NEUTRON DATA

Info Day Bucharest 1

Institute for Reference Materials and Measurements (IRMM)Geel, Belgium

http://www.irmm.jrc.be http://www.jrc.cec.eu.int

NEUTRON DATA

A CHALLENGE FOR SUSTAINABLE, CLEAN ENERGY

C.Borcea


OUTLOOK

• INTRODUCTION

• NEUTRON DATA (ND): WHY AND HOW

• ND AT IRMM NP

• CONCLUSION


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


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


systematicslevel densitiesspins, parities

standards

shielding

waste Safetymargins

Higher burn-up

Temperatureeffects

sustainability

theory

Neutrondata

safety

ADS , HTR


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.


NUCLEAR ENERGY KEY ISSUES

• SAFETY (keff)

• SUSTAINABLE (BU, CLOSED CYCLE)

• WASTE (P&T)

• NONPROLIFERATION


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


WASTE PROCESSING: P&T

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


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


57Fe(n,np)56Mn

Neutron energy (MeV)

15 20

Cro

ss

se

cti

on

(m

b)

0

50

100

150EXFORIkeda et al.ENDF/B-VI JENDL-3.2JEF-2.2

this work

Example 1: large uncertainties in data files due to lack of experimental data

ILLUSTRATION

IRMM

previous knowledge

extrapolations based on previous

knowledge


61Ni(n,p)61Co

2 4 6 8 10 12 14 16 18 200

40

80

120

61Co: N=24/2.499 MeV; 6.48/-.89: D0=1.50 keV

N=11/1.682 MeV; 6.85/-.87: 0.95 N=24/2.499 MeV ; 6.85/-.75: 1.04 TALYS_0.49

Paul (1953)Cross (1963)Preiss (1960)Qaim (1977)Bahal (1984)Qaim (1984)ViennotRibansky (1985)Viennot (1991)Molla (1991)Osman (1996)Val'ter (1962)Levkovskiy (1969)IRMM

cros

s se

ctio

n (

mb

)

neutron energy (MeV)

Example 2: large uncertainties in data files due to inaccurate experimental data

ILLUSTRATION

predictions from model codes


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


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?


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


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

High-resolution neutron

cross-section data

measurements

7 MV VdG

150 MeV Electron Linac

Facilities: GELINA and VdGexclusively used for neutron production


E1

vL

T

Le-

150 MeV

n

Geel Electron Linear Accelerator GELINA:

Continuous energy spectrum,

Time-of-flight measurements

U


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


CERN TOF Facility

spallation neutron source

24 GeV protons, 3·1013 p/pulseΔt ~10 ns, frequency ~0.4 Hz

Pb target: 40 cm x 40 cm diam. + water moderator Neutron production rate:

~ 2·1016 n/pulse ~ 1016 n/s ~forward directed

fixed flight path L: 200 m~7·106 n/cm2 per pulse (2.4 s)

single user facility, En < 109 eVvery high n flux per pulseradioactive targets, rare isotopes

GELINA

electrons bremsstrahlung neutrons

0.15 GeV electrons, 7.5·1011 e- /pulse Δt = 1 ns, frequency : 800 HzU target: torus, 3 cm x 30 cm outer diam. ( + water moderator )Neutron production rate:

~ 4·1010 n/pulse~ 3·1013 n/s ~isotropic

several stations with L ~ 10 m - 400 m~3·103 - 2 n/cm2 per pulse (1.2

ms)

multi-user facility, En < 10 MeVvery high energy resolution, flux ~ 1/3 of TOF in resonance

region


Van de Graaff acceleratormonochromatic neutrons via nuclear reactions

He)n,d(T 4e.g.:

d

n

Ti/T


radiotoxic inventory

Typical radiotoxic inventory as a function of timein Sv per metric ton of heavy metal

fissionproducts


contribution from long-lived fission products

radiotoxic inventory


129I130I

130Xe

-

12.4 h

1.6 107 a

+ n

feasibility studies:capture and transmission experiments

at GELINA (collab. with CEA)

Example: long-lived fission product 129I via neutron capture:129I (1.6 107 a) + n 130I (12.4 h) 130Xe (stable)

Nuclear Waste Transmutation

stable


High Resolution Measurements on High Resolution Measurements on 9999 Tc at GELINA Tc at GELINA


A. Borella,P. Schillebeeckx

400000 425000 4500000

20

40

60

80

100 Y

exp

YENDF/B-VI

YThis Work

Ca

ptu

re Y

ield

/

mb

Neutron Energy / eV

206Pb(n,): res. shape analysis

304 resonances observed (221 in evaluated files)

E0, g up to 620 keV (before up to 200 keV ); gn up to 80 keV

Experiments at GELINA


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


1.0 1.2 1.4 1.6 1.8 2.00.00

0.05

0.10

0.15

Inel

asti

c C

ross

Sec

tio

n [

b]

Energy [MeV]

0.0

0.1

0.2

0.3

Our Data ENDF/B-VI

27Al Inelastic Neutron Scattering

E=1.0145 MeV

E=0.8438 MeV


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


207Pb(n,n’) and (n,2n) measurements

200 m FP, Gelinafast flux

8 ns FWHM TOF-resol.4 HPGE (3x 95%, 1x 80 %)

Continuous energy up to 20 MeV

High resolution at low energy

Mihailescu et al.Rudolf et al.


207Pb(n,n’)


209Bi(n,n’), Deduced total inelastic


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)


CONCLUSION

• HIGH QUALITY NEUTRON DATA ARE NECESSARY

• COMPLEMENTARITY AND COOPERATION

• MEASUREMENT-EVALUATION CYCLE

• ATRACT NEW INSTITUTIONS/PEOPLE

• COMMUNICATE!

NEUTRON DATA

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