Inherently Safe Nuclear Reactors for Reducing Greenhouse Emissions - PowerPoint PPT Presentation

About This Presentation
Title:

Inherently Safe Nuclear Reactors for Reducing Greenhouse Emissions

Description:

Whenever We Discuss Measures and Technologies for Reducing Greenhouse Emissions, ... worst nuclear accident was at Three Mile Island (Harrisburg) in the USA in 1979. ... – PowerPoint PPT presentation

Number of Views:132
Avg rating:3.0/5.0
Slides: 33
Provided by: uct7
Category:

less

Transcript and Presenter's Notes

Title: Inherently Safe Nuclear Reactors for Reducing Greenhouse Emissions


1
Inherently Safe Nuclear Reactors for Reducing
Greenhouse Emissions
  • Andrew Kenny
  • Energy Research Centre (ERC)
  • University of Cape Town
  • South Africa

2
Whenever We Discuss Measures and Technologies for
Reducing Greenhouse Emissions, There is an
Elephant in the Room
Wind Power
Carbon sequestration
Nuclear Power
Solar Power
Energy efficiency
Biofuels
Geothermal energy
Wave Power
Hydro power
3
Advantages of Nuclear Power
  • Safety.
  • By far the best safety record of any large scale
    source of electricity (full energy cycle cradle
    to grave)
  • Waste.
  • Waste is small, solid, stable and easy to store
    so that it presents no danger to man or the
    environment
  • Economics.
  • Among the cheapest, if not the cheapest, source
    of electricity in Europe, Japan and the USA
  • Sustainability.
  • Enough uranium thorium in the crust sea to
    provide the world with electricity until the sun
    turns into a Red Giant

4
Advantages of Nuclear Power (continued)
  • Security of Fuel Supply.
  • Stable fuel prices. Long term storage easy.
  • Siting
  • Can be sited wherever you want. (Fuel cheap
    easy to transport).
  • Reliable Despatchable
  • When you want the power, you can have it (unlike
    wind solar)
  • High load factors
  • Greenhouse Emissions
  • Among the lowest, if not the lowest, greenhouse
    emissions per unit of electricity of any source
    of energy (full energy cycle cradle to grave
    fuel preparation, construction, operation,
    decommissioning etc)

5
Number of Energy Accidents from 1969 to 1996
with at least 5 Fatalities(Paul Scherrer
Institut, "Severe Accidents in the Energy
Sector)
6
The Worst Nuclear Accident at a Nuclear Power
Station in the West
  • In over 45 years of operating nuclear power
    station in the Western world, the worst nuclear
    accident was at Three Mile Island (Harrisburg) in
    the USA in 1979. It was a partial meltdown.
  • The consequences of the accident were these
  • deaths 0
  • injuries 0
  • health aftermath 0
  • (Pennsylvania Dept of Health Study)

7
Some Recent Energy Accidents
  • Natural Gas Well Burst China, Chongqing,
    December 2003
  • Toxic fumes of natural gas and sulphurated
    hydrogen
  • At least 233 people died soon after
  • About 42,000 people were evacuated
  • A total of 10,175 people were either hospitalized
    or treated and discharged
  • (Reuters News Service 30 Dec 2003)
  • Natural Gas Plant Explosion, Algeria, Skikda, Jan
    2004
  • 20 people killed soon after
  • 74 injured (IOL Website 20 Jan 2004)
  • Russian mine blast, Tiazhina pit, Kemerovo
    region, Siberia, Apr 04
  • 47 miners died (BBC News, 13 April 04)
  • Belgium gas blast, near Brussels, Jul 2004
  • At least 14 dead, 200 injured (BBC, 30 Jul 2004)
  • China coal mine blast, Daping Mine, city of
    Xinmi, Henan province, Oct 2004
  • 148 dead (BBC News, 21 Oct 2004)
  • China coal mine blast, Chenjiashan mine, Shaanxi
    province, central China, Dec 04
  • 166 dead (BBC News, 1 Dec 2004)
  • Texas oil refinery explosion, Mar 2005
  • At least 14 people killed

8
Greenhouse emissions for Full Energy Chain of
different Generation TechnologiesJ F van de
Vate. Elsevier. Energy Policy. Vol 25 No1 1997
9
Nuclear Weapons Proliferation
  • This is a very serious problem.
  • But it is a political problem, which has little
    to do with nuclear power.
  • Israel has nuclear weapons but no nuclear power
    station.
  • Sweden, Finland, Japan, Switzerland etc have
    nuclear power stations but no nuclear weapons.
  • The only solution to this problem is by honest
    political commitment and by reforming the
    Non-Proliferation Treaty.
  • For example, if all nations agreed to a strict
    ban on uranium enrichment above 10, enforced by
    inspection, this would greatly reduce the danger
    of weapons proliferation.
  • You could have a similar ban on the production of
    weapons grade plutonium.

10
Disadvantages of Nuclear Power
  • Poor public perceptions
  • Contrary to evidence, many people believe nuclear
    is dangerous and has a major waste problem
  • High capital costs
  • To a large extent both of these can be blamed on
    the existing designs of nuclear power reactors

11
Existing Reactors Light Water Reactors (LWRs)
  • They generate 87 of world nuclear power
  • Advantages
  • Reliable
  • Excellent safety record
  • Disadvantages
  • High power density
  • Complicated expensive
  • Safety comes at the high cost of expensive,
    ACTIVE safety systems
  • Essentially an big submarine propulsion unit
  • Ideal for a submarine but not ideal for a power
    station
  • The world is waiting for a better reactor

12
The New Nuclear Generation Inherently Safe
reactors
  • Various designs are being considered.
  • The one discussed here is the South African
    Pebble Bed Modular Reactor (PBMR)

13
Fundamental Design Philosophy of PBMR
  • The fundamental design philosophy is inherent
    safety.
  • No human error or equipment failure can cause an
    accident that endangers the public. This
    includes total loss of cooling at 100 power.
  • There are no safety systems. Safety is built in.
  • The control rods and small absorber spheres can
    shut the reactor down quickly but are not
    necessary for safety. They are operating
    systems.
  • Simple, small, cheap design. Low capital costs.
    Quick construction time.

14
Aims of PBMR Project
  • Capital costs
  • 1000 / kW
  • Construction Time
  • 24 months per unit
  • Emergency Planning Zone
  • 400 metres
  • No LWR can come close to matching this

15
Features of PBMR (power unit)
  • Coolant helium (inert chemically and
    radiologically)
  • Moderator graphite
  • Fuel enriched uranium (about 9.5)
  • Configuration Fuel pellets embedded in graphite
    spheres (pebbles)
  • Power cycle Brayton (heated helium drives gas
    turbine)
  • Power density about 6 kW/l (PWR 50 kW/l )
  • Unit Size about 180 MWe (440 MWt)
  • size limited so that surface area/mass always
    sufficient to ensure enough loss of radiant heat
    to prevent dangerous temperatures
  • Highest coolant temperature about 900C
  • Highest coolant pressure about 90 bar
  • Efficiency 42

16
PBMR Main Power System
17
Thermo Hydraulic Layout
5
7
6
3
2
T
PT
LPC
HPC
4
1
7
S
8
18
PBMR Module
19
Pebble Fuel
20
Fuel Design, Handling Disposal
  • Extremely stable fuel, even up to high
    temperatures
  • Heat is generated throughout each Pebble
  • flat temperature profile no hot spots
  • Pebbles are constantly removed and sampled (by
    machine)
  • if useful energy remains, put back into reactor
  • if spent, put into storage tank, where it remains
    for the life of the plant
  • Multiple barriers around each fuel pellet and
    encasement in graphite
  • makes it extremely difficult to use waste fuel
    for weapons
  • makes waste disposal very easy (each Pebble is
    its own containment)

21
Control
  • Reactor runs at steady temperature of about
    1100C. Doppler effect (passive)
  • Control rods small absorber spheres can shut
    the reactor down.
  • Power control comes from adjusting the mass
    (pressure) of helium in the circuit
  • tanks putting helium into circuit
  • or tanks receiving helium from circuit
  • Additional control from turbine by-pass valve
  • The PBMR is load following

22
Reactor Unit
23
Why Dangerous Nuclear Accidents are Impossible
for the PBMR
  • 1. Uncontrolled Reactivity (Chernobyl)
  • Impossible because good physics ensures that the
    reactor is always under control at all power
    ranges and for all transients.
  • 2. Fuel Damage by Overheating (Three Mile Island)
  • Impossible because the small design ensures even
    in the worst accident (total loss of coolant at
    100 power) sufficient heat will be naturally
    dissipated to keep fuel temperatures below the
    level at which they begin to sustain damage.
  • Normal fuel temperature 1100ºC
  • Worst accident temperature 1400ºC
  • Fuel damage begins slowly at 1600ºC

24
(No Transcript)
25
Turbo Generator System
26
Additional Advantages of PBMR
  • Units can be grouped together in modules of
    eight, sharing facilities
  • 8 x 180 MW 1440 MW
  • Small unit size and quick construction times
    gives planning flexibility to power utilities

27
Additional Uses of PBMR
  • Hydrogen Production
  • thermo-chemical
  • Desalination

28
History Future of PBMR
  • 1967 to 1989. Germany runs 15 MWe AVR Pebble
    Bed reactor. Highly successful.
  • 1985 to 1989. Germany builds 330 MWe THTR
    reactor. Too big. Loses inherent advantages of
    AVR. Teething problems. Political problems.
    Shut down.
  • (Klaus Töpfer, Germanys Minister of Nuclear
    Power and Environment when the original pebble
    bed programme in Germany closed down, stated in
    Davos, Jan 2003 Germany had made a mistake in
    halting the High Temperature Reactor programme.)
  • 1993. Eskom looks for future economic
    generating technologies, including nuclear. IST
    shows it the Pebble Bed concept. Eskom adopts it
    for study.
  • 1995 to 1999. Feasibility study, concept
    design, costing.
  • Cabinet support. Commercial partners. Licence
    EIA application.
  • 2002. Business case completed. (McKinsey)
  • 2003. Favourable Record of Decision on EIA by
    DEAT
  • 2004. South African Government designates PBMR as
    a national strategic project.
  • 2005. Successful appeal by anti-nuclear group
    against procedures of EIA.
  • Future, if necessary approvals are granted
  • 2007 Construction begins on Koeberg site 2007.
  • 2011 Unit comes on stream.

29
PBMR Site
30
Conclusion
  • If the pilot plant proves successful,
  • the PBMR will be able to provide South Africa
    with safe, clean, sustainable, economic
    electricity
  • and it will be able to offer the same to the rest
    of the world
  • including the countries gathered here.

31
The EndThank You
32
Acknowledgements
  • Technical slides and drawings from
  • PBMR Company, South Africa
  • IST, South Africa
  • Please do not publish any of them without
    permission from the PBMR Company as some of the
    information shown might now be out of date
Write a Comment
User Comments (0)
About PowerShow.com