FINAL radiation Flashcards
The phenomenon of radioactivity is concerned with changes within the _____ of atoms while chemical phenomena are due to changes and interactions among _____ ______.
nuclei
orbital electrons
Usually a stable atom has a set number of neutrons and protons
=Adding ______ to chemical makeup creates an unstable nucleus which is called an ______
neutrons
Isotope
Getting rid of two neutrons and two protons is called
Alpha particle
2 ways to rebalance
remove extra neutron or remove a few electrons and neutrons changing to new element
IR stands for
3 thingy’s
Ionizing Radiation comes from Radioactivity in 3 forms:
- Alpha particles
- Beta Particles(Electrons)
- Photons(gamma and x-rays)
What does IR do?
- Radiation oxidizes cells- strips electrons from atoms(free radicals and ion pairs)
- Radiation ionizes water in cells
H2O->45% OH, 10% H, 45% e* - Radiation ionizes DNA, lipids, & proteins
ionization
removal or addition of an electron, becoming positive or negative
oxidization
stealing electron makes positive
Alpha particles can be most damaging because
they interact with cells they come in contact with because it is bigger
Sources of radioactive material(3)
1.NORM (naturally occurring radioactive material)
Uranium (238U) & thorium (232Th) and their decay products
Potassium-40 (40K) – 0.01% of K in a banana
Carbon-14 (14C) –created by n bombardment in the air
- Fission Products
Iodine-131 (131I)
Cesium -137 (137Cs)
Strontium-90 (90Sr) - Neutron Activation Products
Lots, including plutonium (239Pu is a fissile fuel)
Critical Isotopes
Thorium, Uranium
_____ is used mostly for energy production
Uranium
Nuclear Fuel Cycle
Thorium + Uranium
Uranium 238
Radioactive Uranium from the sun in earth
_____ Billion years for Uranium 238 to break down
Thorium 234 halflife in ___ days
4.5
27
mining uranium means _____ ends up in tailings ponds
radium
Radon causes ____ cancer
lung
A series is going ___ the periodic table
up
Worlds largest high yield uranium mine
McArthur River Mine
Nuclear Reactor
Every reactor needs:
Fuel rods (235U or 239Pu) to begin a chain reaction
Control rods (Cd or B) to absorb neutrons
Moderator to slow neutrons down for fission
Water supply to condense steam and cool reactor core
The moderator can be
plain water
heavy water
graphite
The moderator was graphite at Chernobyl
Moderator in Chernobyl was
graphite
Moderator in Canada is
Heavy water
PU is
Plutonium
Chernobyl
April 26, 1986
Reactor fuel was 2 years old
Personnel were trying to run the reactor off “decay heat” from fission products
Power surge led to a loss of containment
Graphite moderator ignited and melted the fuel
Fallout went all over Europe with the wind
Sarcophagus for Chernobyl cost
new one will cost
800 million
1.4 Billion
Spent Nuclear Fuel
Fuel remains in a reactor for 1.5 years but then must be removed to prevent “excess decay heat”
The spent nuclear fuel (SNF) is stored for 10 years in water, then moved to dry storage.
To increase wet pool storage space, SNF in pools was “reracked”
Without cooling water, the SNF would catch fire
Fukushima reactor ___ started problems
4
Cleanup of Fukushima
Initial roadmap is a 30-40 year operation
Estimated cost of $58 billion (US)
Cannot approach 2 reactors until 2020 at the earliest
Radiation to intense for photographic assessment
Still developing new technologies – with the inevitable failures !
Handling circumstances not previously encountered or even envisioned
