Nuclear Reactor Safety Concerns

1.
Element Electrons Protons Neutrons Half-Life
Strontium-90 38 38 (90-38)=52 28.79 year
Casium-137 55 55 (137-55)=82 30.17 years
Iodine-131 53 53 (131-53)=78 8.02 days
2. Sr-90 has a half-life of 28.79 years.
Radioactive decay series is given by the formula
N ( t )=No e−λt
Where N ( t ) is the mass or number of particles at a time t, N0 is the initial mass or number
of particles, λ=ln 2 ÷ halflife
In this case,
N0=1.6
Half-life=28.79 years
t=2008-1952=56 years
In this case
λ=ln 2 ÷28.79=0.0241
N ( 56 )=1.6 e−0.0241×56=0.415 g
3.
N0=24 g
N ( t ) =3 g
t 1
2
=8.02 days
In this case,
λ=ln 2 ÷ 8.02=0.08643/day
But
N ( t )=No e−λt
Hence
3=24 e−0.08643 t

0.125=e−0.0864 t
Solving for t by introducing ln on both sides of the equation, we obtain
ln ( 0.125 )=−0.08643 t
t=24.06 days
Date=1+24= 25th January 2014
4.
N0=0.1mg
N ( t )< 0.001mg
t 1
2
=120 days
In this case,
λ=ln 2 ÷120=5.776 ×10−3 /day
But
N ( t )=No e−λt
Hence
0.001=0.1 e5.776 ×10−3 t
0.01=e−5.776× 10−3 t
Solving for t by introducing ln on both sides of the equation, we obtain
ln ( 0.01 ) =−5.776 ×10−3 t
t=797.26 days
1 year=365 days
797.26 days= (797.26/365) =2.184 years.
5. Isotopes are atoms of the same with element with the dame atomic number with different
mass number (due to difference in number of neutrons)
From the question, e and f are isotopes
6.
Element Identity
a Magnesium

b Carbon-12
c Chromium
d Lithium
e Sodium-24
f Sodium-23
7.
Ion Number of
protons
Number of
electrons
a Mg 12 10 (+2) Positive
b F 9 10 (-) Negative
c S 16 18 (-2) Negative
d Au 79 76 (+) Positive
8. Ionization radiation refers to a radiation that carries enough amount of energy capable of
detaching an electron or electrons from atoms or molecules thus ionizing them. It is made
up of energetic subatomic particles, either ions or atoms moving at high velocities, and
electromagnetic waves that are travelling at high energy end of the electromagnetic
spectrum.
The basic process by which ionization radiation can damage living cells.
Radiation damages living cells by two basic process. Radiation can either strike
components of a living cell such as DNA directly hence ionizing and damaging the cell.
Radiation can also ionize the water molecules thus producing free radicals that damages
the living cell.
9. Main safety concerns about a nuclear reactor
 Natural disasters. Some natural disasters such as tsunamis and earthquakes can
damage nuclear power plant. Fukushima plant for instance was damaged because