NRC Science 101: Understanding Ionizing Radiation – It’s Not That Bohr-ing!

Harry Anagnostopoulos
Health Physicist

science_101_squeakychalkIn this post, we will be discussing ionizing radiation. But to do that, we first have to talk about radiation, in general, and then build up to the concept of ionization.

In previous NRC Science 101 posts, we’ve talked about the composition of an atom, including electrons, protons and neutrons. In 1913, physicist Niels Bohr made adjustments to an earlier model which imagined that the structure of an atom was similar to a solar system: electrons in circular orbits around a “sun” otherwise known as an atomic nucleus.

While modern atomic science has a more accurate understanding of the atom, Bohr’s model is still useful. It is easy to visualize and helps us to think about the relationship between electrons and energy. So, for the purposes of this post, let’s use Bohr’s atomic model.

Radiation is simply the transfer of energy through a medium. The medium can be anything: water, air or even the vacuum of outer-space. The transfer of energy can be carried out by particles or by electromagnetic waves.

Let’s conduct a small experiment. Imagine putting your face close to (but not touching) a bare 100-watt light bulb in a lamp. If you did this, and closed your eyes, could you still tell if the light was on? Could you feel the heat on your face, even though you are not touching the bulb?

Of course you could. That’s radiation! Light, heat, pressure waves in the air (sound), radio signals, and x-rays are all forms of radiation.

atom2As noted in prior NRC Science 101 posts, the core of an atom (the nucleus) is surrounded by orbiting electrons, like planets or comets around a sun. The number of electrons (each with one negative electric charge) usually equals the number of positive charges in the center (from an equal number of protons). These charges cancel out. However, if an orbiting electron is pushed out of its orbit (due to it absorbing energy from an outside source), the charges are now unequal.

The result? An “ion pair” has been formed. The creation of an “ion pair” is called . . . ionization.

Ionizing radiation is radiation with enough energy to create ion pairs in atoms. It is ionizing radiation that is of particular interest to the NRC because of its potential to cause health effects (as will be discussed in a future post).

cometearthTo help you visualize this, think again about Bohr’s model. Imagine a comet (standing in place of an electron) passing through our solar system. As the comet approaches the sun, it feels an intensifying push as light from the sun imparts more and more energy to the comet. Eventually, there is so much “push” that the comet either changes speed or changes direction. Now where will it go? Will it now be on course to strike a planet or will it veer out of our solar system? It’s exactly what could happen to an electron in the subatomic universe it occupies.

But this example is nothing compared to the bizarre realm of atomic physics where a solar system (an atom) might spit out a mini-version of itself, split into two, or where two twin comets (electrons) might appear out of nothing! And there’s more! However, you will have to wait until a later post.

Author: Moderator

Public Affairs Officer for the U.S. Nuclear Regulatory Commission

20 thoughts on “NRC Science 101: Understanding Ionizing Radiation – It’s Not That Bohr-ing!”

  1. Thank you Moderator for re-posting my comment and facilitating a fair discussion of very important topics about radiation.

  2. Garry Morgan

    Submitted on 2014/02/26 at 2:55 pm | In reply to George Rublein.
    There is evidence that the supporters of the Radiation Hormesis theory are delusional. I distinctly remember a so called scientist recommending we disperse radioactive waste across our atmosphere as a solution to our gigantic and growing nuclear trash/waste problems. By doing this it would cure us from all of our sicknesses, according to the so called scientific reasoning.

    There are several medical studies which have demonstrated that low levels of ionizing radiation are harmful, particularly to women and children.

    Of course radiation levels are being reconsidered, since hundreds of billions of dollars are riding on the insanity of the aftermath of Fukushma.

    Reposted by the Moderator on behalf of Garry Morgan

  3. If a comment adheres to our comment guidelines, it is posted. If a comment generally does not apply to the post under which it is submitted, it is posted in the Open Forum section.


  4. We will be anxiously awaiting whether you tell the truth concerning the biological effects of low level radiation.

    You mention Fukushima as a rally for education. After Fukushima, the nuclear industry’s efforts are now focused on increasing “radiation” doses to the point of ridiculousness. “Make Radiation Visible” and the public will determine if you are meeting your mission goals.

    “Make Radiation Visible” and we shall see if you are telling the truth. Publish in real time on the web all secondary containment, auxiliary building and perimeter real time monitoring data from all nuclear facilities, fuel manufacturers and nuclear trash dumps. Currently the NRC’s “radiation” reporting system supports the “fox guarding the hen house” system.

    Again, the mission for the NRC is explained: To Protect Public Health and Safety

    Every action the NRC performs, including this forum site, is indicative of your ability and mission to regulate the nuclear industry and nuclear materials under your jurisdiction. Propaganda disguised as information is not regulation or governance, it is a front for further propaganda and support of the nuclear industry, it is not supportive of your regulatory mission. There would be value if the post strings were left intact, but that has not been the case. As you say below: “Further comments debating the pros or cons of nuclear power, whether the civilian power industry or as here, including the early weapons production program, will be moved to the Open Topics Forum. Moderator.”

    Mr. or Ms. Moderator, you did remove or move postings. Shouldn’t you allow the challenges, or are you afraid of the challenges? Every post that you removed or moved, that I saw, was about radiation and your mission. Where may those postings be found, what is the link to where the postings have been moved?

    What is next, an NEI representative coming aboard professing that “Plutonium is safer than coffee.” An actual statement from an alleged nuclear engineer at a public function. Is this an education string about radiation vs ionizing radiation or a propaganda string in support of the nuclear industry?

  5. We created the NRC Science 101 series based on feedback we received from the public in general and teachers specifically, after the Fukushima, that basic science information would be helpful, especially since much of the content on our website is written for stakeholders with considerable nuclear industry knowledge. There will be a future Science 101 on the biological impact of radiation.


  6. Thank you Harry Anagnostopoulos for your post .There’s really a great 101 entry in Wikipedia on Ionizing radiation. A world of knowledge at our finger tips everyone reading your post has access to the www. What we can’t seem to grasp as the reason’s why the NRC is often condesending adding insult to injury…REALLY
    Growing up I went to schools near NUCLEAR power Reactors as my late father an engineer help to build many of them. Moving from state to state during the Nuclear Power Building Boom. I meet and was befreinded by many lovely people. We knew then about Ionizing Radiation and other fall out hazards what we know now. Most of these nice people did not. The nuclear Power Plants brought jobs and promises of a better future outstanding PR !
    I often get e-mails from people I met along the way , sometimes even asking me if I know why the cancer rates are so high thier areas, sometimes with a list of school mates that have died of cancer or a mention of thier own children having cancer and so on. One of these is on her third bout of cancer she doesn’t have long it would be a really great parting gift to her to know the reasons why.

    This new report documents some of your above mentioned health effects Nuclear Power Health Impact Study

    So please do cut to the chase what is the NRC ‘s position on health effects of Ionizing radiation?

  7. Mr. Rublein or whomever: There is reason to fear that which is promoting a hundred billion dollar++ industry founded on nuclear weaponry.

    Nuclear Physics 101 or natural, self sustaining nuclear reactions in Africa, the sun, the center of the earth or universe is not the mission of OUR government regulator. Safety and health of the citizenry is their business. The topic makes for interesting discussion, but it is not “germane” to the regulators mission found here thus described: NRC Mission — To Protect Public Health and Safety

  8. Mr. or Ms Moderator, thank you. the post is very germane. It is my position that the original post downplays the significance of ionizing radiation generated by nuclear materials such as nuclear fuels, nuclear reactors, etc. The analogy of a light bulb as compared to ionizing radiation from such sources is propaganda. It is my position that the regulator regulate and leave the propaganda education to the DOE and the NEI.

  9. Mr. Morgan – As you see, your earlier comment was indeed posted despite not being totally germane to the subject of the blog post above. We have no problems with you calling us names or questioning our intelligence, integrity and honesty, though we do ask you to be respectful to other blog readers and commenters. And we hope that you realize that in any normal workday the Office of Public Affairs is dealing with numerous calls from the public, the media, and of course various tasks generated from within the agency in addition to managing this blog. While we do not censor comments that meet our very basic and generous guidelines, sometimes the flow of business prevents us from posting them immediately.

  10. OMG! Self sustaining nuclear chain reactions lasting a few hundred thousand of years were discovered in 1972 in Africa.
    Nuclear energy must be respected but there is no need for irrational fear. You have a greater risk of being killed on the highway than from nuclear power. Good luck in dealing with your fear of radiation.

  11. The subject post clearly distinguishes the light bulb example from ionizing radiation. It does not promote the nuclear industry, but rather explains a small part of the very basic science of nuclear physics. Further comments debating the pros or cons of nuclear power, whether the civilian power industry or as here, including the early weapons production program, will be moved to the Open Topics Forum.

  12. I have noticed my reply to Mr. Rublein is not present. It was important and descriptive of the regulator and the nuclear industry. Was it censored, or does the truth concerning nuclear power deaths and sickness, via our government’s statistics, disturb the NEI’s puppet masters, the NRC? Will you also censor this reply? Being honest seems to be a problem with the NRC. I ask of you to post the reply to Mr. Rublein

    If you post my previous critical reply to Mr. Rublein that is great, and appreciated. However, not to post it is indicative of a regulator which serves as a puppet to the NEI and has a penchant for propaganda and censorship while not allowing citizen comments on this governmental communications resource.

  13. Yes, acute amounts of ionizing radiation has harmful biological effects but so does drinking excessive amounts of water or breathing pure oxygen. The linear model of radiation exposure where it is assumed that any amount of radiation is harmful is being reconsidered by the scientific community. L.E. Feinendegen in his article “Evidence for Beneficial Low Level Radiation Effects and Radiation Hormesis” from the British Journal of Radiology Radiation suggests that low doses of ionizing radiation may be beneficial, stimulating the activation of repair mechanisms that protect against disease, that are not activated in absence of ionizing radiation. The reserve repair mechanisms are hypothesized to be sufficiently effective when stimulated as to not only cancel the detrimental effects of ionizing radiation but also inhibit disease not related to radiation exposure. If this is true, then chronic low doses of ionizing radiation could act to immunize us to cancer.

  14. Great post. Ionizing radiation which has a higher frequency and shorter wavelength than nonionizing radiation, has many uses but can be a health hazard; exposure to it can cause burns, radiation sickness, cancer and genetic damage.

  15. You say: “The article is describing the difference between radiation, which is the transfer of energy without being in contact with the source of energy, and IONIZING radiation which causes the production of ions.” That is true, I read the article very carefully and that is the reason I say it is propaganda to downplay the risk of ionizing radiation generated by nuclear reactors and the nuclear fuels process. I want the regulator to regulate, not issue forth a program of a maskirovka for school children.

  16. Of course it is describing radiation, that is not the point of my post. The point is the description of radiation originating from a source such as a light bulb as compared to ionizing radiation from a nuclear reaction or highly radioactive spent fuel. The NRC is responsible for regulating the nuclear industry, not propagandizing the dangers of ionizing radiation from nuclear fuel facilities and nuclear reactors. There is no comparison in the heat from a light bulb and ionizing radiation from a source such as spent nuclear fuel, a nuclear reactor or the nuclear fuels process.

    Here is an OMG statement – “We now know that nuclear reactions occur naturally in the earth.” And you think nuclear power plants and nuclear weapons are natural?

    Speaking of fear – citizens should be very concerned about the propensity to propagandize nuclear power as safe and clean. It kills and has cost American tax payers over $10 billion dollars in nuclear worker health care costs, and that is just a fraction of the real costs of health care for nuclear workers as not all sites are counted in the EEOICP. Tens of thousands of American nuclear workers have been sickened and died as a result of the nuclear fuel process. Like the warmth of a light bulb, was that what the families were told of their sick or dead family members?

    Propaganda – this is the same type of propaganda which attempts to convince American citizens that nuclear powered automobiles and aircraft are feasible. Yea I’m afraid of nuclear engineers who spin and deceive in the attempts to justify this dangerous energy form and its expense as a safe, clean and to cheap to meter form of power generation.

    Nuclear power reactors and nuclear weapons are inseparable. Do not play down the risks of dangerous nuclear power, its costs and the massive amounts of nuclear spent fuel trash that is increasing as we type. Tell the truth, stop the propaganda of the Atoms for Peace Program, it is antiquated.

  17. The article is describing the difference between radiation, which is the transfer of energy without being in contact with the source of energy, and IONIZING radiation which causes the production of ions. You need to read more carefully.

  18. Garry, ionizing radiation has been around since the earth was formed. It is still being formed naturally in our own atmoshere from atoms in the atmoshere absorbing neutons from outer space. We now know that nuclear reactions occur naturally in the earth. Life on earth evolved with background radiation. What the lesson attempts to do is educate. With eduaction comes understanding and putting risks into proper perspective. For example, you have a greater risk of dying from cancer from UV radiation from the sun than you do from working at a nuclear power plant for 50 years. It is good to educate the public about radiation and nuclear power to prevent the irrational fear of the unknown. I think it is you who is spreading propaganda by peddling fear.

  19. Equating a nuclear reaction to a light bulb is propaganda and ridiculous. It is like comparing apples and poisonous mushrooms and saying it is ok to eat either one. Ionizing radiation…potential to cause health effects, you think?

    You are attempting to simplify nuclear devices and dangerous substances in a description which facilitates propaganda, not accuracy nor science.

    Here’s an image for you – are you suggesting that the NRC wizards of propaganda place their collective heads next to unprotected spent nuclear fuel rods?

    Your analogies are propaganda designed to lessen the risks and dangers of nuclear power.

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