======================================================================
= Radium =
======================================================================
Introduction
======================================================================
Radium is a chemical element; it has symbol Ra and atomic number 88.
It is the sixth element in group 2 of the periodic table, also known
as the alkaline earth metals. Pure radium is silvery-white, but it
readily reacts with nitrogen (rather than oxygen) upon exposure to
air, forming a black surface layer of radium nitride (Ra3N2). All
isotopes of radium are radioactive, the most stable isotope being
radium-226 with a half-life of 1,600 years. When radium decays, it
emits ionizing radiation as a by-product, which can excite fluorescent
chemicals and cause radioluminescence. For this property, it was
widely used in self-luminous paints following its discovery. Of the
radioactive elements that occur in quantity, radium is considered
particularly toxic, and it is carcinogenic due to the radioactivity of
both it and its immediate decay product radon as well as its tendency
to accumulate in the bones.
Radium, in the form of radium chloride, was discovered by Marie and
Pierre Curie in 1898 from ore mined at Jáchymov. They extracted the
radium compound from uraninite and published the discovery at the
French Academy of Sciences five days later. Radium was isolated in its
metallic state by Marie Curie and André-Louis Debierne through the
electrolysis of radium chloride in 1910, and soon afterwards the metal
started being produced on larger scales in Austria, the United States,
and Belgium. However, the amount of radium produced globally has
always been small in comparison to other elements, and by the 2010s,
annual production of radium, mainly via extraction from spent nuclear
fuel, was less than 100 grams.
In nature, radium is found in uranium ores in quantities as small as a
seventh of a gram per ton of uraninite, and in thorium ores in trace
amounts. Radium is not necessary for living organisms, and its
radioactivity and chemical reactivity make adverse health effects
likely when it is incorporated into biochemical processes because of
its chemical mimicry of calcium. As of 2018, other than in nuclear
medicine, radium has no commercial applications. Formerly, from the
1910s to the 1970s, it was used as a radioactive source for
radioluminescent devices and also in radioactive quackery for its
supposed curative power. In nearly all of its applications, radium has
been replaced with less dangerous radioisotopes, with one of its few
remaining non-medical uses being the production of actinium in nuclear
reactors.
Bulk properties
======================================================================
Radium is the heaviest known alkaline earth metal and is the only
radioactive member of its group. Its physical and chemical properties
most closely resemble its lighter congener, barium.
Pure radium is a volatile, lustrous silvery-white metal, even though
its lighter congeners calcium, strontium, and barium have a slight
yellow tint. Radium's lustrous surface rapidly becomes black upon
exposure to air, likely due to the formation of radium nitride
(Ra3N2). Its melting point is either 700 °C or 960 °C and its boiling
point is 1737 °C; however, this is not well established.
Both of these values are slightly lower than those of barium,
confirming periodic trends down the group 2 elements.
Like barium and the alkali metals, radium crystallizes in the
body-centered cubic structure at standard temperature and pressure:
the radium-radium bond distance is 514.8 picometers.
Radium has a density of 5.5 g/cm(3), higher than that of barium, and
the two elements have similar crystal structures (bcc at standard
temperature and pressure).
Isotopes
======================================================================
Radium has 33 known isotopes with mass numbers from 202 to 234, all of
which are radioactive. Four of these - (223)Ra (half-life 11.4 days),
(224)Ra (3.64 days), (226)Ra (1600 years), and (228)Ra (5.75 years) -
occur naturally in the decay chains of primordial thorium-232,
uranium-235, and uranium-238 ((223)Ra from uranium-235, (226)Ra from
uranium-238, and the other two from thorium-232). These isotopes
nevertheless still have half-lives too short to be primordial
radionuclides, and only exist in nature from these decay chains.
Together with the mostly artificial (225)Ra (15 d), which occurs in
nature only as a decay product of minute traces of neptunium-237,
these are the five most stable isotopes of radium. All other 27 known
radium isotopes have half-lives under two hours, and the majority have
half-lives under a minute. Of these, (221)Ra (half-life 28 s) also
occurs as a (237)Np daughter, and (220)Ra and (222)Ra would be
produced by the still-unobserved double beta decay of natural radon
isotopes. At least 12 nuclear isomers have been reported, the most
stable of which is radium-205m with a half-life between 130~230
milliseconds; this is still shorter than twenty-four ground-state
radium isotopes.
(226)Ra is the most stable isotope of radium and is the last isotope
in the decay chain of uranium-238 with a half-life of over a
millennium; it makes up almost all of natural radium. Its immediate
decay product is the dense radioactive noble gas radon (specifically
the isotope (222)Rn), which is responsible for much of the danger of
environmental radium. It is 2.7 million times more radioactive than
the same molar amount of natural uranium (mostly uranium-238), due to
its proportionally shorter half-life.
A sample of radium metal maintains itself at a higher temperature than
its surroundings because of the radiation it emits. Natural radium
(which is mostly (226)Ra) emits mostly alpha particles, but other
steps in its decay chain (the uranium or radium series) emit alpha or
beta particles, and almost all particle emissions are accompanied by
gamma rays.
Experimental nuclear physics studies have shown that nuclei of several
radium isotopes, such as (222)Ra, (224)Ra and (226)Ra, have
reflection-asymmetric ("pear-like") shapes. In particular, this
experimental information on radium-224
has been obtained at ISOLDE using a technique called Coulomb
excitation.
Chemistry
======================================================================
Radium only exhibits the oxidation state of +2 in solution. It forms
the colorless Ra(2+) cation in aqueous solution, which is highly basic
and does not form complexes readily. Most radium compounds are
therefore simple ionic compounds, though participation from the 6s and
6p electrons (in addition to the valence 7s electrons) is expected due
to relativistic effects and would enhance the covalent character of
radium compounds such as RaF and RaAt. For this reason, the standard
electrode potential for the half-reaction Ra(2+) (aq) + 2e(-) → Ra (s)
is −2.916 V, even slightly lower than the value −2.92 V for barium,
whereas the values had previously smoothly increased down the group
(Ca: −2.84 V; Sr: −2.89 V; Ba: −2.92 V). The values for barium and
radium are almost exactly the same as those of the heavier alkali
metals potassium, rubidium, and caesium.
Compounds
===========
Solid radium compounds are white as radium ions provide no specific
coloring, but they gradually turn yellow and then dark over time due
to self-radiolysis from radium's alpha decay. Insoluble radium
compounds coprecipitate with all barium, most strontium, and most lead
compounds.
Radium oxide (RaO) is poorly characterized, as the reaction of radium
with air results in the formation of radium nitride. Radium hydroxide
(Ra(OH)2) is formed via the reaction of radium metal with water, and
is the most readily soluble among the alkaline earth hydroxides and a
stronger base than its barium congener, barium hydroxide. It is also
more soluble than actinium hydroxide and thorium hydroxide: these
three adjacent hydroxides may be separated by precipitating them with
ammonia.
Radium chloride (RaCl2) is a colorless, luminescent compound. It
becomes yellow after some time due to self-damage by the alpha
radiation given off by radium when it decays. Small amounts of barium
impurities give the compound a rose color. Its It is soluble in
water, though less so than barium chloride, and its solubility
decreases with increasing concentration of hydrochloric acid.
Crystallization from aqueous solution gives the dihydrate RaCl2·2H2O,
isomorphous with its barium analog.
Radium bromide (RaBr2) is also a colorless, luminous compound. In
water, it is more soluble than radium chloride. Like radium chloride,
crystallization from aqueous solution gives the dihydrate RaBr2·2H2O,
isomorphous with its barium analog. The ionizing radiation emitted by
radium bromide excites nitrogen molecules in the air, making it glow.
The alpha particles emitted by radium quickly gain two electrons to
become neutral helium, which builds up inside and weakens radium
bromide crystals. This effect sometimes causes the crystals to break
or even explode.
Radium nitrate (Ra(NO3)2) is a white compound that can be made by
dissolving radium carbonate in nitric acid. As the concentration of
nitric acid increases, the solubility of radium nitrate decreases, an
important property for the chemical purification of radium.
Radium forms much the same insoluble salts as its lighter congener
barium: it forms the insoluble sulfate (RaSO4, the most insoluble
known sulfate), chromate (RaCrO4), carbonate (RaCO3), iodate
(Ra(IO3)2), tetrafluoroberyllate (RaBeF4), and nitrate (Ra(NO3)2).
With the exception of the carbonate, all of these are less soluble in
water than the corresponding barium salts, but they are all
isostructural to their barium counterparts. Additionally, radium
phosphate, oxalate, and sulfite are probably also insoluble, as they
coprecipitate with the corresponding insoluble barium salts. The great
insolubility of radium sulfate (at 20 °C, only 2.1 mg will dissolve in
1 kg of water) means that it is one of the less biologically dangerous
radium compounds. The large ionic radius of Ra(2+) (148 pm) results in
weak ability to form coordination complexes and poor extraction of
radium from aqueous solutions when not at high pH.
Occurrence
======================================================================
All isotopes of radium have half-lives much shorter than the age of
the Earth, so that any primordial radium would have decayed long ago.
Radium nevertheless still occurs in the environment, as the isotopes
(223)Ra, (224)Ra, (226)Ra, and (228)Ra are part of the decay chains of
natural thorium and uranium isotopes; since thorium and uranium have
very long half-lives, these daughters are continually being
regenerated by their decay. Of these four isotopes, the longest-lived
is (226)Ra (half-life 1600 years), a decay product of natural uranium.
Because of its relative longevity, (226)Ra is the most common isotope
of the element, making up about one part per trillion of the Earth's
crust; essentially all natural radium is (226)Ra. Thus, radium is
found in tiny quantities in the uranium ore uraninite and various
other uranium minerals, and in even tinier quantities in thorium
minerals. One ton of pitchblende typically yields about one seventh of
a gram of radium. One kilogram of the Earth's crust contains about 900
picograms of radium, and one liter of sea water contains about 89
femtograms of radium.
History
======================================================================
Radium was discovered by Marie Skłodowska-Curie and her husband Pierre
Curie on 21 December 1898 in a uraninite (pitchblende) sample from
Jáchymov. While studying the mineral earlier, the Curies removed
uranium from it and found that the remaining material was still
radioactive. In July 1898, while studying pitchblende, they isolated
an element similar to bismuth which turned out to be polonium. They
then isolated a radioactive mixture consisting of two components:
compounds of barium, which gave a brilliant green flame color, and
unknown radioactive compounds which gave carmine spectral lines that
had never been documented before. The Curies found the radioactive
compounds to be very similar to the barium compounds, except they were
less soluble. This discovery made it possible for the Curies to
isolate the radioactive compounds and discover a new element in them.
The Curies announced their discovery to the French Academy of Sciences
on 26 December 1898. The naming of radium dates to about 1899, from
the French word 'radium', formed in Modern Latin from 'radius'
('ray'): this was in recognition of radium's emission of energy in the
form of rays. The gaseous emissions of radium, radon, were recognized
and studied extensively by Friedrich Ernst Dorn in the early 1900s,
though at the time they were characterized as "radium emanations".
In September 1910, Marie Curie and André-Louis Debierne announced that
they had isolated radium as a pure metal through the electrolysis of
pure radium chloride (RaCl2) solution using a mercury cathode,
producing radium-mercury amalgam. This amalgam was then heated in an
atmosphere of hydrogen gas to remove the mercury, leaving pure radium
metal.
Later that same year, E. Ebler isolated radium metal by thermal
decomposition of its azide, Ra(N3)2. Radium metal was first
industrially produced at the beginning of the 20th century by Biraco,
a subsidiary company of Union Minière du Haut Katanga (UMHK) in its
Olen plant in Belgium. The metal became an important export of Belgium
from 1922 up until World War II.
The general historical unit for radioactivity, the curie, is based on
the radioactivity of (226)Ra. it was originally defined as the
radioactivity of one gram of radium-226,
but the definition was later refined to be .
Luminescent paint
===================
Radium was formerly used in self-luminous paints for watches, aircraft
switches, clocks, and instrument dials and panels. A typical
self-luminous watch that uses radium paint contains around 1 microgram
of radium. In the mid-1920s, a lawsuit was filed against the United
States Radium Corporation by five dying "Radium Girls" - dial painters
who had painted radium-based luminous paint on the components of
watches and clocks. The dial painters were instructed to lick their
brushes to give them a fine point, thereby ingesting radium.
Their exposure to radium caused serious health effects which included
sores, anemia, and bone cancer.
During the litigation, it was determined that the company's scientists
and management had taken considerable precautions to protect
themselves from the effects of radiation, but it did not seem to
protect their employees. Additionally, for several years the companies
had attempted to cover up the effects and avoid liability by insisting
that the Radium Girls were instead suffering from syphilis.
As a result of the lawsuit, and an extensive study by the U.S. Public
Health Service, the adverse effects of radioactivity became widely
known, and radium-dial painters were instructed in proper safety
precautions and provided with protective gear. Radium continued to be
used in dials, especially in manufacturing during World War II, but
from 1925 onward there were no further injuries to dial painters.
From the 1960s the use of radium paint was discontinued. In many cases
luminous dials were implemented with non-radioactive fluorescent
materials excited by light; such devices glow in the dark after
exposure to light, but the glow fades. Where long-lasting
self-luminosity in darkness was required, safer radioactive
promethium-147 (half-life 2.6 years) or tritium (half-life 12 years)
paint was used; both continue to be used as of 2018. These had the
added advantage of not degrading the phosphor over time, unlike
radium. Tritium as it is used in these applications is considered
safer than radium, as it emits very low-energy beta radiation (even
lower-energy than the beta radiation emitted by promethium) which
cannot penetrate the skin,
unlike the gamma radiation emitted by radium isotopes.
Clocks, watches, and instruments dating from the first half of the
20th century, often in military applications, may have been painted
with radioactive luminous paint. They are usually no longer luminous;
this is not due to radioactive decay of the radium (which has a
half-life of 1600 years) but to the fluorescence of the zinc sulfide
fluorescent medium being worn out by the radiation from the radium.
Originally appearing as white, most radium paint from before the 1960s
has tarnished to yellow over time. The radiation dose from an intact
device is usually only a hazard when many devices are grouped together
or if the device is disassembled or tampered with.
Use in electron tubes
=======================
Radium has been used in electron tubes, such as the Western Electric
346B tube. These devices contain a small amount of radium (in the form
of radium bromide) to ionize the fill gas, typically a noble gas like
neon or argon. This ionization ensures reliable and consistent
operation by providing a steady current when a high voltage is
applied, enhancing the device's performance and stability. The radium
is sealed within a glass envelope with two electrodes, one of which is
coated with the radioactive material to create an ion path between the
electrodes.
Quackery
==========
1918 ad for Radior, one of several cosmetic products claiming to
contain radium for its purported curative properties
Radium was once an additive in products such as cosmetics, soap, razor
blades, and even beverages due to its supposed curative powers. Many
contemporary products were falsely advertised as being radioactive.
Such products soon fell out of vogue and were prohibited by
authorities in many countries after it was discovered they could have
serious adverse health effects. (See, for instance, 'Radithor' or
'Revigator' types of "radium water" or "Standard Radium Solution for
Drinking".) Spas featuring radium-rich water are still occasionally
touted as beneficial, such as those in Misasa, Tottori, Japan, though
the sources of radioactivity in these spas vary and may be attributed
to radon and other radioisotopes.
Medical and research uses
===========================
Radium (usually in the form of radium chloride or radium bromide) was
used in medicine to produce radon gas, which in turn was used as a
cancer treatment. Several of these radon sources were used in Canada
in the 1920s and 1930s.
However, many treatments that were used in the early 1900s are not
used anymore because of the harmful effects radium bromide exposure
caused. Some examples of these effects are anaemia, cancer, and
genetic mutations. As of 2011, safer gamma emitters such as (60)Co,
which is less costly and available in larger quantities, were usually
used to replace the historical use of radium in this application, but
factors including increasing costs of cobalt and risks of keeping
radioactive sources on site have led to an increase in the use of
linear particle accelerators for the same applications.
In the U.S., from 1940 through the 1960s, radium was used in
nasopharyngeal radium irradiation, a treatment that was administered
to children to treat hearing loss and chronic otitis. The procedure
was also administered to airmen and submarine crew to treat
barotrauma.
Early in the 1900s, biologists used radium to induce mutations and
study genetics. As early as 1904, Daniel MacDougal used radium in an
attempt to determine whether it could provoke sudden large mutations
and cause major evolutionary shifts. Thomas Hunt Morgan used radium to
induce changes resulting in white-eyed fruit flies. Nobel-winning
biologist Hermann Muller briefly studied the effects of radium on
fruit fly mutations before turning to more affordable x-ray
experiments.
Production
======================================================================
Uranium had no large scale application in the late 19th century and
therefore no large uranium mines existed. In the beginning, the silver
mines in Jáchymov, Austria-Hungary (now Czech Republic) were the only
large sources for uranium ore. The uranium ore was only a byproduct of
the mining activities.
In the first extraction of radium, Curie used the residues after
extraction of uranium from pitchblende. The uranium had been extracted
by dissolution in sulfuric acid leaving radium sulfate, which is
similar to barium sulfate but even less soluble in the residues. The
residues also contained rather substantial amounts of barium sulfate
which thus acted as a carrier for the radium sulfate. The first steps
of the radium extraction process involved boiling with sodium
hydroxide, followed by hydrochloric acid treatment to minimize
impurities of other compounds. The remaining residue was then treated
with sodium carbonate to convert the barium sulfate into barium
carbonate (carrying the radium), thus making it soluble in
hydrochloric acid. After dissolution, the barium and radium were
reprecipitated as sulfates; this was then repeated to further purify
the mixed sulfate. Some impurities that form insoluble sulfides were
removed by treating the chloride solution with hydrogen sulfide,
followed by filtering. When the mixed sulfates were pure enough, they
were once more converted to mixed chlorides; barium and radium
thereafter were separated by fractional crystallisation while
monitoring the progress using a spectroscope (radium gives
characteristic red lines in contrast to the green barium lines), and
the electroscope.
After the isolation of radium by Marie and Pierre Curie from uranium
ore from Jáchymov, several scientists started to isolate radium in
small quantities. Later, small companies purchased mine tailings from
Jáchymov mines and started isolating radium. In 1904, the Austrian
government nationalised the mines and stopped exporting raw ore. Until
1912, when radium production increased, radium availability was low.
The formation of an Austrian monopoly and the strong urge of other
countries to have access to radium led to a worldwide search for
uranium ores. The United States took over as leading producer in the
early 1910s, producing 70 g total from 1913 to 1920 in Pittsburgh
alone.
The Curies' process was still used for industrial radium extraction in
1940, but mixed bromides were then used for the fractionation. If the
barium content of the uranium ore is not high enough, additional
barium can be added to carry the radium. These processes were applied
to high grade uranium ores but may not have worked well with low grade
ores. Small amounts of radium were still extracted from uranium ore by
this method of mixed precipitation and ion exchange as late as the
1990s, but as of 2011, it is extracted only from spent nuclear fuel.
Pure radium metal is isolated by reducing radium oxide with aluminium
metal in a vacuum at 1,200 °C.
In 1954, the total worldwide supply of purified radium amounted to
about 5 lb.
Zaire and Canada were briefly the largest producers of radium in the
late 1970s. As of 1997 the chief radium-producing countries were
Belgium, Canada, the Czech Republic, Slovakia, the United Kingdom, and
Russia. The annual production of radium compounds was only about 100 g
in total as of 1984; annual production of radium had reduced to less
than 100 g by 2018.
Modern applications
======================================================================
Radium is seeing increasing use in the field of atomic, molecular, and
optical physics. Symmetry breaking forces scale proportional to which
makes radium, the heaviest alkaline earth element, well suited for
constraining new physics beyond the standard model. Some radium
isotopes, such as radium-225, have octupole deformed parity doublets
that enhance sensitivity to charge parity violating new physics by two
to three orders of magnitude compared to (199)Hg.{{multiref2|
{{cite journal
|title=Nuclear Time-Reversal Violation and the Schiff Moment of
$^{225}\mathrm{Ra}$
|first1=J. |last1=Dobaczewski
|first2=J. |last2=Engel
|date=13 June 2005
|journal=Physical Review Letters
|volume=94 |issue=23 |page=232502
|doi=10.1103/PhysRevLett.94.232502 |pmid=16090465
|arxiv=nucl-th/0503057 |s2cid=328830
|url=
https://link.aps.org/doi/10.1103/PhysRevLett.94.232502
|via=APS.org
}}|
|
}}
Radium is also a promising candidate for trapped ion optical clocks.
The radium ion has two subhertz-linewidth transitions from the ground
state that could serve as the clock transition in an optical clock. A
(226)Ra+ trapped ion atomic clock has been demonstrated on the to
transition, which has been considered for the creation of a
transportable optical clock as all transitions necessary for clock
operation can be addressed with direct diode lasers at common
wavelengths.
Some of the few practical uses of radium are derived from its
radioactive properties. More recently discovered radioisotopes, such
as cobalt-60 and caesium-137, are replacing radium in even these
limited uses because several of these isotopes are more powerful
emitters, safer to handle, and available in more concentrated form.
The isotope (223)Ra was approved by the United States Food and Drug
Administration in 2013 for use in medicine as a cancer treatment of
bone metastasis in the form of a solution including radium-223
chloride. The main indication of treatment is the therapy of bony
metastases from castration-resistant prostate cancer.
(225)Ra has also been used in experiments concerning therapeutic
irradiation, as it is the only reasonably long-lived radium isotope
which does not have radon as one of its daughters.
Radium was still used in 2007 as a radiation source in some industrial
radiography devices to check for flawed metallic parts, similarly to
X-ray imaging. When mixed with beryllium, radium acts as a neutron
source. Up until at least 2004, radium-beryllium neutron sources were
still sometimes used,
but other materials such as polonium and americium have become more
common for use in neutron sources. RaBeF4-based (α, n) neutron sources
have been deprecated despite the high number of neutrons they emit
(1.84×10(6) neutrons per second) in favour of (241)Am-Be sources. ,
the isotope (226)Ra is mainly used to form (227)Ac by neutron
irradiation in a nuclear reactor.
Hazards
======================================================================
Radium is highly radioactive, as is its immediate decay product, radon
gas. When ingested, 80% of the ingested radium leaves the body through
the feces, while the other 20% goes into the bloodstream, mostly
accumulating in the bones. This is because the body treats radium as
calcium and deposits it in the bones, where radioactivity degrades
marrow and can mutate bone cells. Exposure to radium, internal or
external, can cause cancer and other disorders, because radium and
radon emit alpha and gamma rays upon their decay, which kill and
mutate cells. Radium is generally considered the most toxic of the
radioactive elements.
Some of the biological effects of radium include the first case of
"radium-dermatitis", reported in 1900, two years after the element's
discovery. The French physicist Antoine Becquerel carried a small
ampoule of radium in his waistcoat pocket for six hours and reported
that his skin became ulcerated. Pierre Curie attached a tube filled
with radium to his arm for ten hours, which resulted in the appearance
of a skin lesion, suggesting the use of radium to attack cancerous
tissue as it had attacked healthy tissue.
Handling of radium has been blamed for Marie Curie's death, due to
aplastic anemia, though analysis of her levels of radium exposure done
after her death find them within accepted safe levels and attribute
her illness and death to her use of radiography. A significant amount
of radium's danger comes from its daughter radon, which as a gas can
enter the body far more readily than can its parent radium.
Regulation
============
The first published recommendations for protection against radium and
radiation in general were made by the British X-ray and Radium
Protection Committee and were adopted internationally in 1928 at the
first meeting of the International Commission on Radiological
Protection (ICRP), following preliminary guidance written by the
Röntgen Society. This meeting led to further developments of radiation
protection programs coordinated across all countries represented by
the commission.
Exposure to radium is still regulated internationally by the ICRP,
alongside the World Health Organization. The International Atomic
Energy Agency (IAEA) publishes safety standards and provides
recommendations for the handling of and exposure to radium in its
works on naturally occurring radioactive materials and the broader
International Basic Safety Standards, which are not enforced by the
IAEA but are available for adoption by members of the organization. In
addition, in efforts to reduce the quantity of old radiotherapy
devices that contain radium, the IAEA has worked since 2022 to manage
and recycle disused (226)Ra sources.
In several countries, further regulations exist and are applied beyond
those recommended by the IAEA and ICRP. For example, in the United
States, the Environmental Protection Agency-defined Maximum
Contaminant Level for radium is 5 pCi/L for drinking water;
at the time of the Manhattan Project in the 1940s, the "tolerance
level" for workers was set at 0.1 micrograms of ingested radium.
The Occupational Safety and Health Administration does not
specifically set exposure limits for radium, and instead limits
ionizing radiation exposure in units of roentgen equivalent man based
on the exposed area of the body. Radium sources themselves, rather
than worker exposures, are regulated more closely by the Nuclear
Regulatory Commission, which requires licensing for anyone possessing
(226)Ra with activity of more than 0.01 μCi. The particular governing
bodies that regulate radioactive materials and nuclear energy are
documented by the Nuclear Energy Agency for member countries for
instance, in the Republic of Korea, the nation's radiation safety
standards are managed by the Korea Radioisotope Institute, established
in 1985, and the Korea Institute of Nuclear Safety, established in
1990 and the IAEA leads efforts in establishing governing bodies in
locations that do not have government regulations on radioactive
materials.
Bibliography
==============
*
*
*
* Alternate source:
https://sgp.fas.org/othergov/doe/lanl/lib-www/books/rc000041.pdf
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=========
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Original Article:
http://en.wikipedia.org/wiki/Radium
