Monday, March 14, 2011

From Chernobyl to Fukushima

In conjunction with colleagues, I authored this report after Chernobyl.  Reactor design, those that have been built since then, are vastly improved in the area of safety.  Nevertheless, the idea of keeping an International Nuclear Response Team ready to go is still timely.

International Nuclear Incident Response

July 13, 1997

Prepared for International Monetary Fund
by International Nuclear Incident Response

The Need

Of the 432 nuclear power stations in operation in 29 countries (as of 1995), most have demonstrated safety levels and generate power with less environmental impact than any fossil fuel or hydroelectric stations of similar, megawatt for megawatt.  Western Europe, in particular, has no better alternative for generating electric power and, even in the aftermath of Chernobyl, no European country has renounced nuclear energy as a power source.  Nuclear power now generates roughly 20% of the world’s supply, and this dependency will increase.  There is no substitute in sight until fusion power becomes commercially feasible.  The environment impact of coal is far worse, even in terms of released radiation, than historic operation records of nuclear power plants have been in Europe and the United States.  Indeed, the record of clean nuclear power generation by Western Europe is unmatched by any coal, oil or  hydroelectric power source.

Chernobyl 4

Nevertheless, the Chernobyl incident of April 26, 1986, remains the worst industrial accident and the worst nuclear incident in history.  The release of radioactivity exceeds the Hiroshima and Nagasaki bombings by 200 times.  The direct and indirect ten year costs of the explosion, cleanup, crop losses, population relocation, ongoing medical expenses and the ensuing safety measures at the other Chernobyl plants which remain in operation are about $400 billion US and the twenty year cost will probably total one half trillion dollars US.  Thirty‑one lives were  lost and about 155 more people among the 800,000 who are considered part of the liquidation crew, are suffering from acute  radiation sickness.  Practically 72% of the liquidators are in poor health today.  Another 5,237 people in the area are disabled for reasons stemming from the disaster.  Twenty‑four thousand five hundred square kilometers of land, which includes some of the world’s best cropland, are contaminated at levels considered dangerous and will remain dangerous for at least two generations.  About 225,000 people have been evacuated and resettled, and this is not enough.  2.4 million people now live on land considered contaminated.  Children of the residents within the 30 kilometer zone have mutations which will be passed on to further generations.  Thyroid cancer in the children who were under 8 years old at the time of the disaster are 200 times normal.  One hundred ninety‑two metric tonnes of enriched uranium and plutonium were in that core, and 80 percent was blown into the environment.  The estimated release amounted to 6.4 billion curies.  One curie carried in one’s pocket will kill with a probability of 50%.  The hastily erected steel and concrete sarcophagus is beginning to crumble, leaks are increasing, and it is possible that the pool of uncontrolled fuel may be melted into a puddle at the bottom of the mess and could cause another explosion.

Chernobyl Impact
The Chernobyl incident was a significant factor in the breakup of the USSR.  It would be a destabilizing influence in any country.  The costs of such an incident, even when borne by the international community as it had been for Chernobyl, still acts as a major brake on the local and regional economies.  Ensuing economic hardships aggravate the economic instability, creating an irresistible political force.
Risk Assessment
There are 18  RBMK reactors similar to Chernobyl still operating in Eastern Europe and Russia.  In addition there are six more graphite‑moderated power reactors operating in other parts of the world.  These reactors are unstable at low power output and have a tendency to develop hot spots leading to thermal runaway conditions and may escalate to the hydrogen explosion and burning graphite that destroyed Chernobyl 4.  Worse, they do not have true containment structures, which would have kept Chernobyl from spewing its core.  Over the next twenty years we can expect two more Level Seven incidents from these reactors.  A Level Seven incident results in major damage and serious loss of life.  The unmitigated costs of these events would probably be similar to Chernobyl.
In addition, we can expect about ten events of Level Four and above over the next twenty years, resulting in loss of life and requiring an emergency response for radiation leakage.  The reactor meltdown at Three Mile Island was a Level Five incident.  These could occur in any of the aging boiling water reactors common in the United States and elsewhere, especially where containment vessels are showing signs of deterioration.  Finally, there are an unknown number of nuclear powered vessels in the world, including icebreakers and military transports using pressurized water reactors.  Russia, in particular, intends to build many of these for floating power generation and export to other countries.  The record of these PWR reactors is not public and no estimate of the risk is possible here.  We suspect, however, that the major risk is the risk of refueling, transport and storage of the fuel rods.
These Level Four, Five and Six incidents may result in costs of $2 billion US to $20 billion US each, if left to normal mitigation.
In total, the international costs associated with nuclear incidents, in our estimation, may reach $1.8 trillion US in the next twenty years, including Chernobyl, at demonstrated mitigation levels.  We propose to reduce this cost and risk by a large factor using a number of methods developed with the hindsight of Chernobyl. 

Treaties and Politics
Politically, the nations of the world have looked at nuclear incidents as a byproduct of war and its preparations.  The major risks today seem to be squarely in the utilitarian, even commercial, domain.  The major international treaty which commits the nuclear‑capable countries to some level of responsibility is the Nuclear Non‑Proliferation Treaty, which requires immediate disclosure of nuclear incidents and cooperation in the mitigation of effects.  More recently, this position was reinforced by the Convention on Early Notification and the Convention on Assistance in Case of a Nuclear Accident or Radiological Emergency.  These were drafted in response to Chernobyl and are now in effect. Finally, the dumping of low‑level radioactive wastes is addressed by the 1993 Amendment to the London Convention on Radioactive Material Dumping, which has not been ratified yet by Russia.
In every nuclear incident there has historically been reluctance on the part of the country involved to advertise details of its plight to the very nations that it needs for assistance.  There have been no international accredited institutions without political affiliations capable of meaningful response, except, perhaps, International Red Cross/ Red Crescent, in its area of expertise.  The unhesitating use of Red Cross because of its helpfulness and lack of political affiliation, is indicative.
Trustees of INIR are American, Polish, Ukrainian, and more.  We are pursuing an international charter, international siting, international sources of funding and an international agenda.  Our goal is to remediate and mitigate the damage from nuclear incidents without regard to affiliation or citizenship. 

Methods and Technologies
INIR is being formed to mitigate and remediate environmental damage from nuclear incidents and, where possible, nuclear waste incidental to such incidents.  Our methods rely on several new technologies that were not available at Chernobyl and which, in retrospect, would have substantially reduced the death toll, time to recovery, and costs of this disaster.  These methods are:
            1. Creation of an internationally chartered private foundation (non‑profit) without a political agenda, to respond quickly to nuclear incidents wherever in the world they might occur.
            2.  Maintain a fleet of Boeing 747‑200 and Russian AN‑147 heavy lift airplanes at two major sites in the world (Anchorage and Amsterdam ‑ six aircraft total), together with the specialized equipment, crew and staff to be set up onsite within twenty‑four hours of a reported incident.  These aircraft will be especially set up with roll‑on, roll‑off capability and raw materials bins.
            3.  Keep on file the construction details of every registered reactor type in such form that it can be quickly used for finite element analysis of weaknesses and repairs.  Duplicate the files and computation facilities so that a FEM technician and computer is onsite in the first plane load.
            4.  Build a pair of SulPol factories in roll‑on, roll‑off containers that will fly to the incident site and set up a SulPol factory in twenty‑four hours.
            4.  Use of SulPol, a polymerized sulfur formulation, to strengthen the outer layers of the Chernobyl sarcophagus and fill cracks in containment vessels prone to weathering, porosity, and oozing of lubricants.  SulPol does not require water and sets in twenty minutes.  It is two to four times stronger than concrete and does not shrink upon curing.  It adheres to aggregate with five times the tenacity of concrete.  It is thermally non‑conductive, self‑extinguishing and completely non‑toxic.  One of the  locally obtainable  ingredients is used engine oil.
            5.  Use of SulPol to encapsulate high‑level radionuclides recovered from adjacent areas on site.
            6.  Use of SulPol to create water barriers and surface water containments to prevent leaching of mobile radionuclides and fission products into the water table.  SulPol is impervious to water and can be formed underwater.
            7.  Development and maintenance of a number of robot probes capable of entering moderate radiation areas inaccessible to humans for damage  assessment.  Each team would also have a few Unmanned Aerial Vehicles to survey buildings from aloft and sample plumes, and quickly map radioactivity in the surrounding area. Each of these would be equipped with GPS satellite location and self‑contained DR systems to map the information back to a central computer.  In this manner a reliable site estimate could be worked up quickly.  The telemetry and remote control technologies will be similar to those developed for the Mars Sojourner probe.  The probes would carry video cameras and radiation instruments, a sophisticated radio capable of coding a weak signal for clear communication through barriers and transponders, a programmable onboard response system, and autonomous safety systems.  One of the devices is an extrudable probe with sensors that can be poked around corners or obstacles.  Another is a tiny radio transponder that can be dropped on command to ensure communication inside shielded buildings.  Finally, a short‑lived disposable sensing grenade can be “tossed” into areas so hot even the probe could not operate there.
            8.  Soils contaminated with cesium 137, strontium 90 and radionuclides, including transuranic radionuclides, can be remediated with one or more crops of Rapeseed, which seems to have an affinity for heavy elements, grows quickly and is quite hardy.   Rapeseed is rich is combustible oils which not only power the incinerator but may yield some useful waste heat.  The plants are then harvested, incinerated in ovens with exhaust scrubbers, and the radioactive ashes mixed with SulPol and buried in prepared partitions in the sarcophagus.  Soils so heavily contaminated that they would be uninhabitable for generations may be remediated in this way in a year or two.
            9.  Similarly, ponds and pools can be remediated with water hyacinth, a plant so hardy as to be considered a pest.  The plants are then dredged from the water and incinerated similar to the Rapeseed.  Reduction of waterborne contaminants is essential to keep them out of aquifers and rivers.  The lack of such a solution threatens the Dnieper, near Chernobyl,  and perhaps the Black Sea today.
            10.  Maintain a research staff to further refine methods, strategies and technologies in the above areas and incorporate useful methods and technologies as they become available.

The technologies proposed for INIR are unique in their assemblage for the purpose of Nuclear Incident Response.  None are new or unproven.
Strategic Deployment
Anchorage, Alaska and Amsterdam, Holland have been chosen to base duplicate fleets of three planes each, in order to minimize travel time and refueling stops.  Anchorage is within non‑stop travel time for a 747 to the entire Pacific Rim, including the Kamchatka and China.  Amsterdam is a short flight to all parts of the Europe and Western Russia, including the Russian fleet storage area at Andreeva.  The only unprotected parts of the world are in the Southern Hemisphere.  As they develop the requirement, a fleet will be deployed there, perhaps in Australia. 
One of the considerations of the site choice is access by all the nuclear powers without fear of interdiction and reasonable customs laws, as well as being desirable sites for people to live when they are not risking their lives.
Each heavy lift aircraft can carry 35 to 45 metric tonnes (80,000 to 100,000 lbs) of cargo, depending on the fuel requirement for the flight.  The planes have been chosen for their reliability and are, even so, backed up with a spare. 
SulPol plants are contained in two or three 40 foot containers that roll on the planes with undercarriage dollies that are pulled by truck tractors.  Each site will have a SulPol plant and spare parts.
The operations HQ is another 40' container, complete with independent diesel power generators and computers.  Part of this container is the ROV/UAV lab with the robots and their gear, ready to make on the spot repairs and modifications.
Two aircraft will arrive onsite with the SulPol plant and the HQ container.  These will deploy immediately.  Subsequent trips will bring in raw materials, if needed, cranes and special SulPol applications equipment, and more personnel.  The third aircraft will remain in the home port for backup unless a Level Seven response is required.

SulPol Polymerized Sulfur
SulPol is a patented superior formulation for polymerized sulfur.  It is 97% sulfur.  No water is used in the formulation and it is therefore useable in dry areas or where water is contaminated or the utilities are inoperable.  It is at least twice as strong as concrete, binds very aggressively to a large number of aggregates, and is impervious to environmental organic acids and alkalis, salt and fresh water.  Aggregated with lead from old car batteries and boron ( used in reactor moderator rods), it is seven times better at stopping radiation than concrete per unit thickness.  It is not damaged by secondary decay from neutron radiation such as emitted by reactor cores.  A thermoplastic, it is tough and not brittle.  It is immune to the alkali reaction which weakens concrete.  It is thermally non‑conductive and self‑extinguishing.  It melts at 120 degrees C. and is therefore normally not used to encapsulate high‑level reactor wastes when there is a possibility of generated heat.
It is environmentally stable, non‑polluting and non‑toxic.  The formulation can include used motor oil, an otherwise noxious waste product.
Bioremediation of Nuclear Contamination
Data to be supplied by Bohdan.
Remote Telemetry Probes
Crawling through narrow cracks and fissures in a crumbling building too radioactive for humans in protected clothing, a small, cat‑sized probe can go where no one has gone before, such as the surface of Mars.  These are quite distant relatives of the radio controlled vehicles sold in hobbyist stores.  We will require two generic types: ROV’s (Remote Operated Vehicles), which are semi‑autonomous, remotely directed telemetry stations on wheels; and UAV’s (Unmanned Aerial Vehicles the size of a large model airplane), which are less autonomous remotely piloted surveyors on wings.  Each response team will have two complete ROV’s, two complete UAV’s, spare parts, and a repair/modification lab.  Along with the operators will be software and hardware specialists for similar purposes.
Some situations may require an remote underwater vehicle, but we intend to carry sufficient spare parts to assemble an instrumented underwater probe without remote capability.  Most of the sites have rather shallow storage pools and water is a good absorber of radiation.
The six‑wheeled configuration with an articulated chassis similar to the Martian Sojourner is quite good at negotiating broken terrain strewn with debris.  The vehicle, which we will call MUSKRAT because of its sinuous movements, will be preloaded with a route and can follow that route autonomously unless overridden by the operator.  On the operator’s screen, he/she will draw a route through a diagram of the building.  The computer interface will compile that route to a series of movement commands that the MUSKRAT will follow.  Instantaneous telemetry will allow the operator to see whatever MUSKRAT sees; a small video camera with 40:1 telephoto capability and a steadying device will be mounted in a low forward‑looking position.  The lens will be protected from smearing by a number of cover slides that can be dropped one at a time on operator command when the camera’s vision becomes obscured.  A three‑axis periscope can be inserted into the visual path for elevating the view without endangering the camera.  The same periscope can be used for distance ranging by simply converging two superimposed views of an object similar to the mariner’s sextant.
MUSKRAT will carry an extrudable snout about 1.5 meters long with a tiny wide angle TV camera on the tip.  Controlled by motor‑actuated tendons in a manner analogous to an elephant’s trunk, this device will allow MUSKRAT to peer around corners and obstacles safely.  The snout camera, as well as the main camera, will have infrared sensitivity sufficient to see dangerously high temperatures, and will be equipped with IR filters to perform this operation.
In the body of MUSKRAT will be a crude gamma ray spectrometer capable of determining the nature of the radioactive substances, and a rate dosimeter to determine the strength of the source.  Sound, temperature, air velocity and direction, and subsonics transmitted through the wheels will complete MUSKRAT’s instrumentation.
Communication to and from MUSKRAT will be by frequency‑agile, 20 centimeter full duplex radio, developed from existing cellular telephone technologies and using similar error protection codes.  Video out will use JPEG bandwidth compression, decompressed by standard commercially available chips in the operator’s station. A secondary subchannel will carry data from the other instruments which will be polled on a standard commercial GPIB bus interface.
MUSKRAT will calculate its position, when possible, by onboard GPS, a standard commercial version.  Once out of satellite view, MUSKRAT will calculate its DR position by keeping track of wheel revolutions and turns.  The vehicle’s exact position will be displayed on the operators’s console.
The operator’s console will be a customized commercial notebook computer with PCMCIA interface cards to the communications gear and special software developed from commercial navigation programs and CAD software.  At deployment it will be downloaded from the mainframe files with the best available 3D drawings of the building, converted to the format required for MUSKRAT.
Inside a steel‑shelled building, MUSKRAT’s direct radio communications will be shielded.  Therefore, at intervals determined by the operator or preprogrammed, MUSKRAT will drop one of its three transponders and shift to another frequency.  The transponders will relay communications around corners.
However rugged, MUSKRAT will encounter environments in which it would not survive.  Nevertheless, some data will be necessary from these areas.  MUSKRAT will therefore carry a small compressed air launcher (“FORE”), precalibrated with a selection of trajectories and exit velocities, to throw a golf‑ball sized miniprobe into hot spots.  We have devised a tiny high flux rate dosimeter and a very simple crude gamma ray spectrometer to fit into the golf ball.  The surface of the golf ball will have a fuzzy texture to minimize rolling and will be marked with targets suitable for optical ranging from MUSKRAT.  Upon ejection they will deploy three stubby antennas for one‑way communication to MUSKRAT.  These golf balls are designed to survive only long enough to get a series of instrument readings.  MUSKRAT will carry several of them.
MUSKRAT’s outer shell will be a disposable plastic chosen to be resistant to contamination.
We visualize the UAV as a rather large model airplane chosen for low airspeed stability and easy handling and capable of a five pound payload, possibly a biplane, and an eight hour (one shift) endurance.  We have therefore dubbed it LINDBERGH.  The airborne unit will be in constant real‑time communication with the operator’s console, unlike MUSKRAT.  It will be instrumented with the usual flight instruments in electronic form:  artificial horizon, barometric altimeter, airspeed, stall warning.  By telemetry, we will be able to implement a two axis autopilot simply by adding control software to the operator’s console, which will otherwise be similar to the MUSKRAT console.  However, the LINDBERGH console will have a provision for two‑person control: an operator and an observer.  The observer will keep watch via LINDBERGH’s observation camera, steerable by mirror in the belly of the plane.  With a joystick he/she can zoom and pan to keep a passing object in view.  The operator can accomplish this objective on solo flights by laying out a search pattern on a topographic grid and turning on the autopilot, leaving LINDBERGH under automatic control for direction and altitude.
LINDBERGH will carry a forward piloting camera similar to MUSKRAT’s snout camera, a more sensitive gamma ray spectrometer and rate dosimeter, and an onboard GPS.  LINDBERGH will also carry a small vacuum apparatus and several sampling bottles in order to sample smoke plumes and dust particles for laboratory analysis.
LINDBERGH’s assignments will include aerial building survey and land contamination survey in order to get quick assessments for leakage and bioremediation possibilities.

Containment Vessels and Sarcophagus Modeling
NASTRAN running on a 50‑100 megaflop supermini the size of a packing crate.  Two technician’s consoles, a RAID5 100MB disk array, IR and 100Xten connections to the ROV/UAV consoles.  Special tools for rapid estimation.  Shapes and materials lib for SulPol.  ROV/UAV compilers/downloaders.

Contaminant Mapping
3D false color topos from collected UAV data conformed to local topographical data, on a GPS grid.  Project analysis: too hot, salvageable, too dilute.  Best cost and time effective strategies.  Weather and climate data for plants. Population demographics and classification for environmental dependency (urban, rural, farm, fishing, etc.).

Personnel Dosimetry
Rate vs total dose.  Real‑time Becquerel counters with totalizers and UPC scanout in a cheap badge.  Bioassay dosimetry vs a badge.  Bioassay implants with real‑time readout.
Dose management in operations personnel, INIR personnel, and affected citizenry.  Food intake, air and water dosimetry using the same dosimeters and a software analysis

Funding Requirements
Funding for INIR would be primarily from the IMF and related sources.  A small stream of revenues may result from licenses and insurance recoveries where available and from private sources through donations (INIR will be a United States 501 (c) (3) charitable organization), but there is no private source sufficient to fund this program.  In fact, without INIR and its like, there is no way for the international community to insure against a common risk that is really part of the cost of nuclear power.  Without INIR, no government of a nuclear‑powered nation can honestly represent the interests and protect the civil rights of its citizens and may be forced to respond inefficiently in areas in which it is poorly equipped at its own enormous expense.
Summary of Funding Requirements: Ten Years (in $ millions US):

07 thru 17

OPS (operations) is the fund from which response teams operate.  This sum is kept in trust and allocated as needed for incident responses. The first three years reflect a buildup of this fund.  A Level Seven response is estimated at $5 billion US; a Level Five response is estimated at $1 billion US.  Funding for the repair of the Chernobyl sarcophagus is included in 1997.
Equip (equipment) includes six heavy lift airplanes with RoRo modifications at $50 million each, two transportable SulPol plants, 4 remote operated SulPol applications cranes,  4 ROV’s and 4 UAV’s, and the two mobile computer/telemetry centers.
R&D (research and development) includes ROV and UAV development, purchase of software and training for the FEM power station models, SulPol process applications improvements, reinforcing materials and underwater chemistry, and site equipment development.
Admin (administration) includes office space, insurance, salaries and wages, fees, legal, and related ongoing expenses not part of an operation.

Founding Trustees
Subsequent to funding, this list will change.  However, the founders, by virtue of their abiding interest in this program, are committed to participate on any level appropriate.
Bohdan Zakiewicz
Dr. Zakiewicz is the inventor and patent holder of SulPol.  A Polish national who commutes to California, Dr. Zakiewicz has written a proposal for the repair of the damaged sarcophagus at Chernobyl 4 which has been recommended by the Ukrainian Academy of Sciences and was given a $3.1 billion US grant by the Group 7 countries for this project.  The grant remains unfunded, however, and it appears it will be used for other purposes not directly related to the repair. 
Dr. Zakiewicz is also the major contributor to the bioremediation technology.  His background in chemistry and mineral processing is central to this proposal.

Vladimir M. Chernousenko
Dr, Chernousenko was head of the liquidators in the 10 km “Special Zone” surrounding Chernobyl and the author of “Chernobyl, Insight from the Inside” (1991, Springer Verlag).  He is also a member of the Ukrainian Institute for Theoretical Physics.  Few, if any people left alive today have more scientific and practical insight into the methods of this proposal.
Dr, Chernousenko has not yet consented to this appointment, but we have hopes he will.

Ken Brody

Mr. Brody, a former physicist and computer scientist, is best known for the design of the Tricon‑1 fault‑tolerant computer, which was designed to prevent such cockpit errors as the one which destroyed Three Mile Island.  Emergency shutdown installations all over the world use this computer system.
He is the major contributor in robotics and computer systems and the author of this grant proposal.  He is an American citizen residing in California.
Lee Bray
Captain Bray is the senior pilot for American Express, flying a Boeing 727‑200.  He knows every major airport in the world, the intimate details of creating and servicing a fleet of heavy‑lift airplanes, the costs, FAA and international requirements, and the necessary modifications to achieve our goals. His contribution to the logistics and deployment of our response team is essential.
He is a former Flying Tiger pilot.  He is an American citizen residing in Anchorage, Alaska.


SulPol Characteristics
Radionuclides and Half Lives

Reactor cores contain, initially, enriched uranium:  natural uranium, mostly 238U92 enriched with a few percent of    235U92 or an artificial element, plutonium 244Pu94, in the form of metallic pellets or uranium oxide inserted into a rod.  While radioactive and poisonous, by themselves the fuel rods are not producing much energy, although they may be warm.  They emit gamma rays, electrons and helium nuclei (beta and alpha particles), but especially they emit neutrons  which are moving too fast to be useful.  Using water or a graphite moderator to slow the neutrons down allows them to be absorbed by other nearby uranium atoms making those atoms unstable.  The unstable atoms split (fission) in a number of ways, leaving radioactive isotopes of thorium, radium, radon, lead, strontium, cesium and others (radionuclides).  Most important, each uranium fission produces two new neutrons capable of causing further fissions.  If there are enough slow neutrons and enough nearby uranium atoms, the chain reaction becomes self‑sustaining.  The masses of the fission products are a few percent less than their parent atom.  This lost mass is converted into energy by the famous equation E=mc2.  The c in the equation is the speed of light, so the tiny mass loss is multiplied by 9 x 1016 which accounts for the tremendous energy of a fission reactor.  The chain reaction is controlled by absorbing some of the neutrons in control rods usually containing boron.  Sliding these rods in and out of the reactor is the main control on energy output.
When the reactor is operating, the radionuclides accumulate in the fuel rods and some of the other atoms in the reactor may become radioactive as well.  In general, elements below thorium (element 90) in the periodic table do not spontaneously fission, although most have radioactive isotopes.  The isotopes vary greatly in their stability, which we describe as the time it takes half of them to decay, or half‑life.  In order to be dangerous to the environment, the half‑life must be longer than a few hours and the emitted radiation must be powerful enough to cause biological damage.  A beta ray (high speed electron) must be 70 keV (thousand electron volts) to penetrate skin.  However, if the radioactive isotope can be absorbed into tissue, there is no protection from even weak radiation.  Therefore, certain moderate life radionuclides that can be absorbed into the food chain are considered the most dangerous.  These are strontium 90Sr38 and cesium  137Cs55, which are incorporated into bone and connective tissue in small quantities but enough to cause biological damage.  In addition, there are some short‑lived isotopes of iodine that are absorbed into the thyroid, causing serious problems in small children under the age of eight.  Making sure there is plenty of non radioactive iodine in the body with iodine tablets can greatly lessen this problem.
When a reactor spews its core into the environment, the unspent fuel and its high mass fission products (transuranic radionuclides) and lower mass bioactive radioisotopes are released.  Radon is a heavy gas, and travels on the wind.  Smoke sized particles, mostly lighter isotopes, can be wind‑borne and if conditions are right they will reach the high‑level steering winds and the jet stream and circle the globe, although this is unlikely.  Locally, particles “fall out” of the air and coat the ground, where moisture and rain can carry them deeper.  Therefore a core explosion tends to cause a very local fallout of transuranic isotopes and as well as more regional and, perhaps, international contamination due to strontium, cesium and iodine.  Rain, snow and water movements may spread the contaminants until at last they are either diluted to safe levels or they are no longer radioactive.  It is the generally accepted practice to clean up and dispose of, as far as possible, transuranic isotopes and sequester the remaining heavily contaminated areas forever, and to remove as much of the moderately contaminated lighter radionuclides as possible from contact with potable water and populations of  humans and wildlife.  INIR has methods to expedite this basic strategy.
Transuranic radionuclides consist of a number of isotopes whose half lives range up to 700 million years, which, of course, is why they are still around.  All are intensely powerful radiation emitters, with alpha particles, beta particles commonly in the 3 to 8 MEV range, and gamma radiation.
The dangerous isotope of iodine,126I53  , has a half life of 13 days, but a weak isotope, 129I53 has a half life of 17 million years.  Half lives for 90Sr38     and  137Cs55  ,respectively, are 29.1 years and 30.2 years, although there are other isotopes with shorter lives that are dangerous as well.  These are beta emitters typically in the .2 to 2.5 MEV range and produce some gamma radiation as well.
It is possible to clearly identify a radioactive contaminant by its gamma ray spectrum, since this form of radiation is not easily shielded by soil or vegetation.

Radioactivity Units

The detection of one radiation particle is a Becquerel (Bq), the Standard International (SI) unit of radiation.  Most of us are more familiar with the common standard, the Curie (Ci), which is 3.7 x 107 Bq.  These units measure the total amount of radioactive material, which would ordinarily be emitted over the lives of the isotopes.
The Gray (Gy) is the SI unit of absorbed dose.  It depends on how many radiation particles strikes each kilo of flesh.  The common standard is the rad, which is .01 Gy.
To confuse the issue further, not all the radiation you get gets you.  Some passes through, some does not penetrate.  Therefore there is a unit for the biological equivalent dose, the sievert (Sv), which converts to the more common rem: 1 rem = .01 Sv.  A lifetime safe radiation dose is considered about 37 rem or .37 Sv.  Natural sources, such as cosmic rays and radiation from rocks, can account for 12 to 20 rem.
An electron volt is the measure of the velocity of a particle.  A beta ray is a fast electron moving close enough to the speed of light so it emits a kind of shock wave, or Bremstrahlung, as it passes through a medium as dense as air.  Electrons of at least 70 keV are required to penetrate the epidermis.  Alpha particles, being far heavier, move more slowly.  Alpha particles of 7.5 MeV are required to penetrate skin.

Basic Reactor Types

1.  Handbook of Chemistry and Physics, 77th edition, David R. Lide, Editor in Chief, 1996, CRC Press
2.  Trade and Environmental Data Base, Case no 228 “Chernobyl Nuclear Accident”,
3.  Ministry of Foreign Affairs, Japan, “The Moscow Summit on Nuclear Safety and Security”,
4.  V. Chernousenko, “Chernobyl, Insight from the Inside”, 1991, Springer‑Verlag
5.  The Uranium Institute,
6.  Planet ENN, April 22, 1996, “Chernobyl Ten Years After”, Henry Wasserman
7.  Clean Power Journal, Summer 1996, “Report from Chernobyl”, Ed Smeloff
8.  Science News Online, April 27, 1996, “Radiation Damages Chernobyl Children”, Steve Sternberg,
9.  Critical Mass Energy Project, 9 Oct 1996, “ Worst 25 US Nuclear Reactors”, Lisa Marina Brooks
10.  United States of America Nuclear Regulatory Commission, Briefing on Containment Degradation, Oct 16, 1996
11.  Institute for Energy and Environmental Research,
12.  Cannon Valley Web, “The Virtual Nuclear Tourist!!!”
13.  H. Semat, “Atomic and Nuclear Physics”,Holt, Rinehart & Winston

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