Radiation Chernobyl

Ten years passed since the biggest radioactive catastrophe in the history of humanity happened at the Chernobyl nuclear power plant. The Russian State medical dosimetric Register was founded after this catastrophe At present in the Register they keep a medical and radiation-dosimetric information about 435.276 persons. 

The accident at the Three Mile Island (TMI) plant in Pennsylvania in 1979 led to many safety and environmental improvements (4—6). No harm from radiation resulted to TMI workers, to the pubHc, or to the environment (7,8), although the accident caused the loss of a 2 x 10 investment. The accident at the Chernobyl plant in the Ukraine in 1986, on the other hand, caused the deaths of 31 workers from high doses of radiation, increased the chance of cancer later in life for thousands of people, and led to radioactive contamination of large areas. This latter accident was unique to Soviet-sponsored nuclear power. The Soviet-designed Chemobyl-type reactors did not have the intrinsic protection against a mnaway power excursion that is requited in the test of the world, not was there a containment building (9—11). 

A much more serious nuclear accident occurred at Chernobyl in the USSR on April 26, 1986, when one of the Chernobyl units experienced a full-core meltdown. The Chernobyl accident has been called the worse disaster of the industrial age. An area comprising more than 60,000 square miles in the Ukraine and Belarus was contaminated, and more than 160,000 people were evacuated. However, wind and water have spread the contamination, and many radiation-related illnesses, birth defects, and miscarriages have been attributed to the Chernobyl disaster. 

Half-lives span a very wide range (Table 17.5). Consider strontium-90, for which the half-life is 28 a. This nuclide is present in nuclear fallout, the fine dust that settles from clouds of airborne particles after the explosion of a nuclear bomb, and may also be present in the accidental release of radioactive materials into the air. Because it is chemically very similar to calcium, strontium may accompany that element through the environment and become incorporated into bones once there, it continues to emit radiation for many years. About 10 half-lives (for strontium-90, 280 a) must pass before the activity of a sample has fallen to 1/1000 of its initial value. Iodine-131, which was released in the accidental fire at the Chernobyl nuclear power plant, has a half-life of only 8.05 d, but it accumulates in the thyroid gland. Several cases of thyroid cancer have been linked to iodine-131 exposure from the accident. Plutonium-239 has a half-life of 24 ka (24000 years). Consequently, very long term storage facilities are required for plutonium waste, and land contaminated with plutonium cannot be inhabited again for thousands of years without expensive remediation efforts. 

The nuclear explosions that devastated Hiroshima and Nagasaki killed 100,000 to 200,000 people instantaneously. Probably an equal number died later, victims of the radiation released in those explosions. Millions of people were exposed to the radioactivity released by the accident at the Chernobyl nuclear power plant. The full health effects of that accident may never be known, but 31 people died of radiation sickness within a few weeks of the accident, and more than 2000 people have developed thyroid cancer through exposure to radioactive iodine released in the accident. Even low levels of radiation can cause health problems. For this reason, workers in facilities that use radioisotopes monitor their exposure to radiation continually, and they must be rotated to other duties if their total exposure exceeds prescribed levels. 

Bunzl K, Kracke W, Agapkina GI, et al. 1998. Association of Chernobyl-derived 239+240Pu,241 Am, 90Sr and 137Cs with different molecular size fractions of organic matter in the soil solution of two grassland soils. Radiat Environ Biophys 37 195-200. 

Knatko VA, Mayall A, Drugachenok MA, et al. 1993. Radiation doses in southern Byelorussia from the inhalation of specific radionuclides following the Chernobyl accident. Radiat Prot Dosim 48(2) 179-183. 

It should be noted that there is intense controversy as to the health effects of radiation doses below about 100 mSv per year. This estimate of 15,000 annual cancer deaths from indoor radon, as well as estimates of tens of thousands of eventual cancer deaths from Chernobyl exposures, is obtained by applying the linearity hypothesis. This hypothesis has been adopted by most regulatory agencies but is strongly contested by some scientists who believe it overestimates the effects of radiation at low dose levels. Of course, if calculations based on this hypothesis overestimate the deaths from indoor radon, they also overestimate the effects of potential radiation from a waste repository. 

Radiation is one of the most important known environmental stimuli of cancer development. This environmental factor becomes especially dangerous for humans living in the areas affected by irradiation from nuclear accidents. Earlier we found that the administration of a mixture of vitamin E and a-lipoic acid to children living in the area of Chernobyl nuclear accident significantly and synergistically suppressed leukocyte oxygen radical overproduction [211]. Thus a-lipoic acid and a-lipoic acid + vitamin E supplements may be of interest as antioxidant preventive agents for the treatment of radiation-induced cancer development. 

Today, the most important environmentally damaging anthropogenic radiation comes from atmospheric testing of nuclear weapons conducted 20 to 30 years ago, authorized discharges to the sea from nuclear reprocessing plants, and from the Chernobyl accident in 1986 (Aarkrog 1990). 

Figure 32.6 Chernobyl air plume behavior and reported initial arrival times of detectable radioactivity. Plume A originated from Chernobyl on April 26, 1986 Plume B on April 27-28 and Plume C on April 29-30. The numbers indicate initial arrival times 1, April 26 2, April 27 3, April 28 4, April 29 5, April 30 6, May 1 7, May 2 and 8, May 3. (From United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). 1988. Sources, Effects and Risks of Ionizing Radiation. United Nations, New York. 647 pp.)... 

Acute biological effects of the Chernobyl accident on local natural resources were documented by Sokolov et al. (1990). They concluded that the most sensitive ecosystems affected at Chernobyl were the soil fauna and pine forest communities and that the bulk of the terrestrial vertebrate community was not adversely affected by released ionizing radiation. Pine forests seemed to be the most sensitive ecosystem. One stand of 400 ha of Pirns silvestris died and probably received a dose of 80 to 100 Gy other stands experienced heavy mortality of 10- to 12-year-old trees and up to 95% necrotization of young shoots. These pines received an estimated dose of 8 to 10 Gy. Abnormal top shoots developed in some Pirns, and these probably received 3 to 4 Gy. In contrast, leafed trees such as birch, oak, and aspen in the Chernobyl Atomic Power Station zone survived undamaged, probably because they are about 10 times more radioresistant than pines. There was no increase in the mutation rate of the spiderwort, (Arabidopsis thaliana) a radiosensitive plant, suggesting that the dose rate was less than 0.05 Gy/h in the Chernobyl locale. 

Cristaldi, M., L.A. Ieradi, D. Mascanzoni, and T. Mattei. 1991. Environmental impact of the Chernobyl accident mutagenesis in bank voles from Sweden. Inter. Jour. Radiation Biol. 59 31-40. 

Hagen, U. 1990. Molecular radiation biology future aspects. Radiation Environ. Biophys. 29 315-322. Hakanson, L. and T. Andersson. 1992. Remedial measures against radioactive caesium in Swedish lake fish after Chernobyl. Aquat. Sci. 54 141-164. 

After the nuclear explosion at Chernobyl in 1986, Anatoly and other professors and physicians created a foundation, For the Children of Chernobyl. Their goal was to send children abroad for the summers for a reprieve from radiation exposure which impairs their immune systems and has resulted in unprecedented levels of thyroid cancer in children and adults. The first host country to respond to their call for help was India. Before long, the foundation was sending 30,000 children every summer to host families and programs in many countries, including Germany, England, Japan, the U.S., Spain, Italy and France. 

A kind of shelter was built around the Chernobyl nuclear block after it exploded. It was okay for some time, but then huge cracks developed. It still spews radiation, which comes through all the cracks. On certain days you can feel it. Anyone can tell you when there was another spew of radiation, because you feel dizzy or you get a headache. One of my students had family who lived near Chernobyl, and... 

The Chernobyl accident was in many ways the worse possible scenario having an exposed reactor core and roofless building. Two plant workers died from the blast and fire, 22 other plant workers and 6 firefighters received huge radiation doses and died within months. 

It is highly improbable that a nuclear fission power plant would ever explode like a nuclear bomb, but a loss of coolant accident could result in a melt down condition. In a melt down, a large amount of radiation can be released at ground-level. A nuclear or conventional chemical or steam explosion could disperse much of the radioactive particles into the atmosphere. This is essentially what happened when the Chernobyl gas explosion occurred in the Soviet Union in 1986. 

Highly publicized nuclear accidents such as those that occurred at Chernobyl and Three Mile Island must be considered anomalies. Nuclear power plants have multiple safety measures in place to prevent radiation leaks. The small amount of radioactive waste produced by nuclear reactors is controlled and usually contained in the plant facility. 

Experience from the 1986 Chernobyl reactor accident in the Ukraine shows the potential magnitude and impact of a terrorist attack on a nuclear power plant. The accident involved an explosion in a reactor that releases very high levels of radiation for miles surrounding the reactor site. Low levels of radiation were spread by wind currents throughout Europe and the rest of the world. According to Caldicott 2002,... 

Melin J. and Wallberg L. Distribution and retention of cesium in Swedish boreal forest ecosystems, in The Chernobyl fallout in Sweden, results from a research program on environmental radiology, ed. J. Moberg, Stockholm, Swedish Radiat. Protect. Inst., 1991, pp. 467-475. 

Shell W.R., Linkov I., Belenkaja E. Radiation dose from Chernobyl forests Assessment using FORESTPATH model // Proc. of the 1-st international conference (Minsk, Belarus, 18-22 March, 1996). - Luxembourg, 1996.-P. 217-220. 

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