1.4-Fast Reactor Physics - 2 Reactivity Feedbacks and Fuel ...
Fast Reactor Physics -MikityukTH2013
Transcript of 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
2
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
3
Fast reactors: breeding.
4
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
5
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.
6
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
7
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
8
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.
9
Fast reactors: past and future.
10
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.
11
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
12
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)
13
Sustainability Safety
Economics
Reliability
Proliferation-resistance
Generation-IV systems: keywords
14
Fast reactors: few R&D projects in Europe.
15
European sodium-cooled fast reactor.Power: 3600 MWthCoolant: sodium@1 barFuel: (U-Pu)O2Clad: stainless steel
ESFREURATOM FP7 project
16
Lead-cooled fast reactor demonstrator.Power: 300 MWthCoolant: lead@1 barFuel: (U-Pu)O2Clad: Stainless steel
ALFREDConsortium:
Italy,Romania,Poland, …
17
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, …
18
Fast reactors: could Th be a fuel?
19
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
20
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)
21
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?
22
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
23
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
24
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
25
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
26
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:
27
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
28
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
29
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
30
Summary.
31
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.
32
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.
Thank you. Questions?