2013-08-11

08-11-2013: BSinSF (Bad Science in Science Fiction)

Peacekeeper is still in the hands of my grammatically correct wife. As much as I would like to, I'm not going to rush her. I also read a chapter of the completed novel at the writer's group yesterday and received some good feedback.

Today I've decided to begin a new phase in my blogging. Instead of writing about my writing (which is why I started this blog in the first place) and what's been going on in my life, I've decided to make it more interesting. This post is the first in a series of posts on bad science in science fiction. Getting the numbers right is very important in scifi because if you don't, somebody is going to notice. Even something as mundane as the size of a rotating space station must be checked. I do write scifi that uses questionable science (shields, stardrive, etc) but I strive to keep the technology within limits as well as making the numbers and behavior believable.

In this first post of BSinSF (Bad Science in Science Fiction) I'm going to cover a subject I'm very familiar with – nuclear power. I've been in the nuclear power field for more than 35 years and while that doesn't qualify me as an expert it certainly means I know what I'm talking about. I was a reactor operator for 11 years in the Navy and I now work at a nuclear power plant as a technician.

Contamination vs radiation: This is a common misperception. Radiation is particles or photons (usually gamma rays) that are emitted from a radioactive source. This includes an operating reactor. Contamination is a radioactive source in an undesired location. Think of it like this—contamination is like radioactive dust which emits radiation. Contamination can usually be removed unless you get it inside you and then it is still removed by biological action. Radiation can be stopped by shielding and it does not 'melt' things as I've recently heard on a poor television broadcast. Radiation will also not cause contamination. Neutron radiation can cause non-radioactive materials to become radioactive but other types cannot do so.

Critical reactors: This is actually a good thing! A sub-critical reactor is one in which the power level is dropping. Super-critical means the power level is rising which is also normal because it's how you raise power in a fission reactor. Critical, is simply the definition of a reactor running at a steady power level. For those of you who remember Voyage to the Bottom of the Sea – forget everything you learned in that show concerning nuclear power; it's all wrong! There is another form a criticality called 'prompt critical'. This is virtually impossible to achieve in modern reactors. Prompt criticality will destroy a reactor but will not result in a mushroom cloud nuclear explosion. The primary reason this cannot happen in a power reactor is that the fuel used in the core is not the same as that used in a nuclear bomb and it is not even close to the correct configuration. The explosions at Chernobyl and SL-1 were steam explosions caused by a prompt-criticality event—not a nuclear explosion.

Nuclear reactors: There are two basic types that we know of: fission and fusion. Fission reactors operate by the splitting of heavy atoms. Gross power level is controlled by inserting and removing control rods from inside the core. Fine power level is controlled by a natural feedback process involving the density of water. Basically, the hotter the water gets the less power the reactor produces. This 'negative feedback' allows the reactor to be easily controlled. Fusion reactors generate power by smashing very light elements together. This is how the sun produces power. Fusion reactors require some way of heating the fuel and keeping it confined. This is usually accomplished by magnetic fields or lasers. Neither type of reactor can explode in the nuclear sense of the word. If a fusion reactor is damaged it will simply stop operating. If a fission reactor is damaged and not kept cool the fuel will eventually overheat and melt. The extreme heat of the melting fuel will cause water to be split into oxygen and hydrogen resulting in a hydrogen explosion which is what happened at Fukushima and Three Mile Island.

The bottom line is this: If you use a nuclear reactor to power something in your story and that reactor experiences a problem, you should do the research first to find out if the accident you describe can actually occur. When in doubt, talk to someone who understands nuclear power. There's a lot of people out there who think they know how this stuff works but who really don't. Talk to someone in the industry—most people are glad to talk about it.


Feedback on the contents of this blog are welcome. If you would like additional details or would like to see a specific subject covered please let me know. I can be reached at: author at dougfarren dot com