International Atomic Energy Agency

Advances in Nuclear Data
RA Forrest
Ft
Nuclear Data Section
Department of Nuclear Sciences and Applications

Introduction• Nuclear Data underpin all of Nuclear
S iScienceandd TTechnology
h l• Nuclear Data include static andreaction properties of nuclides• Compilation and Evaluation• Stored in Data libraries and Databases• Distribution by Data Centres• FreelyFl available,
il bl bbutt nott cost-freetf
tot
produceR. A. Forrest, PHYSOR 2014

2International Atomic Energy Agency

Static Nuclide PropertiespS i paritySpin,itEnergy transitiontiti
H lf lif
Half-life
Mass, decay
dmode
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Static Nuclide Propertiesp• ENSDF• DDEP• LiveChart• Nuclear Data Sheets• Decay data files (JEFF, ENDF/B)• AME• NUBASE

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How Many Nuclides?
Nuclides?
• Stables (~254), Ground States, Measured,
B t
BetweenD
Drip-lines
i li• ~3500 nuclides reasonably
y well described• BUT many cases where [g.s. ↔ isomer] orJ or T½ differ in various sources• A definitive list of nuclides not available
 Produce as part of RIPL Required for new XML format (GND)

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Experimentalp
Reaction Data
• Compilation of journal papers → EXFORInternational
Network of Nuclear
Reaction Data
CentresEXFOR

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International Atomic Energy Agency

EXFOR• Details of 20,465 experiments (12,376,750
data points)• Searching and visualisation• Renormalisation
 Monitor reactions changed
 Automatic or manual• Ensures that EXFOR data remains relevant
for users

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International Atomic Energy Agency

Manual Renormalisation
Original

Corrected

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International Atomic Energy Agency

Data for 27Al(n,p)( ,p)*=Corrected
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Physicalycross sections• Cross section is a continuous curve,
producedddb
by a modeld l coded• e.g.
g EMPIRE and TALYS• Result determined by choice ofparameters (RIPL)• Evaluation = Code + Experimentalpdata• Complete = All reactions + Uncertainty• Collections
C ll ti
off evaluations
l ti= LibLibrary• e.g.
g JEFF,, JENDL,, ENDF/B/
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International Atomic Energy Agency

Data for 27Al(n,p)( ,p)Uncertainty
estimate

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International Atomic Energy Agency

Data Libraries• Traditional evaluated libraries are notcompletel t• ‘New’ approachpp((since 2008)) are the
TENDL libraries (TALYS + Expertise)• For TENDL-2013
TENDL 2013
• Incident p
particles = {{n,p,d,t,h,,}p}• 2630 Targets, Energy 0-200 MeV• Complete,Cl t iincluding
l dicovariancesi• Also includes ‘random’ libraries
R. A. Forrest, PHYSOR 201412International Atomic Energy Agency

Multiplep Libraries• The various evaluated libraries are‘diff‘differentt versions
ioff theth truth’t th’• Need to do better!
• WPEC Subgroup 40 (CIELO) uses
international collaboration → best
evaluation for 1H, 16O, 56Fe, 235,238U, 239Pu• If successful then need to consider moretargets perhaps as a Network (similar totargets,NRDC) coordinated by IAEA
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International Atomic Energy Agency

Standards• The neutron cross section standards area sett off very precisely
i l kknown crosssections that everything else is measured
relative to• Nine reactions [1H(n,n),H(n n) 3He(n,p),He(n p) 6Li(n,t),Li(n t)10B(n,)…] in particular energy ranges• Currently IAEA coordinating an updatey a series of meetings,
g expectedptobyproduce new version in 2016
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International Atomic Energy Agency

Standards10B(n,)Branching
hiratio datafrom IRMM
Geel
presented atp
IAEA Meetingin July 2013
SSee
INDC(NDS)0641
Analysis inprogresspg
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International Atomic Energy Agency

Point 1Unique
Nuclide list

CIELO
evaluations

UNIFICATION
Renormalized
experimental
data

R. A. Forrest, PHYSOR 2014

Cross
sectionStandards

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Structures and Formats• To enable data to be efficiently used
they must be stored in an agreed format• The ENDF-6 format has been used fordecades• BUT nearing the end of its life andthrough WPEC Subgroup 38 a newstructurett
isi proposed,d implementedilt d ini
XML format (GND)• Many advantages, but modernisation
costs
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International Atomic Energy Agency

Structures and Formats• ENDF-6 formats include details of theproduct nuclide – leads to inconsistency
e.g. Q-values incorrect• Use a separate product database withlinks• ENSDF and EXFOR in XML (or outputs inXML) willill allowllb
bettertt iinterconnectionttioffdata and better answers• Practically will need to run ENDF-6 andXML in parallel for several years
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International Atomic Energy Agency

RIPL• Model codes require many parameters(optical modelmodel, levels
levels, fission barriers)• Consistent set available in RIPL,
developed over 20 years at IAEA
• New CRP to improve further• Definitive list of nuclides

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International Atomic Energy Agency

Point 2
RIPL –
parameterlibrary

Range ofApplications

COMPLETENESS
GND format –stores moredata

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TENDL ‘complete’completelibraries

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Reaction connections
Data mining theEXFOR databased t businginetwork theory
J A Hirdt,J.A.
Hirdt D.A.
D A Brown
87,925 nodes
276,852 edges
Importance ofstandards

Photonuclear data
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International Atomic Energy Agency

Covariance• Connections  Correlations• Uncertainty
Ut i t as a ‘sum‘
off squares’’ isi onlyltrue if quantities are uncorrelated• Need covariance matrix to propagate
uncertainty data correctly• If quantities represented by n values
then covariance data requires ~n2• ENDF formatting only allows a subset ofcovariances to be represented
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International Atomic Energy Agency

Covariance• The form of covariance depends on how
it was produced,
produced it is not measurable
measurable, solong as it is mathematically correct thenmany versions
ioff a covarianceimatrix
i areppossible• Not [Right/Wrong] But [Useful/not Useful]• ExperimentalEit l  TheoreticalThti l Covariance
Ci• Useful covariance must be based on ALL
available data
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International Atomic Energy Agency

Uncertainty
y – 88Sr(Sr(n,p(n,p),p))88Rb,pCalculated withrandomised parameters

Large variation in existingevaluations
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International Atomic Energy Agency

Total Monte Carlo ((TMC))• TMC is a complementary approach tousing covariance matrices• Pioneered by Arjan Koning and Dimitri
Rochman [Nuc. Data Sheets 113 (2012)
2841 2934]
2841–2934]• Sample model parameters → Random
ENDF libraries
lib i → A
Applicationli ti
coded →
Multiple values of required quantity (q)→<q> +q
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International Atomic Energy Agency

GEN--IV Fast Reactor
GEN• Vary the 23Na data and look at thevariation of the Sodium Void Coefficient• 800 MCNP runs
• Difficult because finding difference
between 2 values (with and without Na)• Vary 238U data and look at variation ofinventories of actinides• 250 FISPACT runs

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International Atomic Energy Agency

TMC results

Variation in finalquantities based onvariation in nuclear dataR. A. Forrest, PHYSOR 2014

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Point 3
Correlation
Covariance

Relativemeasurements

CONNECTIONSAll data inXML

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Networkscollaboration

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Validation• Comparison of library data withexperiment typically for a well definedexperiment,
object – integral data
• Results in well defined neutron spectra• What can be done when no experiments?

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International Atomic Energy Agency

Automatic Validation

Thanks:a s: Arjan
ja Koningo g

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Nuclear data cycle
yMeasurements

Needs
Applications

BBenchmarking
hki

EXFOR

Model codes
DATA
LIBRARIES

Processing

RIPL

Evaluations

Formatted file
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International Atomic Energy Agency

Point 4
High quality
Model codes

High quality
measurements

CORRECTNESS
Validation
Benchmarking

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Appropriate
processing →Application
libraries
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Nuclear data needs
Unification

C
CorrectnesstResources= Funding +People

C
Completenessl tConnections
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International Atomic Energy Agency

Data Centres• Collaboration is carried out in Networks
such as NRDC and NSDD
• For NRDC the Core Centres are:
 US National Nuclear Data Center OECD NEA Data Bank
 IAEA Nuclear Data Section
 Russian
R iNuclear
N lData
D t CenterC t• Work is much appreciatedpp((Reviews),),
BUT continued funding essential
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International Atomic Energy Agency

www--nds.iaea.org
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International Atomic Energy Agency

Conclusions• Exciting time
 CIELO evaluations
 New standards and libraries
 New XML formats• Networks and Data Centres working well
• BUT changes to collaboration andformats must be adequately funded• Users must appreciate importance ofNuclear Data – Support (Pay)R. A. Forrest, PHYSOR 201436

International Atomic Energy Agency

Thank you!

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International Atomic Energy Agency