It decays into stable rubidium
-85, with a half-life
of 10.756 years and a maximum decay energy
of 0.687 MeV
. Its most common decay (99.57%) is by beta particle
emission with maximum energy of 687 keV
and an average energy of 251 keV. The second most common (0.43%) is by beta particle emission (maximum energy of 173 keV) followed by gamma ray
emission (energy of 514 keV).
In terms of radiotoxicity
, 440 Bq of Kr-85 is equivalent to 1 Bq of radon-222
, without considering the rest of the radon decay chain.
Other decay modes have very small probabilities and emit less energetic gammas.
The only other long-lived radioisotope of krypton is krypton-81
with a 210,000 year half-life; others have half-lives of less than two days.
Krypton-85 is produced in small quantities by the interaction of cosmic rays
with the stable krypton-84
(which is present in concentrations of about 1 cm3 per cubic meter). However, since the mid-1940s, much larger quantities have been artificially produced as a product of nuclear fission
. When uranium-235
, or another fissile
nucleus fissions, it usually splits into two large fragments (fission products
) with mass numbers around 90-140, and two or three neutrons
. About three atoms of krypton-85 are produced for every 1000 fissions (i.e. it has a fission yield of 0.3%).
About 5 megacuries
) of the isotope was released into the atmosphere as a result of nuclear weapons tests
between 1945 and the end of atmospheric testing in 1962. The 1979 accident at the Three Mile Island nuclear power plant
released about 50 kilocuries (1,900 TBq) of Kr-85 into the atmosphere
and the Chernobyl accident
released about 5 megacuries (190 PBq).
(The Fukushima nuclear disaster is estimated to have released between 20-200 megacuries of Krypton 85 from three melted down reactors and multiple spent fuel pool melt downs/fires/explosions). The atmospheric concentration of Krypton-85 peaked in around 1970, when it reached around 10 pCi/m3 (around 0.4 Bq/m3).
Since then the cessation of atmospheric weapons tests and the reduced production of plutonium has, because of the short half-life of the isotope, led to a sharp reduction in the atmospheric concentration, according to the Human Health Fact Sheet.
For wide-area atmospheric monitoring, krypton-85 is the best indicator for clandestine plutonium separations.
Uses in Industry
Krypton gas is used in arc discharge lamps commonly used in the entertainment industry for large HMI film lights, certain projector lamps, as well as High Intensity Discharge
The existence of Kr-85 in discharge tube of the lamps can make the lamps easy to ignite.
According to Consumer Alerts; “exposure to Krypton-85 can also happen when a particular type of light bulb lamp breaks or explodes inside of a TV projector, due to overheating.
Short-term effects of Krypton-85 exposure are dizziness, nausea, vomiting, and loss of consciousness. Long-term effects are more serious. According to the Department of Energy (DOE) exposure to Krypton-85 can increase the likelihood of cancer.
The sealed spark gap assemblies contained in ignition excitors used in some older turbine/jet engines contain a very small amount of krypton-85 in order to obtain consistent ionization levels and uniform operation. The amount of radiation from the average gap is approximately the same as that of a radium-dial wrist watch but should be handled carefully.
Krypton-85 was used in cold-cathode voltage regulator electron tubes, such as the type 5651.
Krypton-85 is used to test for leaks in semiconductors (MIL-STD-883H) and piping.”
The picture above shows how Krypton 92 and Krypton 36 is produced by fission inside of a nuclear reactor, along with the energy used to produce electricity.
Some pro nuclear apologists claim that nuclear energy is ‘green’. However, studies show that nuclear energy is the opposite of green.
Nuclear Power; EXPENSIVE, Dirty, Dangerous And Toxic; via A Green Road
Super Solar Storm To Hit Earth In 2013 ‘Carrington Effect’; 400 Nuke Plants Will Melt Down/Explode; via A Green Road http://agreenroad.blogspot.com/2012/03/super-solar-storm-predicted-to-hit-2013.html
12 reasons why all nuclear power plants must be shut down; via A Green Road http://agreenroad.blogspot.com/2012/03/12-reasons-why-all-nuclear-power-plants.html
One study shows Krypton 85 interferes with the water balance of earth’s atmosphere. “The study shows that krypton-85 from nuclear fission enhances air ionization and, thus, interferes with the atmospheric-electrical system and the water balance of the earth atmosphere. This is reason for concern: There are unforeseeable effects for weather and climate if the krypton-85 content of the earth atmosphere continues to rise. There may be a krypton-specific greenhouse effect and a collapse of the natural atmospheric-electrical field. In addition, human well-being may be expected to be impaired as a result of the diminished atmospheric-electrical field. There is also the risk of radiochemical actions and effects caused-by krypton-85-containing plumes in other air-borne pollutants like the latters’ transformation to aggressive oxidants. This implies radiation smog and more acid rain in the countries exposed. This study summarizes findings gained in these issues by various sciences, analyses them and elaborates hypotheses on the actions and effects of krypton-85 on the air, the atmosphere and the climate.”
What Is Krypton?
Krypton is a colorless, odorless, tasteless gas about three times heavier than air. It was discovered in 1898 by Sir William Ramsay and Morris Travers in the residue left after evaporating water, oxygen, nitrogen, helium, and argon from a sample of liquid air. The name comes from the Greek work kryptos, meaning hidden. As a noble gas, krypton is generally inert and forms very few chemical compounds. It occurs in nature as six stable isotopes. (Isotopes are different forms of an element that have the same number of protons in the nucleus but a different number of neutrons.) Krypton-84 is the most prevalent, comprising about 57% of natural krypton. The other five stable isotopes and their relative abundances are krypton-78 (0.4%), krypton-80 (2.3%), krypton-82 (12%), krypton-83 (11%), and krypton-86 (17%).
Eleven major radioactive isotopes of krypton exist of which only two – krypton-81 and krypton-85 – have half-lives long enough to warrant concern.
Krypton-81 has a half-life of 210,000 years, and krypton-85 has a half-life of 11 years; the half-lives of the other krypton isotopes are less than two days.
Radioactive Krypton-85 gas is the isotope of concern at Department of Energy (DOE) environmental management sites such as Hanford. Radioactive Krypton 85 gas is produced by the fissioning of uranium and plutonium and is generated by spent nuclear fuel.
The major source of krypton-85 is nuclear fission. When an atom of uranium-235 (or other fissile nuclide) fissions, it generally splits asymmetrically into two large fragments – fission products with mass numbers in the range of about 90 and 140 – and two or three neutrons. (The mass number is the sum of the number of protons and neutrons in the nucleus of the atom.) Krypton-85 is one such fission product with a fission yield of about 0.3%. That is, three atoms of krypton-85 are produced per 1,000 fissions.
An estimated 5 million curies of krypton-85 were released to the atmosphere as a result of nuclear weapons tests from 1945 through 1962.
A large commercial nuclear power plant produces about 300,000 curies of krypton-85 per year, essentially all of which is retained within the fuel elements. This gaseous radionuclide is a component of spent nuclear fuel and is generally released to the atmosphere when the fuel is reprocessed, or when it melts down due to a nuclear accident.
How Much Krypton Is In The Environment?
The highest concentrations of krypton are in the atmosphere. Krypton is present in air at a concentration of about 3 parts per million by volume. On a mass basis, the concentration is about 3 mg/kg. For comparison, the krypton concentration in the atmosphere of Mars is about 1/3 this amount. Krypton is naturally present in the earth’s crust at a concentration of about 0.15 micrograms per kilogram (µg/kg), and its concentration in seawater is about 0.21 µg/liter. Radioactive Krypton-85 gas has been (and still is being) released to the atmosphere during nuclear fuel reprocessing activities and as in the past as due to past above ground nuclear weapons tests.
In 1970, the concentration of radioactive human produced Krypton-85 in the atmosphere reached about 10 picocuries (pCi)/m, mainly from nuclear weapons tests and plutonium production activities. The concentration is significantly lower now due to the relatively short half-half of this radionuclide, the cessation of above ground nuclear weapons tests worldwide by 1980, and the shutdown of plutonium production facilities at DOE sites.
Neither the oceans nor the land surfaces act as significant sinks for this radionuclide. Krypton-85 is in spent nuclear fuel stored at certain sites (such as the DOE Hanford Site).
What Happens to Radioactive Krypton 85 in the Body?
As a noble gas, krypton does not generally participate in any
biological processes. After being taken into the body, a very small amount can be dissolved in the bloodstream and distributed to organs and tissues throughout the body. Nevertheless, the tissue of most concern from exposure to a cloud of krypton-85 gas is generally the skin, with most of the dose resulting from the beta particles associated with its radioactive decay.
What Are the Primary Health Effects From Exposure To Krypton 85?
The main health concern is the increased likelihood for cancer induction, and the exposure pathway of most concern is external exposure in a cloud of gas. The radiation dose for krypton-85 (the primary isotope of concern) from an external cloud of gas is more than 130 times higher than the dose from any gas in the lungs and more than 200 times higher than that from any gas in body organs and tissues after being taken into the body.
Krypton 81 Emits Gamma Rays
For kypton-81, most of the dose is associated with gamma rays that will irradiate all tissues and organs of the body. Gamma radiation is very powerful and can penetrate the whole body.
“RADIOACTIVITY HAZARDS: WARNING! Krypton-85 is a radioactive isotope. Krypton-85..exposure to significant quantities may be harmful.
Krypton-85 generates beta particles and gamma rays and poses an external radiation hazard. Upon inhalation of Krypton-85 gas, this isotope can be incorporated into the body’s cells and emit radiation energy to surrounding tissues. Exposure to this product should be kept to levels as low as reasonably achievable. Refer to applicable standards and regulations for workplace limits on radiation exposure.”
Krypton 85 Emits Beta Particles
In contrast, much of the dose for kypton-85 is from beta particles, and the skin is the primary tissue of concern. (Although if inhaled on ingested with food or water, beta particles can cause damage or initiate cancer via cell to cell contact.)
“Beta doses to cells possibly critical to human tumor formation from the beta emitter 85Kr have been estimated. These critical cells are hemopoietic stem cells, osteoprogenitor cells on bone surfaces and basal cells in bronchial epithelium. Cells in bone marrow and on bone surfaces are irradiated because of the solubility of noble gases in body tissue.
The doses estimated here are much lower than the beta skin dose, but these cell doses are thought to be more pertinent in estimating health effects. The annual absorbed beta dose rates for the current global level of 85Kr of 15 pCi/m3 are 1 x 10-3 mrad for cells on bone surfaces, 2 x 10-5 mrad for hemopoietic stem cells and 3 x 10-4 mrad for basal cells in bronchial epithelium. For comparison, the annual alpha dose rates from the average concentration of 100 pCi/m3 of the naturally occurring noble gas 222Rn and its daughter products are 2.5 x 10-2, 3.6 x 10-2 and 27 mrad, respectively, to the same three cell types.”
Krypton 85 can be transformed into “aggressive oxidants.” Oxidants are not healthy… and may initiate all kinds of unhealthy processes in the body…http://www.opengrey.eu/item/display/10068/255704
What Is the Risk?
Radiation doses from inhaling or ingesting krypton are unknown and unstudied. In contrast to most other radionuclides, lifetime cancer mortality risk coefficients have not been developed for the inhalation and ingestion of krypton isotopes. The only pathway for which cancer mortality risk coefficients have been developed is external exposure. (Internal Krypton gas exposure studies have not been done, and this is where most damage is done.)
External gamma risk coefficients for krypton-81 and krypton-85 were used to estimate lifetime cancer mortality risks for submersion in krypton clouds. If it is assumed that krypton releases occurred and 100,000 people were continuously exposed to a cloud of air with an average concentration of 1 pCi/cm3 over a period of one year, then the estimated number of fatal cancers in this group of 100,000 would be 2 for krypton-81 and less than 1 for krypton-85. (However, internal exposure can greatly increase this number of cancers and fatalities over time, but this has not been studied, so the true negative health effects of radioactive Krypton gas are unknown.)
(For more information, see the companion fact sheet on Radioactive Properties, Internal Distribution, and Risk Coefficients and the accompanying Table 1.) Source:
“Fluorine can react with noble gases such as krypton and xenon.” CreationWiki – Recent changes [en]
Both radioactive Xenon gas and radioactive Krypton gas react with Flourine, which is a heavy metal poison.
Only one nuclear isomer
(long-lived excited nuclear state), fluorine-18m, has been characterized.
Its half-life before gamma ray emission
is 160 nanoseconds
. This is less than the decay half-life of any of the fluorine radioisotope nuclear ground states except numbers 14–16, 28, and 31.
Fluorine’s chemistry is dominated by its tendency to gain an electron. It is the most electronegative
element and a strong oxidant. The removal of an electron from a fluorine atom requires so much energy that no known oxidant can oxidize fluorine to any positive oxidation state
Fluorine gas is highly reactive with other substances both because of the strong bonds it forms with other atoms and because of the relative weakness of the fluorine–fluorine bond. That bond energy is significantly weaker than those of dichlorine or dibromine molecules and similar to the easily cleaved oxygen–oxygen bonds of peroxides
or nitrogen–nitrogen bonds of hydrazines
The covalent radius of fluorine in difluorine molecules, about 71 picometers, is significantly larger than that in other compounds because of the weak bonding between fluorine atoms.
Reactions with fluorine are often sudden or explosive. Many generally non-reactive substances such as powdered steel, glass fragments and asbestos
fibers are readily consumed by cold fluorine gas. Wood and even water burn with flames when subjected to a jet of fluorine, without the need for a spark.
Fluorine forms compounds, fluorides
, with all elements except neon
. All of the elements up to einsteinium
, element 99, have been checked except for astatine
Fluorine is also known to form compounds with rutherfordium
, element 104,
, element 106.
Several heavy radioactive elements have not been fluoridated because of their extreme rarity, but such reactions are theoretically possible.
All metals react with fluorine, but conditions vary with the metal. Often, the metal must be powdered because many metals passivate
(form protective layers of the metal fluoride that resist further fluoridation). The alkali metals
react with fluorine with a bang (small explosion), while the alkaline earth metals
react at room temperature as well but not as aggressively.
“Later, in 1898 he also discovered, by fractional distillation of liquid air, neon ( “the new one”), krypton ( “the hidden one”) and xenon ( “the strange one”).”
During a nuclear accident, the first things to be released because of the meltdown of the nuclear fuel rods are the lighter nuclear gases; “first, a range of less-dangerous gases are liberated, including tritium, krypton and xenon.”
A large but invisible gas cloud rises up from any nuclear facility that is having a meltdown, and then travels around the world… “According to Arnie Gunderson, a former U.S. nuclear power plant operator: events over the last day indicate that volatile radioactive elements such as xenon, krypton, cesium, iodine, and strontium are already being released from the Fukushima nuclear reactor.”
“In a total meltdown, several radioactive gases are released… including nitrogen-16, tritium and krypton.”
Krypton gas is not a ‘natural’ harmless, inert or stable substance. It is a radioactive substance that causes cancer, just like radioactive Xenon gas, also released by nuclear reactor accidents, spent fuel reprocessing, and plutonium production.
Radioactive Xenon Gas; Dangerous And Lung Cancer Causing Isotope; via A Green Roadhttp://agreenroad.blogspot.com/2012/10/radioactive-xenon-gas-dangerous-and.html
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Krypton 85 Dangers, Cancer Causing Health Effects, Risks, And Hazards; via A Green Roadhttp://agreenroad.blogspot.com/2013/01/krypton-85-dangers-cancer-causing.html