0

Feasibility of Innovative Partitioning and

Transmutation that Leave No HLW Behind

IL SOON HWANG

SNU Nuclear Engineering Department

Technical Meeting on Advanced Fuel Cycles for Waste Burden Minimisation

June 21-14, 2016

IAEA, VIC

1

ROK

Taiwan

Japan

2

Geological Disposal of SNF, HLW, ILW (reducing granite~500m)

Environment-friendliness & Proliferation-resistance

1. Leaching & Migration of Radio-nuclides into Biosphere 2. Human Intrusion after the Institutional Control Period 3. Nuclear Safeguard against Plutonium Extraction

2 1

Pu 100 kg

3

ROK IAEA

Se-79 I-129

C-14

Sn-126

Th-229

Zr-93

Direct Disposal

1. Environment-friendliness predicted by GoldSim®

no recycling

of spent fuel

Uranium

ore

Time (years)

Rad

ioto

xic

ity

(re

lati

ve

to u

raniu

m o

re)

recycling

of spent fuel

Duration 1/1,000x

transmutation

of spent fuel

4 Prof. H.A. Abderrahim

2. Human Intrusion

ㅉ

5

Direct Disposal PUREX (99.9% Pu)

ICRP Upper IAEA

ICRP Lower

U Mining

Adv. Pyrox (99.9% TRU)

WIPP

Dose Upon Human Intrusion after the Institutional Control Period

(from EU-Red Impact Study Results & SNU Study on WIPP)

2. Human Intrusion

6

US Exposure NCRP-60

2 million holes in US, with half million new holes per year

Human Intrusion Risk Assessment Methods

System definition : Define events that can change the repository system regarding both time and space. Derive event tree or failure tree of system and variables affecting the system.

Probability(frequency) calculation : Estimation of probability of variables consisting of event tree or failure tree. Based on extrapolation of historical data.

Simulation and Assessment : Dose calculation, sensitivity analysis by Monte-Carlo method, optimization of system.

Nation Approach Estimation Methodology

U.S. • Exploratory drilling as main assessment scenarios.

• Based on historical data.

• Human intrusion by Poisson process with time-independent rate.

• Projection of past drilling records near repository site area.

Canada • Scenario judgement by expert elicitation. • Based on historical land use data. • Optimization of repository design based on

PSA results.

• Conditional probability change in future by using sub-Markov model.

• Consideration of social aspects by Bayesian statistical approach to pooling experts opinion.

U.K. • Various simple and comprehensive scenarios. • Future probability change using Markov chain model.

Finland • Scenario judgement by expert elicitation • Projection of historical data • Uncertainty in human intrusion scenarios

Japan • Additional safety assessment scenario for assuring system reliability

• Human intrusion by Poisson process with time-independent rate.

• Projection of past drilling records near repository site area.

8

3. SNF Repository as Potential Pu Mine

Geological repository: practical, sustaining barrier?

Scenarios INFCE, 1970 Peterson, 1996

Repository in granite Repository in salt Yucca Mountain

Shaft drilling • 4 months

• 25 M$ • 2~6 months • 6~8 weeks

Tunnel excavation • 12~18 months

• 100 M$ • 12~18 months

• 6 ~ 12 months

• 2.5~7.4 M$

[data from Amund ] World drilling speed record: 1) Vertical Drill 1.43 km/day in 1997 on the Satun A-17 well by Unocal Thailand. 2) Horizontal Drill 2.23 km/day in 2014 by Baker

9 June. 30, 2015 NUTRECK Weekly Meeting

Spent fuels, bury or eliminate? : safeguards problems

3. SNF Repository as Potential Pu Mine

2015 Global, Paris, France

WIPP Waste Acceptance Criteria

1) α-emitter activity concentration ≤ 1.6 E+6 Bq/g

2) Heat Density ≤ 0.5 W/m3

Can All P&T Wastes Meet WIPP Standards?

September 23, 2015 10

Isotopic Feed to Pyroprocessing

Isotopic Feed to Final Waste Decontamination Factor (DF) =

Cd for Pyroprocessing vs. Bi for PyroGreen

11 September 23, 2015 2015 Global, Paris, France

Advantage of Bi-based PyroGreen

• Phase diagram of Bi-Pu and Bi-La

September 23, 2015 2015 Global, Paris, France 12

Proliferation-Resistance of Bi-based PyroGreen

• Experimental results:

• With BiCl3 in LiCl-KCl-UCl3 (Blue line) -> Bi film electrode

• Without BiCl3 in LiCl-KCl-UCl3 (Red line)

2015. 9. 4. 원자력선진기술연구센터 진도회의 13

O1

R1

O2

R2

O’2

R’2

R’1

O’1

Peak 1: U(IV)/U(III)

R1: -0.013 V at Bi film

O1: 0.168 V at Bi film

R’1: -0.383 V at W

O’1: -0.237 V at W

Scan rate: 300 mV/s

Peak 2: U(III)/U(0)

R2: -1.136 V at Bi film

O2: -0.929 V at Bi film

R’2: -1.592 V at W

O’2: -1.416 V at W

R’2: U3+ + e -> U

R2: U3+ + e -> U

U + 2Bi -> UBi2

456 mV

U13 nanoparticle formation

Calculating

for 1.4 ps

Proliferation-Resistance of Bi-based PyroGreen

• Ab-initio modeling on Bi-U formation

September 23, 2015 2015 Global, Paris, France 14

2015 Global, Paris, France

U 0.941972 Zr 2560TRU 0.011589 U 0.9419723

NM 0.0106049 RE 0.014097 TRU 0.0115886Tc 0.001015 RE 0.0140971

Sr 0.0010716Cs 0.0032152Tc 0.0010148 U 226.6031I 0.0003081

Zr 2560NM 0.0106049 U 9418.7811 U 9418.781 U 9418.781

TRU 115.8746 TRU 115.8746 TRU 115.8746RE 140.95739 RE 140.9574 RE 140.9574 U 47.09391Sr 10.715381 Sr 10.71538 Sr 0.107154 TRU 0.579373Cs 32.148411 Cs 0.642968 Cs 0.00643 RE 126.8616Tc 10.146985 Tc 0.20294 Tc 0.20294 97.04916I 3.0806919 I 0.030807 I 0.030807

NM 106.0384 NM 30.18913 NM 30.18913

U 9419.7231 Cs 31.50544 Sr 10.60823 U 9371.687TRU 115.88619 Tc 9.944045 Cs 0.636539 TRU 115.2952 U 179.5092RE 140.97149 I 3.049885 Sr 0.107154Sr 10.716452 NM 75.84926 Cs 0.00643Cs 32.151626 Tc 0.20294Tc 10.148 I 0.030807I 3.081 RE 14.09574 U 177.2597

Zr 2560 NM 30.18913 TRU 6.952476NM 106.049 RE 8.457443

Sr 0.004243Cs 0.063654

SrCO3 10.56579Tc 9.944045I 3.049885 NM 75.849264 U deopsit 9514.743

TRU 6.952476 U 8920.797Cs 31.505443 Sr 0.042433 RE 8.457443

Cs 0.636539 TRU 0.579373 U 237.177RE 126.8616

U 34.20425U 0.941972 NM 75.85987 TRU 118.8706

TRU 0.011589 Tc 0.001015 Sr 0.03819 RE 5.991742RE 0.014097 Cs 0.572885 Sr 0.107154

Cs 0.006430.000404 Cs 32.07833 NM 30.18913 I 0.030807

2500 Sr 10.60398 Tc 0.20294 U 33.1781271.63324 TRU 115.8665

RE 1.471484

U 0 U 0.975156 U 1.026128TRU 0.002161 U 0.033184 TRU 0.125314 TRU 3.583499RE 116.9845 TRU 0.115886 RE 1.273272 RE 131.3819Sr 0.107154 RE 118.2437 Sr 0.107154Cs 0.00643 Sr 0.107154 Cs 0.00643I 0.030807 Cs 0.00643 I 0.030807

TRU 0.002161 I 0.030807 U 1.936562RE 116.9845 TRU 3.58887Sr 0.010715 RE 13.26552Cs 0.000643I 0.030807

Sr 0.096438Cs 0.005787

TRUs

RAR

(TRU

Oxide Fuel

Fabrication

Waste stream

2

Dross

Cathode

Consolidation

Salt

Zone Refining

PyroRedsox Electrowinning

Cathode

Forming

Zr recycle

Flowsheet and Mass Balance of 10 MTHM of Oxide Fuel with 4.5 wt% U-235, 45,000 MWD/MTU, 10-years Cooling

Salt

Zone Refining

Electrorefining

Waste stream

1

Uranium

Cs, Sr Interim

storage

Waste stream

1

RE/TRU

Chlorination

Cadmium

distillation

Hull salt

purification

Chopping/

DecladdingVoloxidation

Hull

electrorefining

Carbonization

Electrolytic

reductionSNF

Off-gas

treatment

Transmutation

Target

Cs, Sr Interim

storage

VitrificationSalt

Purification

UCl3 Formation

Cl2

Salt Recycle

Bismuth

Salt Recycle

Bismuth

Recycle

Anode Sludge

Salt

Filter

Salt

recycle

September 23, 2015 15

PyroGreen Flowsheet (OECD/NEA Report)

2015 Global, Paris, France September 23, 2015 16

Liquid Cadmium & LiCl-KCl Liquid Bismuth or Lead-Bismuth

PyroGreen Flowsheet built on KAERI’s Work

Decontamination Factor of Bi-based PyroGreen

17 September 23, 2015 2015 Global, Paris, France

• Electrochemical Hydrodynamic Model

• Benchmark using Experimental Data (Kinoshita, 1999)

September 23, 2015 2015 Global, Paris, France 18

Cs and Sr Removal by Zone Refining

● Axial impurity distributions

● Decontamination factor map

-15 -10 -5 0 5 10 15

-16

-14

-12

-10

-8

-6

-4

-2

0

Y (

mm

)

Z (mm)

0.6500

1.913

3.175

4.438

5.700

6.963

8.225

9.488

10.75

0 200 400 600 800

1E-4

1E-3

0.01

0.1

Imp

uri

ty c

on

cen

tra

tio

nPosition (mm)

Initial concentration

y0z0

y12z0

y16z0

avg

complete mixing

Avg: 5.06, Complete mixing : 9.70

Heater traverse rate :

2mm/min

Heater traverse rate :

2mm/min

-15 -10 -5 0 5 10 15

-16

-14

-12

-10

-8

-6

-4

-2

0

y (

mm

)

z (mm)

4.8805.4976.1156.7327.3507.9678.5859.2029.820

0 200 400 600 800

1E-4

1E-3

0.01

Imp

uri

ty c

on

cen

tra

tio

n

position (mm)

Initial concentration

y0z0

y12z0

y16z0

average

complete mixing

Avg: 7.99, Complete mixing : 9.70

Heater traverse rate :

0.5mm/min

Heater traverse rate :

0.5mm/min

Cs & Sr Recovery up to DF=300 and salt recycling

Hide-out into Crevice Break and Leakage

19 September 23, 2015 2015 Global, Paris, France

Process Hide-out and Leakage Control

Al2O laser surface treatment

Al2O3*CaO laser surface treatment

as received Al2O3 Al2O3 (LT) Al2O3*CaO (LT)0

2000

4000

6000

8000

10000

12000

Inte

nsity

Intrusion depth of Bi

100nm

200nm

300nm

Li, Bi intrusion

test

as received Al2O3 Al2O3 (LT) Al2O3*CaO (LT)0

100000

200000

300000

400000

500000

600000

Inte

nsity

Intrusion depth of Li

100nm

200nm

300nm

500oC

260oC

Crucible remains Intact

after 100 thermal cycles

II. Previous Studies

20

Ref [1] R.Fujita, et al., DEVELOPMENT OF ZIRCONIUM RECOVERY PROCESS FOR ZIRCALOY CLADDINGS AND

CHANNEL BOXES FROM BOILING WATER REACTORS BY ELECTROREFINING IN MOLTEN SALTS, ICAPP 2005

Toshiba Corp.’s Study (2005) – BWR Channel Box [1]

Fig2. The results of electrorefining tests in molten salts

After the Electrorefining, DF of the Co ≅ 200/Step

• Operating temperature is still high and fluoride corrosion could also occur.

Fig1. The Schematic experimental apparatus

for electrorefining

IV. Experimental Results : Cyclic Voltammetry for Nb

The formation of Niobium nonstoichiometric chlorides

(y+1)Nb(III) + (3y+2)Cl- + e- → Nby+1Cl3y+2 for y=0.5, 2, 3, 4, 5, 6, 7

Predominant niobium subchloride : Nb3Cl8

R6 reaction is cause by Nb3Cl8 Cluster (Nb3Cl8 Solubility < 0.5wt.% in LiCl-KCl @ 500°C)

O4 : Nb(IV)→Nb(V)+e-

R1 : Nb(V)+e- → Nb(IV)

R2 : Nb(IV)+e-→Nb(III)

R4 : Nb(III)+3e-→Nb(0)

R3 : Nb(III)+e-→Nb(II)

R6 : Nb(II)+2e-→Nb(0)

R5 : mNb(III)+ye-

→NbCln (n : 2~3)

Electro

de

Nb

Nb2

+

Nb3

+

Nb4

+

Nb5

+

NbCln

n=2.33~3.13

- Disproportionation reaction of Nb ions

O1 : Nb(II)→Nb(III)+e-

O2:Nb(0)→Nb(III)+3e-

O3: Nb(III)→Nb(IV)+e-

21

EW Radioaitivity for Nb-94, Co-60 : 0.1 Bq/g

EW Radioaitivity for Ni-63 : 100 Bq/g

VLLW Radioaitivity for Nb-94, Co-60 : 10 Bq/g

LLW Radioaitivity for Nb-94 : 111 Bq/g

VLLW Radioaitivity for Ni-63 : 1E+04 Bq/g

LLW Radioaitivity for Ni-63 : 1.11E+07 Bq/g LLW Radioaitivity for Co-60 : 3.70E+07 Bq/g

ILW(Nb94)

ILW(Nb94)

VLLW(Nb94)

EW(Nb94)

22

V. Experimental Results : Electrorefining

Element Radioactivity(Bq/g) DF

Nb-94 8.34E+06 7100

Co-60 2.37E+07 ∞

Ni-63 1.26E+06 ∞

For the lab-scale experiment, there are 3 steps to need to be exemption wastes.

Element Step 0 Step 1 Step 2 Step 3

Nb-94 ILW ILW VLLW EW

Co-60 LLW EW EW EW

Ni-63 LLW EW EW EW

• Radioactive level of wastes – electrorefining steps

23

Cost Benefit of Zr Decontamination for CANDU Pressure Tube

• Economical effect on the disposal cost

• Radioactive wastes volume reduction effect

Fig.1. Expected wastes mass of the CANDU

pressure tubes in KOREA

• Assumption

Pressure Tube lifetime : 30yr

Replacement number : 1

Zr wt% in Zr-2.5Nb : 96.93955

(According to ASTM B353-12)

Zr recovery rate : 99%

Vitrification waste density : 2,230kg/m3

Final wastes level : E.W → Recylcing

Packing Factor : 0.8

Disposal Cost : ₩ 1.219E7 /drum

• Reduction Disposal Cost

: total wastes disposal cost – wastes disposal cost expect Zr = wastes disposal cost for Zr recovered

= 184E3 kg÷2230kg/m3÷0.2m3/drum÷ 0.8 × ₩ 1.219E7/drum × (0.9693955×0.99)= ₩ 6 billion

• Opportunity cost for Zr recycling

: $60/kg[1] × 184E3 kg × (0.9693955×0.99) × ₩ 1,200/$ = ₩ 12.7 billion

• Total economical effect on the disposal cost : ₩ 18.7 billion

• Total wastes mass

: 23ton/unit * 4 unit * 2 = 184 ton

• 184E3 kg÷2230kg/m3÷0.2m3/drum÷ 0.8 × (0.9693955 × 0.99) = 495 Drums

Ref [1] E.D.Collins, et al., Recycle of Zirconium from Used Nuclear Fuel Cladding: A Major Element of Waste Reduction ,

WM2011 Conference

Sustainability of Nuclear Energy

7persons /km2 503persons /km2

24

Sustainability of Nuclear Energy

1978 2016 2020 2023. 2024 . 2025 2028 2030 2040 2051

Interim Storage Site Selection

URL Opening

Kori#1 Start-up

Kori Pool 1st Filled

10 NPPs End of Design Life

Kori+ Hanul 2nd Pool Filled

Hanbit Pool 1st Filled

6 NPPs End of Design Life

Interim Storage Site Open

HLW Repository Opening

NPP Timeline

PECOS

MOTIE Roadmap May 24, 2016

Failure of Peaceful Nuclear Energy?

26

Taiwan on April 28, 2014

ROK

Taiwan

Japan

North Korea

Proliferation

Accident

Environment Economy

Climate Change

27

Proliferation-resistance Environment-friendliness Accident-tolerance Climate-protection Economy

“PEACE”

Global Challenge in Nuclear Energy

Multilateral SNF Management Options

28

Option Description Key Technology Potential Partner

#1

Regional SNF repository

- Simplest solution for SNF

disposal

- Requirement for geological

stability

- Non-nuclear state can be a host

Geological disposal

or deep repository;

transportation

ROK, Taiwan, Japan,

Australia and USA

(+ IAEA)

#2

Regional reprocessing

and storage

- Utilizing regional reprocessing

cap.

- Assurance of service supply

- Joint control of separated

Pu/U/MA

Reprocessing (e.g.

PUREX); storage of

TRUs elements;

transportation

ROK, Taiwan, Japan,

China, USA and

Russia (+ IAEA)

#3

Multilateral partitioning

and transmutation

- Based on innovative

technologies

- Reducing burden of high-level

waste disposal

- Need to cooperate from R&D

step

Partitioning

(metallurgical

process) and

transmutation (fast

reactor or ADS);

transportation

ROK, Taiwan, Japan,

China and USA

(+ IAEA)

* PUREX: Plutonium Uranium Extraction * TRUs: Transuranic elements * ADS: Accelerator-driven System

June 07, 2016 H Noh – Ph.D. Dissertation Defense

29 June 07, 2016 H Noh – Ph.D. Dissertation Defense

Selecting multilateral approach to SNF management in

Northeast Asia

Option 2 Option 3 Option 1

Nuclear Safety

Nuclear

Security &

Non-

proliferation

Technology

Economics

Domestic

Acceptance

Environmental

Impact

Multilateral

Acceptance

Level 1: Goal

Level 2: Evaluation Criteria

Level 3: Alternatives

Availability

Suitability

Accessibility

System

Resilience

Accident

tolerance (O)

Accident

tolerance (T)

Physical

Protection

Proliferation

Resistance

& Int’l

Regime/Norm

Radiological

Non-

radiological

Internal Cost

Cost of Social

Conflict

Environmental

Cost

Public

Acceptance

Political

Support

Ethical

Consideration

Multilateral

Identity

Intention for

Hosting

Institutionaliz

ation

Multilateral SNF Management Options

30

Collective opinion of expert group - Experts prefer option #1(Regional SNF repository) as a multilateral strategy for SNF

management in NEA region - This scenario earns high ratings in the key criterions (Nuclear security & nonproliferation,

nuclear safety) - Scenario #3 (Multilateral P&T) is slightly preferred than #2 (Regional reprocessing & storage);

one of noticeable thing is that #3 overwhelms others in the aspects of all criterions on domestic and multilateral acceptances

0.506

0.221 0.273

Regional SNFrepository

Regionalreprocessing &

storage

Multilateral P&T

June 07, 2016 H Noh – Ph.D. Dissertation Defense

0.000

0.050

0.100

0.150

0.200Technology

Nuclear Safety

Nuclear Security &Nonproliferation

EnvironmentalImpact

Economics

DomesticAcceptance

MultilateralAcceptance

AHP Study through Expert Survey

31

Multi-lateral Approach for P&T

- Small LFR

Spent fuel take-back “CRADLE-TO-GRAVE”

Regional Fuel Cycle Park

GNEP/IFNEC (IAEA-USA)

Regional P&T in Black-Box

Recommendations

• Nuclear energy will emerge as global challenge

• Direct Disposal of SNF can pass very high risk to future generations on;

• Radiation exposure due to inadvertent human intrusion

• Proliferation by providing easily accessible Pu-mines

• Advanced P&T technology for decontaminating and incinerating actinides and LLFP can lead to all wastes meeting the safety standards of WIPP, without leaving any HLW and risk to future generations.

• Advanced P&T can be made proliferation-resistant by Multi-lateral Approach to ALL Fuel Cycles

32