Transmutation Capabilities of GEN-IV Reactors

Frank Goldner, PhD
Robert Versluis, PhD
U.S. Department of Energy
Global Nuclear Energy Partnership Program
September 28, 2006
1ABSTRACT
The Generation IV reactors all have the potential to play a significant role in future scenarios dealing
with transmutation of spent fuel from LWR power reactors. The nature of the flux spectrum, thermal
or fast, is the major factor in the effectiveness of transmuting various transuranic isotopes. We
conclude that each Generation IV reactor concept could have a role, if properly coordinated andsupported by significant development programs
The fast reactor concepts (liquid metal and gas-cooled) are the most effective in net consumption ofunwanted actinides (plutonium, neptunium, americium and possibly curium. Thermal spectrum
concepts (water-cooled reactors with and without inert-matrix cores, high-temperature gas-cooled
reactors with and without inert-matrix cores, and liquid-salt-cooled thermal reactors) all canpotentially reduce some of the minor actinides - even if only used in a single pass. Teamed up withsubsequent fast reactor irradiations to reduce higher minor actinides (specifically americium andcurium), their use could result in reducing the number of fast burner reactors required, per spent-fuelproducing LWR, compared to a system of only LWR and fast burner reactors.
Further evaluations of national and worldwide scenarios involving candidate Generation IV reactors
appears worthwhile to explore and optimize potential spent LWR fuel transmutation scenarios.
Frank Goldner
Rob Versluis

2

Acknowledgements
We wish to gratefully acknowledge support from thefollowing:• Dr. Robert Hill of Argonne National Laboratory forproviding mass flow information of GNEP alternatives
under consideration• Dr. Francesco Venneri of General Atomics forproviding HTGR Deep Burn and graphics information,and• Dr. Charles Forsberg of Oak Ridge National Laboratory
for Molten Salt Reactor mass flow information3

Next Generation Nuclear Plant (NGNP)
Attributes– Helium coolant up to 1000ºC
outlet temp
– Modular 300-600 MWTh
– Prismatic block or pebble bedcore– TRISO particle fuel– Demonstration plant possible by2017

Benefits– Attractive safety aspects– Helium Brayton cycle conversion
with high efficiency– Clean and efficient hydrogenproductionViability Issues– High temperature materials– Fuel performance and reliability– Hydrogen production
technologies– Intermediate heat exchanger– Waste generation
FuelParticle

Pin Cell4

Supercritical-Water-Cooled Reactor (SCWR)
Attributes– Advanced reactor cooledby water above critical point(374 °C, 22.1 MPa)
– Direct-cycle cooling
Benefits– Simplified system; fewercomponents; compact– Thermal efficiency
approaches 44%– Economic– Builds on existing technology
Viability Issues– Coolant flow stability against
oscillations– Thermal and heat-transfer
properties– Safety concept and fueldesign criteria– Materials5Gas-Cooled Fast Reactor (GFR)
Attributes• He coolant, 850°C outlet temperature• 600 MWth/ 288 MWe• Direct-cycle gas-turbine
Benefits• Efficient electricity generation• High U-resource utilization• Waste minimization• Possible hydrogen production
Viability Issues• Fuel and materials development
challenges• Active safety systems needed attargeted power density due torelatively low thermal inertia and poor
heat transfer characteristics ofcoolant at low pressure• Economics

6

Lead-Cooled Fast Reactor (LFR)
Attributes– Pb or Pb/Bi coolant– 500°C to 800°C outlet
temperature– U-TRU nitride fuel– 25–200 MWe– 15–30 year core refueled asa cartridge

Benefits– Small size tailored to needs
for remote or distributed
generation– No need for on-site fuelstorage or local fuel cycle
infrastructure– Design simplification

Viability Issues– Control of corrosion– Coolant activation– Seismic safety– Qualification of Russian data7

Sodium-Cooled Fast Reactor (SFR)
Attributes– Sodium coolant, outlet
temperature 550°C– Primary system atatmospheric pressure– Efficient electricity
generation– 1000-5000 MWthBenefits– Advantageous actinide
management– Efficient conversion of fertile
uranium– Metal or MOX fuel withadvanced recycling

Viability Issues– Development of oxide fuelfabrication technology– Sodium leak prevention– Economics
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Molten Salt Reactor (MSR)
Attributes– Molten salt fuel mixture– 1000 MWe net power– Efficient electricity
generation

Benefits– Inherently safe
– Potential for hydrogenproduction– Actinide burning– Efficient fuel utilization– Low pressure reduce stresson vessel and pipingViability Issues– Molten salt chemistry andcontrol– Compatibility of fuel withstructural materials,
graphite, and heatexchangers– Reliability of materials andcorrosive effects
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Concepts Detailed in Presentation to Illustrate Potential
for Significant Actinide Consumption• For Fast Spectrum Reactors: two sodium cooled
liquid metal fast reactor cases- conversion ratio, CR = 0.5- conversion ratio, CR = 0.25
For Thermal Spectrum Reactors:- a “Deep Burning” High Temperate Gas Reactor- a Molten Salt Reactor operating in a continuous
recycle mode

10100 GW(e) LWR once-through option – U.S. Reference

LWR Fuel Fab –1,950 tons/yr

U

100 GWe - 300 GWth

LWRs

100 ton/yr Fission Prod.
25 ton/yr TRU+ 1,825 U

33% efficient power conversion
50,000 MWD/MT

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Equilibrium Example #1 - Advanced Burner Reactor
at equilibrium feed rate – Much Less TRU to RepositoryU
1,090 ton/yr LEU
LWR Fuel Fab
1,170 tons/yrUL

0.1% TRU process loss
60 GWe - 182 GWth

LWRs

UREX

64 ton/yr Fission Prod.
0.02 ton/yr TRU

15 ton/yr TRU40. GWe - 105 GWth

CR=0.50

Sodium - ABRs
CR=0.50

PYRO

30 ton/yr Fission Prod.
0.1 – 1 ton/yr TRU

0.1 - 1 % TRU process lossA

ABR Fuel Fab
12Equilibriun Example #2 – Low CR Advanced Burner Reactor
at equilibrium feed rateU1,280 ton/yr LEU
LWR Fuel Fab
1,370 tons/yr

0.1% TRU process loss
70 GWe - 212 GWthUL

LWRs

UREX

72 ton/yr Fission Prod.
0.02 ton/yr TRU

18 ton/yr TRU
30 GWe - 78 GWth

CR=0.25

Sodium - ABRs
CR=0.25

PYRO

22 ton/yr Fission Prod.
0.08 – 0.8 ton/yr TRU

0.1 - 1 % TRU process lossA

ABR Fuel Fab13

Am Target Behavior in Fast and Thermal Systems
Am Target in Thermal System

Am Target in Fast System

1000

1000
Pu238

Pu238

Am241
800

Am241
800

Am243

Am243
Cm

SUMTOT

Mass (kg/IHMMT)

Mass (kg/IHMMT)

Cm
600

400

200

SUMTOT
600

400

200

000

510152025

Irradiation Time (year)

3035

400

510152025303540

Irradiation Time (year)• Am transmuted more quickly in a thermal spectrum• For either system, multi-recycle will be required• A thermal region in a fast reactor may combine
benefits of both systems
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Representative Cases Showing the Potential of Thermal
Spectrum Systems to Effect Actinide Consumption• Three HTGR “Deep Burn” related cases- once through HTGR reference case
- LWR feeding a Deep Burn HTGR
- LWR, followed by HTGR deep burn feeding aliquid metal fast reactor• A Molten Salt Reactor continuous recycle
case

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Irradiation of TRU-loaded TRISO in MHRs - General Atomics
Inert Matrix Case – utilizing “Deep Burning” HTGR0.50.4

0.3
Pu-2390.2

Pu-240Pu-241

Pu-2420.1

Cm-244Am-241

Pu-238

Np-237

Cm-244Am-243Am-243001 1021

2 1021

3 1021

4 1021

5 1021

6 1021

Fast Neutron Fluence
Deep Burn Range is Defined as 600,000 MWD/MT ~ at mid-fluence range
above
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General Atomics: MHR once-through TRU Reduction option
with 15% uranium enriched fuelHigh temperature Reactor
48% efficient power conversion
MHR Fuel FabU

Smaller waste output due to:Higher efficiency
Higher burnup
Less U-238

100 GWe - 210 GWthMHRs80 ton/yr Fission Prod.
10 ton/yr TRU
114 ton/yr Fission Prod.
24 ton/yr TRU

48% efficient MHRs are possible withtoday’s technology (850 °C);
150,000 MWD/MT burnup

2.4 X reduction in TRU waste
without reprocessing –comparedto the LWR base case17

17.500 ton/yr U

General Atomics Message: Full TRU Deep Burn MHRs: to significantly
reduce waste accumulation from LWRs without further TRU
recycling/management operations”

1,550 ton/yr LEUULWR Fuel Fab

82.5 GWe – 250. GWthLLWRs

U

114 ton/yr Fission Prod.
24 ton/yr TRU

UREX

94 ton/yr Fission Prod.
0.2 ton/yr TRU

20 ton/yr TRU

17.5 GWe - 35 GWth
Full-TRU DB-MHRs

TMHR TRISO Fuel Fab

70% TRU waste reduction
w/respect to all-LWR scenario
Heat Load reduced 2-3x

NO further TRU reprocess

13 ton/yr Fission Prod.
7 ton/yr TRU
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16,000 ton/yr U

General Atomics Message: “For the ultimate reduction in TRU waste
accumulation: use 2-tier TRU management with Deep Burn MHRs and ABRs. ““Actinide Management Island”

1,500 ton/yr LEU

LWR Fuel FabUU

114 ton/yr Fission Prod.
24 ton/yr TRU

UREX

90 ton/yr Fission Prod.
0.2 ton/yr TRU

78.5 GWe – 235.5GWthL

LWRs
16.5 GWe - 33 GWthActinide
Management
DB-MHRs
IslandCo-located Plants
PYRO
5 GWe - 15 GWth

19 ton/yr TRU

MHR Fuel Fab

20 ton/yr Fission Prod.
0.05 - .4 ton/yr TRU

Sodium - ABRs
ABR Fuel FabA

5x reduction in required # of ABRs
and processing requirements
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Molten Salt Reactor (MSR) – Significant Potential

Attributes– Molten salt fuel mixture– Large net power capability– Efficient electricity generation

Benefits– No solid fuel fabrication (no Am and Cm handling problem)– Homogeneous fuel salt that allows actinide burning without the needto blend before being fed to the reactor– Large specific power with a small fissile inventory per GW(e)– Inherently safe (low pressures, passive decay heat removal, etc.)– Potential for hydrogen production– Efficient fuel utilization

Viability Issues (Different mission than the original MSR breeder mission)– Molten salt chemistry, process scale up, and control– Reactor physics and safety analysis– Optimum system design20

Molten Salt Reactors(Liquid Fuel Reactors With
Fuel Dissolved In Coolant)
Off-gas
SystemPrimarySalt Pump

SecondarySalt Pump

Fuel Dissolved inMolten Fluoride Salt

Coolant Salt

Graphite
Moderator

Hot Molten Salt

Generator

Heat
Exchanger
ReactorFuel Salt

Critically Safe,
Passively Cooled
Dump Tanks(EmergencyCooling andShutdown)

Recuperator

PurifiedSalt

Gas
Compressor

FreezePlugCooling Water

Chemical Processing(Collocated or off-site)

02-131R221

LWR-MSR Burner Case -at equilibrium feed rate

U1,400 ton/yr LEU
LWR Fuel Fab
1,500 ton/yrUL

0.1% process loss
77 GWe - 230 GWth

LWRs

UREX

84 ton/yr Fission Prod.
0.02 ton/yr TRU

19 ton/yr TRU

CR=0
η=45%

23 GWe - 50 GWthMSRs
CR=0Extract
FP

19 ton/yr Fission Prod.
0.04-0.4 ton/yr TRU

0.1-1% process loss

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Summary
The Generation IV reactors all have the potential to play a rolein future scenarios dealing with transmutation of spent fuel from
LWR power reactors – assuming successful research,development, and demonstration.
• Fast reactors can effectively consume all transuranics• Thermal reactors appear suited for limited transmutation -unless fertile-free (“inert matrix”) fuel is used in which case oncethrough can be beneficial – potentially, with follow on multi-recycle
in a fast reactor, or with a multi-recycle Molten Salt Reactor
operating in a burner mode with significant TRU reduction potential• Current U.S. policy of no separated Pu leads to development ofrecycling of LWR spent fuel transuranics, without separated Pu(UREX), and consumption of transuranics in a fast spectrum reactor
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