of fuel assemblies at FD.
- To provide access to the most important and easy to interpret websites providing information about the radiological impact of the FD accident in Japan and in the U.S.
- To promote the our recently published Nuclear Information Handbook.
- To provide updates about the situation in Japan, including reports on ongoing radiological monitoring and/or the lack thereof.
The predecessor of the museum, the Center for Biological Monitoring (CBM) in Hulls Cove, Maine, was the sponsor of RADNET: Information about Source Points of Anthropogenic Radioactivity: A Freedom of Nuclear Information Resource. This pre-blog era website was active from the early days of the internet until 2000, when CBM was incorporated within the Environmental History Department of the newly incorporated Davistown Museum, a 501 (c) (3) organization. The contents of this blog, which includes comments and information pertaining to the Fukushima Daiichi disaster, are extracted from the online archives of RADNET and worldwide sources cited below. This material is published as a component of the museum's Nuclear Information Handbook (Special Publication 62). This handbook is available on amazon.com in paperback and Kindle formats and is the 22nd publication issued by the Pennywheel Press and its editor, H. G. Brack. This blog is a working draft of the first section of this Handbook and may be updated even as the first edition goes to press. Revised editions of the Handbook will be printed as additional information becomes available about the accident at the Fukushima Daiichi facility, or at any other location where a nuclear accident of global significance ocurrs in the future. Editorial comments and additional information are always welcomed. Please contact firstname.lastname@example.org. As a 501 (c) (3) organization, the Davistown Museum welcomes donations to support the compilation of this blog and publication of the Nuclear Information Handbook.
This Nuclear Disaster in Japan blog, the RADNET archives, and the Nuclear Information Handbook, provide no information on the health physics impact of any nuclear accident or source point of anthropogenic radioactivity. Other than the Wikipedia sievert synopsis reprinted below, the mission of this blog and the Nuclear Information Handbook is to provide nuclide-specific data on radioactive contamination in abiotic and biotic environments documented in the reporting units described below. The FDA contamination guidelines, generic exposure guidelines, and RADNETs terrestrial contamination levels of concern provide essential information allowing the general public to evaluate the significance of data being reported in Japan, US, and elsewhere.
Radiation Reporting Units
Ambient Radiation Exposure: Dose Reporting Units
· microsieverts per hour (μSv/hr)
· millisieverts per hour (mSv/hr)
· millisieverts per year (mSv/yr)
· nanograys per hour (nGy/hr)
· micrograys per hour (μGy/hr)
· aerial monitoring of ambient radiation: millirems per hour (mR/hr)
· 1 rem (R) = 0.01 sieverts (Sv)
· 1,000 millionths of a sievert (1,000 μSv) = 1 thousandth of a sievert (1 mSv)
Activity Reporting Units Expressed in Becquerels
· 1 curie = 37 billion becquerels = 37 GBq; to convert curies to becquerels, multiply by 37 billion
· air: microbecquerels per cubic meter (µBq/m3)
o airborne contamination may be in the form of dust, other particulates, or water vapor, including evaporated steam
o After the Fukushima Daiichi disaster, the Japanese government reported ambient air concentrations in “tens of thousands of terabecquerels per hour”; one terabecquerel equals one trillion becquerels.
o To convert becquerels per cubic meter to microbecquerels per cubic meter, multiply the Bq/m3 times 1 x 10-6
· aerial surveillance of gross beta/gamma ground contamination: (Bq/m2)
· surface contamination: becquerels per square meter (Bq/m2)
· surface contamination as measured in bequerels are also reported using prefixes:
o 1 MBq (M = mega = million) = 1,000,000 bequerels = 27 microcuries = 27 μCi
o 1 GBq (G = giga = billion) = 1,000,000,000 Bq = 27 millicuries = 27 mCi
o 37 GBq = 37,000,000,000 Bq = 1 Curie = 1 Ci
o 1 TBq (T = tera = trillion) = 1,000,000,000,000 becquerels = 27 Curies = 27 Ci
o 1 PBq (P = peta = quadrillion) = 1, 000,000,000,000,000 becquerels = 27,000 Curies = 27,000 Ci = 27 kCi
· milk and water: becquerels per liter (Bq/l)
o high contamination levels in water samples are sometimes reported in becquerels per cubic centimeter (Bq/cm3). A liter contains 1,000 cubic centimeters
· food: becquerels per kilogram (Bq/kg)
Other Activity Reporting Units
· The US has a tradition of reporting radioactivity in disintegrations per minute (d.p.m.) especially for low levels of radioactivity associated with weapons testing fallout
· To convert d.p.m. (disintegrations per minute) to becquerels, divide by 60 (e.g. 180 d.p.m. = 3 Bq)
· To convert becquerels to d.p.m., multiply by 60
· Older protection action guidelines use the reporting unit microcurie (μCi) to delineate intervention levels (1 μCi = 1,000,000 picocuries = 37,037 Bq) (United States Department of Health and Human Services 1982)
· Up until recently, the United States used the now antiquated reporting system of picocuries; 1 Bq = 27 picocuries
o To convert picocuries to becquerels, divide by 27 (27.027)
o To convert becquerels to picocuries, multiply the number of becquerels by 27 (27.027)
o To convert picocuries per cubic meter to becquerels per cubic meter, multiply pCi/m3 times 0.037
Energy Reporting Units
· 1,000,000 electron volts (eV) = 1 MeV (1 mega-electron volt)
· 1,000 electron volts (eV) = 1 meV (1 milli-electron volt)
f = quadrillionths = femto = 10-15
P = quadrillion = peta = 1015
p = trillionths = pico = 10-12
T = trillion = tera = 1012
n = billionths = nano = 10-9
G = billion = giga = 109
μ = millionths = micro = 10-6
M = million = mega = 106
m = thousandths = milli = 10-3
k = thousands = kilo = 103
- An international unit of radiation dosage, which measures the amount of radiation that is absorbed by a person, usually expressed in microsieverts or millesierverts. One sievert is equal to 100 REMs, a dosage unit of X-ray and gamma ray exposure.
- One disintegration per second of a radioactive material, also defined as "The activity of a quantity of a radioactive material in which one nucleus decays per second."
There are four basic pathways of human exposure to radiation resulting from nuclear accidents of any kind:
- External: Accident location radiation shine, plume cloud shine, ground shine, shine from contaminated clothing and shoes
- Absorption by dermal deposition
- Inhalation: Plume inhalation and re-suspended ground deposition
- Ingestion: Primary (from foliar and surface contamination), Secondary (via direct pathways to human consumption such as the forage-cow-milk pathway), and Tertiary (via indirect pathways to human consumption, e.g. the incorporation of contaminated whole foods such as milk, whey, wheat, corn, or soy into processed foods and their redistribution to markets in areas unaffected by ground deposition)
- Inhalation of biologically significant radioisotopes, including radioiodine, plutonium, cesium, and strontium particles
- External exposure to cloud and ground shine
- Exposure to contaminated surface water and contaminated surfaces will continue long after plume passage
- After airborne plume particles have been deposited or have dissipated, ambient air and skin surface measurements provide almost no information about exposure.
- Immediate exposure to contaminated air, or the contamination that might be on clothing or exposed skin, as measured in microsieverts, does not provide information about total exposure via absorption, inhalation, and ingestion.
- The key question is, in fact, what is the “long term exposure” of an individual to contaminated food products via ingestion? The inhalation and absorption pathway or the ingestion of contaminated drinking water may be the most important exposure routes for individuals living near the accident site, including residents of Tokyo, during southern and southwesterly wind flows, but the ingestion pathway provides most of the exposure to individuals not living near the reactor site. Transfer of radioactive contamination into the food chain, especially in vegetables, wheat, soy, corn, milk, meat, and high fructose corn syrup, can provide exposure to individuals and communities that have experienced no radioactive fallout whatsoever from the Fukushima Daiichi accident.
MOX fuel derived plutonium, curium and Americium isotopes will characterize reactor 3 emissions. Pathways of importance are inhalation of plume cloud particles and inhalation of resuspended particulates after deposition by rainfall events. If criticality in the Fukushima Daiichi reactor 3 reaches full meltdown status, contamination patterns will be hemispheric in distribution.
Background RadiationTotal background radiation exposure averaged over large population groups (i.e. the entire population of the United States) is reported as 6.2 mSv/yr. This hypothetical exposure level assumes no person is being exposed to the plumes of any ongoing nuclear accident. "Background radiation" can be divided into two components.
- Exposure to naturally occurring radiation, such as radon gas, cosmic radiation, and the ubiquitous naturally occurring radioactive substance potassium (K). (See the notorious banana equivalent dose noted below.) Approximately half of background radiation is from naturally occurring sources.
- Exposure to routine anthropogenic sources such as radiological imaging (mammograms, CT scans, dental x-rays, radiation therapy, and nuclear medicine facilities.) Gackground radiation also includes exposure to the cumulative fallout from past nuclear weapons tests, residual accumulations of Charnobyl contamination, other nuclear power and fuel reprocessing accidents, the ongoing operation of nuclear power plants, and fossil fuel burning, especially coal.
The estimated exposures from background radiation noted below represent the average exposure of hundreds of millions of people. In reality, such "background exposure" varies widely with geographical location, exposure to sunlight via sunbathing, and use of medical technologies such at CAT scans (see below).
Annual exposure from all sources of background radiation (naturally occurring and anthropogenic) typically averages:
- 0.0062 sieverts per year (Sv/yr)
- 6.2 millisieverts per year (mSv/yr)
- 620 millirems per year (mR/yr)
- 6200 microsieverts per year (uSv/yr)
- 1.7 millirems per day (mR/day)
- 17 microsieverts per day (uSv/day)
- 0.017 millisieverts per day (mSv/day)
- 0.7 microsieverts per hour (uSv/hr)
- 0.07 millirems per hour (mR/hr)
EPA Action Levels
The level of exposure that the EPA considers actionable is 1000 mR, or 1 R, over four days. Measurements of radiation at these levels would trigger actions contained in the Protective Action Guidelines for Nuclear Incidents (http://www.epa.gov/rpdweb00/rert/pags.html) published in 1992. 1000 mR over four days can be broken down into the following daily and hourly exposure levels that should be a concern to all citizens and can easily be compared to the "background" radiation levels noted above.
- 250 millirems per day (mR per day)
- 0.0025 sieverts per day (Sv/day)
- 2.5 millisieverts per day (mSv/day)
- 2,500 microsieverts per day (uSv/day)
- 10.415 millirems per hour (mR/hr)
- 0.10415 millisieverts per hour (mSv/hr)
- 104.15 microsieverts per hour (uSv/hr)
- The famous banana equivalent dose (BED) is derived from the fact that bananas contain the ubiquitous naturally-occurring radioactive isotope potassium (K): (1/2T = 1 billion years). Of all the potassium in the world, 0.0117% consists of this nearly harmless naturally occurring radioisotope. One gram of potassium has an activity level of 30 Bq. The relative insignificance of radioactive potassium in bananas should not be used to divert attention from the presence of biologically significant quantities of isotopes such as radioiodine or plutonium: 15 Bq of iodine-131 is a biologically significant activity level; 2.5 Bq/kg of plutonium-239 in any food mandates extreme precautionary measures. (wikipedia.org/wiki/Banana_equivalent_dose).
- Average hourly radiation exposure: 2.8 microsieverts
- Background radiation exposure: 3 millisieverts/year (varies widely with geographical location and may be as much as 20 times higher in sections of India, Iran, and Europe)
- Total average radiation dose from all sources received by a person living in the U.S.: 6.2 millisieverts/year
- Mammogram: 3 millisieverts
- Chest CT scan (computed tomography or CAT scan): 6 to 18 millisieverts
- Limit of exposure for nuclear workers for one year: 50 millisieverts (mSv)
- Emergency workers at the Fukushima Daiichi site: 250 millisieverts (mSv)
- Peak radiation dose at the boundary of the Fukushima Daiichi nuclear power station on March 16, 2011: 400 mSv per hour
United States Food and Drug Administration. (March 5, 1997). Draft: Accidental radioactive contamination of human food and animal feeds: Recommendations for state and local agencies. Center for Devices and Radiological Health, U.S. FDA, Washington, D.C.
- This draft was issued on 3/5/97, but not received as requested for review by RADNET until August 9, 1997. This proposed draft represents a radical revision of the 1982 FDA recommendations, which are rescinded by these proposed standards.
- Derived intervention levels are far stricter (more conservative) than the 1982 regulations. Derived intervention levels for the radiocesium group (1,160 Bq/kg for 15 year old = 31,320 picocuries/kg) are far closer to the "levels of concern" which resulted in seizure of food containing 10,000 picocuries/kg of radiocesium following the Chernobyl accident.
- The most radical change in these guidelines is the inclusion of numerous additional radionuclides for consideration following a nuclear reactor or other type of nuclear accident. (See Appendix E). The derived intervention level for transuranic nuclides such as 238Pu, 239Pu and 241Am range from 2.0 to 2.5 Bq/kg for a 3 month old infant. These more inclusive guidelines are an acknowledgment of the lessons of the Chernobyl accident, i.e. a major nuclear accident includes many different radionuclides whose health physics impact can not be delineated by a single protection action guideline standard such as 10,000 picocuries (370 Bq).
- The one significant unfortunate lapse in this draft is the use of the "number of samples contaminated above regulatory limits" to summarize contamination levels derived from the Chernobyl accident without reference to the specific levels of contamination in the samples analyzed. (See tables C-1, C-2, and C-3). This continues the FDA inclination to withhold nuclide-specific data after incidents of widespread contamination of foodstuffs. The substitution of an arbitrary action limit to replace nuclide-specific data illustrates that the FDA is still inclined to withhold information about rising levels of radioactive contamination in the food chain. In the event of another accident, the use of this arbitrary limit raises the question: will the FDA withhold data if contamination trends up towards the derived intervention level? All levels of contamination below the DIL are, after all, "below regulatory limits."
- "Recommendations on accidental radioactive contamination of human food and animal feeds were issued in 1982 by the Food and Drug Administration (FDA) (FDA 1982, Shleien et al 1982). Since then, there have been enough significant advancements related to emergency planning to warrant updating the recommendations." (pg. 1).
- "DILs [Derived Intervention Levels] are limits on the concentrations permitted in human food distributed in commerce. ... Comparable limits were not provided in the 1982 FDA recommendations. DILs apply during the first year after an accident." (pg. 3).
- "The 1982 FDA recommendations were developed from the prevailing scientific understanding of the relative risks associated with radiation as described in the 1960 and 1961 reports of the Federal Radiation Council (FRC 1960, 1961). Since 1982, FDA and the other federal agencies in the United States have adopted the methodology and terminology for expressing radiation doses provided by the International Commission on Radiological Protection (ICRP) in 1977 (ICRP 1977, ICRP 1984a, EPA 1987)." (pg. 5).
- "The equation given below is the basic formula for computing DILs.
- "The food monitoring results from FDA and others following the Chernobyl accident support the conclusion that I-131, Cs-134 and Cs-137 are the principal radionuclides that contribute to radiation dose by ingestion following a nuclear reactor accident, but that Ru-103 and Ru-106 also should be included (see Appendix C)." (pg. 10). ... "DIL is equivalent to, and replaces the previous FDA term Level of Concern (LOC)." (pg. 12).
- "The types of accidents and the principal radionuclides for which the DILs were developed are:
- nuclear reactors (I-131; Cs-134 + Cs-137; Ru-103 + Ru-106),
- nuclear fuel reprocessing plants (Sr-90; Cs-137; Pu-239 + Am-241),
- nuclear waste storage facilities (Sr-90; Cs-137; Pu-239 + Am-241),
- nuclear weapons (i.e., dispersal of nuclear material without nuclear detonation) (Pu-239), and
- radioisotope thermoelectric generators (RTGs) and radioisotope heater units (RHUs) used in space vehicles (Pu-238)." (pg. 13).
- "For each radionuclide, DILs were calculated for six age groups using Protective Action Guides, dose coefficients, and dietary intakes relevant to each radionuclide and age group. The age groups included 3 months, 1 year, 5 years, 10 years, 15 years and adult (>17 years). The dose coefficients used were from ICRP Publication 56 (ICRP 1989)."
|intervention level of dose (Sv)|
|DIL (Bq/kg) =|
|f x Food Intake (kg) x DC (Sv/Bq)|
- 0 - 0.25 Sv (0 - 250 mSv): None
- 0.25 - 1 Sv (250 - 1000 mSv): Some people feel nausea and loss of appetite; bone marrow, lymph nodes, and spleen damaged
- 1 - 3 Sv (1000 - 3000 mSv): Mild to severe nausea, loss of appetite, infection; more severve bone marrow, lymph node, and spleen damage; recovery probable, not assured
- 3 - 6 Sv (3000 - 6000 mSv): Severe nausea, loss of appetite; hemorrhaging, infection, diarrhea, peeling of skin, and sterility; death if untreated
- 6 - 10 Sv (6000 - 10,000 mSv): Above symptoms plus central nervous system impairment; death expected
- Above 10 Sv (10,000 mSv): Incapacitation and death
- 3.7 Bq/m2: Begin monitoring of ambient exposure radiation levels (microsieverts per hour), terrestrial contamination levels above background (Cs-137, Bq/m2), and rainwater (I-131, Bq/l) via the EPA, CDC, DOE, FDA, IAEA, state, and local websites.
- 37 Bq/m2: Expand monitoring to include measurements of local contamination of food, water, and milk by indicator nuclides I-131 and Cs-137 as measured in Bq/kg or Bq/l. Begin protective actions: avoid exposure to rainfall events, remove shoes and clothing before entering domestic environments, and shower after exposure to rain.
- 370 Bq/m2: Expand protective actions: stay indoors whenever possible, close windows, seal openings, cover gardens with tarps, shelter livestock, avoid ingestion of leafy vegetables and fruits harvested in fallout areas. Expand monitoring of food, water, and milk; discard or avoid ingesting foods and water contaminated by the indicator nuclides I-131 and Cs-137 above 370 Bq/kg or Bq/l (10,000 picocuries, the protection action level used by the US FDA to dispose of imported foods contaminated by Chernobyl-derived fallout). Continue monitoring of ambient radiation levels.
- 3,700 Bq/m2: Expand protective actions to restrict movement of children, outside workers, nonessential travel, and recreational activities such as hiking and sunbathing. Closely monitor food, milk, and water intake, sources, and radiation levels. Continue use of information technology to keep informed of ongoing emissions. Immediate sheltering is the best option to avoid exposure to a passing plume.
- 37,000 Bq/m2: Prepare to evacuate to a safer zone, e.g. the southern hemisphere or another planet.
Nuclear weapons fallout levels
- Denmark: maximum fallout deposition occurred in 1963: 988 Bq/m2 Cs-137 (RISO National Lab)
- US: maximum fallout deposition occurred in 1963: +/-2,500 Bq/m2 Cs-137 (downwind) Weapons testing location depositions were much higher but deposition levels are classified information.
- Denmark: Denmark was considered an "unaffected" area; maximum deposition was 1,210 Bq/m2 Cs-137 in 1986
- Northern England, Sweden, Finland: +/-100,000 Bq/m2 Cs-137 (1986)
- Areas of maximum fallout in Russia: +/-1,000,000 Bq/m2 Cs-137
The ultimate size and impact of the unfolding accident at the Fukushima Daiichi plant in Japan is unknown. With good luck and effective countermeasures, the source term releases at Fukushima Daiichi could be one or two orders of magnitude less than the source term releases from Chernobyl. Unfortunately, given the complexity of the Daiichi reactor complex, which includes three at-risk reactor vessels and four at-risk spent fuel pools, the worst case scenario could involve source term releases one order of magnitude above that of the Chernobyl accident. The New York Times had an excellent summary of the number of fuel assemblies in the reactor vessels and spent fuel pools at the Japan facility in its Friday, March 18th edition. A summary of this information follows this overview. It could take weeks, months, or even years before the Japanese and U.S. governments and the IAEA (International Atomic Energy Agency) will be able to provide even the most preliminary estimates of release inventories.
Once an accident plume has passed, measurements of ambient radioactivity levels provide little or no information about exposure. The tragedy of the ongoing Japan disaster is that radioactivity will be emitted continuously for a long period of time; its terrestrial deposition will depend on accident duration, accident intensity, wind direction, and ocean current dispersal of liquid contaminants. Rhetorical commentary on the accident plume, such as “radioactivity is low” or “such and such location will have a minimum impact from this accident” should have zero credibility. The actual evaluation of the amount of radioisotopes in the environment must await laboratory analysis of the contaminant load in impacted abiotic and biotic media. In places such as California, Oregon, and Washington, which began receiving tiny amounts of radioactivity on Saturday (3/19/11), an evaluation of the significance of the radiological impact of the Fukushima Daiichi accident can only be measured by a laboratory analysis of the soil deposition of the indicator isotope radiocesium, as measured in becquerels per square meter. If new cesium deposits can be documented (on top of old weapons testing and Chernobyl radiocesium baseline deposits), new deposits of radioiodine-129 (1/2 T = 8 days), and other biologically significant isotopes, including MOX fuel-derived plutonium-239 (1/2 T ±24,000 years,) will also be present. The analytic techniques that measure gamma and beta emitting radiocesium will not apply to alpha emitting plutonium, which will require additional time consuming laboratory measurements.
- How many becquerels per square meter of the accident indicator isotope cesium-137 have been deposited in my community?
- How many becquerels per liter of cesium-137 are in the milk, including breast milk, that my children are drinking?
- How many becquerels of I-131 are in public and private drinking water supplies that my family is utilizing?
- How many becquerels of I-131 are in milk, including breast milk, that my children are drinking?
- Reactor 1: 400 in reactor vessel and 292 in spent fuel pool
- Reactor 2: 548 in reactor vessel and 587 in spent fuel pool
- Reactor 3 with MOX fuel: 548 in reactor vessel and 514 in spent fuel pool
- Reactor 4: 0 in reactor vessel and 1,479 in spent fuel pool
- Reactor 5: 548 in reactor vessel and 826 in spent fuel pool
- Reactor 6: 764 in reactor vessel and 1,136 in spent fuel pool
- Common storage spent fuel pool: 6,291
Accurate Publicly Available Information?Two key issues bedevil the accurate reporting of the extent of contamination from any nuclear accident and the health physics significance of accident emissions. The preceding series of definitions will hopefully mitigate the first issue: the confusing terminology of the many reporting units used by various governmental, corporate (e.g. TEPCO), and environmental organizations. The second issue is much more difficult to alleviate: the lack of knowledge of the reporters and commentators who provide news about the Fukushima Daiichi disaster and other accidents. A March 23, 3011 article in the Wall Street Journal graphically illustrates this conundrum. Carl Bialik reports Tokyo Electric Power Company's main gate gamma radiation level reading at 240 microsieverts per hour (uSv/hr), a fairly low reading considering that seven nuclear accidents are occurring all at once, and then reports spinach collected "60 miles southwest of the plant last Friday contained 54,000 becquerels of the radioactive element iodine-131." He continues, "All the numbers add up to a reassuring picture of the very low risks from the radiation emitted from Fukushima so far, which is less than the amount people typically get from common sources such as the sun, medical tests, and air travel." (Bailik 2011). Given the FDA derived intervention level of 167 Bq/kg for radioiodine-131 for a one year old child and the annual, daily, and hourly background exposures noted above, The Wall Street Journal report becomes a pardigm for the misinformation that will characterize most reporting on the ongoing Fukushima Daiichi accidents.
Fukushima Daiichi Radiological Surveillance Data
Radiation Surveillance Data Sources
Dr. Ryugo Hayano of Tokyo University's Compiled Timelines -- Timelines of radiation data on Twitter, same data on Lockerz here: http://lockerz.com/gallery/9699108
Radiation Monitoring Map in Japan -- Shows individual monitoring points with the recent data in a line graph
Compilation of Information from the Japanese Government -- WIDE project's compilation of links
SPEEDI -- System for Prediction of Environment Emergency Dose Information, shows disaster prevention data
Japan Open Radiation Dashboard -- Shows graphs of radiation data by prefecture
Realtime Map of SPEEDI -- Shows levels at each monitoring station, color coded
Spreadsheet of Current Reactor Conditions -- Shows actions being taken on each reactor
MEXT - Japan's ministry of Education, Culture, Sports, Science and Technology's readings by prefecture
Excerpts from Michiko Otsuki's blog (a TEPCO worker on the scene)
Where are the Clouds? -- A blog covering the movement and impact of the radioactive plume
US. Department of Energy -- Links to slideshows of graphical representations of aerial monitoring data over time
EPA's RadNet map
Another RadNet map interface
Black Cat Systems Online Geiger Counter Nuclear Radiation Detector Map -- Amateur network of Geiger counters
RadiationNetwork.com -- another amateur Geiger counter network
Oregon State Department of Health Monitoring Data -- Updated daily
Texas A&M Plume Trajectory Projections
MIT Nuclear Information Hub
Reuter's Japan Earthquake Blog
Sources From Other Countries:
IRSN, Institut de Radioprotection edt de Surete Nucleaire (French)
NILU - Realtime mapping of radioactive releases
Weather.co.uk's Radiation data Set Maps -- Shows various monitoring stations and the change in radiation levels over time
Any information or sources of similar data would be greatly appreciated!
- To convert picocuries to becquerels, divide by 27 (27.027).
- To convert d.p.m. (disintegrations per minute) to becquerels, divide by 60.
- To convert becquerels to picocuries, multiply the number of becquerels by 27 (27.027).
- To convert picocuries per cubic meter to becquerels per cubic meter, multiply pCi/m3 times 0.037.
- To convert becquerels per cubic meter to microbecquerels per cubic meter, multiply the Bq/m3 times 1 x 10-6.
- Reactor water system leaks: a very common form of mishap at many nuclear reactor facilities. The release of tritium to groundwater is a tip off of ongoing reactor water system leaks, and has been documented at dozens of US reactors. More serious water system leaks will also release fission products.
- Fuel cladding failure accidents: A fuel cladding failure accident occurred at the Maine Yankee Atomic Power Company in the late 1990s and resulted in the closure of the plant. According to licensee records, 66 failed fuel assemblies released fuel pellets into the reactor water system. Some of these were removed by vacuums and placed in the spent fuel pool, but the majority of fission products remained in the reactor vessel as "low-level radioactive waste" and was buried with the reactor vessel in South Carolina when the facility was decommissioned in 1999. The most notorious fuel cladding failure accident occurred at the Haddam Neck, CT, reactor site and released large quantities of fission products to the atmosphere in the early 1990s.
- Spent fuel pool loss of coolant accident (LOCA): Four LOCAs are now underway at the Fukushima Daiichi complex. Loss of spent fuel pool cooling results in fuel assembly overheating, followed by fuel pellet expansion, fuel assembly swelling, cracking, and deformation. Fuel assemblies may then burst open, releasing fuel pellets as well as fission products into the remaining coolant. A total loss of coolant can result in the gradual melting of the entire fuel pool fuel assembly matrix. The large quantity of fission products being washed out of the Fukushima Daiichi spent fuel pools and into basements, drains, and the marine environment are an indication that a loss of coolant accident is well underway in these units. The timeframe for the duration of an uncontrolled LOCA is unknown but could be measured in months and possibly even years.
- Loss of reactor coolant accident (LORCA): The accident at Three Mile Island was a LORCA that was eventually resolved by the resumption of the cooling of the reactor vessel spent fuel assemblies. LORCAs appear to be underway at three of the six Fukushima Daiichi reactor units. The other three units were not critical, that is undergoing fission chain reactions, at the time the tsunami destroyed the backup cooling systems. A LORCA occurs when a reactor vessel is breached or otherwise damaged and fuel assembly coolant (usually water) is no longer available. The continuing fission chain reaction can intensify resulting in the melting of fuel followed by the melting of the reactor vessel internals, bursting of pipes, and damage to pressure operated relief valves. This is called a "serious core event" and can intensify as a function of time, coolant dispersal, and damage to the pressure vessel as the primary pressure boundary. Once the pressure vessel is breached, large releases of fission products will occur. Continued heating of the fuel assemblies can result in a total meltdown; the extreme heat generated by an ongoing meltdown will eventually result in the melting of the pressure vessel and the dispersal of the molten fuel into the ground or groundwater underneath the reactor vessel. This is the worst case scenario accident for an operating nuclear reactor other than vaporization.
- Vaporization: Vaporization of a nuclear reactor complex, including both the spent fuel pool and the reactor vessel and its fuel assemblies can occur during a nuclear attack. During the Cold War, the United States and Russia both targeted each other's nuclear facilities. Vaporization of a nuclear reactor site or weapons production facility as a result of nuclear war or terrorist attack would result in the dispersal of the entire cumulative inventory of the facility or facilities. The world catastrophe that would follow would result from the efficient vaporization of all onsite fission products, with a release of 25 to 500 times the contamination discharged at the Chernobyl accident.
RADIOMETRIC SURVEY: A radiological survey of a contaminated site, especially sediments, soil, or other media containing sufficient data points to characterize the spread of contamination from a particular source point isometrically, i.e. via contour maps using isopleths which express the values of the data points. Aerial radiometric surveys have been utilized since the 1950's to characterize oil bearing geological formations, by the defense department for analyses of Russian and other weapons production facilities, and after the Chernobyl accident to characterize fallout in Russia, Sweden, and England. Radiometric surveys of fallout patterns from the Japanese disaster will be expressed in becquerels per square meter as soon as state and federal reporting agencies analyze soil samples for contamination. Such survey reports should begin with baseline data documenting weapons testing fallout and Chernobyl accident contamination residues, which existed at the beginning of this accident. Due to the size of the potential release from Japan (±40 million curies of the indicator nuclide radiocesium) and the probable long term emissions scenario (months, possibly years), surface contamination analysis should be done weekly, if not daily, in locations such as the states of California, Oregon, and Washington. Links to other environmental protection and monitoring websites providing information about the accident at Fukushima Daiichi will be posted on this website as they become available.
- sea vegetables: Fucus vesiculosus, brown algae and other benthic algae are among the most sensitive bioindicators and are often used to gauge weapons fallout contamination and nuclear reactor pollution from many radionuclides which these media will readily absorb.
- The terrestrial counterpart to sea vegetables as sentinel organisms are lichens, moss, mushrooms, and grass. Leafy vegetables such as spinach are examples of bioindicators which humans consume directly and which quickly absorb foliar deposition of radiocesium as well as the short-lived radioiodine-131 (1/2T = 8.04 d.). Milk and milk products, as food crop products of the forage-livestock pathway, are bioindicators which concentrate the rapid transfer of radioactive contamination following nuclear accidents and releases. The presence of iodine-131 in milk is a key indicator of the magnitude of a nuclear accident.
- benthic invertebrates: Mussels (mytilus edulis, c. virginica, etc.) are another group of sensitive bioindicators and are also used to evaluate the impact of other types of chemical fallout (see U.S. Mussel Watch sec. 5b).
- fish: Less sensitive than benthic algae (sea vegetables) as bioindicators, fish are an important indicator of the level of human consumption of radioactive contamination. Freshwater fish often show much higher levels of the bioaccumulation of radionuclides and other forms of chemical fallout than marine specimens.
- grazers: reindeer, sheep, goats, and livestock: Products from these participants in the forage-livestock pathway - reindeer (meat), sheep (mutton), goats (cheese and milk), and cattle (milk and meat) - often exhibit rapid bioaccumulation of radioactive contamination.
- 131I: 2,380 pCi/m2 (88 Bq/m2)
- 137Cs: 650 pCi/m2 (24 Bq/m2)
- 134CS: 290 pCi/m2 (11 Bq/m2)
- 103Ru: 720 pCi/m2 (27 Bq/m2) (pg. 8-3)
- 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.
|Fusco, Paul and Caris, Magdalena. (2001). Chernobyl Legacy: Twenty four minutes and zero seconds anti meridian. de.MO, Millbrook, NY.|
|NOTICE TO THE READER: Levels of contamination cited within the Chernobyl data base are peak concentrations unless otherwise noted. Ground deposition activities varied widely in most areas impacted by the Chernobyl accident: A location receiving, for example, 40,000 Bq/m2 could be only a few kilometers from another location receiving an order of magnitude less deposition. Nurmijarvi, Finland, a location with real time data collection capabilities, recorded the highest air concentrations of any location cited in RADNET (over thirty Chernobyl-derived nuclides were observed); ground deposition activities at this location, while elevated, were typical of many locations receiving heavy rainfall associated fallout. The data cited for both ground deposition and contamination of abiotic and biotic media which follow are the highest readings in the survey being cited, unless otherwise indicated.|