REFRESH — Astounding and (Perhaps) Little Known Facts about the NRC and Radioactive Materials

Brenda Akstulewicz
Regulatory Information Conference Assistant

refresh leafNuclear and radiation-related trivia is anything but trivial. It can be unexpectedly interesting – and you may find some of it surprising. This is a REFRESH of some little known “factoids” compiled from folks throughout the NRC.

* In the 1930s, a failed experiment by a Swiss physicist for detecting gas using a radioactive source led to the discovery of smoke detectors when the scientist lit a cigarette and the detector registered a reaction. The NRC approved 70 different smoke detector designs in 2012.

* It is estimated if only one NRC technical reviewer did each design certification application review, it would take 32 years to complete the review.

astronaut2* Some lightning rods contain Radium-226 to make them more effective.

* The NRC’s first Chairman, Bill Anders, was an astronaut on Apollo 8’s mission to the moon.

* NRC Inspectors from Region IV get a lot of frequent flier miles. They review activities in remote locations such as Guam, Saipan and the northern reaches of Alaska, among other locations.

* The NRC was the first federal agency to give the public electronic access to all of its public documents through the groundbreaking system known as ADAMS (Agencywide Documents Access and Management System).

* The final safety evaluation report for the ESBWR design certification document contains about 3,800 pages.

vet* The fastest growing use of nuclear materials in medicine is for diagnostic and cancer treatment procedures in veterinary medicine.

* The indicator lights in early appliances ─ such as clothes washers and dryers, coffeemakers, and stereos ─ used Krypton–85, a radioactive isotope.

* The NRC performs classified reviews of new Naval Reactor submarine and aircraft carrier reactor plants and provides advice to the Navy on the designs. This practice was initiated by President Kennedy in the 1960s.

* Three women have held the title of Chairman — Allison Macfarlane, Shirley Jackson and Greta Dicus.

* In 1992 Hurricane Andrew struck the Turkey Point nuclear power plant in Southern Florida, which prompted the NRC and FEMA to enter into a “Memorandum of Understanding” regarding emergency preparedness.

checklist* NRC’s longest serving commissioner was Commissioner Edward McGaffigan. He served 11 years (from 1996-2007) after appointments twice by President Clinton and once by President Bush. He died while still serving on the Commission.

* On average, NRC expends 6,160 hours of inspection effort at each operating reactor site each year.

This post originally ran in Summer 2013.

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.

NRC Science 101: What is Matter?

Suzanne Schroer
Reliability and Risk Analyst
Office of New Reactors

science_101_squeakychalkIn the last Science 101 post, we talked a little about the law of conservation of mass. Again, that law states that mass can neither be created nor destroyed as part of an ordinary chemical change (or, for that matter, a physical change). In this post, we’ll talk more in depth about what specifically “mass” is.

Everything that exists is made up of matter. It has two fundamental properties: volume and mass. Volume simply refers to the space an object takes up. Depending on the physical state of an object, there are a couple ways to measure volume. If we are trying to measure the volume of a box, for instance, we would multiply the length of the box by its height and by its width.

Let’s say that we have a box with the following dimensions: length = 3 meters (“m”), height = 4m, and width = 5m. Based on those dimensions, our box would have a volume of 60m3 (3m x 4m x 5m = 60m3). That is, again, a measure (in cubic meters) of how much three-dimensional space our box takes up.

If, on the other hand, our object was a liquid, we could use a graduated cylinder (a scientific measuring cup) to measure the volume of our object. This measure would be reported in liters. Again, a liter is just a measure of how much space a liquid takes up. For example, you can purchase soda in 2-liter bottles.soda

Since we’ve been talking a little about measurements, it might make sense at this point to distinguish between quantity and units. Thinking again about our example, the quantity we are trying to measure is volume. The unit we use to report this measurement is in liters or cubic meters.

Now, let’s now talk about the other fundamental property of matter — mass. When we talk about mass, we are referring to how much “stuff” is in an object. To illustrate this, think about two pieces of candy, both of the same kind and both the same size, however one of them is hollow. The candy that isn’t hollow has more mass compared to the hollow candy. Given that we often use scales to measure mass, you might think that mass and weight are the same thing. But they aren’t. Mass is the measure of matter in a particular object. No matter where that object is in the vast universe, it will have the same mass.

scaleWeight, on the other hand, is a measure of how much gravitational force is exerted on an object. While the weight of an object is proportional to its mass (the more mass of an object the more it will weigh), gravity varies according by where you are in the universe or even where you are on Earth—you actually weigh more, because there is a higher gravitational force, on the poles than you would at the equator. So, while an object will have a particular weight here on Earth, it will not have the same weight on the moon. It would, however, have the same mass both places.

Now that we can determine if something is matter (if it has volume and mass), we can use another measurement, density, to determine what kind of matter a substance is. Density is the ratio of how much mass is in an object compared to the volume of that object. Density is calculated by dividing an object’s mass by its volume.

Think back to our box with a volume of 60m3. Let’s say that our box has a mass of 240 grams (g). If that were the case, the density of our box would be 4 g/m3 (240g / 60m3). Density is nothing more than a way of stating how much matter fits within a particular volume. Using the two pieces of candy, while both have the same size (or volume), the solid one has more mass when compared to the hollow one and, as such, the solid candy is more dense (more matter in a particular volume) than the hollow candy.

Because the density of a particular substance (something with a defined composition, such as pure copper), is the same for all pieces of that substance, regardless of size, density is often useful in determining the identity of a particular object. Once we’ve calculated the density of an object, we can compare that value to the known densities for substances to determine what substance we believe the object is.

The author has a bachelor’s degree in Nuclear Engineering and a master’s in Reliability Engineering.