transmutation of long-lived nuclear wastes

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1 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 June 1-6, 2014 ARIS2014

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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 Presentation

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Page 1: Transmutation of  Long-lived Nuclear Wastes

1

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

Page 2: Transmutation of  Long-lived Nuclear Wastes

Background

2

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.

Page 3: Transmutation of  Long-lived Nuclear Wastes

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.

3

Page 4: Transmutation of  Long-lived Nuclear Wastes

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

Page 5: Transmutation of  Long-lived Nuclear Wastes

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

Page 6: Transmutation of  Long-lived Nuclear Wastes

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)

Page 7: Transmutation of  Long-lived Nuclear Wastes

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

7

Page 8: Transmutation of  Long-lived Nuclear Wastes

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

Page 9: Transmutation of  Long-lived Nuclear Wastes

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

9

Page 10: Transmutation of  Long-lived Nuclear Wastes

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

10

Page 11: Transmutation of  Long-lived Nuclear Wastes

11

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

Page 12: Transmutation of  Long-lived Nuclear Wastes

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

12

Page 13: Transmutation of  Long-lived Nuclear Wastes

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)

Page 14: Transmutation of  Long-lived Nuclear Wastes

Design of Beam Window

14

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.

Page 15: Transmutation of  Long-lived Nuclear Wastes

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

15

Page 16: Transmutation of  Long-lived Nuclear Wastes

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

16

Page 17: Transmutation of  Long-lived Nuclear Wastes

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)

17

Page 18: Transmutation of  Long-lived Nuclear Wastes

International Collaboration with MYRRHA

18

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

Page 19: Transmutation of  Long-lived Nuclear Wastes

Working Party to Review Partitioning and Transmutation Technology

19

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.

Page 20: Transmutation of  Long-lived Nuclear Wastes

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

20