status and needs of activation data for fusion robin forrest 1 and jura kopecky 2 1 euratom/ukaea...
TRANSCRIPT
Status and needs of activation data for fusion
Robin Forrest1 and Jura Kopecky2
1 Euratom/UKAEA Fusion AssociationCulham Science Centre, UK
2 JUKO Research, Alkmaar, The Netherlands
This work, supported by the European Communities under the contract of Association between EURATOM/UKAEA, was carried out within the framework of EFDA
OutlineOutlineIntroduction - activation dataEAF data libraries, used in JEFF and FENDLEAF-2007
Suitable for ITER, IFMIF Contents
Validation and testing EXFOR Integral data SACS
Which nuclides and reactions are important?Importance diagramsUncertainty dataDecay dataNeedsQuestions
IntroductionIntroduction
Fusion technology requires good nuclear data for activation calculations
Addressed in Europe by EAF and for ITER by FENDLWhat about needs for IFMIF?Focus is on cross sections, but also need decay dataUncertainty data also needed, what form should these
be, are covariances required?‘Issues’ to do with formats for E > 20 MeVCan subsets of important nuclei and reactions be
defined?How are data validated and tested?Are new data libraries required or should existing ones
be extended and improved?
EAF data librariesEAF data librariesLong history of EAF libraries (> 20 years)Becoming larger and more comprehensivePart of an activation ‘package’ (EASY)EAF-2003 is the recommended FENDL/A-2.1 and JEFF-
3.1/A special purpose filesSince then:
EAF-2005 (60 MeV)EAF-2005.1 (60 MeV, d-induced)EAF-2007 (60 MeV, d-induced, p-induced)
EAF contains (simple) uncertainty data for all n-induced reactions
Decay data (consistent with cross sections)DocumentationValidation reports
EAF-2007EAF-2007
Distributed beginning 2007Builds on EAF-2005.1Details:
65,565 n-induced reactions (10-5 eV - 60 MeV) Isotopes with T½ > 6 hours as targets
66,864 d-induced reactions67,925 p-induced reactionsDecay data for 2,231 nuclidesUncertainty data for all n-induced reactionsPart of EASY-2007
Documentation available on web site (http://fusion.org.uk/easy2007/)
Cross section data > 20 MeV and d- and p- induced data suitable for IFMIF
Validating and testing EAF librariesValidating and testing EAF libraries
Consider only the n-induced data in EAF-2007Huge number (65,565) of reactionsAll methods of testing are built into SAFEPAQ-IICompare with EXFOR (~1,700 reactions)Compare to integral data (~ 450 reactions)Only a small fraction of library can be compared to exp.Statistical Analysis of Cross Sections (SACS) method
Look at all reactions for each reaction typeUses various statistics in scatter plotsTrend lines, identify outliersUsed to test reactions with no experimental data
Integral measurementsIntegral measurements
Existing methods of comparison of activation measurements
with calculations proceed as follows:Measure amount of activity by detector, assign it to particular
daughter nuclidesCalculate with an inventory code the predicted activity using
the correct materials, irradiation history and neutron spectrumAt a time where a radionuclide dominates calculate C/E for the
activityPresent C/E for a range of radionuclides
This can only be done once a data library exists to provide input to the code
EASY methodEASY methodAs before measure amount of activity by detector, run
inventory code and calculate (C/E)activity
Use the FISPACT pathways method to determine the
pathways that are responsible for the production of each
radionuclideIf one pathway is responsible (can be extended) then find
the value of the library cross section averaged in the neutron spectrum (C)
Find E = C / (C/E)activity this is the measured value of the effective cross section
E is input into SAFEPAQ-II in the same way as other experimental data
During the development of the next data library the preliminary data can be adjusted using the integral data
8989Y(n,2n)Y(n,2n)8888Y – integral (EAF-2005)Y – integral (EAF-2005)Integral C/E for Y-89(n,2n)Y-88
C/E
Neutron Spectrum
C/E = 0.8621
C/E = 1.1112
C/E = 1.0259
C/E = 1.1378
C/E = 1.4887
1.10
0.91
0.80
1.00
1.20
1.40
1.60
fns_7hour fns_5min fng_Y tud_Y rez_DF
New data
Ignore?
Y-89(n,2n)Y-88
Final
Cro
ss s
ection (
b)
Energy (eV)
0.0E+00
3.0E-01
6.0E-01
9.0E-01
1.2E+00
1.5E+00
1.0E+07 2.0E+07 3.0E+07 4.0E+07 5.0E+07 6.0E+07
SystmPAT79RI 99KGU00LAS75KYU79MOH84ANL87BRC81LAS75KOS81FEI89FEI89SAV98BRC02RI 99LAS75AUB76JAE93LAS77AEP89
8989Y(n,2n)Y(n,2n)8888Y – differentialY – differential
Region probed by rez_DF
Remains validated
Integral C/E for W-182(n,p)Ta-182C
/E
Neutron Spectrum
C/E = 1.0621
C/E = 0.8521
C/E = 1.0667
C/E = 1.2081 C/E = 1.2009
C/E = 0.1542
C/E = 1.3182
1.20
0.83
0.00
0.50
1.00
1.50
sneg_1 sneg_1 fzk_ss316
fng_tung.asc sneg_2 fzk_2 rez_DF
182182W(n,p)W(n,p)182182Ta - integralTa - integral (EAF-2007 prelim) (EAF-2007 prelim)
Ignore?
New data
W-182(n,p)Ta-182
Final
Cro
ss s
ectio
n (b
)
Energy (eV)
0.0E+00
5.0E-03
1.0E-02
1.5E-02
2.0E-02
2.5E-02
0.0E+00 1.0E+07 2.0E+07 3.0E+07 4.0E+07 5.0E+07 6.0E+07
SystmSys20RI 03RI 03KOS93JUL75 gJUL75 nLRL59LNZ97NAG92 nRI 03RI 03 n
182182W(n,p)W(n,p)182182Ta - differential Ta - differential (EAF-2007 prelim) (EAF-2007 prelim)
Remains validated (as sum)
Region probed by fzk_ss316 & rez_DF
Testing large activation libraries – EAF-2007Testing large activation libraries – EAF-2007
65,565 reactions
448 reactions with integral data
1,715 reactions with differential or integral data
How to test?
Statistical analysis of cross sections (SACS)Statistical analysis of cross sections (SACS)
Systematics show that measured cross sections at particular energies have a good correlation with parameters such as A or s = (N - Z) / A
Work on maximum cross sections by Manokhin for (n,2n) shows similar trend
Such data easily extracted from EAF-2007 or one of the data sources and displayed as scatter plot against A, Z or s
Trend lines can be added and reactions discrepant from the trend identified
Ti-50(n,2n)Ti-49
Final
Cro
ss s
ectio
n (b
)
Energy (eV)
0.0E+00
2.0E-01
4.0E-01
6.0E-01
8.0E-01
1.0E+00
1.0E+07 2.0E+07 3.0E+07 4.0E+07 5.0E+07 6.0E+07
Definition of statisticsDefinition of statistics
max
Emax
½
EAF-2005.1 – EAF-2005.1 – maxmax((ss) for (n,p)) for (n,p)(n,p) for Final
Max
cro
ss s
ectio
n (b
)
Asymmetry (s)
1E-03
1E+01
1E-02
1E-01
1E+00
0.00 0.05 0.10 0.15 0.20 0.25
Trend line
Discrepant reactions
(n,p) for FinalNO A<20
Max
cro
ss s
ectio
n (b
)
Asymmetry (s)
1E-03
1E+01
1E-02
1E-01
1E+00
0.00 0.05 0.10 0.15 0.20 0.25
EAF-2007 – EAF-2007 – maxmax((ss) for (n,p)) for (n,p)
Improvement
(n,p) for FinalScore = 0 Score > 0
Wid
th a
t ha
lf-m
ax X
S (
eV)
Asymmetry (s)
0E+00
1E+07
2E+07
3E+07
4E+07
5E+07
0.00 0.05 0.10 0.15 0.20 0.25
EAF-2007 – EAF-2007 – ½½((ss) for (n,p)) for (n,p)
Backed by exp
10 MeV
30 MeV
(n,a) for Final
Wid
th a
t ha
lf-m
ax X
S (
eV)
Asymmetry (s)
0E+00
1E+07
2E+07
3E+07
0.00 0.05 0.10 0.15 0.20 0.25
EAF-2007 – EAF-2007 – ½½((ss) for (n,) for (n,))
Trend
Outlier
(n,2n) for FinalNot important Important
Max
cro
ss s
ectio
n (b
)
Asymmetry (s)
1E-02
1E+01
1E-01
1E+00
0.00 0.05 0.10 0.15 0.20 0.25
EAF-2007 – EAF-2007 – maxmax((ss) for (n,2n) new options) for (n,2n) new options
Can display reactions that are ‘important’ (based on EAF-2003 analysis)
(n,g) for FinalEven Z Odd Z
Cro
ss s
ectio
n: 3
0.0
keV
(b)
aU
1E-05
1E+01
1E-04
1E-03
1E-02
1E-01
1E+00
0 25 50 75 100 125 150 175 200
EAF-2007 – EAF-2007 – 330keV0keV((aUaU) for (n,) for (n,))
Odd and Even Z targets New systematic?
Importance diagramsImportance diagrams
A neutron spectrum needed for activation calculationsFISPACT output files contain a large amount of dataHow to summarize – ideally as a picture?Importance diagrams give a picture of the dominant nuclides
for all neutron energies and all decay timesThey are largely independent of the neutron fluxSet of activation calculations for mono-energetic neutronsIdentify dominant nuclides for a quantity e.g. activityFind regions in (decay time, energy) space where a nuclide
contributes more than 50%Now able to cover energy < 60 MeV
Dose rate importance diagram for CuDose rate importance diagram for Cu
Zn-65 contributes > 50%
E > 20 MeV new. New dominant nuclides?
Heat output importance diagram for CrHeat output importance diagram for Cr
52V produced by 50Cr(n,)51Cr()51V(n,)52V
52V produced by 52Cr(n,p)52V and 53Cr(n,d)52V
Importance diagramsImportance diagrams
Diagrams for all elements (EAF-2003) in ‘Activation Handbook’ (544 pages)
Analysis shows:754 of the 1,917 nuclides describes activation properties of all
elements < 20 MeV1,314 of the 12,617 reactions needed for all dominant nuclidesAllows focus on important nuclides and reactions
Currently updating with EAF-2007 dataEnergy now includes 20 – 55 MeVSearch for new dominant nuclidesIdentification of important reactionsThis allows a focus on the most relevant nuclides and
reactions hence the most significant improvement in data
Importance diagrams for EAF-2007Importance diagrams for EAF-2007New primary nuclides are seen for E > 20 MeV
For V: 48V, 44Sc and 40K So far data for H – Xe analysed
15 new primary nuclides109 new secondary nuclidesSome swapping of primary ↔ secondary
New primary nuclides 7Be, 11C, 48Ca, 50Cr, 66Ga, 72As, 76Br, 82mRb, 86Y, 108Cd, 114Cd,
109Sn, 124Sn, 124I and 124Xe‘Exotic’ reactions seen for E > 20 MeV
54Fe(n,d)49V in pathways → 39Ar, 42Ar and 44Sc18% of 39Ar formed has 54Fe(n,d)49V as first step
For Fe irradiationEAF-2003, 3 reactions on 54FeEAF-2007, 10 reactions on 54Fe
Uncertainty in EAFUncertainty in EAF
Only for n-induced data2 – 4 variance values per reactionNo covariance dataAlso use T½
Can be used by FISPACT → uncertainty on activity etcPlans to extend this in future (using calculated uncertainties
from TALYS by varying parameters)Are covariances needed?Large extension to FISPACT so covariances could be usedNo data for d- and p-induced librariesAt present no JEFF/A or FENDL/A data
Decay dataDecay data
Decay data for all nuclides produced in reactions/decays needed for activation calculations
Ongoing work in evaluation of fusion relevant nuclidesResults → JEFF and EAFCarried out by Serco (Alan Nichols)Currently 21 nuclides are being evaluated:45mSc, 70Ga, 71Ge, 75Ge, 75mGe, 79Se, 90Y, 90mY, 90Nb, 90mNb,
98Tc, 113Cd, 113mCd, 121Sn, 121mSn, 166Dy, 170Tm, 176mYb, 184Re, 189mOs, 190Pt
Results will be included in EAF-2009
Format issuesFormat issues
EAF-2003 converted to ENDF format = JEFF-3.1/AThis can also be done for EAF-2007 but
What about data E > 20 MeV?At present ~ 50 ‘non-standard’ MTCould lump to total cross sectionSeveral ways of converting EAF → ENDFWhat about uncertainty data?
Development needs (activation)Development needs (activation)
Include uncertainties for d- and p-induced librariesImprove uncertainties (more groups) for n-induced libraryMore differential data especially ~ 20 MeV for nMore integral measurements > 20 MeV for nBetter model calculations for important reactions
QuestionsQuestions
Do we need a FENDL/A-3 library?EAF-2007 available, should this be recommended for a new
FENDL activation library?Should d- and p-induced data be included?Should uncertainty data be included?Should FENDL ‘add value’ by improving a subset of
reactions or uncertainty data?New measurements?Formats?What about validation?Time scale?