chunk_id string | chunk string | source_url string | title string | chunk_idx int64 | chunk_start_char int64 | chunk_end_char int64 |
|---|---|---|---|---|---|---|
dev-6923-222 | The cities of the Confederacy included most prominently in order of size of population: | dev-6923 | Confederate States of America | 222 | 118,203 | 118,290 |
dev-6923-223 | (See also Atlanta in the Civil War, Charleston, South Carolina, in the Civil War, Nashville in the Civil War, New Orleans in the Civil War, Wilmington, North Carolina, in the American Civil War, and Richmond in the Civil War). | dev-6923 | Confederate States of America | 223 | 118,291 | 118,517 |
dev-6923-224 | The CSA was overwhelmingly Protestant.[316] Both free and enslaved populations identified with evangelical Protestantism. Freedom of religion and separation of church and state were fully ensured by Confederate laws. Church attendance was very high and chaplains played a major role in the Army.[317] | dev-6923 | Confederate States of America | 224 | 118,518 | 118,818 |
dev-6923-225 | Some denominations experienced a North—South split around 1861 on the issue of slavery and also due to the ongoing political climate. In the wake of the Second Great Awakening, Baptists and Methodists together formed majorities of both the white and the slave population (see Black church). Both broke off from their N... | dev-6923 | Confederate States of America | 225 | 118,819 | 120,195 |
dev-6923-226 | The southern churches met the shortage of Army chaplains by sending missionaries. The Southern Baptists started in 1862 and had a total of 78 missionaries. Presbyterians were even more active with 112 missionaries and early 1865. Other missionaries were funded and supported by the Episcopalians, Methodists, and Luthera... | dev-6923 | Confederate States of America | 226 | 120,196 | 120,580 |
dev-6923-227 | Military leaders of the Confederacy (with their state or country of birth and highest rank)[325] included: | dev-6923 | Confederate States of America | 227 | 120,581 | 120,687 |
dev-5026-0 | The Chernobyl disaster, also referred to as the Chernobyl accident, was a catastrophic nuclear accident. It occurred on 26 April 1986 in the No.4 light water graphite moderated reactor at the Chernobyl Nuclear Power Plant near Pripyat, a town in northern Ukrainian Soviet Socialist Republic which was part of the Soviet ... | dev-5026 | Chernobyl disaster | 0 | 0 | 333 |
dev-5026-1 | The event occurred during a late-night safety test which simulated a station blackout power-failure and in which safety systems were deliberately turned off. A combination of inherent reactor design flaws and the reactor operators arranging the core in a manner contrary to the checklist for the test, eventually resulte... | dev-5026 | Chernobyl disaster | 1 | 334 | 1,275 |
dev-5026-2 | The Chernobyl accident dominates the energy accidents sub-category of most disastrous nuclear power plant accident in history, both in terms of cost and casualties. It is one of only two nuclear energy accidents classified as a level 7 event (the maximum classification) on the International Nuclear Event Scale, the oth... | dev-5026 | Chernobyl disaster | 2 | 1,276 | 1,949 |
dev-5026-3 | During the accident, blast effects caused 2 deaths within the facility, later 134 were hospitalized with acute radiation symptoms, of which 28 firemen and employees died in the days-to-months afterward from the effects of acute radiation syndrome, in addition, approximately 14 cancer deaths amongst this group of initia... | dev-5026 | Chernobyl disaster | 3 | 1,950 | 2,652 |
dev-5026-4 | The remains of the No.4 reactor building were enclosed in a large cover which was named the "Object Shelter". It is often known as the sarcophagus, with the purpose of reducing the spread of the remaining radioactive dust and debris from the wreckage and the protection of the wreckage from further weathering. It was fi... | dev-5026 | Chernobyl disaster | 4 | 2,653 | 3,307 |
dev-5026-5 | The accident motivated safety upgrades on all remaining Soviet-designed reactors in the RBMK (Chernobyl No.4) family, of which eleven continued to power electric grids as of 2013.[10][11] | dev-5026 | Chernobyl disaster | 5 | 3,308 | 3,495 |
dev-5026-6 | The disaster began during a systems test on 26 April 1986 at reactor 4 of the Chernobyl plant near Pripyat and in proximity to the administrative border with Belarus and the Dnieper River. There was a sudden and unexpected power surge. When an emergency shutdown was attempted, a much larger spike in power output occurr... | dev-5026 | Chernobyl disaster | 6 | 3,496 | 4,333 |
dev-5026-7 | 36 hours after the accident Soviet officials enacted a 10-kilometre exclusion zone which resulted in the rapid evacuation of 49,000 people primarily from Pripyat, the nearest large population centre.[15] Although not communicated at the time, an immediate evacuation of the town following the accident was not advisable ... | dev-5026 | Chernobyl disaster | 7 | 4,334 | 4,973 |
dev-5026-8 | As the plumes and subsequent fallout continued to be generated, the evacuation zone was increased from 10 to 30Â km about one week after the accident. A further 68,000 were evacuated, including from the town of Chernobyl itself.[15] The surveying and detection of isolated fallout hotspots outside this zone over the fol... | dev-5026 | Chernobyl disaster | 8 | 4,974 | 6,163 |
dev-5026-9 | In 2017 Philip Thomas, Professor of Risk Management at the University of Bristol found upon using the Years of potential life lost metric, that "Relocation was unjustified for 75% of the 335,000 people relocated after Chernobyl", finding that just 900 people within the 220,000 relocated during the second evacuation, wo... | dev-5026 | Chernobyl disaster | 9 | 6,164 | 6,718 |
dev-5026-10 | Russia, Ukraine, and Belarus have been burdened with the continuing and substantial decontamination and monthly compensation costs [19][20][24] of the Chernobyl accident. Although certain initiatives are legitimate, as the director of the UN Development Program Kalman Mizsei noted, “an industry has been built on this u... | dev-5026 | Chernobyl disaster | 10 | 6,719 | 7,117 |
dev-5026-11 | The accident raised the already heightened concerns about fission reactors worldwide, and while most concern was focused on those of the same unusual design, hundreds of disparate electric-power reactor proposals, including those under construction at Chernobyl, reactor No.5 and 6, were eventually cancelled. With the w... | dev-5026 | Chernobyl disaster | 11 | 7,118 | 7,711 |
dev-5026-12 | The accident also raised concerns about the cavalier safety culture in the Soviet nuclear power industry, slowing industry growth and forcing the Soviet government to become less secretive about its procedures.[27][notes 1] The government coverup of the Chernobyl disaster was a catalyst for glasnost, which "paved the w... | dev-5026 | Chernobyl disaster | 12 | 7,712 | 8,083 |
dev-5026-13 | A report by the International Atomic Energy Agency examines the environmental consequences of the accident.[14] Another UN agency, UNSCEAR, has estimated a global collective dose of radiation exposure from the accident "equivalent on average to 21 additional days of world exposure to natural background radiation"; indi... | dev-5026 | Chernobyl disaster | 13 | 8,084 | 8,687 |
dev-5026-14 | Estimates of the number of deaths that will eventually result from the accident vary enormously; disparities reflect both the lack of solid scientific data and the different methodologies used to quantify mortality—whether the discussion is confined to specific geographical areas or extends worldwide, and whether the... | dev-5026 | Chernobyl disaster | 14 | 8,688 | 9,056 |
dev-5026-15 | In 1994, Thirty-one deaths were directly attributed to the accident, all among the reactor staff and emergency workers.[32] As of the 2008 UNSCEAR report, the total number of confirmed deaths from radiation was 64 and this is expected to continue to rise. | dev-5026 | Chernobyl disaster | 15 | 9,057 | 9,312 |
dev-5026-16 | The Chernobyl Forum predicts that the eventual death toll could reach 4,000 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 approximatel... | dev-5026 | Chernobyl disaster | 16 | 9,313 | 9,856 |
dev-5026-17 | In a peer-reviewed paper in the International Journal of Cancer in 2006, the authors expanded the discussion on those exposed to all of Europe (but following a different conclusion methodology to the Chernobyl Forum study, which arrived at the total predicted death toll of 4,000 after cancer survival rates were factore... | dev-5026 | Chernobyl disaster | 17 | 9,857 | 10,311 |
dev-5026-18 | The risk projections suggest that by now [2006] 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 ... | dev-5026 | Chernobyl disaster | 18 | 10,312 | 10,760 |
dev-5026-19 | Two anti-nuclear advocacy groups have publicized non-peer-reviewed estimates that include mortality estimates for those who were exposed to even smaller amounts of radiation. The Union of Concerned Scientists (UCS) calculated that, among the hundreds of millions of people exposed worldwide, there will be an eventual 50... | dev-5026 | Chernobyl disaster | 19 | 10,761 | 11,493 |
dev-5026-20 | Along similar lines to the UCS approach, the 2006 TORCH report, commissioned by the European Greens political party, likewise simplistically calculates an eventual 30,000 to 60,000 excess cancer deaths in total, around the globe.[37] | dev-5026 | Chernobyl disaster | 20 | 11,494 | 11,727 |
dev-5026-21 | The Russian founder of that region's chapter of Greenpeace authored a book titled Chernobyl: Consequences of the Catastrophe for People and the Environment, which suggests that among the billions of people worldwide who were exposed to radioactive contamination from the disaster, nearly a million premature cancer death... | dev-5026 | Chernobyl disaster | 21 | 11,728 | 12,749 |
dev-5026-22 | On 26 April 1986, at 01:23 (UTC+3), reactor four suffered a catastrophic power increase, leading to explosions in its core. This dispersed large quantities of radioactive isotopes into the atmosphere[43]:73 and caused an open-air fire. The fire increased the emission of radioactive particles, carried by the smoke, as t... | dev-5026 | Chernobyl disaster | 22 | 12,750 | 13,306 |
dev-5026-23 | In steady state operation, a significant fraction (over 6%) of the power from a nuclear reactor is derived not from fission but from the decay heat of its accumulated fission products. This heat continues for some time after the chain reaction is stopped (e.g., following an emergency SCRAM) and active cooling may be re... | dev-5026 | Chernobyl disaster | 23 | 13,307 | 13,902 |
dev-5026-24 | Since cooling pumps require electricity to cool a reactor after a SCRAM, in the event of a power grid failure, Chernobyl's reactors had three backup diesel generators; these could start up in 15 seconds, but took 60–75 seconds[43]:15 to attain full speed and reach the 5.5‑megawatt (MW) output required to run one main p... | dev-5026 | Chernobyl disaster | 24 | 13,903 | 14,234 |
dev-5026-25 | To solve this one-minute gap – considered an unacceptable safety risk – it had been theorized that rotational energy from the steam turbine (as it wound down under residual steam pressure) could be used to generate the required electrical power. Analysis indicated that this residual momentum and steam pressure might be... | dev-5026 | Chernobyl disaster | 25 | 14,235 | 14,724 |
dev-5026-26 | This capability still needed to be confirmed experimentally, and previous tests had ended unsuccessfully. An initial test carried out in 1982 indicated that the excitation voltage of the turbine-generator was insufficient; it did not maintain the desired magnetic field after the turbine trip. The system was modified, a... | dev-5026 | Chernobyl disaster | 26 | 14,725 | 15,324 |
dev-5026-27 | The test focused on the switching sequences of the electrical supplies for the reactor. The test procedure was expected to begin with an automatic emergency shutdown. No detrimental effect on the safety of the reactor was anticipated, so the test programme was not formally coordinated with either the chief designer of ... | dev-5026 | Chernobyl disaster | 27 | 15,325 | 15,828 |
dev-5026-28 | According to the test parameters, the thermal output of the reactor should have been no lower than 700Â MW at the start of the experiment. If test conditions had been as planned, the procedure would almost certainly have been carried out safely; the eventual disaster resulted from attempts to boost the reactor output o... | dev-5026 | Chernobyl disaster | 28 | 15,829 | 16,237 |
dev-5026-29 | The Chernobyl power plant had been in operation for two years without the capability to ride through the first 60–75 seconds of a total loss of electric power, and thus lacked an important safety feature. The station managers presumably wished to correct this at the first opportunity, which may explain why they continu... | dev-5026 | Chernobyl disaster | 29 | 16,238 | 16,797 |
dev-5026-30 | The experimental procedure was intended to run as follows: | dev-5026 | Chernobyl disaster | 30 | 16,798 | 16,856 |
dev-5026-31 | The conditions to run the test were established before the day shift of 25 April 1986. The day-shift workers had been instructed in advance and were familiar with the established procedures. A special team of electrical engineers was present to test the new voltage regulating system.[49] As planned, a gradual reduction... | dev-5026 | Chernobyl disaster | 31 | 16,857 | 17,350 |
dev-5026-32 | At this point, another regional power station unexpectedly went offline, and the Kiev electrical grid controller requested that the further reduction of Chernobyl's output be postponed, as power was needed to satisfy the peak evening demand. The Chernobyl plant director agreed, and postponed the test. Despite this dela... | dev-5026 | Chernobyl disaster | 32 | 17,351 | 18,294 |
dev-5026-33 | At 23:04, the Kiev grid controller allowed the reactor shutdown to resume. This delay had some serious consequences: the day shift had long since departed, the evening shift was also preparing to leave, and the night shift would not take over until midnight, well into the job. According to plan, the test should have be... | dev-5026 | Chernobyl disaster | 33 | 18,295 | 18,772 |
dev-5026-34 | The night shift had very limited time to prepare for and carry out the experiment. A further rapid decrease in the power level from 50% was executed during the shift change-over. Alexander Akimov was chief of the night shift, and Leonid Toptunov was the operator responsible for the reactor's operational regimen, includ... | dev-5026 | Chernobyl disaster | 34 | 18,773 | 19,254 |
dev-5026-35 | The test plan called for a gradual decrease in power output from reactor 4 to a thermal level of 700–1000 MW.[51] An output of 700 MW was reached at 00:05 on 26 April. Due to the reactor's production of a fission byproduct, xenon-135, which is a reaction-inhibiting neutron absorber, core power continued to decrease wit... | dev-5026 | Chernobyl disaster | 35 | 19,255 | 20,465 |
dev-5026-36 | The reactor was now producing 5 percent of the minimum initial power level established as safe for the test.[48]:73 Control-room personnel decided to restore power by disabling the automatic system governing the control rods and manually extracting the majority of the reactor control rods to their upper limits.[52] Sev... | dev-5026 | Chernobyl disaster | 36 | 20,466 | 21,362 |
dev-5026-37 | The operation of the reactor at the low power level and high poisoning level was accompanied by unstable core temperature and coolant flow, and possibly by instability of neutron flux, which triggered alarms. The control room received repeated emergency signals regarding the levels in the steam/water separator drums, a... | dev-5026 | Chernobyl disaster | 37 | 21,363 | 22,029 |
dev-5026-38 | When the power level of 200Â MW was achieved, preparation for the experiment continued. As part of the test plan, extra water pumps were activated at 01:05 on 26 April, increasing the water flow. The increased coolant flow rate through the reactor produced an increase in the inlet coolant temperature of the reactor cor... | dev-5026 | Chernobyl disaster | 38 | 22,030 | 22,558 |
dev-5026-39 | The flow exceeded the allowed limit at 01:19, triggering an alarm of low steam pressure in the steam separators. At the same time, the extra water flow lowered the overall core temperature and reduced the existing steam voids in the core and the steam separators.[56] Since water weakly absorbs neutrons (and the higher ... | dev-5026 | Chernobyl disaster | 39 | 22,559 | 23,214 |
dev-5026-40 | All these actions led to an extremely unstable reactor configuration. Nearly all of the control rods were removed manually, including all but 18 of the "fail-safe" manually operated rods of the minimal 28 which were intended to remain fully inserted to control the reactor even in the event of a loss of coolant, out of ... | dev-5026 | Chernobyl disaster | 40 | 23,215 | 24,284 |
dev-5026-41 | At 1:23:04Â a.m., the experiment began. Four of the main circulating pumps (MCP) were active; of the eight total, six are normally active during regular operation. The steam to the turbines was shut off, beginning a run-down of the turbine generator. The diesel generators started and sequentially picked up loads; the g... | dev-5026 | Chernobyl disaster | 41 | 24,285 | 24,982 |
dev-5026-42 | Because of the positive void coefficient of the RBMK reactor at low reactor power levels, it was now primed to embark on a positive feedback loop, in which the formation of steam voids reduced the ability of the liquid water coolant to absorb neutrons, which in turn increased the reactor's power output. This caused yet... | dev-5026 | Chernobyl disaster | 42 | 24,983 | 25,659 |
dev-5026-43 | At 1:23:40, as recorded by the SKALA centralized control system, a SCRAM (emergency shutdown) of the reactor was initiated. The SCRAM was started when the EPS-5 button (also known as the AZ-5 button) of the reactor emergency protection system was pressed: this engaged the drive mechanism on all control rods to fully in... | dev-5026 | Chernobyl disaster | 43 | 25,660 | 26,289 |
dev-5026-44 | There is a view that the SCRAM may have been ordered as a response to the unexpected rapid power increase, although there is no recorded data proving this. Some have suggested that the button was not pressed, and instead the signal was automatically produced by the emergency protection system; the SKALA registered a ma... | dev-5026 | Chernobyl disaster | 44 | 26,290 | 27,011 |
dev-5026-45 | After the EPS-5 button was pressed, the insertion of control rods into the reactor core began. The control rod insertion mechanism moved the rods at 0.4 m/s, so that the rods took 18 to 20 seconds to travel the full height of the core, about 7 metres. A bigger problem was the design of the RBMK control rods, which had ... | dev-5026 | Chernobyl disaster | 45 | 27,012 | 28,052 |
dev-5026-46 | A few seconds after the start of the SCRAM, a power spike occurred, and the core overheated, causing some of the fuel rods to fracture, blocking the control rod columns and jamming the control rods at one-third insertion, with the graphite displacers still in the lower part of the core. Within three seconds the reactor... | dev-5026 | Chernobyl disaster | 46 | 28,053 | 28,407 |
dev-5026-47 | The subsequent course of events was not registered by instruments; it is known only as a result of mathematical simulation. Apparently, the power spike caused an increase in fuel temperature and steam buildup, leading to a rapid increase in steam pressure. This caused the fuel cladding to fail, releasing the fuel eleme... | dev-5026 | Chernobyl disaster | 47 | 28,408 | 28,818 |
dev-5026-48 | Then, according to some estimations, the reactor jumped to around 30,000 MW thermal, ten times the normal operational output. The last reading on the control panel was 33,000 MW. It was not possible to reconstruct the precise sequence of the processes that led to the destruction of the reactor and the power unit buildi... | dev-5026 | Chernobyl disaster | 48 | 28,819 | 30,015 |
dev-5026-49 | A second, more powerful explosion occurred about two or three seconds after the first; this explosion dispersed the damaged core and effectively terminated the nuclear chain reaction. This explosion also compromised more of the reactor containment vessel and ejected hot lumps of graphite moderator. The ejected graphite... | dev-5026 | Chernobyl disaster | 49 | 30,016 | 30,542 |
dev-5026-50 | According to observers outside Unit 4, burning lumps of material and sparks shot into the air above the reactor. Some of them fell onto the roof of the machine hall and started a fire. About 25 percent of the red-hot graphite blocks and overheated material from the fuel channels was ejected. Parts of the graphite block... | dev-5026 | Chernobyl disaster | 50 | 30,543 | 31,130 |
dev-5026-51 | After the larger explosion a number of employees at the power station went outside to get a clearer view of the extent of the damage, one such survivor, Alexander Yuvchenko recounts that once he stopped outside and looked up towards the reactor hall he saw a "very beautiful" LASER-like beam of light bluish light, cause... | dev-5026 | Chernobyl disaster | 51 | 31,131 | 31,533 |
dev-5026-52 | There were initially several hypotheses about the nature of the second explosion. One view was that the second explosion was caused by hydrogen, which had been produced either by the overheated steam-zirconium reaction or by the reaction of red-hot graphite with steam that produced hydrogen and carbon monoxide. Another... | dev-5026 | Chernobyl disaster | 52 | 31,534 | 32,472 |
dev-5026-53 | The force of the second explosion, and the ratio of xenon radioisotopes released after the accident, a vital tool in nuclear forensics, indicated to Yuri V. Dubasov in a 2009 publication, that as suggested by checherov before him in 1998, the second explosion could have been a nuclear power transient; the result of the... | dev-5026 | Chernobyl disaster | 53 | 32,473 | 33,932 |
dev-5026-54 | This nuclear fizzle hypothesis, then mostly defended by Dubasov, was in 2017 further analyzed by retired physicist Lars-Erik De Geer in which he puts the hypothesized fizzle event, in greater probability, as the cause of the first explosion.[70][71][72] The more energetic second explosion, which produced the majority o... | dev-5026 | Chernobyl disaster | 54 | 33,933 | 34,771 |
dev-5026-55 | Contrary to safety regulations, bitumen, a combustible material, had been used in the construction of the roof of the reactor building and the turbine hall. Ejected material ignited at least five fires on the roof of the adjacent reactor 3, which was still operating. It was imperative to put those fires out and protect... | dev-5026 | Chernobyl disaster | 55 | 34,772 | 35,552 |
dev-5026-56 | Approximate radiation intensity levels at different locations at Chernobyl reactor site shortly after the explosion are shown in the below table.[74] A dose of 500 roentgens (~5 Sv) delivered over an hour is usually lethal for human beings. | dev-5026 | Chernobyl disaster | 56 | 35,553 | 35,793 |
dev-5026-57 | The radiation levels in the worst-hit areas of the reactor building have been estimated to be 5.6 roentgens per second (R/s), equivalent to more than 20,000 roentgens per hour. A lethal dose is around 500 roentgens (~5 Gy) over 5 hours, so in some areas, unprotected workers received fatal doses in less than a minute. H... | dev-5026 | Chernobyl disaster | 57 | 35,794 | 36,527 |
dev-5026-58 | Because of the inaccurate low readings, the reactor crew chief Alexander Akimov assumed that the reactor was intact. The evidence of pieces of graphite and reactor fuel lying around the building was ignored, and the readings of another dosimeter brought in by 04:30 were dismissed under the assumption that the new dosim... | dev-5026 | Chernobyl disaster | 58 | 36,528 | 37,145 |
dev-5026-59 | Shortly after the accident, firefighters arrived to try to extinguish the fires. First on the scene was a Chernobyl Power Station firefighter brigade under the command of Lieutenant Volodymyr Pravik, who died on 9 May 1986 of acute radiation sickness. They were not told how dangerously radioactive the smoke and the deb... | dev-5026 | Chernobyl disaster | 59 | 37,146 | 37,632 |
dev-5026-60 | Grigorii Khmel, the driver of one of the fire engines, later described what happened: | dev-5026 | Chernobyl disaster | 60 | 37,633 | 37,718 |
dev-5026-61 | We arrived there at 10 or 15 minutes to two in the morning.... We saw graphite scattered about. Misha asked: "Is that graphite?" I kicked it away. But one of the fighters on the other truck picked it up. "It's hot," he said. The pieces of graphite were of different sizes, some big, some small, enough to pick them up... | dev-5026 | Chernobyl disaster | 61 | 37,719 | 38,039 |
dev-5026-62 | We didn't know much about radiation. Even those who worked there had no idea. There was no water left in the trucks. Misha filled a cistern and we aimed the water at the top. Then those boys who died went up to the roof – Vashchik, Kolya and others, and Volodya Pravik.... They went up the ladder... and I never saw th... | dev-5026 | Chernobyl disaster | 62 | 38,040 | 38,376 |
dev-5026-63 | Anatoli Zakharov, a fireman stationed in Chernobyl since 1980, offers a different description in 2008: | dev-5026 | Chernobyl disaster | 63 | 38,377 | 38,479 |
dev-5026-64 | I remember joking to the others, "There must be an incredible amount of radiation here. We'll be lucky if we're all still alive in the morning."[78] | dev-5026 | Chernobyl disaster | 64 | 38,480 | 38,628 |
dev-5026-65 | He also said: | dev-5026 | Chernobyl disaster | 65 | 38,629 | 38,642 |
dev-5026-66 | Of course we knew! If we'd followed regulations, we would never have gone near the reactor. But it was a moral obligation – our duty. We were like kamikaze.[78] | dev-5026 | Chernobyl disaster | 66 | 38,643 | 38,805 |
dev-5026-67 | The immediate priority was to extinguish fires on the roof of the station and the area around the building containing Reactor No. 4 to protect No. 3 and keep its core cooling systems intact. The fires were extinguished by 5:00, but many firefighters received high doses of radiation. The fire inside reactor 4 continued ... | dev-5026 | Chernobyl disaster | 67 | 38,806 | 39,222 |
dev-5026-68 | The fire was extinguished by a combined effort of helicopters dropping over 5000Â metric tons of sand, lead, clay, and neutron-absorbing boron onto the burning reactor and injection of liquid nitrogen. The Ukrainian filmmaker Vladimir Shevchenko captured film footage of an Mi-8 helicopter as its main rotor collided wit... | dev-5026 | Chernobyl disaster | 68 | 39,223 | 39,762 |
dev-5026-69 | From eyewitness accounts of the firefighters involved before they died (as reported on the CBC television series Witness), one described his experience of the radiation as "tasting like metal", and feeling a sensation similar to that of pins and needles all over his face. (This is similar to the description given by Lo... | dev-5026 | Chernobyl disaster | 69 | 39,763 | 40,205 |
dev-5026-70 | The explosion and fire threw hot particles of the nuclear fuel and also far more dangerous fission products, radioactive isotopes such as caesium-137, iodine-131, strontium-90 and other radionuclides, into the air: the residents of the surrounding area observed the radioactive cloud on the night of the explosion. | dev-5026 | Chernobyl disaster | 70 | 40,206 | 40,520 |
dev-5026-71 | Equipment assembled included remote-controlled bulldozers and robot-carts that could detect radioactivity and carry hot debris. Valery Legasov (first deputy director of the Kurchatov Institute of Atomic Energy in Moscow) said, in 1987: "But we learned that robots are not the great remedy for everything. Where there was... | dev-5026 | Chernobyl disaster | 71 | 40,521 | 40,930 |
dev-5026-72 | ‡With the exception of the fire contained inside Reactor 4, which continued to burn for many days.[43]:73 | dev-5026 | Chernobyl disaster | 72 | 40,931 | 41,038 |
dev-5026-73 | The nearby city of Pripyat was not immediately evacuated. The townspeople went about their usual business, completely oblivious to what had just happened. However, within a few hours of the explosion, dozens of people fell ill. Later, they reported severe headaches and metallic tastes in their mouths, along with uncont... | dev-5026 | Chernobyl disaster | 73 | 41,039 | 41,402 |
dev-5026-74 | As the plant was run by authorities in Moscow, the government of Ukraine did not receive prompt information on the accident.[86] Valentyna Shevchenko, then Chairman of the Presidium of Verkhovna Rada Supreme Soviet of the Ukrainian SSR, recalls that Ukraine's acting Minister of Internal Affairs Vasyl Durdynets phoned h... | dev-5026 | Chernobyl disaster | 74 | 41,403 | 42,402 |
dev-5026-75 | A commission was set up the same day (26 April) to investigate the accident. It was headed by Valery Legasov, First Deputy Director of the Kurchatov Institute of Atomic Energy, and included leading nuclear specialist Evgeny Velikhov, hydro-meteorologist Yuri Izrael, radiologist Leonid Ilyin and others. They flew to Bor... | dev-5026 | Chernobyl disaster | 75 | 42,403 | 43,255 |
dev-5026-76 | By 11:00 on 27 April, buses had arrived in Pripyat to start the evacuation.[86] The evacuation began at 14:00. A translated excerpt of the evacuation announcement follows:[87] | dev-5026 | Chernobyl disaster | 76 | 43,256 | 43,431 |
dev-5026-77 | For the attention of the residents of Pripyat! The City Council informs you that due to the accident at Chernobyl Power Station in the city of Pripyat the radioactive conditions in the vicinity are deteriorating. The Communist Party, its officials and the armed forces are taking necessary steps to combat this. Neverthe... | dev-5026 | Chernobyl disaster | 77 | 43,432 | 44,719 |
dev-5026-78 | To expedite the evacuation, residents were told to bring only what was necessary, and that they would remain evacuated for approximately three days. As a result, most personal belongings were left behind, and remain there today. By 15:00, 53,000 people were evacuated to various villages of the Kiev region.[86] The next... | dev-5026 | Chernobyl disaster | 78 | 44,720 | 45,308 |
dev-5026-79 | Evacuation began long before the accident was publicly acknowledged by the Soviet Union. On the morning of 28 April, radiation levels set off alarms at the Forsmark Nuclear Power Plant in Sweden,[89] over 1,000 kilometres (620Â mi) from the Chernobyl Plant. Sweden determined that the radiation had originated elsewhere,... | dev-5026 | Chernobyl disaster | 79 | 45,309 | 45,891 |
dev-5026-80 | At 21:02 the evening of April 28, a 20-second announcement was read in the TV news programme Vremya:[91][92] | dev-5026 | Chernobyl disaster | 80 | 45,892 | 46,000 |
dev-5026-81 | There has been an accident at the Chernobyl Nuclear Power Plant. One of the nuclear reactors was damaged. The effects of the accident are being remedied. Assistance has been provided for any affected people. An investigative commission has been set up. | dev-5026 | Chernobyl disaster | 81 | 46,001 | 46,253 |
dev-5026-82 | This was the entirety of the announcement of the accident. The Telegraph Agency of the Soviet Union (TASS) then discussed Three Mile Island and other American nuclear accidents, an example of the common Soviet tactic of emphasizing foreign disasters when one occurred in the Soviet Union. The mention of a commission, ho... | dev-5026 | Chernobyl disaster | 82 | 46,254 | 46,802 |
dev-5026-83 | Around the same time, ABC News released its report about the disaster.[94] | dev-5026 | Chernobyl disaster | 83 | 46,803 | 46,877 |
dev-5026-84 | Shevchenko was the first of the Ukrainian state top officials to arrive at the disaster site early on 28 April. There she spoke with members of medical staff and people, who were calm and hopeful that they could soon return to their homes. Shevchenko returned home near midnight, stopping at a radiological checkpoint in... | dev-5026 | Chernobyl disaster | 84 | 46,878 | 47,269 |
dev-5026-85 | There was a notification from Moscow that there was no reason to postpone the 1 May International Workers' Day celebrations in Kiev (including the annual parade), but on 30 April a meeting of the Political bureau of the Central Committee of CPU took place to discuss the plan for the upcoming celebration. Scientists wer... | dev-5026 | Chernobyl disaster | 85 | 47,270 | 47,790 |
dev-5026-86 | Several buildings in Pripyat were officially kept open after the disaster to be used by workers still involved with the plant. These included the Jupiter Factory which closed in 1996 and the Azure Swimming Pool which closed in 1998. | dev-5026 | Chernobyl disaster | 86 | 47,791 | 48,023 |
dev-5026-87 | Two floors of bubbler pools beneath the reactor served as a large water reservoir for the emergency cooling pumps and as a pressure suppression system capable of condensing steam in case of a small broken steam pipe; the third floor above them, below the reactor, served as a steam tunnel. The steam released by a broken... | dev-5026 | Chernobyl disaster | 87 | 48,024 | 48,634 |
dev-5026-88 | The smoldering graphite, fuel and other material above, at more than 1200 °C,[96] started to burn through the reactor floor and mixed with molten concrete from the reactor lining, creating corium, a radioactive semi-liquid material comparable to lava.[95][97] If this mixture had melted through the floor into the pool o... | dev-5026 | Chernobyl disaster | 88 | 48,635 | 49,136 |
dev-5026-89 | The bubbler pool could be drained by opening its sluice gates. However, the valves controlling it were underwater, located in a flooded corridor in the basement. So volunteers in wetsuits and respirators (for protection against radioactive aerosols) and equipped with dosimeters, entered the knee-deep radioactive water ... | dev-5026 | Chernobyl disaster | 89 | 49,137 | 50,477 |
dev-5026-90 | Once the bubbler pool gates were opened by the Ananenko team, fire brigade pumps were then used to drain the basement. The operation was not completed until 8 May, after 20,000Â metric tons of highly radioactive water were pumped out. | dev-5026 | Chernobyl disaster | 90 | 50,478 | 50,712 |
dev-5026-91 | With the bubbler pool gone, a meltdown was less likely to produce a powerful steam explosion. To do so, the molten core would now have to reach the water table below the reactor. To reduce the likelihood of this, it was decided to freeze the earth beneath the reactor, which would also stabilize the foundations. Using o... | dev-5026 | Chernobyl disaster | 91 | 50,713 | 51,359 |
dev-5026-92 | It is likely that intense alpha radiation hydrolysed the water, generating a low-pH hydrogen peroxide (H2O2) solution akin to an oxidizing acid.[107] Conversion of bubbler pool water to H2O2 is confirmed by the presence in the Chernobyl lavas of studtite and metastudtite,[108][109] the only minerals that contain peroxi... | dev-5026 | Chernobyl disaster | 92 | 51,360 | 51,688 |
dev-5026-93 | The worst of the radioactive debris was collected inside what was left of the reactor. During clean-up operations, remotely controlled machinery were used to try to move the most highly radiative debris, but these failed in the harsh conditions. Consequently, the most highly radioative materials were shoveled by Cherno... | dev-5026 | Chernobyl disaster | 93 | 51,689 | 52,672 |
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