REPORTERSNirajan khanal&sailesh kapaiar.RADIATION BIOLOGY

Chernobyl plant workers

The Chernobyl disaster was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine (then officially the Ukrainian SSR), which was under the direct jurisdiction of the central authorities of the Soviet Union. An explosion and fire released large quantities of radioactive particles into the atmosphere, which spread over much of the western USSR and Europe

The Chernobyl disaster was the worst nuclear power plant accident in history in terms of cost and casualties, and is one of only two classified as a level 7 event (the maximum classification) on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster in 2011). The battle to contain the contamination and avert a greater catastrophe ultimately involved over 500,000 workers and cost an estimated 18 billion rubles. During the accident itself, 31 people died, and long-term effects such as cancers are still being investigated.

The disaster began during a systems test on Saturday, 26 April 1986 at reactor number four of the Chernobyl plant, which is near the city of Pripyat and in proximity to the administrative border with Belarus and the Dnieper River. There was a sudden and unexpected power surge, and when an emergency shutdown was attempted, an exponentially larger spike in power output occurred, which led to a reactor vessel rupture and a series of steam explosions. These events exposed the graphite moderator of the reactor to air, causing it to ignite.

Chernobyl disaster effectsNational and international spread of radioactive substances

Four hundred times more radioactive material was released from Chernobyl than by the atomic bombing of Hiroshima. The disaster released 1/100 to 1/1000 of the total amount of radioactivity released by nuclear weapons testing during the 1950s and 1960s. Approximately 100,000km of land was significantly contaminated with fallout, with the worst hit regions being in Belarus, Ukraine and Russia. Slighter levels of contamination were detected over all of Europe except for the Iberian Peninsula

Groundwater

Groundwater was not badly affected by the Chernobyl accident since radionuclides with short half-lives decayed away long before they could affect groundwater supplies, and longer-lived radionuclides such as radiocaesium and radiostrontium were adsorbed to surface soils before they could transfer to groundwater. However, significant transfers of radionuclides to groundwater have occurred from waste disposal sites in the 30km (19mi) exclusion zone around Chernobyl. Although there is a potential for transfer of radionuclides from these disposal sites off-site (i.e. out of the 30km (19mi) exclusion zone), the IAEA Chernobyl Report argues that this is not significant in comparison to current levels of washout of surface-deposited radioactivity.

Flora and fauna

After the disaster, four square kilometers of pine forest directly downwind of the reactor turned reddish-brown and died, earning the name of the "Red Forest

After the disaster, four square kilometers of pine forest directly downwind of the reactor turned reddish-brown and died, earning the name of the "Red Forest". Some animals in the worst-hit areas also died or stopped reproducing. Most domestic animals were removed from the exclusion zone, but horses left on an island in the Pripyat River 6km (4mi) from the power plant died when their thyroid glands were destroyed by radiation doses of 150200Sv. Some cattle on the same island died and those that survived were stunted because of thyroid damage. The next generation appeared to be normal.

Mutations in both humans and other animals increased following the disaster. On farms in Narodychi Raion of Ukraine, for instance, in the first four years of the disaster nearly 350 animals were born with gross deformities such as missing or extra limbs, missing eyes, heads or ribs, or deformed skulls; in comparison, only three abnormal births had been registered in the five years prior.Despite these

Mutations in both humans and other animals increased following the disaster. On farms in Narodychi Raion of Ukraine, for instance, in the first four years of the disaster nearly 350 animals were born with gross deformities such as missing or extra limbs, missing eyes, heads or ribs, or deformed skulls; in comparison, only three abnormal births had been registered in the five years prior.Despite these

Thirty one deaths are directly attributed to the accident, all among the reactor staff and emergency workers. An UNSCEAR report places the total confirmed deaths from radiation at 64 as of 2008. The Chernobyl Forum predicts the eventual death toll could reach 4000 among those exposed to the highest levels of radiation (200,000 emergency workers, 116,000 evacuees and 270,000 residents of the most contaminated areas); this figure is a total causal death toll prediction, combining the deaths of approximately 50 emergency workers who died soon after the accident from acute radiation syndrome, nine children who have died of thyroid cancer and a future predicted total of 3940 deaths from radiation-induced cancer and leukemia.

The risk projections suggest that by now Chernobyl may have caused about 1000 cases of thyroid cancer and 4000 cases of other cancers in Europe, representing about 0.01% of all incident cancers since the accident. Models predict that by 2065 about 16,000 cases of thyroid cancer and 25,000 cases of other cancers may be expected due to radiation from the accident, whereas several hundred million cancer cases are expected from other causes.

The accident raised concerns about nuclear power worldwide and slowed or reversed the expansion of nuclear power stations. Also the accident raised concerns about the safety of the Soviet nuclear power industry, slowing its expansion for a number of years and forcing the Soviet government to become less secretive about its procedures. The government coverup of the Chernobyl disaster was a "catalyst" for glasnost, which "paved the way for reforms leading to the Soviet collapse".

NON OCCUPATIONAL HIGH DOSE EXOPSURE

Non-occupational high dose exposure means it doesn't have to do with work.eg.someone have unprotected sex once, it's probable that he do it often. That's an unsafe behavior.this radiation therapy is mostly used to treat in HIV AIDS

The most effective methods for preventing human immunodeficiency virus (HIV) infection are those that protect against exposure to HIV. Antiretroviral therapy cannot replace behaviors that help avoid HIV exposure (e.g., sexual abstinence, sex only in a mutually monogamous relationship with a noninfected partner,abstinence from injection-drug use, and consistent use of sterile equipment by those unable to cease injection-drug use). Medical treatment after sexual, injection-drug--use, or other nonoccupational HIV exposure is less effective than preventing HIV infection by avoiding exposure

In July 1997, CDC sponsored the External Consultants Meeting on Antiretroviral Therapy for Potential Nonoccupational Exposures to HIV. This panel of scientists, public health specialists, clinicians, ethicists, members of affected communities, and representatives from professional associations and industry evaluated the available evidence related to use of antiretroviral medications after nonoccupational HIV exposure. In 1998, DHHS issued a statement that outlined the available information and concluded that evidence was insufficient about the efficacy of nonoccupational postexposure prophylaxis (nPEP) to recommend either for or against its use

Since 1998, additional data about the potential efficacy of nPEP have accumulated from human, animal, and laboratory studies. Clinicians and organizations have begun providing nPEP to patients they believe might benefit. In certain instances, health departments have issued advisories or recommendations or otherwise supported the establishment of nPEP treatment programs in their jurisdictions. In May 2001, CDC convened the second external consultants meeting on nonoccupational post-exposure prophylaxis to review and discuss the available data. This report summarizes knowledge about the use and potential efficacy of nonoccupational post exposure prophylexis(NPEP) and details guidelines for its use in the United States. The recommendations are intended for nonoccupational exposures and are not applicable for occupational exposures.

NUCLEAR ACCIDENT IN BRAZIL (1987)

The radiation accident that took place in Goiania, Brazil, Sept 13, 1987, is the best characterized of radiation accidents giving a clear picture of medical and public health response. A private radiotherapy institute moved to new premises, leaving behind a teletherapy unit containing a Ce-137 source, without notifying authorities and without securing the site. During site demolition, the unit was partly demolished. Two people entered the premises to search for scrap metal and removed the source assembly, taking it home to try to dismantle it. In the attempt, the source capsule ruptured.

The source was in the form of pellets of cesium chloride salt, of the size of rice grains, highly soluble and readily dispersible. They sold the remnants of the source assembly to a junkyard owner. Over a period of five days, friends and family, noticing that the pellets glowed in the dark, took them home as trinkets. Some were played with, contaminating hands, and causing the material to be ingested. The people began showing gastrointestinal and flu-like symptoms, hair loss, and general malaise, not initially recognized as due to irradiation. Public health authorities became aware that a radiation accident may have occurred when one of the victims, making a connection between the illnesses and the source capsule, took the source remnants to the municipal public health department; this action set into play the medical response and remedial actions.

Twenty people were identified by medical triage as needing hospitalization. Triage was performed in a soccer stadium in which 112,800 people were monitored from September 30 through December 21, 1987. 249 people were internally or externally contaminated (skin and/or clothing) and 2000 sq m of the environment was contaminated. Four people died within four weeks of hospital admission. Estimated dosages received ranged from 4.5-6.0 Gy (1 rad=0.o1gy). Two people survived such a dosage.

FUEL PROCESSSING IN JAPAN

Japan Nuclear Fuel Ltd. has announced another delay to the start of its $21 billion nuclear fuel reprocessing plant to March 2016, citing the need to meet new safety standards drawn up after the Fukushima disaster.

After multiple postponements due to construction and equipment failures, the new schedule puts the Rokkasho plant in northern Japan 19 years behind the original 1997 completion date.The facility is the hub of Japans nuclear fuel reprocessing strategy and was designed to separate as much as 8 tons of plutonium a year for use as reactor fuel. China has criticized Rokkashos construction, saying it raises concerns the plutonium could be diverted for use in atomic weapons. Japan has denied any such intentions.

Japan Nuclear Fuel needs to ensure the plant meets safety guidelines set by Japans Nuclear Regulation Authority, according to an Oct. 30 company statement. The regulator was set up after the triple reactor meltdowns at Tokyo Electric Power .Fukushima Dai-Ichi atomic station in March 2011.Rokkasho suffered a power failure following an April aftershock to the March earthquake almost four years ago that wrecked the Fukushima facility. Emergency diesel generators supplied electricity until main power was restored.

The company said it planned to use the additional time to improve measures to deal with serious accidents and to prevent water leakage within the facility, according to the statement.It will also need to resubmit its application to the regulator for safety checks, which the plant must pass before it can begin separating plutonium from spent nuclear fuel, the company said.

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