it can be considered a natural physical phenomenon by the one which some bodies or chemical elements, radioactive calls, emit radiations that have the property of impressing photographic badges, to ionize gases, to produce fluorescence, to cross opaque bodies to the ordinary light, etc. Due to that capacity, you/they is usually denominated ionizing radiations (in contrast with those no ionizing). The issued radiations can be electromagnetic, in form of rays X or gamma rays, or corpuscular, like they can be nuclei of helium, electrons or positrones, protons or others. In summary, it is a phenomenon that happens in the nuclei of certain elements that are able to become nuclei of atoms of other elements. The radioactivity ionizes the means that crosses. An exception constitutes it the neutron that doesn't possess load, but it ionizes the matter in form insinuation. In the radioactive disintegrations several radiation types are had: alpha, beta, gamma and neutrons.
The radioactivity is a property of the isotopes that you/they are" unstable", that is to say that stay in a state excited in its electronic or nuclear layers, with that that, to reach its fundamental state, they should lose energy. They make it in electromagnetic emissions or in emissions of particles with a certain kinetic energy. This takes place varying the energy of their electrons (emitting rays X) or of their nucleones (I line gamma) or varying the isotope (when emitting from the nucleus electrons, positrones, neutrons, protons or heavier particles), and in several successive steps, with what a heavy isotope can finish becoming one much slighter, as the uranium that, with lapsing of the centuries, it finishes becoming lead
In the radioactive processes, particles or electromagnetic radiations are emitted by the
Nucleus. The forms more comunes of the issued radiation traditionally have been classified as alpha (a), Beta (b), AND gamma (g) The radiation. The nuclear radiation takes place in other forms, including the emission of protons or neutrons or spontaneous fission of a massive nucleus.
Of the nuclei that are in the Earth, the great majority is stable. This is this way because almost all lived radioactive nuclei to short they have deteriorated during the history of the Earth. There are 270 stable isotopes approximately and 50 take place radioisotopes in a natural way (radioactive isotopes). Thousands of other radioisotopes have been made in the laboratory
Natural and artificial radioactivity
The radioactivity is a natural phenomenon for which certain atoms change its structure. The understanding of this phenomenon has allowed its application in different activities.
The biggest proportion of the radiation to which we are exposed comes from natural sources - of the space, rocks, floor, dilutes and until of our own body. This radiation is denominated" background radiation" and the levels vary considerably of place in place, in spite of this, the average of received radiation or annual dose it is quite constant. The main source of background radiation is the gas radon, formed basically by the decline of the materials radioactive present in the floor or in certain building supplies.
The radiation that usually causes bigger concern is the produced one for the human activities. The main sources of the same ones include the medical applications of radioactive substances, the radio-active precipitations coming from the rehearsals of nuclear weapons in the atmosphere carried out to great scale before their definitive prohibition, the discharges coming from the nuclear industry and the radioactive waste.
While the quantities of artificial radiation represent a small proportion of the total, their goods can be disproportioned (Chernobyl is an example). Some of the resulting materials of the human activities are not in the nature (as the plutonium) while other that are in the nature, they can be liberated to the same one in different chemical and physical forms, allowing them to be dispersed easily in the atmosphere or to be introduced in the food chains.
The radioactivity doses that can be received vary considerably. The near areas to sources of radioactive discharges, for example, they can receive much higher levels of radiation that the regional or national average.
For this reason, the simple comparison of the background radiation and the artificial radioactivity doesn't necessarily reflect the relative dangers. Also, it has never been demonstrated that it exists something like that like a sure dose of radiation. Among so much, we are increasing the global levels of radiation progressively, what is very preocupante, and this sinks to the possibility of new nuclear accidents.
Nuclear catastrophe in Fujishima bears to the valuation of the use of the nuclear energy April 6 2011
The earthquake and the tsunami of March 11 2011 caused strong damages to the nuclear plants of Fukushima, Japan. In spite of their efforts, the technicians have not been able up to now to put low control the damaged reactors.
The current nuclear crisis in the nuclear plant Fukushima in Japan after the earthquake and the tsunami, it has caused a commotion and many political debates in almost all the countries that use nuclear energy. The repercussions of Fukushima are felt inside with force and outside of domestic.
Next, a summary of the current situation in countries that have nuclear plants or they are neighboring
Four of the six reactors of the nuclear power station of Fukushima are seriously affected after the earthquake of 8,9 grades that Japan whipped on last Friday. The part of the nucleus of the reactors 1,2 and 3 is without funds.
As it informed the Spanish newspaper “The World”, the nuclear fuel is exposed and it lacks the appropriate refrigeration to avoid that the coalition process advances, for what the nucleus of the reactor could melt totally.
The reactor number 1 that exploded first, don't have refrigeration, their vessel it is damaged and a partial coalition of the nucleus has taken place.
Also, after the explosion of hydrogen that took place in the 2, their refrigeration system is practically null and its contention vessel is damaged.
THE MOST DANGEROUS REACTORS
The reactors 3 and 4 have been considered as the most dangerous. The first one, detailed “The World”, it is damaged from Monday, he/she has refrigeration problems, it has produced a partial coalition of the nucleus and their contention system doesn't respond, for what has expelled radioactive particles to the atmosphere. According to the company Tepco, the reactor 4 you encuera in state “critical” because the pool that cools the bars of fuel is totally empty, for what the Japanese Government ordered to the company to inject water in this area “to avoid a nuclear disaster.”
The reactors 5 and 6 refrigeration problems also live since the temperature of their pools it has been increased considerably, although it is in normal levels.
PERJUDICIALITY OF RADIOACTIVE GOODS IN THE ATMOSPHERE
Goods on the man: According to the intensity of the radiation and their localization (it is not the same thing an exhibition to whole body that a single area), the sick person can end up dying in the term from some hours to several weeks. And anyway, if the death doesn't happen in the following months, the patient is able to recover, her expectations of life will have been sensibly reduced.
The noxious goods of the radioactivity are accumulative. This means that they leave adding until a continuous minimum exhibition becomes in dangerous after certain time. Exhibitions to quantities not very high of radioactivity for lingering time they can be in disastrous and fatal goods for the human being. The following list describes the conditions that can be expressed when one is illness victim for radiation.
• nauseas
• vomits
• convulsions
• deliriums
• headaches
• diarrhea
• of denture
• reduction of the red globules in the blood
• reduction of white globules in the blood
• damage to the conduit gastroinstestinal
• of the mucosa of the bowels
• hemorrhages
• sterility
The only solution to eliminate the radioactivity is the time and the cares, besides not continuing exposed to radio-active products.
EVENTS
Stop of the reactors
Liberation of gas in the reactor I
Explosion in the building of the reactor 1
Explosion in the building of the reactor 3 (second)
March 14, at 11:01 o'clock a.m., Japanese hour, he/she registered an explosion of hydrogen in the building of the reactor number 3. As he/she informed the Nuclear and Industrial safe-deposit Agency (NISA) in a remitted report to the International Organism of Atomic energy (OIEA), the structure that contains the reactor" it is intact." As he/she said today the Japanese Government's spokesman, Yukio Edano," the vessel that contains the nucleus of the reactor remains intact after the explosion."
Explosion in the building of the reactor 2 (Third)
March 15 took place an explosion and fire in the building of the reactor 4 The explosion it is attributed to accumulation of catalyzed hydrogen of the bars of fuel deposited in the pool of used fuel of the reactor.
The Japanese authorities have informed the OIEA that radioactivity has been liberated to the atmosphere after the explosion and the fire.
Reactors 5 and 6
CONSEQUENCES
After the failure of the systems of refrigeration of the reactors of the nuclear power station, they were carried out controlled emissions of radioactive gases to the exterior to reduce the pressure in the contention enclosure. It was emitted to the exterior an unascertained quantity of radioactive particles.
Some days later radioactive iodine was detected in Finland. Although in both cases it was discarded that the detected radiation levels were dangerous
The Nuclear Security Council affirms that dangers don't exist for the health.
Poured radioactive to the sea
The first intents of sealing the crack with cement and other methods failed.
The day March 17 the total figure of affected people directly for the incident in the power station belonged to 23 wounded people and more than 20 affected by radioactive contamination. these figures are subject to changes. Dos people that you/they were missing from the day of the earthquake was opposing dead April 1, its death seems to be due to wounds not taken place by the maremoto and earthquake by radiation.
April 1 communicate that at least 21 operatives belonging to the retén that remains in Fukushima to try to control the reactors of the plant already suffer an acceleration in the rhythm of alteration of the DNA for effect of the radiation.
EVENTS
1. The programmed gradual reduction of the level of power of the reactor begins.
4. Reduction of restarted power.
5. I change shift of the personnel
APRIL 26
1. The level of power diminished to 720 MW, and it continued decreasing, in spite of being forbidden.
3. The sign of shot of the turbogenerador was blocked according to the procedures of the test. INSAG-1 declared": This procedure would have saved to the reactor." Nevertheless, it is possible that this procedure retarded the beginning of the accident about 39 seconds.
6. A bomb of additional refrigeration was changed to the right of the refrigeration circuit like part of the supporting procedure. The operation of the additional refrigeration bombs eliminates the heat more quickly from the nucleus, what leads to the decrease of the reactivity and he/she makes even more necessary the elimination of the bars of absorption to avoid a fall in the power. The bombs extracted too much heat (flow) until the point of overcoming the admitted limits. The increase of the flow of heat of the nucleus generated problems with the level of vapor in the batteries.
10. The emergency button (AZ-5) it was pressed by an operator. The control bars began to enter in the nucleus of the reactor and they increased the reactivity in the inferior part of the nucleus
11. The system of protection of emergency of energy rate (trip power) it is activated. The power overcomes the 530 MW.
12. Disconnect of the first couple of the main circulation pumps (MCP) that are out, followed by the second couple's disconnect
14. Reestablishment of the rates of flow 15 percent below the initial rate of the MPC of the left, and 10 inferior percent of one of the MPC that yes it participated in the test and not very reliable readings for the other one.
15. Sign Increase of the pressure in the space of the reactor (rupture of a channel of fuel)), sign Mechanisms variadores of the EPC without feeding source) and sign Failure of the drivers of the controllers of auto feed numbers 1 and 2).
16. According to a note in the newspaper of the engineer's boss of control of the reactor operation: 01:24: Strong blows; the bars RPC stopped to move before arriving to the inferior limit; the switch of ignition of the clutch mechanisms is out
CONSEQUENCES
Minutes after the accident, all the military firemen assigned to the power station were already in road and preparations to control the disaster. The heroic behavior of the firemen during the first three hours of the accident avoided that the fire extended to the rest of the power station. Even so, they requested help to the firemen from Kiev due to the magnitude of the catastrophe. The operators of the plant put the other three reactors in emergency refrigeration. Dos days later, there were 18 very serious wounded and 156 wounded with produced lesions of consideration for the radiation. There still was not a figure of the death toll, but in a nuclear accident it increases day after day the list of victims, until past many years later.
es.wikipedia.org/wiki/Accidente_de_Chernóbil
www.mexicodiplomatico.org/art_diplomatico.../chernobyl.pdf
es.wikipedia.org/wiki/Radiactividad
www.elmundo.es/especiales/2011/.../terremoto_tsunami.html
es.wikipedia.org/wiki/Central_nuclear_Fukushima_I
www.arn.gov.ar/novedades/.../japon_resumen_general_14_03_2011.pdf
www.nonuclear.org.ar/sitio/.../conceptos_basicos_sobre_radiac.pdf
www.greenpeace.org/argentina/.../8/conceptos-basicos-sobre-radiac-2.pdf
Goods on the animals: The liqúeneses are very vulnerable to the radioactive contamination. With the result that many reindeers of Lapland that feed of some liqúeneses called reindeer mosses, had to be sacrificed after the accident of Chernobil.
The only solution to eliminate the radioactivity is the time and the cares, besides not continuing exposed to radio-active products.
Contamination of the atmosphere for residuals or gassy secondary products, solids or liquid that can put in danger the man's health and the health and well-being of the plants and animals, to attack to different materials, to reduce the visibility or to produce unpleasant scents. Among the atmospheric pollutants emitted by natural sources, only the radon, a radioactive gas, an important risk is considered for the health.
As part of their normal operation, the nuclear production liberates poisonous radioactivity in the air, earth and it dilutes.
PARALLEL: CATASTROPHES FUKUSHIMA AND CHERNOBYL
Stop of the reactors
March 11 2011, to the 14:46 JST (standard time of Japan (UTC+9)) an earthquake of 9,0 MW takes place, in the northeast coast of Japan. That day the reactors 1, 2 and 3, they were operating while the units 4, 5 and 6 were in court for a periodic inspection. When the earthquake was detected, the units 1, 2 and 3 faded automatically (called SCRAM in reactors with water in boil).
Due to the electric power interruption to the refrigeration systems was necessary the entrance in operation of the auxiliary systems of electric generation to continue pumping refrigeration water to the nucleus, but the later tsunami also disabled these generating diésel at 15:41 o'clock, causing an ascent of the temperature.
Liberation of gas in the reactor I
The company Tokyo Electric Power Company decided to liberate vapor that contained radioactive material, to reduce the pressure inside the reactor. This vapor explodes destroying half of the building of secondary contention. The camera of main contention resists. The temperature descends and it seems to be controlled the problem.
Explosion in the building of the reactor 1
In the afternoon of the day 12 (11h UTC) an explosion took place in the power station that demolished part of the building, which is attributed to the liberation of hydrogen from the nucleus of the reactor, which reacted with the I oxygenate, producing a combustion,
Explosion in the building of the reactor 3 (second)
March 14, at 11:01 o'clock a.m., Japanese hour, he/she registered an explosion of hydrogen in the building of the reactor number 3. As he/she informed the Nuclear and Industrial safe-deposit Agency (NISA) in a remitted report to the International Organism of Atomic energy (OIEA), the structure that contains the reactor" it is intact." As he/she said today the Japanese Government's spokesman, Yukio Edano," the vessel that contains the nucleus of the reactor remains intact after the explosion." Explosion in the building of the reactor 2 (Third)
An explosion happened in the building of the reactor 2 March 15 to the 6:10 JST (March 14, 21:10 UTC), and the system of suppression of pressure, which is in the part of under the contention vessel, it has been damaged. Time later, the agency Kyodo News informed that the radiation level arrived hourly to the 8.217 micro sievert.
Fire and radioactive flights in the reactor 4
The Japanese authorities have informed the OIEA that radioactivity has been liberated to the atmosphere after the explosion and the fire.
Reactors 5 and 6
The radiation levels to the north of Tokyo overcome in ten to the normal ones
The radiation levels in the city of Maebashi to 100 kilometers to the north of Tokyo are 10 times the normal ones and in Saitama 40 times.
CONSEQUENCES
After the failure of the systems of refrigeration of the reactors of the nuclear power station, they were carried out controlled emissions of radioactive gases to the exterior to reduce the pressure in the contention enclosure. It was emitted to the exterior an unascertained quantity of radioactive particles.
Some days later radioactive iodine was detected in Finland. Although in both cases it was discarded that the detected radiation levels were dangerous
These radiation levels hinder the works of the operatives. Plutonium is also detected outside of the reactors, reasonable possibly of the reactor number 3 that it is the only one that works with that element
The Nuclear Security Council affirms that dangers don't exist for the health.
Poured radioactive to the sea
The first intents of sealing the crack with cement and other methods failed.
The day March 17 the total figure of affected people directly for the incident in the power station belonged to 23 wounded people and more than 20 affected by radioactive contamination. these figures are subject to changes. Dos people that you/they were missing from the day of the earthquake was opposing dead April 1, its death seems to be due to wounds not taken place by the maremoto and earthquake by radiation.
April 1 communicate that at least 21 operatives belonging to the retén that remains in Fukushima to try to control the reactors of the plant already suffer an acceleration in the rhythm of alteration of the DNA for effect of the radiation.
The accident of Chernóbil is the name that it receives the nuclear accident happened in the nuclear power station of Chernóbil (Ukraine) April 26 1986. That day, during a test in which a cut of electric supply, a sudden increase of power in the reactor was simulated 4 of this nuclear power station, it produced the sobrecalentamiento of the nucleus of the nuclear reactor, what finished causing the explosion of the hydrogen accumulated in its interior.
1. The programmed gradual reduction of the level of power of the reactor begins.
2. The reduction of power stopped to the 1600 MW.
3. The system of refrigeration of emergency of the nucleus (ECCS) it was isolated to avoid the interruption of the test later. This fact didn't contribute to the accident, but in the event of having been available it would have reduced its graveness minimumly. The power, nevertheless, it should be had reduced even more. However, the regulator of the electric net of Kiev asked to the operator of the reactor to maintain the minimum of electric power production to satisfy the demand correctly. In consequence, the level of power of the reactor stayed in 1600 MW and the experiment was delayed. Without this delay, the test would have been made the same day.
4. Reduction of restarted power.
APRIL 26
1. The level of power diminished to 720 MW, and it continued decreasing, in spite of being forbidden.
2. With the level of power on the 500 MW, the operator transferred the control from the manual system to the system of automatic regulation. The sign failed or the regulation system didn't respond to this sign, what caused an unexpected fall of power to 30 MW.
4. The power of the reactor rose to 200 MW and it was stabilized. Although the operators of the power station could ignore it, the required margin of operational reactivity was violated (ORM - Operational Reactivity Margin) of 15 bars (minimum). The decision took to carry out the tests they summarize of the turbogenerador with a near power to the 200 MW.
5. The standby circulation pump was changed to the left of the refrigeration circuit with the purpose of increasing the flow of water toward the nucleus.
7. The level of vapor of the battery was not very far from the emergency level. To compensate this, an operator increased the flow of water. This increased the level of vapor, and it also diminished the reactivity of the system. The pressure of the system began to fall and, to stabilize the pressure, it was necessary to turn off the turbine of vapor of the derivation valve.
8. Later calculations to the accident found that the ORM in this point was equivalent to 8 control bars. The operation politicians required a minimum of 15 control bars at every moment.
9. The valves of feeding of the turbine closed to be able to allow that works for inertia. For the 30 later seconds to this moment any emergency intervention is not required on the part of the personnel.
10. The emergency button (AZ-5) it was pressed by an operator. The control bars began to enter in the nucleus of the reactor and they increased the reactivity in the inferior part of the nucleus
11. The system of protection of emergency of energy rate (trip power) it is activated. The power overcomes the 530 MW.
12. Disconnect of the first couple of the main circulation pumps (MCP) that are out, followed by the second couple's disconnect 13. Important increase in the pressure of the batteries of separation of vapor. Strong increase in the level of water of the batteries of separation of vapor.
14. Reestablishment of the rates of flow 15 percent below the initial rate of the MPC of the left, and 10 inferior percent of one of the MPC that yes it participated in the test and not very reliable readings for the other one.
15. Sign Increase of the pressure in the space of the reactor (rupture of a channel of fuel)), sign Mechanisms variadores of the EPC without feeding source) and sign Failure of the drivers of the controllers of auto feed numbers 1 and 2).
16. According to a note in the newspaper of the engineer's boss of control of the reactor operation: 01:24: Strong blows; the bars RPC stopped to move before arriving to the inferior limit; the switch of ignition of the clutch mechanisms is out
17. First explosion.
CONSEQUENCES
Minutes after the accident, all the military firemen assigned to the power station were already in road and preparations to control the disaster. The heroic behavior of the firemen during the first three hours of the accident avoided that the fire extended to the rest of the power station. Even so, they requested help to the firemen from Kiev due to the magnitude of the catastrophe. The operators of the plant put the other three reactors in emergency refrigeration. Dos days later, there were 18 very serious wounded and 156 wounded with produced lesions of consideration for the radiation. There still was not a figure of the death toll, but in a nuclear accident it increases day after day the list of victims, until past many years later. The first approach in helicopter evidenced the magnitude of that happened. In the nucleus, exposed to the atmosphere, the graphite of the same one burned to the red one I live, while the material of the fuel and other metals had become an incandescent liquid mass. The temperature reached the 2.500 °C and in an effect chimney, it impelled the radioactive smoke to a considerable height.
At the same time, those responsible for the region began to prepare the evacuation of the city of Prípiat and of a radius of 10 km around the plant. This first evacuation began in way massive 36 hours after the accident and it took 3 hours in being concluded. The evacuation of Chernóbil and of a radius of 36 km it was not carried out until past six days of the accident. For then there were already more than thousand affected by sharp lesions taken place by the radiation.
The morning of Saturday, several helicopters of the army got ready to hurtle on the nucleus a mixture of materials that consisted on sand, clay, lead, dolomita and absorbent boron of neutrons. When May 13 finished the emissions, some 5.000 t of materials had hurtled to the nucleus.
Finally, the refrigeration system was never implanted and the tunnel was stuffed with concrete to secure the land and to avoid that the nucleus collapsed due to the weight of the heady materials. In one month and 4 days the tunnel ended and the rising of a structure denominated sarcophagus began that it would wrap to the reactor and it would isolate him of the exterior. The works lasted 206 days.
www.mexicodiplomatico.org/art_diplomatico.../chernobyl.pdf
es.wikipedia.org/wiki/Radiactividad
www.elmundo.es/especiales/2011/.../terremoto_tsunami.html
es.wikipedia.org/wiki/Central_nuclear_Fukushima_I
www.arn.gov.ar/novedades/.../japon_resumen_general_14_03_2011.pdf
www.nonuclear.org.ar/sitio/.../conceptos_basicos_sobre_radiac.pdf
www.greenpeace.org/argentina/.../8/conceptos-basicos-sobre-radiac-2.pdf
