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
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