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Analysis You may have seen in the news some panic about a Chinese nuclear reactor going awry and a warning of an “imminent radiological threat”. Well, don’t worry: it’s a routine fuel rod problem.
CNN claimed an exclusive on Monday after seeing a June 8 memo indicating that there was a build-up of “noble gases in the primary circuit” of the cooling system at the Taishan-1 nuclear power plant.
The letter was written by nuclear engineering company Framatome, which is largely owned by French energy giant EDF and was tasked with designing and helping to operate the Franco-Chinese power plant. The facility in Guangdong Province was commissioned in December 2018 and serves the manufacturing centers in Guangzhou and Shenzhen.
Framatome has written to the US Government’s Dept of Energy requesting permission to access US data and technical resources to help resolve the issue. The business further claimed that Chinese regulators were increasing the limit on the amount of gas that can be released from the cooling system, exceeding French safety standards, to prevent the plant from shutting down.
The news of the memo raised fears that a nuclear disaster could be covered up by Beijing. However, the truth is less terrifying.
EDF declared that the accumulation of inert gases believed to be xenon and krypton was due to a fault in one or more of the fuel rods and their seals. These gases were collected, processed and released “in accordance with regulations,” added the electricity giant.
When the uranium in the reactor fuel rods is struck by neutrons and fission, it breaks down into smaller elements, including the radioactive isotopes of iodine, krypton, and xenon. Small amounts of these fission fragments should leak, but if the fuel containers are punctured, ruptured, or have other defects, more material will be released into the cooling loop. This is where the aforementioned accumulation of gas comes from: radioactive fission by-products escaping from the fuel in the primary cooling circuit. This gas had to be removed from the coolant, and the fuel responsible for the leaks may need to be treated.
Damage to fuel rods is not unheard of. A U.S. government report last year said that for pressurized water reactors, there was an average of 1.6 leaking fuel rods per faulty fuel assembly around the world between 1994 and 2004. Each assembly, we note -the, typically holds between 170 and 230 pencils, and up to 65 percent of fuel outages in the United States have been caused by grid-to-rod fretting.
“For pressurized water reactors (PWRs), which are the most common reactor type in the United States as well as the reactor type at the Taishan nuclear power plant, the main causes of fuel leakage are debris and fuel. grid-rod fretting, which occurs when a nuclear fuel rod rubs against the metal spacer grids that hold the rods in place, ”Katie Mummah, a PhD student in nuclear engineering at the University of Wisconsin, told The Register. Madison.
“Corrosion, manufacturing defects and fuel handling errors are less common but still cause occasional failures. Most failures are also quite small, microscopic cracks or hairline cracks. a partial pellet may fall out of the fuel assembly.
Fuel failure … is not desirable as leaking or damaged fuel assemblies require additional investigation and handling. However, they are not considered to be a major safety or security issue.
She added that a fuel rod problem does not usually cause a reactor to shut down. Containers are usually left until the reactor is refueled and then secured.
“Fuel outages are generally not considered to be events requiring press releases,” she said. “They often do not cause any change in the power level of the reactor and usually do not cause the reactor to shut down.
“They are undesirable because leaking or damaged fuel assemblies require additional investigation and handling, and will eventually require different storage and transport containers after unloading a spent fuel pool. However, they are not considered to be a major safety or security issue. “
But what about the detection of krypton and xenon, admittedly radioactive? Well, as rare gases they are chemically inert, so any damage to the plant itself should be minimal or nonexistent.
Xenon-133 is one of the possible fission fragments. It has a habit of sliding through pipes and walls, it has a half-life of just over five days, and it has been approved by the FDA to map lung function and blood flow. The gas decays by beta radiation and also emits a small amount of gamma rays. Xenon-137, meanwhile, has a half-life of around four minutes, and krypton-90 has a half-life of 32 seconds, although other fission fragments can have much longer half-lives. long.
A slight increase in gamma radiation was detected around the plant, suggesting on the one hand that a certain amount of radioactive material has escaped or was removed, and on the other hand, looks like radiation from normal background. So essentially, judging by the numbers from Chinese nuclear monitors, there is little cause for concern.
According to CNN, U.S. officials did not think this episode was a crisis, but said it should be watched. Chinese officials also said the whole affair was not a problem and everyone should just calm down. Of course, they would say that, but it seems, in this case, that they are probably right.
“Since its commercial commissioning, the Taishan nuclear power plant has strictly controlled the operation of units in accordance with operating license documents and technical procedures,” the Chinese government told CNN. “All the operating indicators of the two units have met the requirements of the nuclear safety regulations and the technical specifications of the plants.”
Framatome, meanwhile, said in a public statement that “according to the data available, the plant is operating within safe settings.” The UN’s International Atomic Energy Agency added: “At this point, the agency has no indication that a radiological incident has occurred.
There you have it, a new reactor dealing with the first oscillations of the fuel rods. Far be it from us to take the word of the energy companies, but if we are to panic over a disaster then it should be a real disaster and not an incident that nuclear engineers are more than capable of handling. You can get out of your bunker now.
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