Before the ongoing crisis in Japan, few people were aware that a even a nuclear power plant that has been shut down demands a lot of electricity from an external source, without which it becomes uncontrollable and dangerous. Nuclear engineers, however, are very aware of this fact, and therefore it is standard practice to ensure a number of external sources in case of any accident or failure.
Nevertheless, it’s possible that no nuclear technician would ever have expected to encounter a situation in which 10 reactors in five nuclear power plants would all be shut down in an emergency that also disabled both the distribution grid and emergency diesel generators. Such is the situation at the Fukushima nuclear plant, where on Tuesday morning a third explosion reportedly damaged the suppression chamber of the plant’s second reactor causing a fire to break out in the fourth reactor block.
The emergency at Fukushima has drawn comparisons to the 1986 Chernobyl disaster in The amount of radiation leaked .... was undoubtedly higher than the Japanese authorities claim.Ukraine. But Chernobyl resulted from the negligence of plant operators, who conducted experiments during routine operation of the plant’s reactors, while the emergency at the Fukushima plant has been caused by a natural catastrophe.
Aleš John, Head of the Institute for Nuclear Research in Řež near Prague, echoed the assessment of other nuclear physicists and experts when he told the daily Hospodářské noviny that at Fukushima there is no physical possibility of an atomic explosion similar to that which occurred at Chernobyl.
According to official reports, hydrogen gas from the suppression chambers of the reactors caused the explosions at the Japanese plant.
France’s agency for nuclear safety — the ASN — is less benevolent in its assessment and has classified the Fukushima emergency as level seven in the seven-degree International Nuclear Event Scale — the same as for Chernobyl. Japanese authorities have rated the danger at level four.
The more critical assessment by the ASN reflects the high number of cases of exposure to radiation. As of Monday, some 190 people were reported to have been exposed to dangerous radiation levels and 160 people hospitalized after the first explosion. The death is in the thousands.
The amount of radiation leaked during the explosions and the managed release of pressure from the reactor vessels was undoubtedly higher than the Japanese authorities claim. This was indicated by the fact that the radiation cloud reached the US Navy aircraft carrier the Ronald Reagan, which is providing helicopters and crews for rescue operations. The ship’s crew was ordered to clear decks as the carrier moved further from the Japanese coast.
Czech Office for Nuclear Safety (SÚJB) chairwoman Dana Drábová has announced that increased radiation levels emanating from Japan have been detected in the skies above the Czech Republic, though she emphasized that this poses no health risks.
Perfection has limits
All of Japan’s nuclear plants reacted faultlessly to last Friday’s earthquake: Automatic systems began functioning upon the first tremors, and the back-up diesel generators would have undoubtedly provided power for cooling until the situation had stabilized. But...in some ways the collapse of Japan’s nuclear power plants is a worse experience than Chernobyl all of this perfection has been undermined by a seemingly minor detail — had the nuclear plant designers opted for sea protection defenses against an eight-meter high wave instead of six-meters, all of the nuclear plants on Honshu Island could now be up and running again.
For this reason, in some ways the collapse of Japan’s nuclear power plants is a worse experience than Chernobyl. In contrast with Soviet sloppiness and negligence, efficient and responsible Japanese operators were manning the plants, and while in the Soviet Ukraine there was an old reactor with an even older design, the Japanese reactors are modern with the most reliable safety features.
Not even the most experienced teams of specialists are able to take into account all the possible scenarios that nature could unleash. Following the events in Japan, for the people who decide on such matters, nuclear energy must now seem considerably more dangerous, and more questions will be asked as to whether it’s worth building new nuclear plants given the dangers.
Generators also fail without earthquakes
To simply take into account the experience of the tsunami would demonstrate incomprehension of the challenges posed by nature. Other surprises will undoubtedly be caused by other natural phenomena. Not only earthquakes cause power failures. In 2006, an electrical fault caused the shutdown of a reactor at the Forsmark nuclear plant in Sweden. According to Jan Beránek of Greenpeace, if cooling of the reactor had not restarted when it did, there would have been a meltdown within as little as one hour.
The alarming events in Japan come at a time when Europe has again begun to again embrace nuclear energy in what is being billed as a “nuclear renaissance” by the nuclear engineering industry. The EU energy commissioner said on Tuesday that Member States have agreed to a series of Europe-wide “stress tests” on the region’s nuclear power plants, and individual governments are taking similar measures to reassure the public.
Plans by the Czech state to at least double the output of the Temelín nuclear plant in South Bohemia by adding two new reactors are very advanced. Few believe the government and state-owned power company ČEZ would be willing to scrap the project. Still, it’s highly doubtful that the politicians who proposed the ridiculous legislation that would re-classify nuclear energy as an alternative source of power will dare to mention their initiative again.