Anniversaries: Lest We Forget Chernobyl

Chernobyl Liquidators (1986); location and original source of photograph unconfirmed. Image Source: Progetto Humus via Belarusguide.

Today marks the 25th anniversary of the worst nuclear disaster in history. The meltdown and explosion at reactor #4 of the Chernobyl nuclear power plant near Pripyat, Ukrainian SSR in 1986 was worse than 100 times the Hiroshima and Nagasaki bombs.  Aside from Fukushima, it is the only incident classified as level 7 on the International Nuclear Event Scale.  Below is an overview of Chernobyl, from its construction, to the accident, to the wildlife that lives there now.

Pripyat. Prometheus monument at the time of the town's construction. Image Source: Pripyat.com.

Caption for the above photograph: In the photo foreground there is bronze monument in honor of Greek hero Prometheus. At the background we can see construction of the 4th floor of house number 3 at Kurchatova street.

Constructing the Nuclear Plant at Chernobyl

Before the accident, nuclear power was seen as the safe and cheap energy source of the future.  The town of Pripyat was one of several municipalities dedicated in the USSR to a specific industry.  As a symbol of their ambitions, the town's leaders erected a statue of the Greek Titan Prometheus; it was later moved within sight of the Chernobyl plant. This was inauspicious: Prometheus faced divine punishment because he dared to steal the power of the gods and give it to humans in the form of fire.  Prometheus (who symbolized ingenuity) and his twin brother Epimetheus (who symbolized foolishness) represented humankind to the gods.  The latter accepted Pandora, the first woman, as a gift from Zeus. While Prometheus was punished by having his liver eaten by an eagle, Pandora was a further punishment for Prometheus's transgression. Epimetheus married Pandora, whereupon she opened her famous Box, loosing evil upon the world, with only Hope remaining trapped inside. The statue of Prometheus remains in Pripyat to this day.

For a sense of the optimistic mood under which Chernobyl was constructed, see the video below.

Video of Chernobyl plant construction (1970). Video Source: Youtube.

As is clear with the Fukushima plant in Japan, one major problem with nuclear plants is that they need a continuous supply of electrical power to maintain their cooling systems. At the time of the emergency test that sparked the disaster, the Chernobyl plant had been running for two years without the capacity to withstand a power failure.  There was an unacceptable gap of one minute before back-up diesel generators could kick in to full power and continue pumping the huge volume of water needed to keep the reactor cool; the focus was on Chernobyl's fourth reactor: "The reactor that exploded in Chernobyl consisted of about 1,600 individual fuel channels, and each operational channel required a flow of 28 metric tons (28,000 liters (7,400 USgal)) of water per hour." A test planned on 25-26 April 1986 was meant to correct this problem.

The Disaster

In order to resolve the issue of the poor emergency fail-safe, the plant's personnel lowered the amount of electrical power to the #4 reactor - as would happen in the case of a power brownout.  The idea was to see if the cooling pump could still operate under those conditions.  The electrical engineers who designed the test were experts in electrical generators, not in nuclear reactors. The nuclear reactor specialists had not been consulted regarding the test.

Anatoly Dyatlov, former deputy engineer for operations at Chernobyl. Photo taken in July 1995. Image Source: Nuclear Engineering International.

The director of the experiment was Anatoly Dyatlov (31 March 1931 - 13 December 1995).  He was sentenced in 1987 to ten years in prison "for criminal mismanagement of potentially explosive enterprises."  He later wrote a memoir, Chernobyl. How it Happened, in which he blamed the accident on plant design, not the errors of plant workers.  He died of heart failure before his sentence ended, due to radiation exposure.

The main part of the emergency test was supposed to be completed by the day shift workers on April 25th. However, due to unexpected fluctuations in the power grid, the experiment was delayed into the evening and had to be continued by staff who were not prepared to deal with the earlier stage of test conditions. A rapid fall in power below 50 per cent levels occurred as evening workers left and the night shift came on.

The head of the night shift personnel was Alexander Akimov (6 May 1953-11 May 1986).  Rod Adams explains on Atomic Insights what happened as Akimov began to get confusing data:

On April 26th, 1986, at 1:23 am, Alexander Akimov did what he and thousands of other nuclear plant operators have been trained to do. When confronted with confusing reactor indications, he initiated an emergency shutdown of Unit 4 of the large electricity generating station near Pripyat in the Ukraine. By doing so, he unwittingly initiated an explosion whose effects continue to be felt throughout the world. ...

RBMK reactors can develop what is known as a positive void coefficient of reactivity. ... [That is an] increasing boiling caused by increasing core temperature [that] can lead to an increase in core reactivity, an increase in core power and even more boiling. This positive feedback mechanism is assiduously avoided in most reactor plant designs.

What has not been so well understood is that the shutdown button of an RBMK could, under very special initial conditions, initiate a positive insertion of reactivity that could increase core temperature rapidly enough to cause a steam explosion. No nuclear reactor plant can explode in a manner even remotely similar to an atomic bomb, but, as boiler operators have known for well over a hundred years, a steam explosion can pack quite a punch.

Though much has been made of the lack of a “safety culture,” lack of containment, and violations of procedures by operators, the specific cause of the Chernobyl explosion and subsequent release of radioactive material from the Chernobyl reactor was a shutdown system that initiated a positive reactivity accident. For those readers who have never operated a nuclear reactor, it might be helpful to think of the cause as a brake pedal that – without the driver’s knowledge – transformed itself into an accelerator.

The details of the accident are here and are clearly explained here. Akimov worked with his crew until morning trying to pump water into the reactor to cool it. He died three weeks later from radiation poisoning.   The following videos show the escalation of the disaster and the evacuation of a 30 km zone around the burning reactor. 135,000 people were evacuated from the area, including 50,000 from Pripyat.  For a video of the town before, during and after the evacuation, go here.  Wiki has a page on the effects of the accident here.

First aerial video of the raspberry-coloured radiation fire. Video Source: Youtube.

Initial news reports outside the USSR revealed authorities could not determine the source of excess radiation. Video Source: Youtube.

Evacuation of Pripyat. This film shows sparks on it due to radiation. Video Source: Youtube.

Caption for the above video: The author of this video, Michail Nazarenko, was making a film about an atomic plant and happened to be in Pripyat. He also filmed the evacuation there. At the day of evacuation, the official level of radiation in Pripyat reached 1 Roentgen per hour, but people say it was 7 Roentgens. This makes a difference, because in first case, the population would die within two or three months. While in second, people would die in several days.

The 'temporary' evacuation announcement for Pripyat, informing citizens to leave by 27 April at 2 pm.  Video Source: Youtube.

First Days after the Accident. Video Source: Youtube.

Caption for the above video: This film shows the terrifying images captured by the Russian filmmaker Vladimir Shevchenko on scene at Chernobyl those dreadful days in April 1986. Shevchenko later died suffering from the radiation he exposed himself to. Although his name is not among the official casualties of the accident, this last tragic film of him keeps his name alive forever.

The spread of radiation. Images Source: BBC.

Summaries of the disaster, the radiation plume, the effects on the Ukraine, Russia and neighbouring Belarus and Europe and around the globe are here, here, here and here.

Chernobyl Liquidators (1986). Image Source: Progetto Humus via Belarusguide.

The Aftermath

Eerie photos from inside Reactor #4 have inspired the Millennial survival horror genre. The hastily built concrete sarcophagus that contains the reactor requires constant maintenance.  It will be replaced in 2013 by the 'New Safe Confinement' structure that is meant to last 100 years.

Video Source: Youtube.

The most shocking impact is perhaps in the physical deformity of children born under this cloud of radiation.  For pictures, see here, here, here, here, here and here.  The death toll for the event is hotly debated, and stands somewhere between 4,000 and 1 million.  There were between 300,000 and 800,000 brave workers who participated in the clean-up.  Many died.  Some observed genetic defects in their children: "A sevenfold increase in DNA mutations has been identified in liquidators' children conceived after the accident, when compared to their siblings conceived before. However, the effect diminishes sharply with time." Another outcome of the accident is the sharp rise in thyroid cancer and thyroid problems across Europe and potentially globally.

Animals, Insects, Birds and Plants

Image © Vasily Fedosenko/Reuters. Image Source: Reuters.

Original caption for the above photograph: An elk stands in a forest in the 30 km (18 miles) exclusion zone around the Chernobyl nuclear reactor near the village of Babchin some 370 km (217 miles) southeast of Minsk February 1, 2008.

In 1997, University of Georgia researchers found that Chernobyl's animals and birds had genetically changed, but were not deformed. This apparently was cause for optimism:

"Rodents such as voles show even higher levels of contamination, as much as 10 times the levels found in U.S. rodents. "No one has ever seen levels like that before," Dallas said. UGA researchers also have found genetic changes in these animals. "I use the word change and not damage," Dallas said, because the implications of the changes remain unclear. "We found no deformed animals. None at all."

It's odd that they did not assume that deformed animals died and therefore were not found by their team.  No one knows what the consequences are of having wildlife with altered DNA interbreeding with other genetically altered animals or with normal animals.

Wild boar swimming in the exclusion zone. Video Source: Youtube.

Great big catfish: Chernobyl's cooling pond. Video Source: Youtube.

In 2006, several reports (for example, here and here) circulated that wildlife around Chernobyl was thriving, with casual statements such as the BBC's: "Mouse DNA has changed, but with few visible effects."  In 2009, negative response like this one contradicted that optimism:

The study showed that numbers of bumble-bees, butterflies, spiders, grasshoppers and other invertebrates were lower in contaminated sites than other areas because of high levels of radiation left over from the blast more than 20 years ago. The findings challenge earlier research that suggested animal populations were rebounding around the site of the Chernobyl explosion in Ukraine, which forced thousands to abandon their homes and evacuate the area. Estimates of the number of deaths directly related to the accident vary. The World Health Organization estimates the figure at 9,000 while the environmental group Greenpeace predicts an eventual death toll of 93,000.

"We were amazed to see that there had been no studies on this subject," Anders Moller, a researcher at the National Center for Scientific Research in France, who led the study, said in telephone interview. "Ours was the first study to focus on the abundance of animal populations."

Researchers said they had compared animal populations in radioactive areas with less contaminated plots and found that some were nearly completed depleted of animal life. "There are areas with an abundance of 100 animals per square meter," Moller said. "And then there are areas with less than one specimen per square meter on average; the same goes for all groups of species."

The researchers also found that animals living near the Chernobyl reactor -- which was covered in a protective shell after it exploded in April 1986 -- had more deformities, including discoloration and stunted limbs, than normal. "Usually (deformed) animals get eaten quickly, as it's hard to escape if your wings are not the same length," Moller said. "In this case we found a high incidence of deformed animals." The findings challenge the view of Chernobyl as ecologically sound, despite the fact that Ukrainian officials have turned it into a nature reserve, with wolves, bison and bears.

These concerns originated in a three-year study published by Royal Society Biology Letters (here); there's a report on this article here.

Rabid radioactive wolf in the exclusion zone. Video Source: Youtube.

There is a good blog about animals at Chernobyl here and information about the animals in the exclusion zone here.  There are reports at that site about wolves, boar, deer, badgers, cranes, bears, wild horses and many other species.  There is a whole Youtube channel (here) devoted to videos of Chernobyl's wildlife.

Birds, Animals Insects in the exclusion zone. Above Image Sources: Chernobyl.in.ua.

The Red Forest, a pine forest near the reactor, was so named after the disaster because the pine needles turned from green to crimson due to radiation poisoning.  There are reports on the Red Forest here, here and here.

Image of the Red Forest shows impact of radiation. Image Source: Chernobyl.in.ua.

Chernobyl memorial. Image Source: Chernobyl.in.ua.

Links:
-Maps of fallout - listed country by country
-International Chernobyl Radiological Portal
-Chernobyl Radiation Bibliography
-Chernobyl Forum
-National Museum of Chernobyl
-Cultural impact of Chernobyl disaster
-New Safe Confinement
-Chernobyl Recovery Development Program
-Chernobyl Children's Project International
-Lists of Chernobyl-related charities here and here
-List of Chernobyl-related articles on Wiki (includes lists of people who investigated the disaster in greater depth, among them, Yury Bandazhevsky)
-Photo galleries: here, here, here, here

See my earlier post about Chernobyl.
See all my posts on nuclear topics.