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PRINCIPLESOF
NUCLEAR POWER
INTRODUCTION TONAVAL
ENGINEERING
BASIC SYMBOLS AND NOTATIONS
P
e-
XAZ
where: X is the chemical symbol A is the # of protons plus neutrons Z is the # of protons only
Bohr’s Model
U235
92
EXAMPLE
ISOTOPES
P
e-
N
e-
P N
e-
PN
HYDROGEN DEUTERIUM TRITIUM
BASIC FISSION EQUATION235 236U + n U FF1+ FF2 + 2.43 n + energy92
10 92
* 10
ENERGY RELEASED235U+1n 94Zr + 140Ce+ 2 1n 92 92 92
MASS OF REACTANTS U - 235.04390 amu n - 1.00867 amu------------------------------TOT: 236.95257
MASS OF PRODUCTS Zr - 93.90631 amu Ce - 139.90539 amu 2 n - 2(1.00867) amu------------------------------TOT: 235.82904 amu
mass defect: 236.05257 - 235.82904 = .22353 amu
1 amu = 931.48 MeV where 1 Mev = 1.52x10-15 Btu
Therefore: Binding Energy = 208.21372 MeV
TYPES OF NEUTRONS
Fast neutrons– Have KE of .1 MeV– Produced through fission– Very few will cause fission
Slow neutrons– Have KE of 1 eV– Must be slowed by a MODERATOR– Main producer of fission
THE NEUTRON LIFE CYCLE
Fission - Creates averageof 2.43 neutronsper Fast Neutron
Leakage
Leakage: No Fission
Fast NeutronAbsorbtion
Absorbtion: No Fission
Fast NeutronThermalization
Slow NeutronLeakage
Leakage: No Fission
Slow NeutronAbsorbtion
Absorbtion: No Fission
TERMS RELATED TO REACTIVITY
REACTIVITY-
– Critical
– Sub-Critical
– Super-Critical
UNITED STATES NAVAL REACTORS ARE
PRESSURIZED WATER REACTORS
REACTOR CORE
& PRESSURE
VESSEL
NAVAL REACTOR SAFETY
INHERENT STABILITY WATER IS BOTH MODERATOR
AND COOLANT– POWER GOES UP
– TEMP GOES UP
– DENSITY GOES DOWN
– # THERMALIZED NEUTRONS GOES DOWN
– POWER GOES DOWN
PRESSURIZER
RADIATION & SHIELDING
Must protect personnel from the various types of radiation– Alpha particles ( very large, positive) – Beta particles (tiny, negative)– Gamma rays (no mass, no charge)– Neutrons (large, no charge)
SHIELDING
ADVANTAGES OF NUCLEAR POWER
Allows for truly submersible weapons Allows for truly submersible weapons platformplatform
CVN’s can carry twice the JPF and CVN’s can carry twice the JPF and weapons as a conventional CVweapons as a conventional CV
Extreme endurance (only limited by food)Extreme endurance (only limited by food)
ALL AHEAD FLANK FOR A YEARALL AHEAD FLANK FOR A YEAR
DISADVANTAGES OF NUCLEAR POWER
Considerable cost of construction/ decommission
Great weight of shielding materials Environmental concerns
– Public Information
FISSION YIELD
CURVE The probability
that a particular pair
of fission fragments will be produced
by fission
BINDING ENERGY
ATOMIC NUMBER
ENERGY
MOST STABLE ELEMENT (Fe)