<< Chapter < Page Chapter >> Page >
Typical doses received during diagnostic x-ray exams
Procedure Effective Dose (mSv)
Chest 0.02
Dental 0.01
Skull 0.07
Leg 0.02
Mammogram 0.40
Barium enema 7.0
Upper GI 3.0
CT head 2.0
CT abdomen 10.0

What mass of 137 Cs Escaped chernobyl?

The Chernobyl accident in Ukraine (formerly in the Soviet Union) exposed the surrounding population to a large amount of radiation through the decay of 137 Cs . The initial radioactivity level was approximately A = 6.0 MCi . Calculate the total mass of 137 Cs involved in this accident.

Strategy

The total number of nuclei, N , can be determined from the known half-life and activity of 137 Cs (30.2 y). The mass can be calculated from N using the concept of a mole.

Solution

Solving the equation A = 0.693 N t 1 / 2 for N gives

N = A t 1 / 2 0.693 .

Entering the given values yields

N = ( 6.0 MCi ) ( 30.2 y ) 0.693 .

To convert from curies to becquerels and years to seconds, we write

N = ( 6.0 × 10 6 Ci ) ( 3.7 × 10 10 Bq/Ci ) ( 30.2 y ) ( 3.16 × 10 7 s/y ) 0.693 = 3.1 × 10 26 .

One mole of a nuclide A X has a mass of A grams, so that one mole of 137 Cs has a mass of 137 g. A mole has 6.02 × 10 23 nuclei. Thus the mass of 137 Cs released was

m = ( 137 g 6.02 × 10 23 ) ( 3.1 × 10 26 ) = 70 × 10 3 g = 70 kg .

Significance

The mass of 137 Cs involved in the Chernobyl accident is a small material compared to the typical amount of fuel used in a nuclear reactor. However, approximately 250 people were admitted to local hospitals immediately after the accident, and diagnosed as suffering acute radiation syndrome. They received external radiation dosages between 1 and 16 Sv. Referring to biological effects in [link] , these dosages are extremely hazardous. The eventual death toll is estimated to be around 4000 people, primarily due to radiation-induced cancer.

Got questions? Get instant answers now!

Check Your Understanding Radiation propagates in all directions from its source, much as electromagnetic radiation from a light bulb. Is activity concept more analogous to power, intensity, or brightness?

power

Got questions? Get instant answers now!

Summary

  • Nuclear technology is used in medicine to locate and study diseased tissue using special drugs called radiopharmaceuticals. Radioactive tags are used to identify cancer cells in the bones, brain tumors, and Alzheimer’s disease, and to monitor the function of body organs, such as blood flow, heart muscle activity, and iodine uptake in the thyroid gland.
  • The biological effects of ionizing radiation are due to two effects it has on cells: interference with cell reproduction and destruction of cell function.
  • Common sources of radiation include that emitted by Earth due to the isotopes of uranium, thorium, and potassium; natural radiation from cosmic rays, soils, and building materials, and artificial sources from medical and dental diagnostic tests.
  • Biological effects of nuclear radiation are expressed by many different physical quantities and in many different units, including the rad or radiation dose unit.

Key equations

Atomic mass number A = Z + N
Standard format for expressing an isotope Z A X
Nuclear radius, where r 0 is the radius of a single proton r = r 0 A 1 / 3
Mass defect Δ m = Z m p + ( A Z ) m n m nuc
Binding energy E = ( Δ m ) c 2
Binding energy per nucleon B E N = E b A
Radioactive decay rate d N d t = λ N
Radioactive decay law N = N 0 e λ t
Decay constant λ = 0.693 T 1 / 2
Lifetime of a substance T = 1 λ
Activity of a radioactive substance A = A 0 e λ t
Activity of a radioactive substance (linear form) ln A = λ t + ln A 0
Alpha decay Z A X Z 2 A 4 X + 2 4 H e
Beta decay Z A X Z + 1 A X + −1 0 e + v
Positron emission Z A X Z 1 A X + + 1 0 e + v
Gamma decay Z A X * Z A X + γ

Questions & Answers

general equation for photosynthesis
Ojasope Reply
6CO2 + 6H2O + solar energy= C6H1206+ 6O2
Anastasiya
meaning of amino Acids
AJAYI Reply
a diagram of an adult mosquito
mubarak Reply
what are white blood cells
Mlungisi Reply
white blood cell is part of the immune system. that help fight the infection.
MG
what about tissue celss
Mlungisi
Cells with a similar function, form a tissue. For example the nervous tissue is composed by cells:neurons and glia cells. Muscle tissue, is composed by different cells.
Anastasiya
I need further explanation coz celewi anything guys,,,
Calvin Reply
hey guys
Isala
on what?
Anastasiya
hie
Lish
is air homogenous or hetrogenous
damiane Reply
homogenous
Kevin
why saying homogenous?
Isala
explain if oxygen is necessary for photosynthesis
Allice Reply
explain if oxygen is necessary for photosynthesis
Allice Reply
Yes, the plant does need oxygen. The plant uses oxygen, water, light, and produced food. The plant use process called photosynthesis.
MG
By using the energy of sunlight, plants convert carbon dioxide and water into carbohydrates and oxygen by photosynthesis. This happens during the day and sunlight is needed.
NOBLE
no. it s a product of the process
Anastasiya
yet still is it needed?
NOBLE
no. The reaction is: 6CO2+6H20+ solar energy =C6H12O6(glucose)+602. The plant requires Carbon dioxyde, light, and water Only, and produces glucose and oxygen( which is a waste).
Anastasiya
what was the question
NOBLE Reply
joining
Godfrey
the specific one
NOBLE
the study of non and living organism is called.
Godfrey
Is call biology
Alohan
yeah
NOBLE
yes
Usher
what Is ecology
Musonda Reply
what is a cell
Emmanuel Reply
A cell is a basic structure and functional unit of life
Ndongya
what is biolgy
Hawwi Reply
is the study of living and non living organisms
Ahmed
may u draw the female organ
MARTIN Reply
i dont understand
Asal
:/
Asal
me too
DAVID
anabolism and catabolism
Sani Reply
Anabolism refers to the process in methabolism in which complex molecules are formed "built" and requires energy to happen. Catabolism is the opposite process: complex molecules are deconstructed releasing energy, such as during glicolysis.
Anastasiya
Explain briefly independent assortment gene .
Otu Reply
hi
Amargo
hi I'm Anatalia
Joy
what do you mean by pituitary gland
Digambar
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best University physics vol... course in your pocket!





Source:  OpenStax, University physics volume 3. OpenStax CNX. Nov 04, 2016 Download for free at http://cnx.org/content/col12067/1.4
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'University physics volume 3' conversation and receive update notifications?

Ask