Fast Reactor Physics -MikityukTH2013

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Wir schaffen Wissen – heute für morgen Fast Reactor Physics Konstantin Mikityuk, FAST reactors group @ PSI http://fast.web.psi.ch Thorium Energy Conference 2013 CERN Globe of Science and Innovation Geneva, Switzerland, October 27-31, 2013

Transcript of Fast Reactor Physics -MikityukTH2013

Page 1: Fast Reactor Physics -MikityukTH2013

Wir schaffen Wissen – heute für morgen

Fast Reactor Physics

Konstantin Mikityuk, FAST reactors group @ PSIhttp://fast.web.psi.ch

Thorium Energy Conference 2013CERN Globe of Science and InnovationGeneva, Switzerland, October 27-31, 2013

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Outline. Fast reactors: breeding.

Fast reactors: past and future.

Fast reactors: few R&D projects in Europe.

Fast reactors: could Th become a fuel? Sustainability Safety Proliferation resistance Radiotoxicity and decay heat

Summary: advantages and disadvantages of Th for FR

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Fast reactors: breeding.

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Fast critical reactorA fast neutron critical reactor is a category of nuclear reactor in which the fissionchain reaction is sustained by fast neutrons.

Such a reactor needs no neutron moderator, but must use fuel that is relativelyrich in fissile material when compared to that required for a thermal reactor.

1x10-2 1x10-1 1x100 1x101 1x102 1x103 1x104 1x105 1x106 1x107

Energy (eV)

0x100

1x1014

2x1014

3x1014

4x1014

5x1014

6x1014

7x1014

8x1014

Fluxp

erun

itleth

argy

(cm-2s-1

)

SFR

PWR

SFR PWR

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Breeding

238 239

239

239

92U

93Np

94Pu

91Pa

90Th 232 233

233

233

β–

β–

β–

β–

Thor

ium fu

el cy

cle

Uran

ium fu

el cy

cle

(n,γ)

(n,γ)

fertile

fertilefissile

fissile

23.5

m2.

35 d

22 m

27 d

A production of new fissile isotopes in the nuclearreactor is a kind of transmutation called a breeding andnon-fissile isotopes (U-238 and Th-232), which givebirth to the new fissile isotopes, are called fertile.

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Neutron balance in a critical reactor

A_fissileP = A_fissile + A_fertile + A_parasitic + LR

P = A + LR

keff = Production rate / (Absorption rate + Leakage Rate) = 1

A_fissile A_fissile A_fissile

η = 1 + BR + L

η – Number of n’s emitted per neutron absorbed in fissile fuel

BR – Breeding Ratio: Number of fissile nuclei createdper fissile nucleon destroyed

L – Number of neutrons lost per neutron absorbed in fissile fuel

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Breeding:hfor main fissiles

1x10-2 1x10-1 1x100 1x101 1x102 1x103 1x104 1x105 1x106 1x107

Neutron energy, eV

0

1

2

3

4

Pu-239

U-235

U-233

0x1001x10142x10143x10144x10145x10146x10147x10148x1014

Fluxp

erun

itlet

harg

y(cm

-2s-1

)

SFRPWR

Average number of fission neutrons emitted per neutron absorbed as afunction of absorbed neutron’s energy for three fissile isotopes

Best for breeding

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Breeding

Burning of Pu-239 and U-233 in a fast neutron spectrum (>105 eV) providesthe highest number of fission neutrons per neutron absorbed in fuel.

The extra neutrons can be absorbed by fertile isotopes with a rate which isequal or even higher than the fissile burning rate.

The fast neutron spectrum reactor with BR>1 is called a breeder and withBR=1—an iso-breeder.

Fast neutron spectrum allows to efficiently “burn” fertile U-238 or Th-232—via transmutation to fissile Pu-239 or U-233.

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Fast reactors: past and future.

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First "nuclear" electricity – fast reactor. In 1949 EBR-I – Experimental Breeder Reactor I – was designed at Argonne

National Laboratory. In 1951 the world’s first electricity was generated fromnuclear fission in the fast-spectrum breeder reactor with plutonium fuelcooled by a liquid sodium.

First “nuclear” electricity : four 200-watt light bulbs. Courtesy of ANL.

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Fast reactors: 1946 – 2013MWth

HgHg NaKNa LBE

ClementineEBR-IBR-10

DFRLAMPRE

EBR-IIFermi-1

RapsodieBOR-60SEFORKNK-II

BN-350Phénix

PFROK-550/BM-40A

JOYOFFTF

BN-600Super-Phénix

FBTRMONJU

CEFR

1946 19521951 1964

1958 20021959 1977

1961 19631961 1994

1963 19721967 19831968 20131969 1972

1972 19911972 19991973 20091974 19941974 1990

1977 20131980 19921980 2013

1985 19961985 2013

1994 20102010 2013

USAUSARussiaUKUSAUSAUSAFranceRussiaUSAGermanyKazakhstanFranceUKRussiaJapanUSARussiaFranceIndiaJapanChina

0.0251.2860162.520040552058750563650150140400147029904071465

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The Generation IV International Forum (GIF) is a cooperative internationalendeavor organized to carry out the R&D needed to establish the feasibilityand performance capabilities of the next generation nuclear energy systems.

Argentina, Brazil, Canada, France, Japan, Korea, South Africa, the UK andthe US signed the GIF Charter in July 2001, Switzerland in 2002, Euratom in2003, China and Russia both in 2006.

Six nuclear energy systems were selected for further development:

4. Very-high-temperature reactor (VHTR)5. Supercritical-water-cooled reactor (SWCR)6. Molten salt reactor (MSR)

1. Gas-cooled fast reactor (GFR)2. Sodium-cooled fast reactor (SFR)3. Lead-cooled fast reactor (LFR)

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Sustainability Safety

Economics

Reliability

Proliferation-resistance

Generation-IV systems: keywords

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Fast reactors: few R&D projects in Europe.

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European sodium-cooled fast reactor.Power: 3600 MWthCoolant: sodium@1 barFuel: (U-Pu)O2Clad: stainless steel

ESFREURATOM FP7 project

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Lead-cooled fast reactor demonstrator.Power: 300 MWthCoolant: lead@1 barFuel: (U-Pu)O2Clad: Stainless steel

ALFREDConsortium:

Italy,Romania,Poland, …

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Gas-cooled fast reactor demonstrator.Power: 75 MWthCoolant: helium@70 barFuel: (U-Pu)O2Clad: Stainless steel

2

22

260◙

C

2

2

ALLEGROConsortium:

Czech Republic,Hungary,

Slovakia, …

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Fast reactors: could Th be a fuel?

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Sustainability.

Depleted U stock

Spent fuel cooling

Fuel fabrication

Fastreactors

Geologicrepository

Separationof elements

U-dep

Ac

AcO2 + FP AcO2 + FP

FP + losses

“Ac” = “actinides”,i.e. U + Np + Pu + Am + Cm + ...“FP” = fission products

AcO2

(According to calculations) fast reactors can operate in an equilibrium closed U-Pu fuel cycle with BR=1 (amount of fissile produced = amount of fissileconsumed) fed by only depleted (or natural) uranium

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238237

238

238

237

239

239

239

23523492U

93Np

94Pu

95Am

96Cm

240

240

241

241 242

242 244

244243

245

FP

242 243

+1000

854–140

6

854

1

1853

–16

5–1

5

–146

–678181 102

–8412

–62

10

–6

4 10

–19

9

4

4

–23

–30

28

–421

–33

1717

17

2

2

1

–5–8

–844–1

–142–1000

(Cm)(Am)(Pu)(Np)(U)

242m

feed fuel

6.75

d

2.1

d

23.5

m2.

35 d

7 m

in

14.3

y

4.98

h

26 m

in

16 h

16 h

–1

(n,2n)

β–

(n,γ)

β+

fissionM

mass number

α

EQL-U: mass balance in SFR (simplified model)

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Sustainability.

Could the same reactors operate in an equilibrium closed Th-U fuel cycle?

(According to calculations) the answer is yes, but since no U-233 (main fissileisotope for this cycle) is available, we face a problem

Th disadvantage: How to start thorium fast reactor? What fissile material touse? Plutonium? Uranium-235? Uranium-233 generated somewhere else?

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EQL-Th: mass balance in SFR (simplified model)

237

239

92U

93Np

94Pu

91Pa

90Th 233

233

233

+1000

–35

feed fuel

6 959

95922 m

231

626 h

231 6 232

1.3

d

6

4 234

6.7

h

427 d 955

–877

232 1 79–4

1

234–35

49 235–39

10 236–2

8

8

6.75

d

–26 238

62.1

d

238–4

1

1

–1

1

237

1

228 232

1

FP

–5–2

–957–0

–35–999

(Pu)(Np)(U)(Pa)(Th)

Th advantage: very low amount of minor actinides

Th disadvantage: production of U-232—precursor ofgamma emitters

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U-234U-235U-236U-238

Np-237Np-239Pu-238Pu-239Pu-240Pu-241Pu-242Am-241

Am-242mAm-243Cm-242Cm-244Cm-245Cm-246

0.01 0.1 1 10 100

0.070.01

0.0481.59

0.10

0.3110.17

5.780.660.55

0.360.02

0.150.01

0.110.03

0.02

EQL-U and EQL-Th fuel compositions in SFR (%wt)

Th-228Th-230Th-232Pa-231Pa-233U-232U-233U-234U-235U-236

Np-237Pu-238Pu-239Pu-240

0.01 0.1 1 10 100

0.040.04

85.640.06

0.120.05

9.562.98

0.600.63

0.130.10

0.020.01

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EQL-U and EQL-Th neutron balance

U236U238

Np237Np239Pu238Pu239Pu240Pu241Pu242Am241

Am242mAm243Cm244Cm245Cm246

Structures

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4Th230Th232Pa231Pa233U232U233U234U235U236

Np237Pu238Pu239Pu240Pu241Pu242

Structures

0.0 0.2 0.4 0.6 0.8 1.0 1.2

k-inf = 1.30533 k-inf = 1.17023

Blue bars are isotope-wise contributions to absorption (sum up to 1) Red bars are isotope-wise contributions to production (sum up to k-inf)

Th disadvantage:lower k-infinity

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Safety. We look at just two reactivity effects: Doppler effect and (sodium) void effect

having in mind other reactivity effects (less fuel type dependent)

Thermal expansion effects (not considered)Void reactivity effect

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EQL-U and EQL-Th fuel reactivity effects in SFR

-3.0 -2.5 -2.0 -1.5 -1.0 -0.5 0.0Doppler effect ($)

0.00.51.01.52.02.53.03.54.04.55.05.56.0

Void

effec

t($)

Th-232

U-233U-235

NaCladding

NaCladding

U-238

Pu-239

Pu-240Pu-241

i

i

i

ii

P

A

P

A

0

0

Th advantage:stronger Doppler andweaker void effects

Infinite medium (no leakagecomponent)

Doppler (Nominal → 3100 K)

Void (Nominal → 0 g/cm3)

Isotope-wise decomposition:

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1x10-1 1x100 1x101 1x102 1x103 1x104 1x105 1x106 1x107

Neutron energy, eV

0

1

2

3

4

0x100

2x10-3

4x10-3

6x10-3

8x10-3

(u)

(cm-2s-1

)

SFR

EQL-U and EQL-Th fuel reactivity effects in SFRWhy void effect is weaker in case of EQL-Th?

Sodium removal leads tospectral hardening—shift to the right

Pu-239: grows quicker

U-233: grows slower

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Proliferation resistance.

238 239

239

239

92U

93Np

94Pu

91Pa

90Th 232 233

233

233

β–

β–

β–

β–

Thor

ium fu

el cy

cle

Uran

ium fu

el cy

cle

(n,γ)

(n,γ)

fertile

fertilefissile

fissile

23.5

m

2.35 d

Th disadvantage: fissile precursor has higher halflife, potential to be separated22

m

27 d

Th advantage: misuse of U-233 is protected bypresence of U-232

231

232

232

β–

231

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EQL-U and EQL-Th fuel RT and DH (no FP)

10 100 1000 10000 100000 1000000Time, years

1E-0061E-0051E-0041E-0031E-002

Deca

yhea

t,W/g

SFR-USFR-Th

110

1001000

10000

Radio

toxici

ty,Sv

/g

SFR-USFR-Th

Th advantage: Radiotoxicity and decay heat of EQL fuel are lower for ~10000y

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Summary.

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Summary... Th disadvantages Past and current fast reactors were/are based on U-Pu cycle.

Operational experience with thorium-uranium fuel is low.

Experience in fuel manufacturing and reprocessing is lower for Th-Ufuel compared to U-Pu.

Fissile fuel for Th-U cycle (U-233) is not available.

U-232—precursor of hard gamma emitters—is produced in Th-U cycle(n2n reaction is higher in fast spectrum).

k-infinity of equilibrium fuel is lower for Th-U cycle compared to U-Puone. This means that to reach iso-breeding the blankets of fertilematerial can be required.

Fissile precursor of U-233 (Pa-233) has higher half life (compared toNp-239)—potential to be separated and decayed to pure U-233.

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Summary... Th advantages Calculational analysis with state-of-the-art codes shows that fast

reactor can operate as an iso-breeder in Th-U cycle closed on allactinides.

There is very low amount of minor actinides in EQL-Th fuel cycle.

Doppler effect is stronger and void effect is weaker in EQL-Th fuelcompared to EQL-U.

Misuse of U-233 is protected by presence of U-232 (predecessor ofhard gamma emitters).

Radiotoxicity and decay heat of EQL-Th fuel are lower during the first10000 years of cooling compared to the EQL-U fuel.

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Thank you. Questions?