NEUTRON DATA

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NEUTRON DATA

• A CHALLENGE FOR SUSTAINABLE, CLEAN ENERGY
• C.Borcea

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OUTLOOK

• INTRODUCTION
• NEUTRON DATA (ND) WHY AND HOW
• ND AT IRMM NP
• CONCLUSION

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INTRODUCTION

• RECENT HOT LINES IN THE NEWS
• -CHERNOBYL
• -PRICE OF CRUDE
• IMPLICATIONS
• MAKE NUCLEAR ENERGY SAFE AND CLEAN BY
• -NEW GENERATION OF REACTORS
• -WASTE PROCESSING

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NEUTRON DATA WHAT IS THAT?

• DATA CONCERNING THE CROSS SECTIONS OF NEUTRON
  INDUCED REACTIONS ON VARIOUS MATERIALS
• The neutron can
• -scatter elastically
• -scatter in-elastically (followed by ?
  emission)
• -be captured (followed by gamma end/or
  particle
• emission)
• -induce fission
• -induce a (n,xn) or a (n,cp) reaction

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NEUTRON DATA WHAT FOR?

• REACTORS OF A NEW GENERATION AND/OR ADS
• RADIOACTIVE WASTE PROCESSING
• FUSION REACTORS (ITER)
• SAFETY AND SAFEGUARDS
• MEDICINE, FORENSICS
• ELEMENT TRACING, etc.

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NUCLEAR ENERGY KEY ISSUES

• SAFETY (keff)
• SUSTAINABLE (BU, CLOSED CYCLE)
• WASTE (PT)
• NONPROLIFERATION

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NEW GENERATION REACTORS HOW?

• DESIGN OF INOVATIVE NEW REACTOR TYPES IS DONE
  ESSENTIALLY BY USING
• -PERFORMANT, STATE OF THE ART CODES FOR MONTE
  CARLO SIMULATION and
• -RELIABLE CROSS SECTION LIBRARIES WITH INFO
  CONCERNING THE DATA PRECISSION
• -BENCHMARKING

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WASTE PROCESSING PT

• Radiotoxicity of Nuclear Waste
• production of Pu and "minor actinides" (Np,
  Am,...) by "breeding" (combination of neutron
  capture and beta decay)
• production of long-lived radioactive fission
  products

Partitioning separate and recycle U,
Pu Transmutation "burn" minor actinides (by
neutron-induced fission), "transform" long-lived
fission products into short-lived or
stable isotopes (by neutron capture) requires
fast neutrons
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LIBRARIES WHAT IS THE PRESENT STATUS?

• MANY LIBRARIES, GENERALLY CONCORDANT BUT
• ZONES WHERE DATA ARE ABSENT OR LARGE (20 or
  more) UNCERTAINTIES (especially for structural
  materials but also for MA)
• REGIONS WHERE DATA ARE DISCREPANT
• CROSS SECTIONS EXIST BUT DATA PRECISSION AND
  CROSS INFLUENCE OF DIFFERENT FACTORS (SO CALLED
  COVARANCE MARIX) INSUFFICIENTLY KNOWN OR NOT
  KNOWN AT ALL

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ILLUSTRATION
Example 1 large uncertainties in data files due
to lack of experimental data
extrapolations based on previous knowledge
IRMM
previous knowledge
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ILLUSTRATION
Example 2 large uncertainties in data files due
to inaccurate experimental data
61Ni(n,p)61Co
predictions from model codes
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NEUTRON DATA HOW?

• A NEUTRON SOURCE IS MANDATORY
• THERE IS NOT AN ALL PURPOSE NEUTRON SOURCE
• SUCH FACILITIES ARE HIGH-TECH INSTALLATIONS
  USSUALLY WITH TRANS-NATIONAL ACCESS

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ILUSTRATION NEURON FACILITIES IN THE WORLD

• LOS ALAMOS
• OAK RIDGE
• JAPAN
• RUSSIA
• n_TOF (CERN)
• GELINA (IRMM)
• VdG accelerators (France, Germany, Belgium, etc.)
• HIGH-FLUX REACTORS
• FUTURE SPIRAL2?

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NEUTRON DATA FOCUS ON GELINA

• IRMM A TRADITION IN QUALITY NUCLEAR DATA
• FACILITY, CHARACTERISTICS
• CAPTURE CROSS SECTIONS
• TRANSMISSION CROSS SECTIONS
• FISSION CROSS SECTIONS
• INELASTIC AND (n,2n) CROSS SECTIONS

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Reference Laboratory for Neutron Physics

• Provide European safety authorities and
  industry with neutron data needed for
• the feasibility study of waste transmutation
  facilities and advanced systems
• the safety assessment of nuclear installations
  and the nuclear fuel cycle

7 MV VdG
150 MeV Electron Linac
High-resolution neutron cross-section
data measurements
Facilities GELINA and VdG exclusively used for
neutron production
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Geel Electron Linear Accelerator GELINA
Continuous energy spectrum, Time-of-flight
measurements
n
L
e- 150 MeV
U
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GELINA a powerful neutron source
High-energy electron accelerator
Electron-neutron conversion target

• 150 MeV electron accelerator (10 ns, 10 A)
• pulse compression to 1 ns and 100 A
• 800 bursts / s
• uranium target - mercury cooled
• 4 1010 neutrons / burst

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CERN TOF Facility spallation neutron source 24
GeV protons, 31013 p/pulse ?t 10 ns,
frequency 0.4 Hz Pb target 40 cm x 40 cm diam.
water moderator Neutron
production rate 21016 n/pulse 1016
n/s forward directed fixed flight path L
200 m 7106 n/cm2 per pulse (2.4
s) single user facility, En lt 109 eV very high
n flux per pulse radioactive targets, rare
isotopes
GELINA electrons ? bremsstrahlung ? neutrons
0.15 GeV electrons, 7.51011 e- /pulse
?t 1 ns, frequency 800 Hz U target torus,
3 cm x 30 cm outer diam. (
water moderator ) Neutron production rate
41010 n/pulse 31013 n/s isotropic several
stations with L 10 m - 400 m 3103 - 2 n/cm2
per pulse (1.2 ms) multi-user facility, En
lt 10 MeV very high energy resolution, flux
1/3 of TOF in resonance region
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Van de Graaff accelerator monochromatic neutrons
via nuclear reactions
e.g.
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radiotoxic inventory
Typical radiotoxic inventory as a function of
time in Sv per metric ton of heavy metal
fission products
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radiotoxic inventory
contribution from long-lived fission products
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Nuclear Waste Transmutation
Example long-lived fission product 129I via
neutron capture 129I (1.6 107 a) n ? 130I
(12.4 h) ? 130Xe (stable)
feasibility studies capture and transmission
experiments at GELINA (collab. with CEA)
?
n
129I
? -
130I
1.6 107 a
130Xe
12.4 h
stable
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High Resolution Measurements on 99 Tc at GELINA
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206Pb(n,g) res. shape analysis
Experiments at GELINA
304 resonances observed (221 in evaluated
files) E0, g?? up to 620 keV (before up to 200
keV ) g?n up to 80 keV
A. Borella, P. Schillebeeckx
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Inelastic scattering mechanism by which fast
neutrons lose energy energy spectrum in
accelerator driven systems (ADS) structural
materials (Al,Fe) criticality coolant
materials (Na,Pb) coolant void effect
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27Al Inelastic Neutron Scattering
Eg1.0145 MeV
Eg0.8438 MeV
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58Ni, Inelastic cross section
L. Olah, DNE, HU C. Borcea, SV, RO L.C.
Mihailescu, GH,RO IReS Strasbourg U. and TU
Vienna U. Belgrade nTOF collaboration
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207Pb(n,ng) and (n,2ng) measurements
Mihailescu et al. Rudolf et al.
200 m FP, Gelina fast flux 8 ns FWHM TOF-resol. 4
HPGE (3x 95, 1x 80 )
Continuous energy up to 20 MeV High resolution at
low energy
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207Pb(n,ng)
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209Bi(n,ng), Deduced total inelastic
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ROMANIA AND IRMM-NP UNIT

• VISITING SCIENTISTS (2 SENIOR RESEARCHERS FROM
  NIPNE-BUCHAREST AND 2 PROFESSORS FROM BUCHAREST
  UNIVERSITY)
• DNE (2 SENIOR RESEARCHERS FROM NIPNE-BUCHAREST)
• ONE PHD THESIS DONE IN IRMM (GRANT HOLDER)
• 4 POST-DOCTORAL FELLOWS (NIPNE-BUCHAREST)
• NEURON MEASUREMENTS, EVALUATIONS AND
  APPLICATIONS NEMEA-2 WORKSHOP ORGANIZED BY IRMM
  AND NIPNE AT BUCHAREST (2004)

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CONCLUSION

• HIGH QUALITY NEUTRON DATA ARE NECESSARY
• COMPLEMENTARITY AND COOPERATION
• MEASUREMENT-EVALUATION CYCLE
• ATRACT NEW INSTITUTIONS/PEOPLE
• COMMUNICATE!