Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
The use of the GDT based neutron source as driver in a sub-critical burner of minor actinides
K. Noack
Research Center Rossendorf (Germany)
Budker Institute of Nuclear Physics, September 26, 2006, Novosibirsk, Russia
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Content
Part I: Transmutation of nuclear waste –
a short overview on the actual state
Part II: The GDT as neutron source in a
sub-critical system for transmutation?(~ Presentation at OS`2006, Tsukuba, Japan)
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
To become a long-term sustainable option for the worlds energy supply fission reactor technology must:
maximally use nuclear fuel (uranium) and
minimize its high level waste (HLW)!
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
: Partitioning & Transmutation
Main problem on long-time scale. HLW repository problem !
Goal: To transmute radio-isotopes in short-lived or stable isotopes by neutron reactions!
France, Japan, USA
UraniumU-235: 3-5%U-238: 95-97%
Burn-up Spent nuclear fuel
U: 95.5%
+ TRU isotopes• Pu: 0.9%• MA (Np, Am, Cm): 0.1%
+ Rad. FP isotopes: 0.4%
+ Stable isotopes: 3.2%
3-4 years
# In today´s Light Water Reactors (LWRs):
Problem on short-time scale.
1 LWR (~1.3 GWel.) produces per year (kg):
Pu: ~ 270 Am: ~ 13.5 Np: ~ 13 Cm: ~ 2FPs: ~ 1000
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
(B. Frois)
Classic glass
MA + FP
Pu + MA + FP
FPLight glass
# Radiotoxicity for various options of waste disposal:
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
From: M. Salvatores, FZR-presentation (2005)
FPs~3x102 years
Total
>105 yearsPu & decay products
~104 yearsMAs & decay products
Uranium ore
Tc-99, I-129
102 103 104 105 106
Years after discharge
R
adio
toxi
city
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Geological Disposal
Direct Disposal
Spent Fuelfrom LWRs
# Partitioning & Transmutation of TRUs and FPs:From: M. Salvatores, FZR-presentation (2005)
Dedicated Fuel Fabrication
Pu MA
Partitioning & Transmutation (TRUs and FPs)
Partitioning
Transmutation
Geological Disposal
Dedicated Fuel
Reprocessing
FP
Pu, MA
FPPartitioning
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
# Neutron reactions for transmutation:
• Is the only option for FPs.
• However: secondary nuclei can be also long-lived.
• Thermal or intermediate (En: ~ eV-10 keV) neutrons are necessary.
• Minor actinides are fissionable!
• Fission is the preferable reaction for transmuting MAs : - substantially shorter life-times,
- possibility of „fast systems”.
• „Fast“ neutrons with En > 0.5 MeV are necessary.
Capture Fission
• : „Fast systems” should be a suitable tool for transmuting MAs!
• : Only low transmutation rates of FPs achievable!M. Salvatores: The problem is not yet solved!
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
• A „fast system“ with high neutron flux inside an acceptable large volume!
Fission Technology offers two options:
# An efficient burning of Pu and MA isotopes demands:
„Driven sub-critical system“ „Fast reactor“
– Main class: ADS = Accelerator Driven System
: What is the most important physical difference ?
&
What is the advantage of an ADS compared to FR ?
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
# Neutron field in a reactor:
Solution of the Static Reactor Equation = eigenvalue equation
• Neutron field power distribution in the reactor
• Eigenvalue = keff - “effective multiplication factor”
> 1 - super-critical reactor, P:
keff = 1 - critical reactor, P:
< 1 - sub-critical reactor P:
A minimum on fission reactor physics:
Important phenomenon:
„Delayed“ fission neutrons with a relative portion: eff6.5x10-
3 !
It makes possible to control a fission reactor !
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
1.0
0.99
0.98
„delayed“ super-critical state
1)(kTwitheP(t)
eff
T
t
„prompt“ super-critical state
critical state constant power
1+eff1.0065
eff
super-critical state
sub-critical state
keff 3effeffeff
-4-5pr.
10β1kk
s;1010
: T 0.01 - 0.1 s !!!
3eff
del.45
pr.
101k
s0.1s10 s,1010
: T 100 s !
„driven sub-critical systems“~0.95
?10-3 What is the impact of a
power increase on keff ?
(“reactivity effects”)
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
• Fast reactors:
- eff should be large!
- Positive total reactivity effects (keff ↗) should not appear!
: What is the impact of MAs on these demands?
Reactor safety considerations:
• Driven sub-critical systems: keff ≤ 0.98 !
: „They offer much higher flexibility for burning Pu and MAs than Fast Reactors“ !
In Fast Reactors the maximum allowable fraction of MAs in the fuel is ~ 5 % only !
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
2030 2040 2050 2060 Time
Waste
Strategic role of Driven Sub-critical Sytems in the future of Nuclear (Fission) Energy in US
: The use of the GDT neutron source as driver in a Driven System for transmutation of nuclear waste could be an additional goal for further Research & Development !
M. Cappiello, „The potential role of Accelerator Driven Systems in the US“, ICRS-10 (2004)
Use of ADS
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
- 50
- 40
- 30
- 20
- 10
0
10
20
2 0 4 6 8 10
A
D D
C
C
B
Act. Mineurs Chargés (%)
Variation (%)
B
A: Na-void effect (keff ↗)
B: Doppler-effect (keff↘)C: Burn-upD: eff
Increase of Na-void effect !
Decrease of eff !
Decrease of Doppler effect !
# Effect of MA introduction on reactivity coefficients in a Na-cooled Fast Reactor:
Bad effects by MAs:
Decrease of burn-upGood effect:
From: M. Salvatores, FZR-presentation (2005)
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
THE GDT AS NEUTRON SOURCE IN A
SUB-CRITICAL SYSTEM FOR TRANSMUTATION?
K. Noack
Research Center Rossendorf (Germany)
A. Rogov
Joint Institute of Nuclear Research Dubna (Russia)
A.A. Ivanov, E.P. Kruglyakov
Budker Institute of Nuclear Physics Novosibirsk (Russia)
Open Systems´2006, July 17-21, 2006, Tsukuba, Japan
(With modifications for BINP-presentation)
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
2
Fission reactor technology must recycle spent nuclear fuel and minimize its high level waste (HLW) !
Introduction (1/3)
: Partitioning & Transmutation !
Main problem on long time scale. HLW repository problem !
Goal: To transmutate radio-isotopes in short-lived or stable isotopes by neutron reactions.
Japan (JAEA): „OMEGA“
UraniumU-235: 3-5%U-238: 95-97%
Burn-up Spent nuclear fuel
U: 95.5%
+ TRU isotopes• Pu: 0.9%• MA (Np, Am, Cm): 0.1%
+ Rad. FP isotopes: 0.4%
+ Stable isotopes: 3.2%
3-4 years
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
(B. Frois)
Classic glass
MA + FP
Pu + MA + FP
FPLight glass
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Introduction (2/3) 3
Two efficient ways for transmutation of TRU´s by
neutron reactions:1) Fast reactors (“effective multiplication factor”: keff=1)
2) Sub-critical systems (keff=0.95-0.98) that are driven by an “outer” neutron source
• Advantage: More flexibility because of less stringent safety requirements !
• Requirement: Powerful neutron source !
– „Accelerator Driven Systems“ (ADS)
- Spallation neutron source„ADS“
# Suitability of the GDT n-source for a driven system?
# How does it compare with the ADS?
:
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Introduction (3/3) 4
The idea of a GDT-DS for transmutation:
GDT experimental device (BINP, Novosibirsk)
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
ADS GDT (“basic variant”)
The Neutron Sources 5
Comparison of near-term projects:
2) Energetic efficiencies PAccel. = 20 MWel PNBI = 60 MWel (!)
price [W/(n/s)]: pADS = 1.6x10-11 pGDT = 8.7x10-11 (!)
# Peculiarity of the GDT-source: SGDT = 2 x (1/2) !
1) Total intensities
p-beam: 1 GeV x 10 mA = 10 MW
Yn = 20 n/p (at Pb)
: SADS = 12.5x1017 n/s
n-power: Pn=1.56 MWDT fusion neutrons
SGDT=6.9x1017 n/s
Factor ~ 1.8
Factor ~ 5 !
# SNS (ORNL): 1 GeV x 1.4 mA, 60 Hz pulsed, 28.04.2006 – first neutrons !
Pn0.25 MW
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
# Spallation reaction: neutron yield per proton (Pb, Pb/Bi): K. van der Meer et al., Nucl. Instr. and Meth. in Phys. Res. B 217 (2004) 202-220
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
(From Yu. Tsidulko)
: Pn=
: Pinp= (el. Power)
Power losses
should be
reduced or
recovered!
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
# Features
Calculation Models (1/2) 6
p
Core
Reflector
200
150
120
100 20 14292
50
0
Hei
ght
z (c
m)
Tar
get
Bu
ffer
Voi
d
Radius r (cm)
# OECD-NEA CalculationBenchmark (1999) for anaccelerator-driven MA-burner with nominal power = 377 MW.(Developed from ALMR/PRISM)
# ADS principles
• Dedicated core: Pu & MA Fe, Pb-Bi • Coolant: Pb-Bi eutectic• Reflector: Steel, Pb-Bi• Target: Pb-Bi• Buffer: Pb-Bi
32% , 68%!!!
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Cz
r
Bz
r
Calculation Models (2/2) 7
A
# Geometric systems:
„ADS“ „GDT-DS“ „GDT-DS+B“
# “External” neutron sources:
Spallation spectrum in „GDT-DS“„MIXED“
z
r
Spallation source
DT fusion source – cylinder:Radius: 10 cm
Height: 50 cm
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Neutron Transport Calculations (1/5) 8
• Neutron transport code: MCNP-4C2
• Nuclear data from: JENDL-3.3 (NDC of JAEA)
Tools:
Two types of transport calculations:
• Reactor criticality calculation (without external source) keff
• With external sources
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Neutron Transport Calculations (2/5) 9
Geometry system
´Reactor´ Driven Systems
keff Meff MS hfis / MeV rn,2n
A 0.95856 23.1 ADS 21.5 1316 0.088
B 0.95008 19.0GDT-DS 34.7 2119 1.20
C 0.95817 22.9 GDT-DS+B 44.4 2710 1.73
Calculated integral parameters (per source neutron):
Spall. Sp. 17.5 1070 0.065
Effective multiplicity: Meff=keff/(1-keff)
# Positive feature of 14 MeV neutrons:High probability of n,2n reactions at Pb and Bi !But: No effect at Na !
# 0.95 < keff < 0.96 ! (1999)Bz
r
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
total
n,2n
n,3nn,
10 MeV
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Neutron Transport Calculations (3/5) 10
Flux distributions (per source neutron):
0.E+00
2.E-03
4.E-03
6.E-03
8.E-03
20 30 40 50 60 70 80 90 100
Radius (cm)
Flu
x (n
/(s
cm2 ))
ADS GDT-DS GDT-DS+B ´Reactor´
Total Flux: Radial dependence in core
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Neutron Transport Calculations (4/5) 11
Flux distributions (per source neutron):
0
1
2
3
50 100 150Height z (cm)
Pow
er p
eak
fact
or
ADS GDT-DS+B ´Reactor´
Power peak factor over height at r=21 cm
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Neutron Transport Calculations (5/5) 12
Flux distributions (per source neutron):
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02
Energy (MeV)
Gro
up fl
ux (n
orm
aliz
ed)
ADS GDT-DS GDT-DS+B ´Reactor´
Spectra of energy group fluxes at r=21 cm
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
The MA-burners (1/2) 13
Calculated integral parameters:
Parameter ADS GDT-DS/2* GDT-DS+B/2*
S (1017 n/s) 12.5 3.45 3.45
Pfis (MW) 263 117 150
Nominal Power
377 MW:
1) S´ (1017 n/s) 17.9 11.1 8.67
2) k´eff 0.9707 0.9840 0.9829
* One MA-burner on each side !
x ~1.5!
Today: 0.96 < keff < 0.98 !
0.95817
Q=5.2 Q=2
efffis MSP
0.950080.95856keff:
! 2.5~ x
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
The MA-burners (2/2) 14
2.0E+124.0E+126.0E+128.0E+121.0E+131.2E+131.4E+131.6E+132030405060708090100Radius (cm)Flux (n/cm2 /s) ADSGDT-DSGDT-DS+B/2Reactor
2.0E+12
4.0E+12
6.0E+12
8.0E+12
1.0E+13
1.2E+13
1.4E+13
1.6E+13
20 30 40 50 60 70 80 90 100
Radius (cm)
Flux
(n/
cm2 /s
)
ADS GDT-DS/2 GDT-DS+B/2 ´Reactor´
Radial flux distribution (at nominal power):
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Tritium breeding 14a
T-breedingmodule
# T-breeding module:– ITER inboard module,
– He cooled pebble bed(Be and breeder pebble beds,breeder: Li4SiO4 with 40% Li-6)
– FZKA 6763 (FZ Karlsruhe, 2003)
– 6Li + n 4He + 3H + 4.8 MeV
Result:
355.3 g tritium / f.p. year !
(„basic variant“, sum of both sides)
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Conclusions (1/2) 15
(1) Energetic price of the neutron emission intensities: pGDT 5 x pADS !!!
(2) ADS and GDT neutron source projects do not supply sufficiently high source intensities to operate the MA- burner at nominal power. For that are necessary:
SADS: x ~1.5 SGDT: x ~2.5 (for 2 burners !)
(3) Alternatively, one has to redesign the MA-burner so that for ADS: keff 0.97 for GDT: keff 0.98. !!!
(4) Fusion source neutrons generate a substantially higher fission power in the core by n,2n reactions at the nuclei of the Pb-Bi coolant!
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Conclusions (2/2) 16
(5) The power multiplication factor Q of the driven MA-burners:
QADS 2.6 x QGDT-DS !
(6) For the same power of the driven MA-burners one can expect:
[MA-burning rate]ADS [MA-burning rate]GDT-DS
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
1) Energetic efficiency must be increased!
# The Q-factor must be comparable with that of ADS!
# Increase of Te is the key issue:
Te = 0.75 keV Te 2.25 keV !
inp
effe
inp
fis
P
M)S(T
P
PQ
2) „Next Step“ with a modified MA-burner: Project „π“
# MA-burner*: k*eff=0.98, P*th=500 MW
GDT-NS*: S*=10.8x1017 n/s (P*n=2.5 MW)
instead of: S= 6.9x1017 n/s (Pn=1.56 MW)
by: Te=0.75 keV T*e1.25 keV !
As goal for the GDT neutron source project:
~60%
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
# Pinj=60 MW (el.), Einj=65 keV
2
0.75
„Basic variant“ + 2 burners=
~1.25
3.142 x 500-MW-burners*, k*eff=0.98
Q
5.2
~2.25
2 x 377-MW-burners
Diagram from Yu. Tsidulko
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
Thank you!
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
1) Source strength (neutron power):
# MA-burner: keff=0.98, Pth=500 MW
GDT-NS: S=10.8x1017 n/s (Pn=2.5 MW)
instead of: S= 6.9x1017 n/s (Pn=1.56 MW)
As goal for the GDT neutron source project:
2) Energetic efficiency:
# The Q-factor must be comparable with that of ADS!
# Increase of the electron temperature is the key issue:
Te=0.75 keV Te=2.25 keV !
~60%
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
# Transmutation of 99Tc using neutron capture:R. Klapisch, Europhysics News, Vol. 31 No. 6 (2000); (Proposed by C. Rubbia)
„Adiabatic resonancecrossing“
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
# Flux spectra of the MA-burner and of FR PHENIX:
[104<--------->4x106]
Fast Neutronspectrum
(Na cooled)
From: G. Alberti et al., NSE 146, 13-50 (2004)
„Fast systems“
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
: At high neutron energies (En>0.5 MeV) fission dominates over capture !
FR
FR
FR
FR
# σc and σfis for important TRUs:
E (eV) 104 105 106 107
From: D. Westlen, RIT Stockholm (2001)
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
α – probability of capture
# Advantage of fast neutron spectra for MA-burning:Originally from C. Rubbia
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
„Energy amplifier“ proposed by C. Rubbia (1993):
• Accelerator ↓particle beam↓
• Target↓neutrons↓
• Sub-critical system (arrangement of nuclear fuel)
↓Strong neutron field inside the
whole volume of the fuel systemby means of fissions !
Release ofnuclear energy
Transmutation of nuclear waste !
(protons)
(heavy metal)(spallation)
# Principles of an ADS:
Institute of Safety Research Member Institution of the Scientific Association Gottfried Wilhelm Leibniz
# Schematic view of a lead-cooled Fast Reactor (pool-type):
• Core without external neutron source
• Power control by absorber rods
• Is one of 3 Fast Reactors among 6 reactor types
considered in the GENERATION IV -
International - Forum.