Chernobyl's Legacy
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T. SUESS/TIMMSUESS.COM T. Ghost from the past: encased in crumbling concrete, the deadly contents of Chernobyl’s reactor number 4 still exert a far-reaching effect on the area. Despite those differences, the quarter-cen- tury of work following the Chernobyl disaster will offer some important lessons for Japan Chernobyl’s legacy as the nation begins to assess the health and environmental consequences of Fukushima. Twenty-five years after the nuclear disaster, the clean-up grinds The problems that followed Chernobyl also on and health studies are faltering. Are there lessons for Japan? provide a grim reminder about the value of accurate information. Officials need to tell people immediately how to avoid the initial, BY MARK PEPLOW most dangerous, exposure; yet in the longer term, scientists and the government must bat- tle against unnecessary concern over low-level he morning train from Slavutych the ensuing blaze spewed 6.7 tonnes of material doses of radiation, which often causes more is packed with commuters playing from the core high into the atmosphere, harm than the radiation itself. cards, browsing e-readers, or watch- spreading radioactive isotopes over more than In some ways, the connection between the ing the monotonous flood plains pass 200,000 square kilometres of Europe (see ‘The two accidents may yield the biggest benefits Tby. It looks like any other routine journey to hottest zone’). Dozens of emergency workers for Chernobyl. For a brief window of time, the work. But rather than facing a crush through died within months from radiation exposure world has again focused attention on the largely subway turnstiles at the end of the 40-minute and thousands of children in the region later overlooked work there. The renewed interest trip, the workers are met by a row of full-body developed thyroid cancer. The region around may spur nations to chip in the cash needed to radiation monitors. It is the start of another day the plant became so contaminated that officials complete the clean-up of the site, and to carry at the Chernobyl power plant, the site of the cordoned off a 30-kilometre exclusion zone that out health studies that have languished for want world’s worst civilian nuclear disaster. straddled Ukraine’s border with Belarus. Today, of proper coordination and funding. “In recent As the train trundles through the bleak a staff of about 3,500 enters the zone each day to years, Chernobyl has been neglected by fund- Ukrainian countryside, another nuclear crisis monitor, clean and guard the site, where reme- ing agencies and, to an extent, the scientific is unfolding halfway around the world. Barely diation work will continue for at least another community,” says Jim Smith, a radioecologist a week after the partial meltdown at the Fuku- 50 years (see ‘Half-life of a disaster’). at the University of Portsmouth, UK, who has shima Daiichi nuclear power station, it is no So far, the Fukushima accident is less severe. studied the consequences of the accident for surprise that some of the chatter on the train Radiation levels measured near the Japanese 20 years. “But there is still more to learn from turns to the incident there. “It looks bad,” says power plant have been less than those at Cher- Chernobyl about decommissioning and the one commuter. “But not as bad as Chernobyl,” nobyl after the blast there (see ‘Exposure in con- effects of the radiation,” says Smith, who is he adds, with a hint of grim pride. text’). And although radiation has spread from touring the site with a group of other scientists. When Chernobyl’s reactor number 4 Fukushima, it does not match the amounts that After clearing a security checkpoint, the exploded in the early hours of 26 April 1986, rained down in the region around Chernobyl. visiting researchers board a bus that heads 562 | NATURE | VOL 471 | 31 MARCH 2011 © 2011 Macmillan Publishers Limited. All rights reserved HALF-LIFE OF A DISASTER towards the heart of the ageing power plant. waste — partly because of persistent flooding Owing to a awed safety test, They pass abandoned buildings and bump in some of the waste-storage buildings and 986 Chernobyl's reactor 4 explodes, along potholed roads running beneath arch- reactor 4’s turbine hall. Every month, at least scattering debris from the core ways made of piping; since the accident, pipes 300,000 litres of radioactive water must be 26 APRIL over a wide area. have been laid above ground to avoid disturb- pumped out of the structures and stored on site. ing contaminated soil. The main cause of this flooding is Cherno- 27 APRIL The visitors stop to look at the most visible byl’s brimming cooling pond, which artificially A day after the reminder of the accident, the concrete sar- elevates groundwater levels in the area. Alex- blast, some 44,000 residents are cophagus that entombs the shattered reactor ander Antropov, a Chernobyl veteran with evacuated from building. Completed hastily in November ice-blue eyes and a cool manner to match, is Pripyat, just 3 km from the reactor. AKG-IMAGES/RIA NOWOSTI AKG-IMAGES/RIA 1986, the sarcophagus was built to contain the in charge of a project to decommission the escaping radiation, but it is now crumbling and pond. The term ‘cooling pond’ usually refers streaked with rust. Smith whips a dosimeter to the containers where spent fuel rods are 5 MAY The re in the reactor is nally out of his rucksack and poses for a photograph stored until their radiation dissipates enough extinguished, having released 6.7 tonnes of radioactive material in front of the sarcophagus. The reading is that they can be put into long-term storage. over 200,000 square kilometres. 5 µSv h−1: about 10 minutes of exposure at that But Chernobyl’s pond is actually a vast reser- level equals the same dose as an arm X-ray. voir covering 22 square kilometres into which People and cattle are evacuated from a The plant’s bright main office is a stark con- water from the reactor cooling systems was 6 MAY 30-kilometre exclusion zone around the trast to the sarcophagus. Stained-glass win- discharged. The pond also contains long-last- plant. dows depict — in glorious socialist–realist ing radioactive material such as caesium-137 style — the harnessing of atomic energy. But and strontium-90, which rained down after 4 months after the blast, 28 emergency AUGUST workers have died from acute radiation the plant has not produced power since 2000, the explosion. Besides causing flooding at the sickness, caused by massive doses of when the last reactor was shut down. Valeriy plant, the high water levels in the cooling pond radiation. Seyda, a deputy director of the Chernobyl raise the risk that a weak dyke along its east Nuclear Power Plant, explains that the plant’s side will burst, which would send water cours- top priority now is to construct a new confine- ing into the Pripyat River. Radioactivity in the NOVEMBER Workers complete ment shelter for reactor 4 before the sarcopha- escaping water would be quickly diluted by the a concrete gus becomes too unstable. If it collapses before river, so although it would not significantly sarcophagus the new shell is in place, it could throw up a raise exposure levels for people downstream, it around the cloud of radioactive particles and expose the could cause panic among the local population. shattered reactor I. KOSTIN/SYGMA/CORBIS to limit further deadly remnants of the reactor. Antropov says that his team cannot simply release of radiation. lower the water levels in the pond because they REPLACING THE RUSTING TOMB don’t know what effect microscopic radioactive Cases of thyroid cancer in local children The plan is to build an enormous steel arch sediment particles would have if exposed. In 99 have risen ten-fold from previous levels. adjacent to the reactor and slide it along a run- the meantime, the team maintains the status way to cover the building. The arch will reach quo by pumping water from the Pripyat River 105 metres high, with a span of 257 metres — into the pond at a cost of a few hundred thou- the world’s largest mobile structure, according sand euros per year. But the long-term plan is 2000 to its designers. It is expected to be in place to lower the water level by 7 metres to form a The last of Chernobyl's reactors is switched o. by 2015 and should last for 100 years. It will patchwork of 10–20 smaller ponds that would enable robotic cranes inside to dismantle the keep the most dangerous sediments in place. sarcophagus and parts of the reactor. Long- The project would cost €3 million to €4 million, term plans call for finishing the clean-up work says Antropov. He is already in discussions with The United Nations Chernobyl Forum K. DIORDIEV/REUTERS/CORBIS at Chernobyl by 2065. the relevant regulators and is optimistic that the 2005 reports that no more than 4,000 people Some of the concrete trenches for the necessary feasibility studies and environmental will die from the reactor's fallout. project are in place. But the international impact assessments can be completed. Chernobyl Shelter Fund that supports the But the effort has been a long time coming. 25th anniversary conference expects to US$1.4-billion effort still lacks about half of The decommissioning plan is more than a dec- 20 see lobbying for more funds for that cash, and the completion date has slipped ade old, and was supported by a 2005 survey clean-up and health studies.