fast reactor physics - thorium energy world · 2019. 11. 19. · the fast neutron spectrum reactor...
TRANSCRIPT
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
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 reactor
A fast neutron critical reactor is a category of nuclear reactor in which the fission
chain reaction is sustained by fast neutrons.
Such a reactor needs no neutron moderator, but must use fuel that is relatively
rich 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
Flu
x pe
r un
it le
thar
gy (
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–
Tho
rium
fuel
cyc
le
Ura
nium
fuel
cyc
le
(n,γ)
(n,γ)
fertile
fertile fissile
fissile
23
.5 m
2
.35
d
22
m
27
d
A production of new fissile isotopes in the nuclear
reactor is a kind of transmutation called a breeding and
non-fissile isotopes (U-238 and Th-232), which give
birth to the new fissile isotopes, are called fertile.
6
Neutron balance in a critical reactor
A_fissile
P = A_fissile + A_fertile + A_parasitic + LR
P = A + LR
keff = Production rate / (Absorption rate + Leakage Rate) = 1
A_fissile A_fissile A_fissile
h = 1 + BR + L
h – Number of n’s emitted per neutron absorbed in fissile fuel
BR – Breeding Ratio: Number of fissile nuclei created
per fissile nucleon destroyed
L – Number of neutrons lost per neutron absorbed in fissile fuel
7
Breeding: h for main fissiles
1x10-2
1x10-1
1x100
1x101
1x102
1x103
1x104
1x105
1x106
1x107
Neutron energy, eV
0
1
2
3
4
h
Pu-239
U-235
U-233
0x100
1x1014
2x1014
3x1014
4x1014
5x1014
6x1014
7x1014
8x1014
Flu
x pe
r un
it le
thar
gy (
cm-2s-1
)
SFR
PWR
Average number of fission neutrons emitted per neutron absorbed as a
function 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) provides
the highest number of fission neutrons per neutron absorbed in fuel.
The extra neutrons can be absorbed by fertile isotopes with a rate which is
equal or even higher than the fissile burning rate.
The fast neutron spectrum reactor with BR>1 is called a breeder and with
BR=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 from
nuclear fission in the fast-spectrum breeder reactor with plutonium fuel
cooled by a liquid sodium.
First “nuclear” electricity : four 200-watt light bulbs. Courtesy of ANL.
11
Fast reactors: 1946 – 2013 MWth
Hg Hg NaK Na LBE
Clementine
EBR-I
BR-10
DFR
LAMPRE
EBR-II
Fermi-1
Rapsodie BOR-60
SEFOR
KNK-II
BN-350
Phénix
PFR
OK-550/BM-40A
JOYO
FFTF
BN-600
Super-Phénix
FBTR
MONJU
CEFR
1946 1952
1951 1964
1958 2002
1959 1977
1961 1963
1961 1994
1963 1972
1967 1983
1968 2013
1969 1972
1972 1991
1972 1999
1973 2009
1974 1994
1974 1990
1977 2013
1980 1992
1980 2013
1985 1996
1985 2013
1994 2010
2010 2013
USA
USA
Russia
UK
USA
USA
USA
France
Russia
USA
Germany
Kazakhstan
France
UK
Russia
Japan
USA
Russia
France
India
Japan
China
0.025
1.2
8
60
1
62.5
200
40
55
20
58
750
563
650
150
140
400
1470
2990
40
714
65
12
The Generation IV International Forum (GIF) is a cooperative international
endeavor organized to carry out the R&D needed to establish the feasibility
and performance capabilities of the next generation nuclear energy systems.
Argentina, Brazil, Canada, France, Japan, Korea, South Africa, the UK and
the US signed the GIF Charter in July 2001, Switzerland in 2002, Euratom in
2003, 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.
Reactor vessel
Na
Ar 1 bar
core
Primary
pumpÍ6
SGÍ6
545ºC
395ºC
490ºC
240ºC
Na
~1 barH2O
185 bar
Secondary
pumpÍ6
IHXÍ6
Na
~1 bar
340ºC
525ºC
Air
HXÍ6
35ºC
Na
~1 bar
DHR
HXÍ6
DH
R lo
opÍ
6
Power: 3600 MWth
Coolant: sodium@1 bar
Fuel: (U-Pu)O2
Clad: stainless steel
ESFR EURATOM FP7 project
16
Lead-cooled fast reactor demonstrator.
Core
Primary pumpÍ8
SG
Í8
Reactor vessel
H2O
180 bar
480ºC
Pb
335ºC
450ºC
Feedwater
pump
Ar
1 bar
HP
turbineLP
turbine
Condenser400ºC
DH
R c
on
de
nse
r
H2O
1 b
ar
Power: 300 MWth
Coolant: lead@1 bar
Fuel: (U-Pu)O2
Clad: Stainless steel
ALFRED Consortium:
Italy,
Romania,
Poland, …
17
Gas-cooled fast reactor demonstrator.
Power: 75 MWth
Coolant: helium@70 bar
Fuel: (U-Pu)O2
Clad: Stainless steel
core
Primary
blowerÍ2
HX
Í2
Guard vessel
N2
14 bar
DHR
blowerÍ3
DHR
HX
H2O
10 bar 50ºC
He70bar H2O
65 bar26
0ºC
H2O pool
1 bar 50ºC
530ºC
N2
1 bar
Reservoir
DHR loopÍ3Main loopÍ2
127ºC
197ºC
Air cooler
Í2
1 bar
Water
pumpÍ2
35ºC
125ºC
ALLEGRO Consortium:
Czech Republic,
Hungary,
Slovakia, …
18
Fast reactors: could Th be a fuel?
19
Sustainability.
Depleted U stock
Spent fuel cooling
Fuel fabrication
Fast
reactors
Geologic
repository Separation
of 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 fissile
consumed) fed by only depleted (or natural) uranium
20
238 237
238
238
237
239
239
239
235 234 92U
93Np
94Pu
95Am
96Cm
240
240
241
241 242
242 244
244 243
245
FP
242 243
+1000
854 –140
6
854
1
1 853
–1
6
5 –1
5
–14 6
–678 181 102
–84 12
–62
10
–6
4 10
–1 9
9
4
4
–2 3
–3 0
28
–4 21
–3 3
17 17
17
2
2
1
–5 –8
–844 –1
–142 –1000
(Cm) (Am) (Pu) (Np) (U)
242 m
feed fuel
6.7
5 d
2.1
d
23
.5 m
2
.35
d
7 m
in
14
.3 y
4.9
8 h
26
min
16
h
16
h
–1
(n,2n)
β–
(n,γ)
β+
fission
M
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 fissile
isotope for this cycle) is available, we face a problem
Th disadvantage: How to start thorium fast reactor? What fissile material to
use? 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
959
22
m
231
6 26
h
231 6
232
1.3
d
6
4 234
6.7
h
4 27
d
955
–877
232 1 79
–4
1
234
–35 49
235
–39 10
236
–2 8
8
6.7
5 d
–2 6
238
6 2.1
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 of
gamma emitters
23
U-234
U-235
U-236
U-238
Np-237
Np-239
Pu-238
Pu-239
Pu-240
Pu-241
Pu-242
Am-241
Am-242m
Am-243
Cm-242
Cm-244
Cm-245
Cm-246
0.01 0.1 1 10 100
0.07
0.01
0.04
81.59
0.10
0.31
10.17
5.78
0.66
0.55
0.36
0.02
0.15
0.01
0.11
0.03
0.02
EQL-U and EQL-Th fuel compositions in SFR (%wt)
Th-228
Th-230
Th-232
Pa-231
Pa-233
U-232
U-233
U-234
U-235
U-236
Np-237
Pu-238
Pu-239
Pu-240
0.01 0.1 1 10 100
0.04
0.04
85.64
0.06
0.12
0.05
9.56
2.98
0.60
0.63
0.13
0.10
0.02
0.01
24
EQL-U and EQL-Th neutron balance
U236
U238
Np237
Np239
Pu238
Pu239
Pu240
Pu241
Pu242
Am241
Am242m
Am243
Cm244
Cm245
Cm246
Structures
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Th230
Th232
Pa231
Pa233
U232
U233
U234
U235
U236
Np237
Pu238
Pu239
Pu240
Pu241
Pu242
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)
strongback
diagrid
core
control rods
vessel
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 0.0
Doppler effect ($)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Voi
d ef
fect
($)
Th-232
U-233U-235
NaCladding
NaCladding
U-238
Pu-239
Pu-240
Pu-241
i
i
i
i
i
P
A
P
A
0
0
Th advantage:
stronger Doppler and
weaker void effects
Infinite medium (no leakage
component)
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
h
0x100
2x10-3
4x10-3
6x10-3
8x10-3
(u
) (c
m-2s-1
)
SFR
EQL-U and EQL-Th fuel reactivity effects in SFR
Why void effect is weaker in case of EQL-Th?
Sodium removal leads to
spectral 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–
Tho
rium
fuel
cyc
le
Ura
nium
fuel
cyc
le
(n,γ)
(n,γ)
fertile
fertile fissile
fissile
23
.5 m
2.35 d
Th disadvantage: fissile precursor has higher half
life, potential to be separated 22
m
27 d
Th advantage: misuse of U-233 is protected by
presence 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 1000000
Time, years
1E-006
1E-005
1E-004
1E-003
1E-002
Dec
ay h
eat,
W/g
SFR-U
SFR-Th
1
10
100
1000
10000
Rad
ioto
xici
ty, S
v/g
SFR-U
SFR-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-U
fuel 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-Pu
one. This means that to reach iso-breeding the blankets of fertile
material can be required.
Fissile precursor of U-233 (Pa-233) has higher half life (compared to
Np-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 all
actinides.
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 fuel
compared to EQL-U.
Misuse of U-233 is protected by presence of U-232 (predecessor of
hard gamma emitters).
Radiotoxicity and decay heat of EQL-Th fuel are lower during the first
10000 years of cooling compared to the EQL-U fuel.
Thank you. Questions?