March 15th, 2011
02:29 PM ET

What you should know about radiation

Japanese workers are scrambling to control a nuclear plant after a fire that may have burned several fuel rods. Officials said that the readings at the Fukushima Daiichi nuclear plant Tuesday morning were not at levels to cause “harm to human health,” but anxiety about impending disaster persists. Here's more on radiation sickness and how to combat it.

Radiation levels at the plant Tuesday were between 100 and 400 millisieverts, Japan’s Chief Cabinet Secretary Yukio Edano said. To put that in perspective, in the United States, a person typically gets a radiation dose of 6.2 millisieverts per year.

That dose would quickly dissipate with distance from the plant, and radiation levels quickly fell back to levels where they would be no immediate public health threat, Edano said. Still, people as far as 30 kilometers (18.6 miles) were warned to stay inside.

At the higher end of that spectrum at the Japan plant, exposure to millisieverts for three hours would lead to radiation sickness, and eight hours would be fatal, said Ira Helfand of Physicians for Social Responsibility. But in general, in an emergency situation, keeping it below 500 millisieverts is pretty safe, said Nolan E. Hertel, nuclear engineering expert at Georgia Institute of Technology. And the further away you are from a radiation source, the lower exposure you will have.

Are you confused about what this all means? Here’s a bit of basic science to help explain the science and health effects of radiation.

What is radiation and why is it dangerous?

Atoms become radioactive when they are unstable. In a process called "decay," the atom can split into smaller pieces and release a lot of energy. The types of subatomic particles emitted during a radioactive decay include gamma rays, neutrons, electrons, and alpha particles that shoot through space. Some of these can travel through the human body, damaging cells and posing a hazard for humans.

Alpha particles are relatively heavy and, when emitted, cannot penetrate human skin or clothing, but are harmful if they get into the body otherwise. Beta radiation can cause skin injury and are also harmful to the body internally. Gamma and X-rays are high-energy invisible light that can damage tissue and are most hazardous to humans.

Some elements such as uranium, commonly used as fuel in nuclear power plants, are always radioactive; there is no nonradioactive form of them that naturally occurs in nature.

Radiation from the Japanese power plant is getting into the atmosphere because of the explosions that have happened there, and because it is necessary to vent some of it in order to prevent further damage.

How is radioactivity measured?

Radioactivity of a given sample of a substance is measured in terms of how many atoms are spontaneously disintegrating (“decaying”) every second, according to the U.S. Department of Energy. Specific instruments are designed to detect particular kinds of radiation that get released with each decay.

When we talk about people being exposed to radiation, we use units called rems or sieverts, which measure the biological effect for whole-body radiation. But pay attention to the time period per unit: The longer the exposure, the more dangerous it is.

Geiger counters detect radiation emitted from decaying atoms.

What are some common sources of radiation?

The average annual radiation exposure a person gets from natural sources is about 3.1 millisieverts; in the United States, a person typically gets a total of 6.2 millisieverts in a year because of medical diagnostic procedures and other man-made sources of radiation. The limit for occupational radiation exposure among workers who deal with radioactive material is 50 millisieverts in a year. Here's more on that from the FDA.

To give you a sense of what that means, a chest X-ray delivers a dose of about .02 millisieverts (what you'd get from the natural background radiation in 2.4 days), and a CT to the abdomen carries 8 millisieverts (what you'd get naturally in 2.7 years). But note that these procedures don't last very long; prolonged exposure would be more dangerous.

Although high doses of radiation can lead to cancer, radiation therapy targeted at tumors is used to treat cancer. That dose is about 10,000 times that typical exposure rate for the U.S., but it is applied to the cancerous tissue; the total-body exposure during radiation therapy is much less.

What is the danger level for humans and radioactivity?

Radiation does not affect everyone in the same way, so it’s impossible to say that a particular level is fatal in all cases. But, according to the NRC, scientists believe that half a population would die within 30 days after a full-body dose of 3,500 to 5,000 millisieverts from a few minutes to hours.

The more than 130 plant workers and firefighters who developed acute radiation sickness at Chernobyl received doses of 800 to 16,000 millisieverts.

Studies of populations exposed to high levels of radiation have shown increased risk of cancer. High-dose exposure, above 500 millisieverts, has been associated with leukemia, breast, bladder, colon, liver, lung, esophagus, ovarian, multiple myeloma, and stomach cancers, according to the United States Nuclear Regulatory Commission.

But there is no hard evidence proving that low dose radiation, below 100 millisieverts per year, is likely to cause cancer. People who live in places that have higher levels of background radiation than normal, such as Denver, Colorado, with levels above 10 millisieverts per year, have not shown adverse biological effects, the NRC said. In general, the higher up you are in the atmosphere, the more radiation (rays from the sun and other cosmic sources) you're exposed to, which is why airline pilots and flight attendants also get more radiation exposure than the average person.

CNN's Madison Park and Sabriya Rice contributed to this report.

soundoff (73 Responses)
  1. SDL

    I know the media is trying to qualm fears, but the explanations of radiation damage are really lacking. Even extremely small amounts of radiation can break DNA, but the difference with small amounts is that the body's repair mechanisms almost always are able to recover. At high levels of exposure, the repair mechanisms are apparently overwhelmed. What is NOT known is how often the small exposures and resulting damage escape the repair mechanisms, and thus we really don't know what a "safe" level of exposure is. Even just one tiny mistake in the DNA can increase cancer risk if it is in a "important" part of the DNA. That is why the medical community no longer views CT scans and x-rays as completely harmless and prefers not to expose patients to any additional radiation unless it really is a necessary procedure (when the benefits of the diagnostic outweigh the risks).

    March 15, 2011 at 15:11 | Report abuse | Reply
    • Rigel54

      Well said/written, a good comment. The author of this article is an imbecile. He/she repeatedly fails to mention the time frame of radiation dosages. There is a huge difference between 10 sieverts/secon, 10 sieverts/hour, and 10 sieverts/year. Their TV spokespeople are just as stupid. It's hard to believe they got out of middle school. At least 1/3 of the info they report on this problem is false, sometimes grotesquely so. It's a hard choice between the overt lies of Fox and the gross incompetence of CNN.

      March 16, 2011 at 01:21 | Report abuse |
    • JLS639

      Agree with SDL and Riegel54. Dose per time unit is what is most important. The article hints at that later, but never says it.

      It is worth noting that very often the standard in the military, industry and academic research has been total dose. I do not know if it has changed since the last time I worked with radioactivity. However, industry and the military in particular were resistant to the idea of using dose per time and were fond of pointing out that a pilot would get the same dose over several flights that they were giving a worker over 15 minutes. Since we were not worried about the pilot, the worker must be safe, right? I suspect, based on reading this, that maybe the old "screw the workers" dishonesty of ignoring dose over time and instead opting for absolute dose still applies.

      March 16, 2011 at 08:28 | Report abuse |
    • Bane

      I think SDL is actually a radiation worker of some sort (perhaps a radiation oncology resident or medical physicist) playing dumb with rather mundane trivial tidbits anyone can read in the first page of a radiobiology textbook under the guise of the layperson, to gain somesort of juvenile gratification...did I come close to the mark?

      March 17, 2011 at 04:01 | Report abuse |
    • jasonT

      No I don't think SDL is in Radiation Oncology or a Medical Physicist at all. The comment about the medical community not wanting to use x-ray imaging unless it's considered necessary is some sort of a media based impression or lecture learned. It's true that this is a topic of discussion but it is not standard practice in the US. There are no protocals for tracking radiation dose where imaging is concerned in radiation therapy. I have worked in a hospital for over 8 years and they have no compunction about using x-rays or CTs. In fact I have seen the complete opposite and yes I have worked in medical physics in a radiation oncology department and x-ray imaging was used all the time. The only reason they might hold off is that the insurance companies might refuse to pay if they think it's unnecessary.

      It is not standard practice in the medical physics community (i.e. radiation therapy) to report or track in absorbed dose/time units. In fact it's not important in that arena because the dose rates are known and used to calculate absorbed dose to the treatment volume.

      March 20, 2011 at 00:17 | Report abuse |
    • Michael Lee

      JLS639 I am retired Air Force. I did radiation surveys during my 20 years. We always went by a 2 mR/hr guideline. I retired in 99. They still use the same standards today. I also was in charge of the film badge program. For those not familiar, a film badge is worn by radiation workers (x-ray techs for example). When the results are obtained we look at several factors. The dosage received during the time period the badge was worn, the time period per quarter and the year. If the limit was exceeded for any of these time periods the worker was removed from the area and an investigation wsa done to see why the results were high.
      During actual x-ray serveys we established a 2mR/hr line. No one was allowed to cross this line will the x-ray unit was operating. There were plenty of safety systems in place to ensure no one could be "accidently exposed" to radiation. Thereare 3 methods for limiting the amount of radiation a individual receives, time, shieldiing and distance. Shielding is the best way to protect a person from a radiation source. If that cannot be provided distance is next. The further away from a radiation source the lower your dosage will be. The last and least desiriable is time. A person can be exposed to higher levels of radiation for shorter periods of time and still not exceed the annual dosage amounts. The only problem with tme is it only applys to lowers amounts of radiation. With very high levels, even a short period of time can cause health effects or death.

      March 20, 2011 at 21:02 | Report abuse |
    • Jeremy

      JasonT – I don't know what hospital you worked at for "8 years" but I can tell you as a bona fide layperson that one of the top hospitals in the country, Dartmouth Medical Center, openly states that they avoid unnecessary scans specifically due to radiation.

      My girlfriend was just up there three weeks ago due to severe pains in the region of her kidney. We later found out that she had contracted e. coli but, prior to that diagnosis through bloodwork, they performed an ultrasound and then began discussing whether or not further imaging would be necessary. The lead doctor came into the room at one point and specifically stated that he "did not want to pursue further imaging at this time" because he did not feel the excess exposure to radiation would be fruitful enough to justify it. Those were his words. *shrug*

      March 20, 2011 at 22:12 | Report abuse |
    • JLS639

      @Michael Lee: Thanks for your post. I am glad to hear that the Air Force, at least, is more serious about this than what I had heard.

      My father was in the Air Force, one of my maternal uncles worked in nuclear engineering for the Navy and my other maternal uncle worked in the Navy and several physics departments. They are my sources.

      My father told me about specific incidents where workers received their maximum yearly dose in less than an hour. I will ask him about this the next time I talk to him. He finished the air force in the early 1970's, so standards might have been updated between then and when you worked in the AF.

      My uncle in the Navy said that the Navy cared a lot more for protecting its engineers from radiation exposure than its technicians. They would look the other way when the technicians chose to over expose themselves (often removing their badges to avoid leaving evidence of over-exposure). The Navy did not order them to do this, but did nothing to stop it. My uncle made it very clear the officers new full well what was going on.

      He told me about one incident where 3 technicians received way too much radiation and at least one of them died. They had not realized it was a problem for two reasons: one is that they did not check the room with a geiger counter first (there had been a leak), but the other was that they did not realize the danger. They were blaise about radiation exposure.

      March 20, 2011 at 22:13 | Report abuse |
    • Lisa

      The issue with medical radiation exposure is that a provider will NEVER be sued because he or she ordered a CT scan and the patient developed cancer 20 years later. The chance that the scan would cause the cancer is miniscule, but it isn't zero either. The chance that the same medical provider will be sued for not ordering a CT scan is real, even when the indication to do it is weak.
      I'd like to see dose reported in rem, because dose and exposure are completely different things, and dose depends on the type of radiation and the type of exposure. Is the Sievert even used as a unit of dose?

      March 27, 2011 at 13:03 | Report abuse |

    Not only America and other countries should take a lesson of this nuclear disaster but IRAN must also take a serious note of this incident. Iran and Turkey are also in similar very dangerous seismic zones and have probability of such a strong earthquake. It would be much better for these nations to stay away from any nuclear power plant or weapon storage. It will be much better if Iran's leaders will take a serious note of this matter and take decision in their own interest and abandoned their construction of nuclear facility on their soils. It will surely help them economically and much more politically.

    March 15, 2011 at 15:35 | Report abuse | Reply
  3. MSC CPT Wayne

    In the old units system, 450 rads would be the LD50/30 for the average human. I easily remember the new units by noting that there are 100 rad pennies in one gray dollar. Thus, the new unit gray (one joule/kilogram) ) replaces the rad. So 450 rads is 4.5 gray. Since a rad is nearly the same as a rem (QF=1 for gamma radiation), then the sievert, another new unit, replaces the rem. So we say 450 rem or 4.5 sievert is the LD50/30. That's without medical treatment. With medical treatment, a lot of folks may survive doses as high as 10,000 rads, or 100 sieverts. Radioactive particles that are ingested are particularly dangerous because even when very low doses are observed, given a long enough half life of the radionuclide, the lifetime does may be enormous. Note: In the Portsmouth Shipyard studies, many of the workers are now in there sixties and are suffering from cancer (~ 60% or more). I hope this helps and that I have not made a mistake.

    March 15, 2011 at 15:47 | Report abuse | Reply
    • Elizabeth

      I wonder why they changed the scales; could it be because 450 sounds serious, while 4.5 sounds like it isn't a big deal? Every time measurement scales change, there is more confusion, and more likelihood of forgetting; in some of the substances that have long half-lives, we might have changed nomenclature so many times that none of it will make sense. For example, every Italian city had a different set of liquid measures, so to read an ancient cookbook, one has to do research into the equivalent measurements.

      March 15, 2011 at 22:31 | Report abuse |
    • JLS639

      Elizabeth, they changed the scales because the old ones were all but useless from a medical standpoint for two reasons:

      (1) The old system treated all ionizing radiation the same, regardless of its ability to penetrate biological tissues. An alpha particle carries enormous energy and therefore represented a high dose, but as the article pointed out, they cannot penetrate clothing or the outer layer of skin. Much lower does of gamma radiation which can harm internal organs were counted as low doses.

      (2) The old system did not take into account where the body was exposed. Hands, for example, have much more extensive DNA repair systems than internal organs. Hands can take large doses of radiation with little damage. Testes and ovaries, however, are highly sensitive.

      The newer system takes into account the type of radiation and the area exposed. A large dose of alpha radiation to the hands and feet would be close to 0 sieverts and a small dose of x-rays to the lower abdomen (hitting reproductive tissues) would be a high number of millisieverts.

      March 16, 2011 at 08:37 | Report abuse |
    • Radtech01

      Ahh, this takes me back to x-ray school. What a horrible trip down memory lane-hours and hours of radiation biology class.

      March 16, 2011 at 10:13 | Report abuse |
    • Arne

      Nobody survives a dose of 100 Sv. With or without medical care. A dose of about 10 Sv or more is invariably fatal.

      March 16, 2011 at 17:24 | Report abuse |
    • Terry

      For an educated person, please learn the difference between there and their.

      March 17, 2011 at 02:39 | Report abuse |
  4. lar

    ok i am old school from the nuke plants we used rem and millarim am i right when i do the math the highest level was 40 rem that they have so far? in 12 years at nukes i have a whole body does of 20 rem so far so good knock on wood '
    the highest field aka area i was in was over 50 rim = 50,000 mr how that works to a laymen u can walk in the field say for 10 sec and get hardly and radiation but stand there for a hour and you get 50 rem more then likely your dead i got like 200 mr in like 10 min. back then we could get 240 mr a day so to me thats not alot most days working in them i got les then 10 mr

    March 15, 2011 at 18:01 | Report abuse | Reply
    • Natch

      50 rem will not kill you, unless you already had some pretty serious health issues. You don't start feeling the effects of radiation sickness until at least 100 rem, short term dose. 500 rem was (as stated by Wayne, above you) the LD50/30 dose (meaning 50% of the population could be expected to die within 30 days), and 1000rem is considered the LD100 dose.

      Oh, and the good news, guys? It takes 1500rem to kill off your "little swimmers", so you don't need to worry about that!!

      March 15, 2011 at 21:29 | Report abuse |
    • Mary

      Just that the "little swimmers" will create mutant children..Right??

      March 23, 2011 at 03:30 | Report abuse |
  5. MJB

    In 1985 Russia has their hugh nuclear plant issue since then there has been 50 people diefrom all that. 8 were children that dies from thyroid cancer. Gas explosions, coal miner mishaps and oil have killed more people than nuclear. So we haven't gut all that out. Except Obama stopped some of it. We still do drill in some areas. Obama has got to start up our drilling again
    until something comes along. Solar is very expensive especially for people to have it on their houses. We have tons of sun out here but too expensive. No wind out here so thats out for us. But for now nuclear and oil and goal and gas. We have oil and need to get busy and keep drilling. North dakota is and has been drilling for oil and has got to keep it up.

    March 15, 2011 at 18:41 | Report abuse | Reply
    • Elizabeth

      Drilling and mining are only cheap because the big companies get the land for free. Solar is only expensive because roof tiles etc. are not being mass produced on automated assembly lines, although in countries where that does happen, plenty of people are installing it. I guess you just want to make money on easy drilling.

      March 15, 2011 at 22:40 | Report abuse |
  6. AD

    Is melt down and radiation leakage going to happen? read in

    March 15, 2011 at 18:47 | Report abuse | Reply
  7. Salvatore

    OMG... hide from the sun! Hide from the CMB! Nuclear energy pollutes the air with... steam. But we are ok with burning coal and letting all that byproduct suffocate us every day with no place to hide from it. I would gladly match the mortality statistics between coal and nuclear.

    March 15, 2011 at 19:15 | Report abuse | Reply
    • Maybe Not

      Salvatore, nuclear accidents can turn people into crispy critters! I'd rather see more wind farms and solar power but will take coal over nukes if I had the say.

      March 15, 2011 at 21:48 | Report abuse |
    • Elizabeth

      I agree that coal is extremily dirty: slag, dirty water, possible coal explosions, mining accidents, and yes, radiation from coal dust. But even without nuclear accidents, there is the problem of storing nuclear waste for the hundreds of years; no place on earth is completely safe from earthquakes. In a nuclear accident, nuclear is much worse than coal. Bottom line: there are so many different possibilities with solar, but we've been doing the experiments and proofs for forty years. It's time to stop blocking this development, and implement it. I heard it said that if they turn even part of Death Valley into solar energy, it could power this country. But then we would have to make the high tension line connections, build it, etc. It would be much cheaper to build and connect than even one nuclear power plant or coal plant, and there would be no waste storage. It is the government that is holding this back: major engineering firms take government contracts, which are awarded to the lowest bidder. But there are no bids being offered for this technology, because the government is not looking for the contracts. Plenty of industries are connected to the defense department in contracts, and that isn't considered socialism, but the necessary defense of our country. So why aren't the bids being sought for solar? It seems that there must be lobbyists who are stopping such development.

      March 15, 2011 at 22:48 | Report abuse |
  8. John

    I think for those not in the immediate area of the reactors and those that could be in the path any major nuclear cloud, the info they need to know is how it would affect people on a genetic level. We know that there's been an increase of genetic problems (miscarriages, deformaties at birth, etc) in people along the path of the cloud from Chernobyl. Cancer is one problem of radiation, changes to people's DNA is another.

    March 15, 2011 at 22:00 | Report abuse | Reply
  9. JimG

    This article is lacking. In order to have radiation, you have to have a radioactive source. Those people wearing protective suits are trying to protect themselves from radioactive particles (source) in the air and on the ground. Probably some type of Cesium isotope. This is also known as radioactive contamination.
    Radiation is commonly measured in a dose per hour and just like sunlight, the closer you are to it and the longer you stay exposed to it, the higher the dose.

    March 15, 2011 at 22:44 | Report abuse | Reply
    • SC

      I agree about the source issue in reporting. I regularly hear (even in this article) the mixed use of radiation vs. contamination. The news regularly reports this as one thing. The risks are different. Personal protection is different.

      March 16, 2011 at 12:29 | Report abuse |
    • therm

      Most of the time when I try to explain the difference between radiation and contamination, people don't understand. They think it's all "radiation". If you have "contamination" on your hand, and you walk away from the source of that contamination, guess what, you're still getting irradiated!

      March 19, 2011 at 16:25 | Report abuse |
    • Lisa

      You do not need a radioactive source to have radiation. In medical applications the vast majority of radiation is generated with electricity.

      March 27, 2011 at 13:16 | Report abuse |
  10. lar

    lol all the suits are for is to stop alpah and bata do you think they have lead suits on lol come on now
    and i guess i have been out of the nukes for like 12 years but darn it i am going to get my books out now lol i must be getting old now i thought 50 rm was deadly lol anyways 50 rem i know wouldnt be good for you in the least bit it would be s uper big dose for sure the most i ever got at one time was 400 mr and it was on a bottom head drain and i was in a suit it was supplyed air lol didnt stop gama but the unit was down so no nutron nutron is made when it is running
    anyways makes me wonder how many mr i will get here now days i guess

    March 16, 2011 at 00:56 | Report abuse | Reply
  11. Rich

    Jebus, the author made this article so ponderous for the average, non-occupational (non-nuclear) reader. This could have been greatly simplified.

    March 16, 2011 at 09:59 | Report abuse | Reply
  12. r

    There have been "experts" on Fox News who say that Chernobyl barely resulted in any dangerous levels of radiation at all to anyone. Absolute disregard of the truth and the devastating effects Chernobyl had on people, flora and fauna. It's disgusting. And this morning one of the same experts was saying the same thing again.

    March 16, 2011 at 11:14 | Report abuse | Reply
  13. brad1001

    An explaination of the difference between gamma and beta radiation would have been helpful. Telling people how to avoid it (ingestion, contact, exposure etc) would have been soo much more helpful than lessons in math. Cut and pasted perhaps?

    March 16, 2011 at 13:06 | Report abuse | Reply
  14. Mr. Mackey

    Radiation's bad, mmkay? Really, REALLY bad. Mmkay? You probably want to stay away from it, that's how bad it is, mmkay?

    March 16, 2011 at 14:02 | Report abuse | Reply
    • Mr. Slave

      Oh Jeethus Christh! Oh Jeethus!

      March 16, 2011 at 14:03 | Report abuse |
  15. Larry051967

    Just think about how many people will not understand anything technical and panic. The panic will move the media much more than the facts. California pill supplies are sold out and the message that the US Navy's first response was soap and water was missed.

    March 16, 2011 at 16:35 | Report abuse | Reply
  16. pieRsquared

    Well I hate to hear people talk who have no idea of what the hell they are saying. I have heard 'the same amount you get in a year from background', well great.. What is the rate?? Per hour? Per day? If you get 5 millisieverts over a day vs. over an hour, that is a big difference in dose. I have been hearing a lot of talking heads just repeat some number, It would be nice to hear it as a dose rate..

    March 16, 2011 at 18:04 | Report abuse | Reply
  17. Charlie

    Sanjay Gupta seems like a nice, sincere person.
    Having said that, I think that he and the entire CNN organization ought to be ashamed of Gupta standing on camera and saying his rad meter showed a four fold increase in radiation since being in Tokyo.

    That comment went 100% against all local readings being monitored by various scientists and hobbyists in the greater Tokyo area.

    For a good deal of Tuesday, and pretty much all of Wed. Thurs. and now Friday, rad levels have been exactly normal or a slight amount higher for this time of year.

    Sanjay's report was very irresponsible and sent many people needlessly into a panic.

    March 18, 2011 at 04:35 | Report abuse | Reply
  18. Keith

    can you tell people of what other precautions can be taken, if one is severely allergic to iodide?

    March 19, 2011 at 10:26 | Report abuse | Reply
  19. field worker

    It's unfortunate that the moderator of this blog has allowed the posting to present "out of sequence". It is a sign of the times, articles from credentialed sources are not accurate, nor are they proof-read, or spell checked? It is frustrating for people that desire to share real intellect. It requires "dumbing down" and translation to a "world language".

    March 19, 2011 at 13:05 | Report abuse | Reply
  20. Daniel

    God willing, a reporter out there will read this information from the Canadian Medical Association Journal, and provide a front page report on it. People need to be given the truth that there is, technically, no safe dose of radiation: http://www.cmaj.ca/misc/pr/7feb11_pr.dtl

    March 19, 2011 at 17:09 | Report abuse | Reply
  21. masters student

    Aside from humans, I'm concerned about the effects that the nuclear radiation will cause to the environment while it is diluting across the ocean. How will it damage the ocean and the species within it? Thanks.

    March 19, 2011 at 22:07 | Report abuse | Reply
    • Wayne

      A dangerous radioactive element is Radon. Radon comes from the decay of natural uranium in the soil. An area of one acre 6 feet deep has on an average of 50 pounds of uranium. Radon has a half life of 3.8 days which means it is highly radioactive. On the other hand, spent fuel has a very long half life which means it is very low radioactive.
      Radon causes 21000 deaths a year in the US from lung cancer.

      March 20, 2011 at 14:46 | Report abuse |
  22. jill B

    100mSV/hr is not eqiuvelent to 10 chest xrays
    100mSV is equivalent to 1,000 chest xrays
    why does the media insist on reporting misinformation??
    Why haven't the experts corrected this?
    I am not saying that 1,000 chest xrays will harm you: there are many factors involved and without all the information its hard to say..but the media must think we are idiots who are incapable of doing basic math

    March 19, 2011 at 22:33 | Report abuse | Reply
  23. vshanie

    Look up the word hormesis. Just something to keep in mind.

    March 20, 2011 at 12:23 | Report abuse | Reply
  24. natch

    (from the article) "Geiger counters detect radiation emitted from decaying atoms"

    Um, correction? Geiger counters detect SOME radiation emitted from decaying atoms. Neutrons are not detected by Geiger counters. Neither is Beta or Alpha. Gamma, yes.

    Seriously, can we get an EDUCATED person to write these articles from now on? I've winced more than once, while reading this one!!

    March 20, 2011 at 14:25 | Report abuse | Reply
    • Roark

      The survey meter sitting on my desk detects beta emission just fine. Saying a Gieger instrument doesnt detect beta is just wrong. Many are designed with a "beta window" specifically for this purpose. In the hands of a skilled engineer, getting a gamma plus beta reading followed by a gamma only reading not only lets you more accurately model your exposure limits, it can also give you a good clue what material is actually emitting.

      March 26, 2011 at 00:03 | Report abuse |
  25. Wayne

    A dangerous radioactive element is Radon. Radon comes from the decay of natural uranium in the soil. An area of one acre 6 feet deep has on an average of 50 pounds of uranium. Radon has a half life of 3.8 days which means it is highly radioactive. On the other hand, spent fuel has a very long half life which means the radioactivity is very low.
    Radon causes 21000 deaths a year in the US from lung cancer.

    March 20, 2011 at 14:48 | Report abuse | Reply
  26. HOYA78

    I am an unappologizing tree-hugging, bunny-loving, global-warming believing environmentalist. That's why I suport commercial nuclear power and, more importantly, conservation of energy. The best power plant is the one avoided. It's a shame that more emphasis isn't placed on conservation because the pay off is immediate and inexpensive. At various simposia on climate change, we are warned that we have 20 years or so to reduce the rate of global warming, and then we must begin to lower the global temperature, Yet governments (including the US) talk about a 50-year plan to reduce global warming. Thus, my support for the new generation of nuclear power plants to replace coal plants and to replace nuclear plants designed when Eisenhower was president (look it up). Nuclear is the only large-scale technology that can be put into operation in time to have an effect on global warming and, at the same time, significantly reduce a host of adverse health effects associated with burning fossil fuel. Just looking at radiation doses and ignoring all adverse health effects associated with a coal plant, you will receive 3 times the radiation dose from a coal plant than from a nuclear plant. I don't mean to ignore alternative fuels. They should be strongly supported. But in the time frame important to slowing down global warming, the next 20 years or so, the only available choices seem to be newly designed nuclear power plants and energy conservation. Operation of the new nuclear plants will allow 50 years or so for large-scale alternatives to be developed and put into operaton in great enough numbers to lessen the effects of climate change.

    March 21, 2011 at 15:47 | Report abuse | Reply
  27. biology girl

    radiation levels are higher than at the chernobyl correct right? Because even though theyr under 800 to 16,000 the 100 to 400 mill at the plant are exposure over periods of time and can cause death correct? so its higher levels at the plant right?

    March 22, 2011 at 13:53 | Report abuse | Reply
  28. tina kovacs

    people in the u.s. need to relax. the sun gives off radiation and so does your very popular granite counter tops... yes its a rock from the earth it radioactive too, at a very small dose. In u.s. its all about time distance and sheilding, xray equipment is used to use the lowest dose possible. Its the medical assistants in your doctors office that take xrays you should be worried about, they know nothing about what they are playing with nor do they care about how much radiation the use. A properly trained technician knows what to and the best possible way to protect you if you need to get xrayed.

    March 23, 2011 at 18:41 | Report abuse | Reply
  29. Marcos Rodrihuez

    I live within 15 miles from Turkey Point power plant and it conserns me that we have never received anything regarding any precautions if can take in the event of an accident or some other nuclear emergency!

    I mean nothing at all. I hope the govt provides the community with something now that we know things can go wrong very quickly.

    March 25, 2011 at 21:22 | Report abuse | Reply
    • Gary Schneider

      Nuclear power plants in the US have a 10 mile emergency planning zone, so living 15 miles away you are not provided the information without requesting it. You can contact Florida Power and light, or your state government and request the information that you would like. FYI, if a US plant has an emergency that may require the public to take action, those actions are recommended by the utility, and it is up to your state government to decide whether to perform that action or something else.

      March 27, 2011 at 22:08 | Report abuse |
  30. johnNMurray

    Article correction: "The types of subatomic particles emitted during a radioactive decay include gamma rays, neutrons, electrons, and alpha particles that shoot through space" This is incorrect....Gamma radiation is NOT a particle. The media coverage of this event is terrible.. Guppa mentioned on TV how penetrating Alpha/Beta particles were.....Obviously he hasn't a clue....... I'm a retired nuclear mechanic.

    April 3, 2011 at 11:14 | Report abuse | Reply
  31. just-asking

    Can Prof. johnNMurray please tell us what all the possible causes of gamma rays are and what it usually are associated with?

    April 4, 2011 at 17:18 | Report abuse | Reply
  32. now-telling

    If the velocity of these particles is low, then their penetration ability
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    April 4, 2011 at 18:14 | Report abuse | Reply
  33. Janet Bernath

    New York City has reported radioactive isotopes in the air. How far is this nuclear crisis spreading its damage?

    April 4, 2011 at 20:04 | Report abuse | Reply
  34. Werner P. South Africa

    Notice how Uranium and Plutonium forming Cesium-137, Cesium-134, Iodine131,Tellurium-129, Molybdenum-99 and Cobalt-58 and Radon with lower masses having short half-lives are releasing components that seems to be recycled again by the MOX-fuel much like a magnet or the sun has a recurring field. If E = 0.5 X m X V X V , then more velocity is obtained for the same amount of energy released to a small article. If all the radio active masses between 238 and 58 are not recognized at the reactor as
    radio active elements, they are all there and are being stripped off their layers so quickly that the equipment can't cope. Which one is fact, which one is myth?

    April 5, 2011 at 18:16 | Report abuse | Reply
  35. Werner P. South Africa

    If scientists use the Isotope 14C, with a half-life of 5730 years, to date carbonaceous archeological specimens, for ages up to about 40,000 years, but 238U the most stable uranium isotope, with a half-life said to be 4.51 billion years, can even absorb a neutron or can be reduced in mass within seconds, will they say that Fukushima is the oldest place on the planet or the most recently created?

    April 19, 2011 at 11:11 | Report abuse | Reply
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  40. Alan Ogden

    In 1992 I was exposed and Injested asbestos with cobalt 60 in it at Turkey Point Nuclear plant. FP&L did exrays, nasal smears and other tests. To this day FP&L has not give out the test results. I left TPN and went to A&O in Russelvill and body counted in with the cobalt 60 in me and 30 days body counted out with the same cobalt 60 in me. Went to PSL in Ft Pirece fl and body counted in with high cesium. This is 2015 and I now have Bladder cancer. With what I read Radiation can cause this cancer along with smoking that I never did. Any else have this problem?

    November 3, 2015 at 11:52 | Report abuse | Reply
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