What if meltdown

As a way to cool them down, the entire apparatus is submerged in water. It takes electrical power to maintain the water flow, so if there is a power failure, the nuclear plant's situation becomes critical. Without maintaining the water flow, temperature and pressure in the reactor will continually rise.

At the Fukushima Daiichi plant, a power failure after Friday's earthquake disrupted safety circuits at one of the station's reactors.

Diesel-powered generators at the site also failed. Electric batteries were the only resource left to keep the water-cooling process going, although those had a limited lifespan.

In other words, plant operators could not replace the water - which was quickly heating up and turning into steam - quickly enough. If the process goes unabated, the fuel rods' protective covering can be corrupted or even destroyed, which can then release radioactive gases and hydrogen into the outside environment - a likely cause of the Saturday explosion. Increasing temperatures inside the reactor were producing steam, which caused pressure in the reactor to go up.

To prevent an explosion, engineers released some of the slightly radioactive steam through a valve. Since that measure was only partially successful at lowering the reactor's pressure, officials began to fill the damaged reactor with sea water.

Similar plans were underway for Fukushima plant's other reactors, as engineers had lost the capacity to control their pressure, too. A meltdown has not occurred at the Fukushima power plant or any other of Japan's 55 nuclear power stations. In a complete nuclear meltdown, the fuel rods' contents - uranium and fission by-products such as cesium - can be exposed and sink to the bottom of the reactor.

This, in turn, can lead to uncontrolled reactions and raise the reactor's temperature and pressure even further. At that Pennsylvania nuclear station in a cooling malfunction combined with worker error led to a partial meltdown—about half of the reactor core melted and formed a radioactive puddle at the bottom of the steel pressure vessel. The vessel remained intact, but some radiation did escape from the plant into the surrounding environment. The Chernobyl accident was far more devastating; it rates as a 7, or a "major accident," on the INES scale.

In Ukraine, then part of the Soviet Union, a power surge caused an explosion in one of the plant's reactors, releasing huge doses of radioactive fallout into the air.

Two plant workers died within hours, according to the U. Nuclear Regulatory Commission; 28 more died in the following months from radiation poisoning. The fallout from Chernobyl was widespread, and the health effects of the disaster are difficult to quantify. A report from the United Nations Scientific Committee on the Effects of Atomic Radiation found that 6, individuals who were under the age of 18 in Ukraine, Belarus or Russia at the time of the disaster had by contracted thyroid cancer, "a substantial fraction" of whom likely contracted the disease due to radiation exposure.

John Matson is a former reporter and editor for Scientific American who has written extensively about astronomy and physics. Follow John Matson on Twitter. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue.

See Subscription Options. Go Paperless with Digital. Looking for a better method to cool and contain corium, Louie and colleagues turned to granular carbonate minerals like calcite and dolomite, which they say could be injected into the heart of reactors in the event of a meltdown. They then combined this with both a sample of granular calcite and, for comparison, grains of silicon dioxide sand.

A follow-up experiment, run on a kilogram-scale, also showed that carbonate granules could be successfully applied to contain the molten material. Oliver Alderman of Materials Development Inc. With their initial study complete, the researchers now have a non-provisional patent underway for the injectable safety materials and are also looking to perform even larger-scale tests, but with the incorporation of depleted uranium. Sandia National Laboratories is calling for expressions of interest from other research groups and organizations interested in partnering on future work into this approach to corium containment.

Close search menu Submit search Type to search. Topics Astronomy and space Atomic and molecular Biophysics and bioengineering Condensed matter Culture, history and society Environment and energy Instrumentation and measurement Materials Mathematics and computation Medical physics Optics and photonics Particle and nuclear Quantum. Sign in Register. If you feel embarrassed about revealing your emotions in public, you might examine how you feel about your feelings.

For some people, reducing the hold of such messages requires help from a mental health professional. And what if you feel relieved after a meltdown?

You never need to apologize for your feelings, but you may need to apologize for your behavior or for the way you expressed your feelings. But keep it brief, and focus your energy on understanding what happened and how you can prevent further workplace meltdowns.

The better you get at nipping meltdowns in the bud, the less likely you are to ever have another one. Here are some ideas to get you started:. Develop a stress-reduction plan. Listen to your body. Tight muscles, headaches, and other types of pain and discomfort are telling you something. Find someone to talk to. When something upsetting happens, or you feel chronic stress building up in your life, simply talking about it with someone who can listen nonjudgmentally can have a therapeutic effect.

Sometimes a therapist is the best person to talk to about difficult subjects, but a friend or other trusted acquaintance may also be able to fill this role.