Nuclear power plants originally receive operating licenses for 40 years, but extensive ageing management plans and new monitoring techniques have allowed many plants to extend their operating lifetimes to 60 years or more. Regular inspections check for embrittlement, cracking, corrosion, and degradation that could affect the reactor pressure vessel, piping, concrete containment structures, cables, and buried pipes as they age. Acoustic, guided wave, phased array, and diffuse field monitoring methods can detect tiny cracks or changes earlier than visual inspections. As a result of successful ageing management, several nuclear plants around the world have received approval to operate for lifetimes beyond their original 40-year licenses.
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1. Nuclear Plant Life Extension
Group no: 05
Mohd Tayyab Saeed
Vivek kumar
1
Vishal Varshney
2. Content
Nuclear Energy
Nuclear Radiations
Ageing of plant
Ageing management
Life extension
Various plants working on extended life
Refrences
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3. Nuclear Energy
Energy from nucleus.
Two methods:-
Fission
Fusion
Nuclear Fission - Occurs when neutrons
impact and split the nuclei of certain atoms.
3
4. n
Fast Neutrons are
unsuitable for sustaining
further reactions
235U
n
fast
neutron n Slow neutron
fast
n
neutron
235
U
n
fast neutron
n Slow neutron
Insert a moderator to
4
slow down neutrons
6. Nuclear Reactors
Nuclear Reactor - Device that permits a
controlled fission chain reaction.
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7. Radiation
硫
Alpha ( ) - Moving particles composed of two neutrons
and two protons.
Stopped by layer of skin
Beta (硫) - Consists of electrons.
Stopped by layer of Aluminium foil of 3mm.
Gamma () - rays CANNOT be stopped.
They can be attenuated to safe limits using thick Lead
and concrete
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8. Harmful effects of Radiations
Nuclear radiations composes gamma rays
which causes
Cancer
Genetic alteration
Loss of fast growing cells such as skin cells,
intestinal lining and hair.
Poison the Ecosystem.
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9. Reactors Worldwide
Currently 441 nuclear power reactors in 31
countries.
Combined capacity of 363 gigawatts.
Provide 18% of worlds electricity.
Currently 30 reactors under construction in
10 countries.
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10. Nuclear Power Plant Life
Normally, Nuclear Plant get a license of 40
years.
After taking various ageing management
plans the life of a plant can be extended
upto 60 years.
Researches for new monitoring techniques
which may keep plant operation safely upto
80 years.
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11. What is Ageing?
The International Atomic Energy Agency
(IAEA) defines ageing as a continuous time-
dependent loss of quality of materials, caused
by the operating conditions.
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12. Effect of ageing
Neutrons bombard the pressure vessel
Over period of years that bombardment can
cause reaction that displace atoms in the
material
Produce tiny voids
Reduce the metals toughness and its ability
to resist cracking
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13. Major Concerns
Embrittlement
Cracking in the reactor pressure vessel and
its piping
Degradation of the concrete containment
Ageing Cables
Corrosion in burried water pipes
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14. Plans for managing ageing
Aim: To provide for the timely detection and
mitigation of significant ageing effects.
Periodic inspection of pressure vessel,
concrete containment structure, main pipes
and cables.
New monitoring techniques which are used
to detect tiny voids or cracks.
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16. Acoustic Monitoring
When crack grows in metal, the rupture
releases tiny pulses of acoustic energy
In the same way as earthquake sends out
seismic waves
Sensors detect these waves and can
monitor a developing flaw
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17. Guided wave
Transducer generate ultra- sonic waves
which propagate through metal pipe or the
walls of pressure vessel
Ultrasonic waves scattered provide
indication of cracks or corrosion
It wouldnt require inspector to strip off
insulation to inspect pipes
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18. Phased array
In this technique a group of transmitters
releases separate ultrasonic waves, which
interact to form one larger wave front
By controlling the timing and amplitude of
the individual pulses,researchers can steer
the wave front to scan a structure for flaws.
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19. Diffuse field
To monitor a coarse-grained material like
concrete, a single ultrasonic pulse is intro-
duced into the materials.
Receiver listen for the tiny echoes produced
by the waves interactions with all the grains.
To composite signal creates a distinct
signature for that materials,which will
change if the material degrades.
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20. Plant Life Extension
These Engineering assessments have
established many plants to operate much
longer by managing its ageing effects.
The life can be extended upto 60 years or
even more.
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22. References
IEEE Spectrum , pg no 24-29 , Aug 2012.
US ENERGY INFORMATION ADMINISTRATION, Annual
Energy Outlook 2001 with Projections to 2020, Rep.
DOE/EIA 0383 (2001), US (EIA) (2000).
UNITED STATES- NUCLEAR REGULATORY
COMMISSION, Licensing Renewal (2000) (Available at
http://www.nrc.gov/nrc/reactor/lr/index.html).
T. OTSUKA, Current Status of Life Management Policies
for Nuclear Power Plants Management in Japan, IAEA
Specialists Meeting on Strategies and Policies for Nuclear
Power Plant Life Management, 2830 September 1998.
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