Radiation Safety
Fall 2015
Ohio University Department
of Risk Management and Safety
____________________________
Radiation Safety Office
Alan Watts
Radiation Safety Officer
LEGEND: Suggested Reading
Required Reading
The app for frequent fliers and those who are radiation-conscious
Frequent fliers are now able to monitor their personal radiation exposure when flying using the TrackYourDose
app. Behind the app lies intensive research work undertaken by the Physikalisch-Technische Bundesanstalt (PTB).
Since 1997 PTB has studied the cosmic radiation at typical flight altitudes and, based on this, it has developed
mathematical models for calculating radiation levels. By licensing these mathematical models to the start-up company Esooka, the wider public can now monitor their own radiation exposure during flights. For frequent fliers
and others who are interested in doing this, an app has been on sale at the Apple Store since the end of 2014. To
study the worldwide distribution of radiation exposure through cosmic radiation, PTB’s scientists developed a
carry-on “flight case”. This can measure all the relevant types of radiation, in particular neutron radiation which
is produced in the atmosphere, with regard to their biological effectiveness. The measurement value is called the
“ambient dose equivalent” and is measured in microsieverts (µSv). A ten-hour flight across the North Atlantic,
for instance, results in a radiation exposure of 50 µSv to 100 µSv (5-10 mrem). We can compare this to having an
X-ray at the dentist’s which may lead to between 2 µSv and 6 µSv, depending on the type of X-ray. Click here for
full article!
Editor: Mackenzie Kistler www.ohio.edu/riskandsafety/radiationsafety 1
Who on Earth is Exposed to the Most Ionizing Radiation?
CTRL+click to watch video or find it here
Scientist, Derek Muller, goes all over the world to visit the most radioactive
places on Earth. The results from the Geiger counter are different than you
would expect and closer to you than you would think.
The first stop was in Hiroshima, Japan where just 70
years ago a massive bomb obliterated multiple Japanese
cities. Surprisingly the Geiger counter measured it to
be 0.3 Microsieverts per hour which is the equivalent
of 3 bananas.
Next stop was in a uranium mine in Jachymov, Czech
Republic. This mine happens to be where uranium was
first discovered. This uranium mine was measured to
be only 1.7 microsieverts per hour which is approximately 10 times more than a natural background.
The Radium Institute located in Paris was next. Although Marie Curie has not practiced in this lab in
over 80 years many parts of her lab were still radioactive. For example, her doorknob was 1.5 microsieverts
per hour.
The next destination was right here in the United States
in Trinity Site, New Mexico. This is where the world’s
first nuclear bomb set off over 70 years ago. The entire area was left destroyed. So much heat was given off
by the bomb it fused the sand into green glass called
Trinitite. One hour at the Trinity Site would conclude
in 0.8 Microsieverts but the Trinitite itself read 2.1 Microsieverts.
The most common place to be faced with high amounts
of radiation is in an airplane. The higher the altitude
the less atmosphere you have to shield you. At cruising
altitude the passenger measured 3.3 Microsieverts.
In Chernobyl, Ukraine a reactor statue melted and created so much heat that the top blew off which spread
radioactive isotopes over the area. An hour spent here
measured to be 5 Microsieverts. This is the same amount
of radiation from a dental x-ray.
Next, was Fukushima, Japan where there are black trash
bags along the side of the road to dispose of radioactive
soil. Fukushima measured 10 Microsieverts per hour.
Citizens of Fukushima are expected to obtain an extra
10,000 Microsieverts in their lifetime.
When visiting the basement of Pripyat Hospital in
Ukraine everyone involved had to wear a gas mask and
a suit for protection. Next to the contaminated clothes
of the firefighters who put out the fire of the Chernobyl
Reactor measured 1,500 Microsieverts per hour. Staying
in that area for one hour exposes you to your recommended dose of radiation for an entire year.
The second highest place to take in the most radiation
is in space. Astronauts receive 80,000 Microsieverts per
hour while stationed in space.
The place with the most radiation is completely preventable. This place is a smokers lungs bringing in 160,000
Microsieverts per year. That is 1,600,000 bananas!
www.ohio.edu/riskandsafety/radiationsafety
2
Uranium is a Unique Element, Used in Research, Medicine,
Space Travel, and of course Weapons.
Uranium is the most desirable but terrifying rock known to man. It is associated with some of the world’s
worst disasters such as the Chernobyl nuclear disaster. The title of the video comes from a Physicist
named Otto R. Frisch. He states “A number of ingenious experiments were devised to test the speed of
the fission reaction, and the limit was pushed. But even so, I thought it would be very nice to go one step
nearer to a real atomic explosion. Dick Feynman, who was present, started to chuckle and to say that this
is just like tickling the tail of a sleeping dragon.” If you want to know more hit CTRL+click on the picture
or follow this link: https://www.youtube.com/watch?v=cO57Zm-WNmg
Inventing a Stronger Radiological Waste Bag for
Extra Protection
SRNL: Inventing Extra Protection for High Energy Waste
AIKEN, S.C. (May 5, 2015) – At the Savannah River National Laboratory, the primary goal is innovation for safe and cost effective legacy
waste cleanup. New methods are constantly being explored in order
to protect workers and protect the environment. When Senior Scientist Dr. Aaron Washington realized that a radiological waste bag wasn’t
lasting as long as he would like, he set about inventing a new one. As a
result, Washington and his team of researchers created a “double-ply”
waste containment bag capable of better containing nuclear waste.
Much like a household garbage bag is used to protect waste from leaking into a garbage can, special radiological waste bags are used to keep
radiation from leaking into a storage container. After time, materials
used to create these bags fail due to damage from intense or long-term
exposure to radiation. This can result in contamination and a need to
repackage the contents. To visit their website: http://srnl.doe.gov
www.ohio.edu/riskandsafety/radiationsafety
3
Figure 1. Sources of Radiation Exposure to the U.S. Population
(derived from Figure 1-1 of BEIR 1990)
The accepted value for the average background radiation dose from natural and man-made
sources to people living in the United States is 360-mrem/year effective dose equivalent (EDE)
(BEIR 1990). Figure 1 presents a breakdown of the sources of background radiation and the average annual EDEs associated with those sources, as described by the Committee on the Biological Effects of Ionizing Radiations in their 1990 publication. This figure illustrates that the dose
from exposure to indoor radon (200 mrem/year EDE) represents over 50% of the total dose. The
“other” section in Figure 1 includes per capita2 doses due to occupational exposures of radiation
workers, exposures to the public from emissions from nuclear fuel cycle facilities, and fallout. Of
these minor sources of background radiation exposures, only fallout is discussed in this report,
due to its ubiquitous nature.
Terrestrial Radiation
Terrestrial radiation is radiation from naturally occurring radionuclides in the soil, which include
K-40, Th-232, U-238, Rb-87, and U-235 and their progeny. Some structures, like those made
from concrete, brick, and stone, contain radionuclides and emit radiation. The dose from terrestrial radiation is generally higher in areas with more bedrock, like mountainous regions, and lower in sandy, coastal areas. The annual dose rate from terrestrial radiation ranges from 23 mrem/yr
in the Gulf Coast and Atlantic Coast to 90 mrem/yr on the Colorado Plateau.
Cosmic Radiaiton
Cosmic radiation is radiation that originates from our galaxy (galactic cosmic rays) and from the
sun (solar particle radiation). The radiation from both of these sources is affected by the earth’s
magnetic field. The low-energy radiation is usually deflected by the magnetic field, while the
high-energy rays are able to penetrate the atmosphere. The cosmic radiation dose incurred by
a person on the earth is dependent upon altitude, latitude, and shielding. For the most part, the
dose received from ionizing cosmic radiation at a high elevation is greater than the dose at sea level; and the dose received at high- and mid-latitudes is greater than the dose received at equatorial
areas. This “latitude effect” is due to the fact that more low-energy protons reach the atmosphere
at the poles than at the equator. (See table on pg. 6)
www.ohio.edu/riskandsafety/radiationsafety
4
Figure 2. Average Annual Natural Background Doses (mrem/year) based
on Cosmic Radiation, Terrestrial Radiation, and Mean Indoor Radon
100-200300-400 500-1000
200-300
400-500 not enough data
As you can see, there is variation in average natural background radiation doses throughout the United
States, ranging from 131.5 mrem/year in Florida to 962.9 mrem/year in South Dakota, a difference of
831.4 mrem/yr EDE. The estimated average background dose in Nevada of 221.8 mrem/year is toward
the low end of this range. Keep in mind that these doses do not include other sources of ubiquitous
natural and man-made exposures (i.e., internal, medical, consumer products, and other miscellaneous
sources of exposure), which would add approximately an additional 100 mrem/yr to these exposures.
Radioactivity
What fruit is considered radioactive measured at 0.1 Microsieverts?
A.Apple
B.Banana
C.Grape
D.Kiwi
Which location exposes you to the largest amount of radiation?
A.
Salt Lake City
B.
New York City
C.
Denver
D.
Miami
Which household item gives off the most radiation?
A.
Kitty Litter
B.Toothpaste
C.
Laundry Detergent
For full article check out this link: http://listverse.com/2013/02/06/10-things-you-probably-didnt-know-were-radioactive/
Answers: B, C, A
www.ohio.edu/riskandsafety/radiationsafety
5
Elevation
Cosmic Ray Dose Rate (mrem/yr)
26 mrem/yr
Add 2 mrem/yr
Add 5 mrem/yr
Add 9 mrem/yr
Add 15 mrem/yr
Add 21 mrem/yr
Add 29 mrem/yr
Add 40 mrem/yr
Add 53 mrem/yr
Add 70 mrem/yr or more
Sea Level
Up to 1000 feet above sea level
1000 to 2000 feet above sea level
2000 to 3000 feet above sea level
3000 to 4000 feet above sea level
4000 to 5000 feet above sea level
5000 to 6000 feet above sea level
6000 to 7000 feet above sea level
7000 to 8000 feet above sea level
Above 8000 feet above sea level
Indoor Radon
Radon (Rn-222) is a radioactive gas produced from the decay of radium-226,
which is a member of the uranium-238 decay chain. Radon is colorless, odorless, and is found naturally in almost all types of soil. The amount of radon in
the soil is dependent upon several factors, including concentration of radium in
the soil, the soil’s porosity and permeability, and moisture content. Areas with
particular types of soil/bedrock (i.e., granite and limestone) have been shown
to have higher levels of radon concentrations. Considering a dose rate of 200
mrem/year per pCi/L of measured indoor radon in order to determine the average annual dose for each state (NCRP 1987a) the lowest average radon dose
rate is a low of 79 mrem/yr in Washington as compared to a high of 903 mrem/
yr in South Dakota.
Nevada Test Site and Global Fallout
The radiation dose from fallout is only a small fraction of the total background
dose. The U.S. population receives radiation doses from fallout generated from
two sources: (1) U.S. nuclear weapons tests performed at the NTS, and (2) tests
performed outside the U.S.
Who you gonna call?
Radiation Safety Contacts
Name OUPD
Office Risk Management & Safety
Alan Watts* 593-1911 Cell 593-4176 740-517-5075
Crystal Brooks* 597-2950 330-903-0506
David Schleter* 593-1662 740-591-0557
David Ingram** 593-1705 Jeff Campbell*** 593-1667 740-707-5362 304-615-0795
* RMS Staff
** Chair Radiation Safety Committee
***Interim Associate Vice President, Risk Management
& Safety
www.ohio.edu/riskandsafety/radiationsafety
6