1. Current Status of Spallation Product Data
V.Artisyuk, T.Sawada, M.Saito
Tokyo Institute of Technology
Research Lab. For Nucl. Reactors

2. Neutron production in ADS
Accelerated
charged particles
Spallation target
neutrons

3. Code Validation Sequence
Experiments
Bulk Target
Thin target (foils)
Integral Characteristics
Spatial Distributions
Mass Distribution of
Spallation Products
Accumulation of
Selected
Nuclides
Total Neutron Production
Heat Deposition
Radioactivity accumulation
Transport Phenomena
Nuclear Models

4. Comparison of CASCADE/OINPE and ATRAS Codes I
Experimental Model*
Activation Detectors
R=10 cm
Proton Beam
Lead Target
3µA, 1 GeV
60 cm
*Bakhmutkin S.B., et al, Measuremnts of Nuclides Produced in a Leadt Traget Irradiated by 1 GeV Protons, Sov.Journ., Atomnaya Energija, v.63, 1987, p

5. Experiment:S.Bakhmutkin et al, Sov.J. Atomic Energy, 1987, v.33
S.Takaya, V.Artisyuk, A.Stankovskii, M.Saito, Yu.Korovin,
Validation of Accelerator-Driven Transmutation Code System ATRAS,
2000 Spring Meeting of the Atomic Energy Society of Japan; O-49
Experiment:S.Bakhmutkin et al, Sov.J. Atomic Energy, 1987, v.33

6. Spallation products distribution by charge number Z
Taken from:
G.J.Russell, et al, Introduction to Spallation Physics and Spallation Target Design, Proc.Int.Conf. On Accelerator-Driven Transmutation Technologies and Applications, Las Vegas, NV, 1994, p.96
Taken from:
G.S.Bauer, Physics and technology of spallation neutron sources, Nucl.Instr.Meth. A463 (2001)
“It can be seen that, although in small quantities, most elements of the periodic table are generated in a heavy spallation target. The consequences this has on materials properties and possible reactions is not yet well explored”

7. Spallation products mass distribution
Fig.2. Residue mass production weights for p-induced reactions on a thick cylindrical natPb target (L=100 cm, R=10 cm) at 1 GeV incident energy.
Fig.1. Residue mass production cross-sections for p(1GeV)+208Pb reactions.
Taken from:
L.Donadille, et al, Impact of Various Models on the Production of Spallation Residue Yields and Target Activation, Internal Report of DSM/DAPNIA/SPhN, C.E.A. Saclay, F Gif-sur-Yvette, France (2002)

8. Mass Distribution of Spallation Products (KASCADE Code)

9. On the Status of Fission Products and Spallation Products
G.R.Keepin,
Pjysics of Nuclear Kinetics,
Addison-Wesley Publishing Co,
1965
1.0 GeV+ 208Pb
Titarnko et al, Rusiia, 1999:
About 800 nuclides identified with gamma spectrometry technique
“The measurement of some 120 fission products has now resulted in a reasonably accurate picture of the distribution of mass and cahrge in fission of the major fuels”
208Pb (208 Gev)+H
Wlazlo et al, Europe, 1999:
More than nuclides measured with magnetic spectrometry

10. Current status in getting the
Spallation Products:
Current status in getting the
Reasonably accurate picture of the distributions
What do we have now?
Picture of the distribution?
Accurate picture of the distribution?
What does it mean:
“Reasonably accurate picture of distribution”?

11. Accurate Picture of Distributions?
Comparison of the computer codes’ predictive power
<..> =Σi fi i
i -production cross-section of i-type nuclide
Computer code
Code reference
F-value
LAHET (ISABEL)
R.E.Prael and H.Lichtenstein, LA-UR (1989)
1.92
CEM2k
S.G.Mashnik, et al, Proc. 5-th Intern. Workshop on Simulating Accelerator Radiation Environments, OECD Headquarters, Paris, France, July (2000)
1.62
CASCADE
V.S.Barashenkov, et al, JINR, R , Dubna, Russia (1985)
2.18
YIELDX
R.Silberberg, et al, Astrophys. J., 501, 911 (1998)
2.76
INUCL
G.A.Lobov, et al, ITEP-91, Moscow, Russia (1983)
2.89
CASCADE/INPE
V.S.Barashenkov et al, Atomnaya Energiya, 87,283 (1999) (in Rus)
1.85

12. Code Validation * Wlazlo et al., ADTTA’99, Prague, 1999 Exp *
CASCADE/INPE
Bertini
ISABEL
Dresner
GSI
MCNPX (LAHET mode)
MCNPX (CEM mode)
MCNPX 2.5 (CEM2K improved)
* Wlazlo et al., ADTTA’99, Prague, 1999

13. Quality of cumulative yield cross-sections obtained with
CASCADE/INPE code

14. Spallation products: mass distribution and toxicity*
Fission and evaporation products
Light nuclides
Heavy nuclides *
Annual Limit on Intake (ALI) - is the annual intake of a given radionuclide by "Reference Man" which would result in either a committed effective dose equivalent of 5 rems (stochastic ALI) or a committed dose equivalent of 50 rems to an organ or tissue (non-stochastic ALI)**
3H, -decay,
ALI= 3.0 x109 Bq
99Tc, -decay,
ALI= 2.0 x107 Bq
210Po, -decay,
ALI= 2.2 x104 Bq
Rare
earths
region
** CFR.20.B - The Code of Federal
Regulations, Part 20: Standards for
Protection Against Radiation, Appendix B
Reference model
protons
Pb-Bi 1m 1m

15. Fragment of Chart of the Nuclides Containing Rare Earths20 60
100
140 40 80 Z N
152Gd
1.1x1014y
148Gd
74.6 y
154Dy
3x106y
150Gd
1.79x106y
148Sm
7.x1015y
147Sm
1.1x1011y
146Sm
1.03x108y
144Nd
2.3x1015y
143Nd
12.18
145Nd
8.30
146Nd
17.19
147Nd
10.98 d
148Nd
5.76
144Pm
363 d
145Pm
17.7 y
146Pm
5.53 y
147Pm
2.62 y
148Pm
41.29d
5.370 d
149Pm
2.212 d
145Sm
340 d
149Sm
13.8
150Sm
7.4
148Eu
54.5 d
151Eu
47.8
146Eu
4.59 d
147Eu
24.1 d
149Eu
93.1 d
150Eu
36.9 y
12.8 h
147Gd
38.06 h
151Gd
124 d
149Gd
9.28 d
148Tb
1.08 h
2.30 m
149Tb
4.118 h
4.16 m
150Tb
3.48 h
5.8 m
151Tb h
25 s
152Tb
17.5 h
4.2 m
153Tb
2.34 d
152Dy
2.38 h
153Dy
6.4 h
155Dy
9.9 h
149Dy
4.20 m
0.49 s
150Dy
7.17 m
stable
30d<T1/2<5x108y
10m<T1/2<30d
T1/2<10m
99.9% <  + 
99.9% < 

16. On Mechanism of Rare Earths’ Accumulation
Characteristics of the predecessors of RE alpha-emitters accumulated in various targets irradiated by 1.6 GeV protons
Characteristics of predecessor
Target
Tungsten
Lead
Uranium
Fragment: 146Sm
Yield (at/p)
8.310-4
2.110-4
4.310-5
<Z>
70.0
76.7
88.0
<A>
174.2
193.8
222.1
<Eexc>
342.6
582.4
1005.3
Fragment: 148Gd
3.410-3
8.810-4
8.710-5
70.5
77.6
89.5
175.2
194.3
223.9
314.1
551.3
979.2
Probability to have an excitation energies around 1 GeV (uranium case) is much less than few hundred MeV (tungsten case) needed to evaporate enough nucleons and finally produce RE isotopes. It gives an additional argument that rare earths are the final fragments of evaporation process from excited state after intranuclear cascade reaction

17. Target Design Options USA (ATW project) Lead-Bismuth
“R&D efforts proposed include the design and operation of a Lead Bismuth Eutectic”
A Report to Congress, October 1999, DOE/RW-0519
Lead-Tin eutectic (38.1Pb-61.9 Sn)
“…this alloy does not produce any serious Po or toxic daughter material”
J.PARK et al., Nucl. Eng. Des., 196 (2000)
Europe ( Energy Amplifier ): Lead
“…the use of of Bismuth or of Bismuth-Lead eutectic mixture is not considered as the main
coolant, since Bismuth via the leading single neutron capture produces sizable amounts of
Polonium which is radio-toxic…”
C.RUBBIA et al., IAEA-TECDOC-985 (1997)
JAERI (OMEGA project): Tungsten
T.TAKIZUKA et al., IAEA-TECDOC-985 (1997)
Lead-Bismuth
“A behaviour analysis of Po-210 and spallation products …will be necessary”
K.TUJIMOTO et al, Progress in Nucl. Energy, v.37

18. Key Words and Points for Comparison
Polonium
Spallation Product
Activity
Toxicity

19. stress on short-lived nuclides
Generated toxicity in p- Pb, p-W, and p-Sn interactions as a function of proton energy
stress on short-lived nuclides
Rare earth alpha emitter 148Gd (T1/2=74.6 yr) is identified as the dominating contributor into generated toxicity governed by short-lived nuclides:
in p-W (380 – 1600 MeV) and p-Pb (800 – 1600 MeV) interactions

20. stress on long-lived nuclides
Equilibrium toxicity resulted from p-Pb interaction as a function of proton energy ( associated beam current 1 mA)
stress on long-lived nuclides
Rare earth alpha emitters are identified as the most toxic long-lived nuclides

21. Time-dependent accumulation of key nuclides in bare Pb-Bi target*
Inventory (at.)
Activity (Bq)
Toxicity (ALI) *
diameter 1m, length 1 m.
Proton beam:
1 GeV, 50 mA

22. On Importance of Spallation Products’ Accumulation
ANS meeting, Washington DC, November 17-21, 2002
“ 148Gd Production Cross Section Measurements for Accelerator Target Facilities”, Karen Corzine, Eric Pitcher, Matt Devlin (L ANL), Nolan Hertel (Georgia Tech) p.542
”The activity level of 148Gd is small, but it encompasses almost two thirds of the total dose burden in the LANSCE facilities based on present yield estimates.”

23. Improvement of the models for high energy interactions is a must.
Current Status
In view of insufficient experimental data on their yield in ADS target materials, computer simulation remains to be of importance.
Computer codes reveal a large discrepancy particularly in the region of Rare Earths.
Improvement of the models for high energy interactions is a must.