transmutation of long-lived nuclear wastes
DESCRIPTION
June 1-6, 2014 ARIS2014. Transmutation of Long-lived Nuclear Wastes. Hiroyuki Oigawa Office of Strategic Planning (Nuclear Science and Engineering Directorate, and J-PARC Center) Japan Atomic Energy Agency. Background. Concern to radioactive waste management has been increasing in Japan. - PowerPoint PPT PresentationTRANSCRIPT
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Transmutation of Long-lived Nuclear Wastes
Hiroyuki OigawaOffice of Strategic Planning
(Nuclear Science and Engineering Directorate, and J-PARC
Center)
Japan Atomic Energy Agency
June 1-6, 2014ARIS2014
Background
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Concern to radioactive waste management has been increasing in Japan.
Transmutation technology for long-lived nuclides is drawing the attention from public, media and politicians.
JAEA (former JAERI and PNC/JNC) has been studying this technology for more than 20 years.
The Ministry of Education, Culture, Sports Science and Technology (MEXT) in Japan has launched a Working Party to review Partitioning and Transmutation Technology in August, 2013, and issued an interim report in November, 2013.
Concern to radioactive waste management has been increasing in Japan.
Transmutation technology for long-lived nuclides is drawing the attention from public, media and politicians.
JAEA (former JAERI and PNC/JNC) has been studying this technology for more than 20 years.
The Ministry of Education, Culture, Sports Science and Technology (MEXT) in Japan has launched a Working Party to review Partitioning and Transmutation Technology in August, 2013, and issued an interim report in November, 2013.
Major Long-lived Nuclides in Spent Nuclear Fuel
NuclideHalf-life(year)
Dose coefficient(μSv/kBq)
Mass(per 1tHM)
U-235 0.7B 47 10kg
U-238 4.5B 45 930kg
NuclideHalf-life(year)
Dose coefficient(μSv/kBq)
Mass(per 1tHM)
Pu-238 87.7 230 0.3kg
Pu-239 24k 250 6kg
Pu-240 6.6k 250 3kg
Pu-241 14.3 4.8 1kg
NuclideHalf-life(year)
Dose coefficient(μSv/kBq)
Mass(per 1tHM)
Np-237 2.14M 110 0.6kg
Am-241 432 200 0.4kg
Am-243 7.4k 200 0.2kg
Cm-244 18.1 120 60g
NuclideHalf-life(year)
Dose coefficient(μSv/kBq)
Mass(per 1tHM)
Se-79 0.3M 2.9 6g
Sr-90 28.8 28 0.6kg
Zr-93 1.53M 1.1 1kg
Tc-99 0.21M 0.64 1kg
Pd-107 6.5M 0.037 0.3kg
Sn-126 0.23M 4.7 30g
I-129 15.7M 110 0.2kg
Cs-135 2.3M 2.0 0.5kg
Cs-137 30.1 13 1.5kg
Dose Coefficient: Committed dose (Sv) per unit intake (Bq), indicating the magnitude of influence of radioactivity to human body. α-activity is more influential than β,γ-activity.
Dose Coefficient: Committed dose (Sv) per unit intake (Bq), indicating the magnitude of influence of radioactivity to human body. α-activity is more influential than β,γ-activity.
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Partitioning and Transmutation (P&T)
4
Spent fuelSpent fuel
ReprocessingReprocessing
FP、MAFP、MA
MA (Np, Am, Cm)MA (Np, Am, Cm)
PGM (Ru, Rh, Pd)PGM (Ru, Rh, Pd)
Heat generator (Sr, Cs)Heat generator (Sr, Cs)
Remaining elementsRemaining elements
U、 PuU、 Pu
Geological disposal (Glass waste form)
Transmutation by ADS and/or FR
Utilization and/or disposal
Geological disposal after cooling and/or utilization (Calcined waste form)
Geological disposal (high-density glass waste form)
Partitioning(Example)
Conventional scheme
P&T technology
MA: Minor ActinidesFP: Fission ProductsPGM: Platinum Group MetalFR: Fast ReactorADS: Accelerator Driven System
Recycle
Reduction of Radiological Toxicity by P&T
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
潜在的有害度(Sv)
処理後経過時間(年)
使用済燃料高レベル廃棄物分離変換導入天然ウラン9トン
Radiological Toxicity: Amount of radioactivity weighted by dose coefficient of each nuclide.
Radiological Toxicity: Amount of radioactivity weighted by dose coefficient of each nuclide.
• Normalized by 1t of spent fuel.
• 9t of natural uranium (NU) is raw material of 1t of low-enriched uranium including daughter nuclides.
• Normalized by 1t of spent fuel.
• 9t of natural uranium (NU) is raw material of 1t of low-enriched uranium including daughter nuclides.
Time period to decay below the NU level:
• Spent fuel100,000y
↓• High-level waste 5,000y
↓• MA transmutation 300y
Time period to decay below the NU level:
• Spent fuel100,000y
↓• High-level waste 5,000y
↓• MA transmutation 300y
Reduction
Reduction
Time after reprocessing (Year)
Rad
iolo
gica
l tox
icity
(S
v)
Spent fuel (1t)High-level wasteMA transmutationNatural uranium (9t)
5
How to Transmute MA and LLFP
6
Example of fission reaction of MANp-237
(T1/2=2.14M yr.) Fission reaction(n, f)
Neutron
Mo-102(T1/2=11min.)
I-133(T1/2=21hr.)
T1/2: Half life
Example of capture reaction of LLFP
Neutron
I-129(T1/2=15.7M yr.)Capture reaction
(n, γ)
I-130(T1/2=12hr.)
Β-ray
Xe-130(stable)
Neutron
Fast neutrons (> 1MeV)
Tc-102(T1/2=5s)
Ru-102(stable)
Xe-133(T1/2=5d)
Cs-133(stable)
β-ray β -ray
β -ray β -ray
Note: 10% or less of FPs are Long-lived ones.
Example of (n, 2n) reaction of LLFP
Neutron
Sn-126(T1/2=230k yr.) (n, 2n) reaction
Sn-125(T1/2=9.6d)
Β-ray
Sb-125(T1/2=2.8yr.)
Β-ray
Te-125(stable)
Thermal neutrons
High energy neutrons (> 10MeV)
Cross Sections of Neutron-induced Reaction :Am-241
Chain reactions of fission by fast neutrons are advantageous for transmutation of MA.
Capture
Fission
inelastic
Scattering
Total
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8
Examples of “Reduced Half-life”
“Reduced Half-life” can be written as T1/2 = ln2 / (φ·σ ) , if there is no competitive reaction nor production reaction, where φ is neutron flux and σ is reaction cross section.
Condition of realistic transmutation: φ·σ >1015 (barn/cm2/s)
NuclideHalf-life(year)
ReactionNeutron energy
Cross sectionσ (JENDL-4.0)(barn=10-24cm2)
Neutron flux φ ( /cm2/s)
1013 1014 1015
Reduced half-life (year)
Am-241 432 n,f Fiss. Spec. 1.378 1,600 160 16
Tc-99 211kn,γ Maxwell 23.68 93 9.3 0.93
n,2n 14MeV 1.233 1,800 180 18
Sn-126 230kn,γ Maxwell 0.09 24,000 2,400 240
n,2n 14MeV 1.686 1300 130 13
I-129 15.7Mn,γ Maxwell 30.33 72 7.2 0.72
n,2n 14MeV 1.464 1,500 150 15
Cs-135 2.3Mn,γ Maxwell 8.304 260 26 2.6
n,2n 14MeV 1.61 1,400 140 14
Cs-137 30.1n,γ Maxwell 0.27 8,100 810 81
n,2n 14MeV 1.549 1,400 140 14
Characteristics of ADS:•Chain reactions stop when the accelerator is turned off.
•LBE is chemically stable. High safety can be expected.•High MA-bearing fuel can be used. MA from 10 LWRs can be transmuted.
Characteristics of ADS:•Chain reactions stop when the accelerator is turned off.
•LBE is chemically stable. High safety can be expected.•High MA-bearing fuel can be used. MA from 10 LWRs can be transmuted.
Accelerator Driven System (ADS) for MA Transmutation
Proton beam
MA-fueled LBE-cooled subcritical core
Power generation
To accelerator
To grid Spallation target (LBE)
Super-conducting LINAC
Fission energy
Spallation target
Proton
Long-lived nuclides (MA)
Short-lived or stable nuclides
Fast neutrons
Utilizing chain reactions in subcritical state
Fission neutrons
Transmutation by ADS
Max.30MW
800MW
100MW
170MW
270MWMA: Minor ActinidesLBE: Lead-Bismuth Eutectic
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Steam generator
Primary pump
Reactor vessel
Beam duct
Subcritical coreBeam window Core support
Fuel exchanger
Bending magnet
Movable support
Proton beam
Spallation target
ADS Proposed by JAEA
Conceptual view of 800 MWth LBE-cooled ADS
• Proton beam : 1.5GeV• Spallation target : Pb-Bi• Coolant : Pb-Bi
• Max. keff = 0.97
• Thermal output : 800MWt• MA initial inventory : 2.5t• Fuel composition :
(MA +Pu)Nitride + ZrN • Transmutation rate :
10%MA / Year• 600EFPD, 1 batch
• Proton beam : 1.5GeV• Spallation target : Pb-Bi• Coolant : Pb-Bi
• Max. keff = 0.97
• Thermal output : 800MWt• MA initial inventory : 2.5t• Fuel composition :
(MA +Pu)Nitride + ZrN • Transmutation rate :
10%MA / Year• 600EFPD, 1 batch
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Components of Double-strata Fuel Cycle Concept
Spent fuelReprocessing
Partitioningprocess
U [752t/y]Pu [8t/y]
Fission Products (FP) [39t/y]Minor Actinides (MA) [1t/y]
Fuel fabricationprocess
AcceleratorDriven System
(ADS)
Recovered actinides
Final disposalFission products
Optimization by utilization / Disposal after cooling
Spent fuel
Dedicated transmutation fuel
Reprocessing
Transmutation cycle
Scope of P&T
[800t/y]
[8t/y] [1t/y]
[7t/y]
[1t/y]
[4t/y] [5t/y]
[30t/y]
[8t/y]PGM: Platinum Group Metal
Technical Issues for ADS
• R&D of SC-LINAC• Reliability AssessmentConstruction and operation
of J-PARC accelerator
•Design study on reactor vessel, beam duct, quake-proof structure, etc.
•Fabrication, irradiation and reprocessing tests
•Experiments in existing facilities and analyses
Construction of TEF-P in J-PARC
•Structure•Structure
•Fuel•Fuel
•Accelerator•Accelerator
• Reactor Physics• Control of Subcritical System• Reactor Physics• Control of Subcritical System
•R&D of Pb-Bi technologyConstruction of TEF-T in J-PARC
•Spallation Target, Material•Operation of Pb-Bi system•Spallation Target, Material•Operation of Pb-Bi system
J-PARC: Japan Proton Accelerator Research Complex
TEF-P: Transmutation Physics Experimental Facility
TEF-T: ADS Target Test FacilitySC-LINAC: Superconducting LINAC
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Reliability of Accelerator
13
LANSCE+KEKB
J-PARC
Number of beam trips per year (7,200 hours)
We are comparing the trip rate estimated from data of existing accelerators and the maximum acceptable trips to keep the integrity of the ADS components.
Short beam trip (<10s) can meet the criteria.
Longer beam trip should be decreased by:
Reducing the frequency of trips and
Reducing the beam trip duration
We are comparing the trip rate estimated from data of existing accelerators and the maximum acceptable trips to keep the integrity of the ADS components.
Short beam trip (<10s) can meet the criteria.
Longer beam trip should be decreased by:
Reducing the frequency of trips and
Reducing the beam trip duration
Beam trip duration
0-10s 10s – 5min. >5min.
Acceptable trip rate
Estimation from experiences
Bea
m t
rip r
ate
(tim
es/y
ear)
Design of Beam Window
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Beam window is subjected to severe conditions: High temperature Corrosion and erosion by LBE Pressure difference between vacuum and LBE (~0.8MPa) Irradiation by protons and neutrons
Beam window is subjected to severe conditions: High temperature Corrosion and erosion by LBE Pressure difference between vacuum and LBE (~0.8MPa) Irradiation by protons and neutrons
(2700)
1890
3390
1000
6450
1030
1390
9050
5250
1800
2000
ビーム導入管
ビーム保護管
内 筒
13700
(285)
4610φ
(2700)
1890
3390
1000
6450
1030
1390
9050
5250
1800
2000
ビーム導入管
ビーム保護管
内 筒
13700
(285)
4610φ
Core barrelCore regionReflector
Support structure
Coolant flow
Beam windowBeam ductProton beam
Target region
Beam duct support
Partition wallFlow control nozzle
(2700)
1890
3390
1000
6450
1030
1390
9050
5250
1800
2000
ビーム導入管
ビーム保護管
内 筒
13700
(285)
4610φ
(2700)
1890
3390
1000
6450
1030
1390
9050
5250
1800
2000
ビーム導入管
ビーム保護管
内 筒
13700
(285)
4610φ
Core barrelCore regionReflector
Support structure
Coolant flow
Beam windowBeam ductProton beam
Target region
Beam duct support
Partition wallFlow control nozzle
(unit: Kelvin)
450oC
470oC
490oCビーム窓外表面温度
(unit: Kelvin)
450oC
470oC
490oCビーム窓外表面温度
温度分布TemperatureOuter surfaceTemperatureOf beam window
t 1
t2
r1,i
r1,o
r2,i
r2,o
r3,i
r3,o
θ f
z off
Z i (Z o
)
Xi(=Xo)
・Suffix i: inner, o: outer
θ
x
z
Cylinder
θ t
t3
Top part
Transient part
Transient part
Constantsθ f = 60°
r1,i = 200mmr3,i = 225mmr3,o = 235mm
t1
t2
t3
t 1
t2
r1,i
r1,o
r2,i
r2,o
r3,i
r3,o
θ f
z off
Z i (Z o
)
Xi(=Xo)
・Suffix i: inner, o: outer
θ
x
z
Cylinder
θ t
t3
Top part
Transient part
Transient part
Constantsθ f = 60°
r1,i = 200mmr3,i = 225mmr3,o = 235mm
t1
t2
t3
Temperature at the outer surface of the window can be less than 500ºC. Buckling failure can be avoided by a factor of safety (FS)=3. The life time of the beam window should be evaluated from viewpoints of corrosion
and irradiation. necessity of irradiation data base.
Temperature at the outer surface of the window can be less than 500ºC. Buckling failure can be avoided by a factor of safety (FS)=3. The life time of the beam window should be evaluated from viewpoints of corrosion
and irradiation. necessity of irradiation data base.
Accuracy of Neutronics Design
0.93
0.94
0.95
0.96
0.97
0.98
0.99
1
1.01
BOC EOC
k-eff
, JE
ND
L
JAEA J3.3
JAEA J3.2
JAEA J4.0
J4.0
J3.2, J3.3
Benchmark calculation for 800MWt ADS for BOC and EOC.(Left: Comparison between JENDL-4.0 and JENDL-3.3, Right: Nuclide-wise contribution for differences in k-eff)
241Am
206Pb
207Pb
There is 2% difference in k-eff between JENDL-4.0 and JENDL-3.2, which is too large to design ADS. necessity of integral validation of nuclear data
There is 2% difference in k-eff between JENDL-4.0 and JENDL-3.2, which is too large to design ADS. necessity of integral validation of nuclear data
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Hadron Experimental Facility
50 GeV Synchrotron Materials and Life Science Experimental
Facility
3 GeV Synchrotron
LINAC
To neutrino detector
Jan. 28, 2008
Site for Transmutation
Experimental Facility
Japan Proton Accelerator Research Complex:J-PARC
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Critical Assembly
Pb-Bi Target
250k
W
10W
Proton Beam
Multi-purpose Irradiation Area
Transmutation Experimental Facility (TEF) of J-PARC
ADS Target Test Facility: TEF-TADS Target Test Facility: TEF-TTransmutation Physics
Experimental Facility: TEF-PTransmutation Physics
Experimental Facility: TEF-PPurpose: To investigate physics properties of
subcritical reactor with low power, and to accumulate operation experiences of ADS.
Licensing: Nuclear reactor: (Critical assembly)Proton beam: 400MeV-10WThermal power: <500W
Purpose: To research and develop a spallation target and related materials with high-power proton beam.
Licensing: Particle acceleratorProton beam: 400MeV-250kWTarget: Lead-Bismuth Eutectic (LBE, Pb-Bi)
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International Collaboration with MYRRHA
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Ion Source
FFAG Acc.
TargetProton Beam
KUCA
SubcriticalReactor
Magnets
FFAG Accelerator
KUCA Core
ADS Transmutation plant 30MW-beam, 800MWth
・ Transmute 250kg of MA annually
ADS Transmutation plant 30MW-beam, 800MWth
・ Transmute 250kg of MA annually
TEF in J-PARC250kW-beam ・ LBE target technology ・ Reactor physics of transmutation system
TEF in J-PARC250kW-beam ・ LBE target technology ・ Reactor physics of transmutation system
Experimental ADSMYRRHA ~2.4MW-beam, 50~100MWth
・ Engineering feasibility of ADS and fuel irradiation
Experimental ADSMYRRHA ~2.4MW-beam, 50~100MWth
・ Engineering feasibility of ADS and fuel irradiation
Reactor physics of MA transmutation system and material development for spallation target material
ADS without MA fuel( LBE coolant, Accelerator, Operation of ADS)
Advanced material for beam window
Power
2010 2020 2030 year2050Basic research (LBE loop test, KUCA experiments)
TEF in J-PARC MYRRHA
Purpose
R&D for elemental technology
(LBE target, Reactor physics)
Fuel irradiation,Accumulation of operation
experience of ADS
Power250kW-beam
TEF-P : 500W (max.)2.4MW-beam
Power : 50~100MWth
MAMock-up experiment of
transmutation system with massive MA (kg order)
Irradiation experiment with small amount of MA
Working Party to Review Partitioning and Transmutation Technology
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The Ministry of Education, Culture, Sports Science and Technology (MEXT) in Japan has launched a Working Party to review Partitioning and Transmutation Technology in August, 2013.
An interim report was issued in November, 2013.
Key Descriptions:To reduce the burden of HLW management, it is expected that flexibility in future political decision is extended by showing possibilities of new concepts of back-end with high social receptivity.
The ADS Target Test Facility (TEF-T) is being proposed under J-PARC to verify the feasibility of the beam window. It is appropriate to shift the R&D of the facility to the next stage.
The Transmutation Physics Experimental Facility (TEF-P) is being proposed under J-PARC to overcome difficulties in reactor physics issues such as for a subcritical core and an MA-loaded one. Since this facility is proposed as a nuclear reactor, the safety review by the new regulation is to be applied. With taking care of this point, it is appropriate to shift the R&D of the facility to the next stage.
For MYRRHA Program, it is appropriate to proceed with negotiation about JAEA’s participation at a reasonable level and mutual collaboration with Belgium and other relevant countries.
Progress of the development should be checked according to its stage.
ADS provides us a possibility to flexibly cope with the waste management in various situations of nuclear power.
R&D on ADS and its compact fuel cycle are under way in JAEA, and we are proposing the Transmutation Experimental Facility as the Phase-II of J-PARC.
To overcome various technical challenges for this technology, the international collaboration is of great importance.
ADS provides us a possibility to flexibly cope with the waste management in various situations of nuclear power.
R&D on ADS and its compact fuel cycle are under way in JAEA, and we are proposing the Transmutation Experimental Facility as the Phase-II of J-PARC.
To overcome various technical challenges for this technology, the international collaboration is of great importance.
Concluding Remarks
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