The Government of Ukraine has released several messages on Wednesday warning of the power cut at the Chernobyl nuclear facility, which is in the hands of Russian troops, and of the impossibility of repairing this problem due to the fighting in the area. The Executive has even warned of a possible radioactive leak if the power supply is not restored. The International Atomic Energy Agency (IAEA), although it has once again expressed concern about the consequences that this warlike conflict may have on the country’s nuclear facilities, has nevertheless considered that there is no “critical impact on security” in this moment in the case of Chernobyl, whose reactors are not in operation.
April will mark the 36th anniversary of the Chernobyl disaster, the worst accident at a nuclear power plant ever recorded. The explosion in 1986 of reactor number four of the plant generated this radioactive accident. But the other three reactors continued to function. The last one stopped operating in 2000.
After the shutdown of a reactor in any plant, the used fuel, which is highly radioactive, is usually stored in pools with water for cooling. After the cut of the supply in Chernobyl, registered at 11:22 (local time) on Wednesday, the Ukrainian government has indicated to the Reuters agency that radioactive leaks could occur because the spent nuclear fuel cannot be cooled.
However, the plant has emergency generators that run on diesel. According to a statement released by the Ukrainian nuclear energy regulator, the facilities have enough fuel to run the generators for 48 hours. The IAEA has insisted this Wednesday on the existence of these generators and has recalled, as it did at the beginning of the month, that due to the time elapsed since the Chernobyl accident “the thermal load of the spent fuel storage pool and the volume of cooling water contained in the pool are sufficient to maintain effective heat extraction without the need for electricity. The same happens with the last nuclear fuel elements coming from the reactor that stopped operating in 2000, introduced in the pools of the plant, which would not need that electrical backup to avoid a disaster, experts say.
Alfonso Barbas, a nuclear engineer at Enusa, Spain’s public nuclear fuel company, points out that after a nuclear reactor shuts down, the fuel elements continue to store an enormous amount of heat. But they are losing it exponentially. “As soon as the reactor is turned off, they only conserve 10% of the heat,” he points out, and it continues to reduce at a high speed in the following weeks. “35 years later [del accidente de Chernóbil] the heat that could be expected from each fuel element would be about 500 watts”, the equivalent of less than 10 light bulbs. In Spain, for example, each fuel element weighs between 500 and 1,000 kilograms and is made up of between 250 and 300 fuel rods, adds Barbas.
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The main problem that could be generated if the fuel rods stored a high calorific value would be that the water in the pools in which it is stored would evaporate, generating a radioactive cloud. But that danger, Barbas and the IAEA believe, is not on the table now in the Chernobyl case due to the time that has elapsed and despite the power cut, which is used to keep the water circulating and cooling in the pools. Barbas recalls that, after the Fukushima accident in 2011, stress tests were carried out to check the safety of this type of pool. The conclusion was that under normal conditions the water would not boil and, therefore, evaporate completely.
Barbas believes that we must be attentive to the development of the situation in Chernobyl, which has been in the hands of Russian troops since the beginning of the invasion, but at this time “it does not pose a security risk”, as the IAEA also believes, an organization that has been carrying out a continuous monitoring of the situation since the beginning of the invasion and that until now has not put a hot cloth on the existing risk. But, as Barbas points out, “Chernobyl is not the cause of most concern in Ukraine.” More worrying is what might happen to the 15 active nuclear reactors in the country, which generate about 50% of the electricity Ukraine consumes. “Steps are being taken to make something happen,” says this expert.
In addition to the risk that these active facilities could be intentionally or accidentally damaged in the fighting, the IAEA and international observers are concerned about the situation of personnel working in the country’s nuclear plants and facilities. Rafael Grossi, secretary general of this international organization, has already warned on several occasions that it is essential that plant workers be able to “rest and work regular shifts.” “The ability of staff to make decisions without undue pressure is one of the seven essential pillars of nuclear safety and security” that the IAEA has set to prevent a disaster in a situation like the one in Ukraine, explains this body.
In the case of Chernobyl, the situation of the workers is not good, according to the Ukrainian regulator. “For two weeks now, the staff of the Chernobyl nuclear power plant have courageously and heroically carried out their duties without rotation to ensure the safe operation of the facilities,” Ukraine’s nuclear supervisor said on Wednesday. “I am deeply concerned about the difficult and stressful situation facing the staff of the Chernobyl nuclear power plant and the possible risks that this entails for security,” Grossi also said on Tuesday.
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