Tài liệu chuyên nghành điện hạt nhân - 2 ppt

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Light Water Reactor

Concept

-July 27 Second Period

YOSHIKAWA

Hitachi-GE Nuclear Energy, Ltd.

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1 Concept of Power Plant

2 Configuration of Nuclear Reactor

3 Feature of LWR (Light Water Reactor)

4 BWR and PWR

5 Plant Layout of LWR

6 Concept of Safety Design of LWR

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1 G t St t B il

and send it to Turbine.

How to generate electricity?

2 Drive Turbine with the

Steam’s pressure, then Electricity is generated by the Generator connected

Generator

to the Turbine.

CondenserWater

Steam to Water and send it back to the Boiler.

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Hydroelectric Power Plant

Discharge Canal

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Each type uses steam to work Turbine and Generator

Nuclear Fission

Feedwater Pump

CirculationPump

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Thermal Power & Nuclear Power

Thermal Power Plant Nuclear Power Plant

Fuel Supply Continuously supply Refuel once in 1-2 yearsFuel Supply Continuously supply Refuel once in 1 2 years

Steam Condition at Super critical pressure Saturation pressure

Turbine

above 22MPa

paround 7MPa

removed)

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4 BWR and PWR

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LWR uses Enriched Uranium as a Fuel

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Self sustaining Chain Reaction

at Reactor Core : Critical

Nuclear Fission

Fission

Moderator (Light Water)

Energy

U-235

Thermal Neutron U-235

Absorption generates two or threeNeutrons.

U-238

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How can we make the 1 More Uranium.

Reactor Critical?

1 More Uranium.

a Fuel with Enriched U-235.

b Layout More Fuel in Reactor.

2 More Thermal Neutron.

a Use Neutron Moderator.

3 Reduce Neutron Absorption of U-238.

a Fuel with less U-238.

b Moderate More Neutrons.

4 Reduce Neutron Leakage to Outside of Reactor

a Larger Reactor.

b Use Neutron Moderator.

c Locate Neutron Reflector around Reactor.

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General Configuration Fuel

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Reactor Configuration Fuel

of Light Water Reactor.

Reduce the number of Neutrons by Absorption

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Energy

U-235

(Low Energy)

Energy

Absorption

Control Rods absorb

Water makes more Nuclear Fission of U-

235, and less Absorption by U-238.

U-238

Control Rods absorb

Neutrons.

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LWR is “Light Water-cooled, & Light Water-moderated Reactor”.

LWR (Light Water

Heavy Water Reactor

Gas Cooled Reactor

LWR is Light Water cooled, & Light Water moderated Reactor

(Light Water Reactor

Fuel Enriched U-235 Non enriched U-235

(Natural U 235)

Enriched U-235(Natural U-235)

Coolant Light Water (H2O) Heavy Water (D2O) Helium Gas, Carbon

Dioxide Gas etc

Moderator Light Water (H2O) Heavy Water (D2O) Graphite

Reflector Light Water (H2O) Heavy Water (D2O) Graphite

Control Material Boron (B4C), Hf etc Boron (B4C), Boron (B4C)

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4 BWR and PWR

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Energy

related this Process

U-235

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•Water Density has similar feature, but Void

Effect has larger impact on Reactor Power

Ug + Uf

Ug : Volume of Gas

Uf : Volume of Liquid Moderator

Effect has larger impact on Reactor Power

(High Energy) (Low Energy)

U-235

Moderator Fast Neutron

(High Energy)

Fast Neutron (High Energy)

Void Fraction; High No Interaction

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Doppler Effect

•U-238 absorbs high energy

Neutrons (Fast Neutrons)

•Distribution of U-238 Absorption

Possibility depends on its

Temperature ion(barn)

•When Fuel Temperature is high,

U-238 will absorb the Neutrons

with wider range of Energy due Cross Sect

with wider range of Energy due

to Resonance

•Then Reactor Power will be

reduced

U-238 Absorption Cross Section

Neutron Energy (eV)

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Self Regulating g g

Process of LWR

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Power Control of LWR

Control the number ofNeutron by Absorption Control Rod Position

Dissolve Boron inCoolant and Controlits Density

Control the number ofThermal Neutron by

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Power Control using Void Effect

More Voids in

Reactor Boosted to

Less Voids inReactor Boosted to

Nuclear Fission

Increased

Nuclear FissionNuclear Fission

Increased

Nuclear FissionReduced

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4 BWR and PWR

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Generate Steam by

Boiling Light Water at

Reactor and directly

Pressure Suppression Pool

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Light Water and

Primary Containment Vessel

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Comparison between BWR & PWR p

Simple Configuration (Direct Cycle)

Small Pressure Containment Vessel

Low Power Density in Reactor

Easy Power Control using Void Effect

Need Radiation Shield in Turbine Island

Complex Configuration.(In-direct Cycle)

Large Pressure Containment Vessel with SteamGenerators and Pressurizers as well as ReactorPressure Vessel

High Power Density in Reactor

No Radiation Shield is needed in Turbine Island

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4 BWR and PWR

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Typical Site Layout of LWR yp y

SeawallSeawall

Intake Canal

Sea WaterPath

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Typical Site Layout of LWR

S lid R d W t Turbine, Condenser,

Heat Exchanger Building

Building RadWaste

Building Condensate

Solid Rad Waste.

Oil Tanks

Main Control Room and related System System

Building Stack

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Typical Plant Layout of LWR

Turbine

Circulation Pump

Reactor

Pressure Vessel

Reactor Building Turbine Building

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Condenser Feedwater Line

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4 BWR and PWR

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To Ensure the Plant Safety…

Prevention

of Trouble Occurrence

Prevention of Trouble

Escalation and

Prevention of Release of Radioactive Development

into an Accident

Even if a trouble Develops Into Accident

Substances to the environment

Even if a trouble Occurs

Shutdown Cool Contain

Fail-Interlock Equipment toAutomatically

Shutdown a Reactor

Emergency Core

Cooling

S t

Containment Vessel down

etc.)

Equipment to Promptly detect Troubles

System

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Shutdown Cool down Contain

In Case Trouble occurs,

Quickly Insert all Control

In Case Reactor WaterLevel unusually reduces,

In Case RadioactiveSteam is released toRods into Reactor to

Shutdown

Inject water into Reactor

by Emergency CoreCooling System (ECCS)

t C l d th R t

Primary ContainmentVessel, Prevent aleakage from PCV to

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FIVE Walls for Safety Containment

(1)Fuel Pellet Keep generated Radioactive Substance in Pellets.

Reactor Building

(2)Fuel Cladding Tube Prevent Leakage of Radioactivity generated by Fuel Pellet.

Vessel

Reactor Pressure Vessel

(3)Reactor Pressure Vessel Prevent Leakage of Radioactivity dissolved in Coolant.

Pellet

Cladding Tube

(4)Primary Containment Vessel Prevent Leakage of Radioactivity and Radiation in case of Primary

4m

Loop Line break.

(5)Reactor Building Prevent Leakage of Radioactivity to Fuel Rod

Outside Environment in case Leakage from PCV has occurred.

BWR PWR

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Summary (Key Words)

• Reactor, Steam Line, Turbine, Generator, Condenser, and

Feedwater Line.

• Fuel, Coolant, Moderator, Reflector, and Control Material , , , ,

• Reactor Building, Turbine Building, etc.

• Defense in Depth Shutdown Cool down and Contain

• Defense in Depth, Shutdown, Cool down, and Contain

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Light Water Reactor

Concept

-July 27, Second Period

Hitachi-GE Nuclear Energy, Ltd.

Tiêu đề	Light Water Reactor - Concept
Tác giả	Kazuhiro Yoshikawa
Trường học	University of Electricity and Power Engineering
Chuyên ngành	Electrical Engineering
Thể loại	presentation
Năm xuất bản	2011
Thành phố	Unknown

Định dạng
Số trang	35
Dung lượng	0,92 MB