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)