strategy of nuclear innovation after fukushima-daiichi
TRANSCRIPT
Koji OKAMOTO
Nuclear Professional School,
The University of Tokyo
Strategy of nuclear Innovation
after Fukushima-daiichi accident
from the view point of academia
Innovation for Cool Earth Forum
October 5-6, 2016, Tokyo, JAPAN
Pros / Cons for Nuclear Energy
Pros
Huge and stable energy source
CO2 free
Few fuel and few waste
Plutonium mine (fuel breeding)
Cons
Huge consequence with nuclear accident
Management for Radioactive material
Affected by social environment
Plutonium management (nonproliferation)
Superior energy source under no accidents
Important technical Lessons Learned
from Fukushima-Daiichi Accident
• External Event consideration
• Accident Management – Countermeasure for Total Station Blackout,
– Loss of Ultimate Heat Sink and
– Huge area damage
– Containment Vessel Protection
– Training and Education for Utility/Regulator
• Emergency preparedness
Improvements are strongly needed
Post-Fukushima Nuclear Plant
• Anyway SAFE
• Release of radioactive material should be
practically eliminated.
• Secure the reactor by multiple layer of
protection and mitigation strategy.
• High-level radioactive waste should be
reduced and safely disposed.
Demands for Nuclear Power
• 3E+S (Energy security, Economics, Environment + Safety)
• CO2 free energy source
• Japan has few natural resources (95% of Energy resources have to be imported)
Safe Nuclear Reactor;
Severe Accident is practically eliminated
Co2 free energy source for 2030~2050
Steal
making
13 %
Civil
13%
Automobile
17 %
Others
23 %
Power generation
26 %
Petrochemistry
8 %
For the Cool Earth,
CO2 free Power Generation is not enough
11.9 hundred million tone (2010)
CO2 Emission
Industrial Heat and Transportation
should be CO2 free
Fast Breeder Reactor
• Safety Nuclear Power System
– Natural circulation can cool reactor without electricity
– MONJU R&D, incl. Safety researches
– Future Commercial FR plant design
• Reduction of High-level radioactive waste
– Transmutation of Minor Actinide using MONJU
• Fuel Cycle Technologies
– Production of Plutonium
• High-temperature (500℃) energy source
– Desalination, high-temperature steam
Schematic of Monju
Electricity Output : 280MWe (714MWt), Sodium-cooled, MOX-fueled
Primary sodium cooling loop Water/steam system
Secondary sodium
Primary sodium
Intermediate Heat Exchanger (IHX)
Primary Circulating
pump
Core
Air cooler
（AC)
Evaporator (EV)
Turbine Generator
Feed water pump
Sea water pump
Condenser
Secondary sodium cooling loop
Secondary Circulating
pump
Super heater (SH)
SH
EV ＩＨＸ
ACS
SH
EV ＩＨＸ
ACS
SH
EV ＩＨＸ
ACS
R/V ＴＢ
loop C
loop B
loop A Temperature, flowrate etc.
Primary sodium reactor vessel inlet/outlet: 529/397˚C, 5100 t/h/loop
Secondary sodium IHX inlet/outlet: 325/505˚C, 3700 t/h/loop
Steam at the turbine inlet: 483˚C, 12.5MPa, 1137 t/h
8
R&D on “Monju”
Aggregate of the fast breeder reactor technology Core and fuel technology
Confirmation of higher isotopes of Pu core
characteristics based on the actual reactor data.
Equipment and system design technology
Plant system design technology
Design technology of large sodium equipment
Sodium handling technology
Development of in-service-inspection technology for
the reactor vessel, etc.
Plant operation and maintenance technology
Establishment of a maintenance program in light of the
characteristics of the FBR power plant, etc.
Irradiation test (X-ray CT image)
Core design approach and core
management technology
Examples of specific reflections
Reactor kinetic characterization
and shielding evaluation methods
Aging characteristics and Integrity
of sodium equipment
R&D for reducing the waste volume and radiotoxicity Evaluate of the MA transmutation and the irradiation behavior
by full-scale irradiation tests with MA-bearing MOX fuel, etc.
R&D of enhanced safety Demonstrate the decay heat removal in the actual plant as a
feature of the sodium-cooled FR with natural circulation
◉Aggregate the outcome of the FBR technology development including the
technical feasibility of the FBR plant, and Reflect it in the next reactor design
by utilizing "Monju“ of our own design, manufacturing, and construction.
Na management techniques of
loop-type FR power plant
High-Temperature Gas-cooled Reactor
• Super Safety
– No Severe Accident (Inherent Safety with physics)
• Large negative reactivity feedback
• Cooling without electricity
• Confine FP inside the fuel particle
• High temperature heat
– Desalination, Electricity, Process heat, ….
• Stability of high-level waste
– Spent TRISO fuel contains FP stably over 100,000 years
Stop
Cool
Confine
11
GTHTR300: Gas Turbine High Temperature Reactor 300
Reactor
Turbine Generator
Core
Precooler
Recuperator
Compressor
Main Specifications
Reactor thermal power : 600MW
Reactor outlet temperature: 850ºC
Reactor inlet temperature : 587 ºC
Coolant pressure : 7 MPa
Electric power : 275MW
Generating efficiency : 45.8%
JAEA Design
Multi-purpose HTGR Electricity, Hydrogen, Heat, Water
GTHTR300
One unit of HTGR supply capacity
60,000Nm3/day Hydrogen
Heat supply to industries
40,000t/day desalination
300MWe Electricity
Contribution in non-electricity area
Potentiality of HTGR for GHG reduction in Japan
13
Steal
making
13 %
Civil
3%
Automobile
17 %
Others
23 %
Power generation
26 %
CO 2 emission
11.9 hundred million tone (2010 )
Civil
13 %
Others
23 %
Power generation
26 %
30 ％ decrease Decrease with HTGR
Petrochemistry 3 % Steal making 4% Automobile 1 %
Hi. temp.
heat
H 2
HTGR (600 MW)
Steal making with H 2 reduction Petrochemical plant Fuel - cell powered automobile
H 2 (Fuel)
16 ％ decrease
HTGR : 30 units
Hi. temp. heat, H 2 ( reductant )
9% decrease
HTGR : 20 units
Hi. temp. heat, Steam
5% decrease
HTGR : 15 units
Steam
1 unit = 4 HTGRs
Petrochemistry 8 %
Time
Short time scale（sec~min）
Utilize large core heat capacitance
Nuclear
Solar ・Wind
Long time scale（hr~day）
Control power/thermal ratio
according to power demand. GTHTR300 renewable hybrid system
Constant
＋ Constant power
H2
GTHTR300 nuclear-renewable hybrid system
H2 plant
Precooler
Recuperator
Power generation
rate control
Heat supply
rate control
Control flow
Coolant flow
IHX
Renewable energy power plant
Reactor
Core
Allowable core thermal capacitance: 850 MJ/oC
Power
synthesisConstant
power
Electric grid
Coolant inventory Bypass flow rate
Power
output
Power
output
Generator
Gas turbine
Pow
er
genera
tion r
ate
14
Summary
• Safety Nuclear System is available
• Fast Breeder Reactor
– Safety with natural circulation
– MONJU Restart
– Reduce CO2 with high temperature
• High Temperature Gas-cooled Reactor
– Super-Safety during operation and disposal
– Reduce CO2 with H2 production and
Industrial heat
– Combination with Renewable energy