Tag Archives: neutrons

Yes, Apollo Flew Through the Van Allen Belts Going to the Moon

Conspiracists who believe the moon landings were faked like to claim the astronauts could not have survived the trip because of exposure to radiation from the Van Allen radiation belt (http://tinyurl.com/p7khram).

Of course, they are wrong. Again.

Related: Moon Landing Conspiracy Theory

25 Mind Bending Scientific Truths To Challenge Your Brain

By list25 via YouTube

From the video description:

It doesn’t take much to realize that science is awesome! For example, you probably already know that everything is made up of atoms. Those atoms have a few protons and neutrons in the nucleus and then they are surrounded by electrons that orbit the nucleus like little moons (simplified explanation). At any rate, the most interesting thing about atoms is that they are about 99.99% empty space. That’s right. This screen consists of atoms. And those atoms consists of almost nothing. So why is it that you don’t see right through the screen. In fact, how is it that we can see/feel/stand on anything at all? It’s because of forces. Those atoms in the table (in spite of just being mostly empty space) actually repel the atoms (aka empty space) in your hand. So what you are touching isn’t actually a “thing”. When you touch something you are actually experiencing a repulsive force, kind of like gravity. And since those empty atoms reflect photons, you cannot see through them. You only see the photons being reflected off of what is essentially empty space. Crazy right?!

See we told you science was awesome! Just wait til you read about all the other scientific truths found in this list! So if you’re ready to give your brain a challenge, read on! These are 25 mind bending scientific truths to challenge your brain.

Fukushima vs Chernobyl vs Three Mile Island

Years after the disaster, some claim that Fukushima radiation is still going to cause widespread death.

Brian DunningBy Brian Dunning via skeptoid.com
Read Podcast transcript below of Listen here

In March of 2011, an undersea earthquake sent tsunamis thundering across Japan, killing nearly 20,000 people and creating the most expensive natural disaster in history. Among the casualities was the Fukushima Daiichi Nuclear Power Plant, which was almost completely submerged by the tsunamis; an unprecedented event. Power was lost (obviously), cooling systems stopped, and the net result was a complete meltdown of three of the plant’s reactor cores. It was a perfect storm of worst case scenarios. And now, even years afterward, some are calling it a worldwide radiation disaster, worse than even Chernobyl, that will produce a staggering death count for decades or even centuries. Today we’re going to evaluate these assertions and see if we can separate fact from fiction.

Fukushima_250pxWith the shocking end-of-the-world-scenario headlines — such as “Your Days of Eating Pacific Ocean Fish Are Over” and “28 Signs That The West Coast Is Being Absolutely Fried With Nuclear Radiation From Fukushima” — either Fukushima was the worst environmental disaster ever, or some of the worst misinformation ever is being trumpeted. To find out which, we’ll put it into context with the two other best known nuclear disasters: the 1986 explosion of a reactor at the Chernobyl plant in the Ukraine, and the 1979 partial meltdown of a reactor at the Three Mile Island plant in Pennsylvania.

The most important technical point to understand about various reactor kinds is the moderator. The moderator is a substance that slows down the fast neutrons being shed by the radioactive uranium fuel, converts the kinetic energy into thermal energy, and turns them into slow, thermal neutrons. A thermal neutron is much more likely to strike another uranium nucleus. This allows a chain reaction, in which the fuel produces enough heat to power a conventional steam generator. Most nuclear reactors use water as the moderator. Put uranium fuel rods into water, in the proper configuration, and you’ll get a chain reaction.

Chernobyl, however, was a very different type of machine. It was what we call an atomic pile, the devices first designed during World War II to produce plutonium for atomic weapons. The atomic pile is literally a pile of graphite blocks, half a meter long and a quarter meter square, with a hole bored through the long axis. These graphite blocks were used as the moderator.

chernobyl_mapThe problem with building a reactor out of graphite blocks is that graphite burns. Contain burning graphite within a concrete structure, and it explodes. This is exactly what happened at Chernobyl, and it’s exactly why nobody would ever build a graphite-moderated reactor today; the whole reactor core was literally a bomb waiting to go off.

Three Mile Island and Fukushima were both water moderated reactors. This was one of the most significant safety improvements of the early 1950s. Fukushima’s basic design is one of the earliest, called a BWR (boiling water reactor). The moderating water, which is also the cooling water, is directly boiled and drives a steam generator. The reason the Fukushima accident happened is that all sources of power were destroyed by the tsunami, including backups, backups, and their backups; and without the pumps to keep the system circulating, the cooling water boiled completely away, and the fuel melted. For months, firehoses sprayed water into the open reactors to prevent open flames from pumping radioactive smoke into the atmosphere. This contaminated water was barely containable; it leaked into the ocean, and was stored in anything that could be used as a tank.

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