JAPAN - (AP) - Japan ranked its nuclear crisis at the highest possible severity on an international scale - the same level as the 1986 Chernobyl disaster - even as it insisted Tuesday thatradiation leaks are declining at its tsunami-crippled nuclearplant.
The higher rating is an open acknowledgement of what was widelyunderstood already: The nuclear accident at the Fukushima Dai-ichiplant is the second-worst in history. It does not signal aworsening of the plant's status in recent days or any new healthdangers.
Still, people living nearby who have endured a month of spewingradiation and frequent earthquakes said the change in status addedto their unease despite government efforts to play down any notionthat the crisis poses immediate health risks.
Miyuki Ichisawa closed her coffee shop this week when thegovernment added her community, Iitate village, and four others toplaces people should leave to avoid long-term radiation exposure.The additions expanded the 12-mile (20-kilometer) zone where peoplehad already been ordered to evacuate soon after the March 11tsunami swamped the plant.
"And now the government is officially telling us this accidentis at the same level of Chernobyl," Ichisawa said. "It's veryshocking to me."
Japanese nuclear regulators said the severity rating was raisedfrom 5 to 7 on an international scale overseen by the InternationalAtomic Energy Agency due to new assessments of the overallradiation leaks from the Fukushima Dai-ichi plant.
According to the Vienna-based atomic energy agency, the newranking signifies a major accident that includes widespread effectson the environment and people's health. The scale, designed byexperts convened by the IAEA and other groups in 1989, is meant tohelp the public, the technical community and the media understandthe public safety implications of nuclear events.
The International Atomic Energy Agency said Japan's decision didnot mean the disaster had been downplayed previously.Early actions by Japanese authorities - evacuations, radiationwarnings and the work at the plant to contain leaks - showed theyrealized the gravity of the situation, Denis Flory, an IAEA deputydirector general, said.
The upgraded status did not mean radiation from the plant wasworsening, but rather reflected concern about long-term healthrisks as it continues to spew into the air, soil and seawater. Mostradiation exposures around the region haven't been high enough yetto raise significant health concerns.
Workers are still trying to restore disabled cooling systems atthe plant, and radioactive isotopes have been detected in tapwater, fish and vegetables.
Iitate's town government decided Tuesday to ban planting of allfarm products, including rice and vegetables, expanding thenational government's prohibition on growing rice there.
Japan's prime minister, Naoto Kan, went on national televisionand urged people not to panic.
"Right now, the situation of the nuclear reactors at theFukushima plant has been stabilizing step by step. The amount ofradiation leaks is on the decline," he said. "But we are not atthe stage yet where we can let our guard down."Japanese officials said the leaks from the Fukushima plant sofar amount to a tenth of the radiation emitted from Chernobyl, butabout 10 times the amount needed to reach the level 7 threshold.They acknowledged the emissions could eventually exceedChernobyl's, but said the chance that will happen is very small.However, regulators have also acknowledged that a more severenuclear accident is a distinct possibility until regular coolingsystems are restored - a process likely to take months.
"Although the Fukushima accident is now at the equal level asChernobyl, we should not consider the two incidents as the same,"said Hiroshi Horiike, professor of nuclear engineering at OsakaUniversity. "Fukushima is not a Chernobyl."
In Chernobyl, in what is now the Ukraine, a reactor exploded onApril 26, 1986, spewing a cloud of radiation over much of theNorthern Hemisphere. A zone about 19 miles (30 kilometers) aroundthe plant was declared uninhabitable.
Thirty-one men died mostly from being exposed to very highlevels of radiation trying to contain the accident. But there is noagreement on how many people are likely to die of cancers caused byits radiation.
No radiation exposure deaths have been blamed on the leaks atFukushima Dai-ichi. Two plant workers were treated for burns afterwalking in heavily contaminated water in a building there.The tsunami, spawned by a 9.0-magnitude earthquake, knocked outcooling systems and backup diesel generators, leading to hydrogenexplosions at three reactors and a fire at a fourth that wasundergoing regular maintenance and was empty of fuel. Workers havebeen improvising for weeks with everything from helicopter drops tofire hoses to supply cooling water to the plant.Hidehiko Nishiyama, a spokesman for Japan's Nuclear andIndustrial Safety Agency, noted that unlike in Chernobyl there havebeen no explosions of reactor cores, which are more serious thanhydrogen explosions."In that sense, this situation is totally different fromChernobyl," he said.NISA officials said they raised the incident level because ofthe cumulative amount of radioactive particles released into theatmosphere. Other factors included damage to the plant's buildingsand accumulated radiation levels for its workers.The revision was based on cross-checking and assessments of dataon leaks of radioactive iodine-131 and cesium-137. Officials didnot say why they skipped level 6 or when exactly the radiationlevel exceeded the level 7 threshold.Based on government estimates, the equivalent of 500,000terabecquerels of radiation from iodine-131 has been released intothe atmosphere since the crisis began, well above the several tensof thousands of terabecquerels needed to reach level 7. Aterabecquerel equals a trillion becquerels, a measure of radiationemissions. The Chernobyl incident released 5.2 millionterabecquerels into the air.
"We have refrained from making announcements until we havereliable data," Nishiyama said. He also emphasized that no moremajor leaks are expected from the reactors, though he acknowledgedmore work is needed to keep the reactors stable.Work to stabilize the plant has been impeded by continuedaftershocks, the latest a 6.3-magnitude quake Tuesday that promptedplant operator Tokyo Electric Power Co., or TEPCO, to temporarilypull back workers. Work removing highly radioactive water, anecessary step before cooling systems can be restored, finallyresumed around 7:30 p.m.In his televised address, Kan gave the nation a pep talk,telling people to focus on recovering from the disasters that arebelieved to have killed 25,000 people.
"Let's live normally without falling into excessiveself-restraint," he said. "We should eat and drink products fromthe quake-hit areas as a form of support."
Many of the more than 14,500 people still listed as missing fromthe quake and tsunami are thought to have been swept out to sea. Amonth after the disaster, more than 145,000 people are still livingin shelters.Among them is Kenichi Yomogita, a plumbing contract worker atFukushima Dai-ichi who was off work the day of the tsunami and hasnot returned. His hometown of Tomioka is in the evacuation zone,and he thinks it will be at least three years before he can return.For now he is living at a shelter in Koriyama, and said theupgraded crisis level has not improved his hopes.
"At first the reality of this situation didn't sink in," hesaid, "but this news shows how serious it is."