Total Monte Carlo and related applications of the TALYS code system
Arjan Koning
NRG Petten, the Netherlands
Technical Meeting on Neutron Cross-Section Covariances
September 27-30 2010, IAEA, Vienna
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Contents
• Introduction: TALYS code system• Implications and possibilities:
- Large scale nuclear data library production (TENDL)- “Total” Monte Carlo uncertainty propagation- Random search for the best data library
• Conclusions
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TALYS code system
A loop over nuclear physics, data libraries, processing and applications:
• Resonance parameters + uncertainties• An EXFOR database with more uncertainties than errors • The TALYS code • The Reference Input Parameter Library (RIPL)• Software for remaining reaction types (nubar, fns + unc.)• For many nuclides: A set of adjusted model parameters +
uncertainties + “non-physical evaluation actions”• All major world libraries• The ENDF-6 formatting code TEFAL• NJOY, MCNP(X) + other codes• A script that drives everything
The secret: Insist on absolute reproducibility
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ResonanceParameters
.TARES
Experimental data
(EXFOR)
Nucl. model parameters TALYS
TEFAL
Output
Output
ENDFGen. purpose
file
ENDF/EAFActiv. file
NJOY
PROC.CODE
MCNP
FIS-PACT
Nuclear data scheme + covariances
-K-eff
-Neutron flux
-Etc.
-activation
- transmutation
Determ.code
Other(ORIGEN)
+Uncertainties
+Uncertainties
+Covariances
+Covariances +Covariances
+(Co)variances
+Covariances
+Covariances
TASMAN
Monte Carlo: 1000 TALYS runs
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Uncertainties for Cu isotopes
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Application 1: TENDL
TALYS Evaluated Nuclear Data Library, www.talys.eu/tendl2009
• n, p, d, t ,h, a and g libraries in ENDF-6 format • 2400 nuclides (all with lifetime > 1 sec.) up to 200 MeV• Neutrons: complete covariance data (MF31-MF35)• MCNP-libraries (n,p and d) and multi-group covariances (n only)• Production time: 2 months (40 processors)Strategy:• Always ensure completeness, global improvement in 2010, 2011.. • Extra effort for important nuclides, especially when high precision
is required (e.g. actinides): adjusted parameters (data fitting). These input files per nuclide are stored for future use.
• All libraries are always reproducible from scratch• The ENDF-6 libraries are created, not manually touched• Zeroing in on the truth for the whole nuclide chart at once
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TENDL: Complete ENDF-6 data libraries
MF1: description and average fission quantitiesMF2: resonance dataMF3: cross sectionsMF4: angular distributionsMF5: energy spectraMF6: double-differential spectra, particle yields and residual productsMF8-10: isomeric cross sections and ratiosMF12-15: gamma yields, spectra and angular distributionsMF31: covariances of average fission quantities (TENDL-2010)MF32: covariances of resonance parametersMF33: covariances of cross sectionsMF34: covariances of angular distributionsMF35: covariances of fission neutron spectra (TENDL-2010) and
particle spectra (TENDL-2011)MF40: covariances of isomeric data (TENDL-2011)
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IAEA covariance visualisation system (V. Zerkin)
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Application 2: “Total” Monte Carlo
• Propagating covariance data is an approximation of true uncertainty propagation (especially regarding ENDF-6 format limitations)
• Covariance data requires extra processing and “satellite software” for application codes
• Alternative: Create an ENDF-6 file for each random sample and finish the entire physics-to-application loop. (Koning and Rochman, Ann Nuc En 35, 2024 (2008)
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ResonanceParameters
.TARES
Experimental data
(EXFOR)
Nucl. model parameters TALYS
TEFAL
Output
Output
ENDFGen. purpose
file
ENDF/EAFActiv. file
NJOY
PROC.CODE
MCNP
FIS-PACT
Nuclear data scheme + covariances
-K-eff
-Neutron flux
-Etc.
-activation
- transmutation
Determ.code
Other(ORIGEN)
+Uncertainties
+Uncertainties
+Covariances
+Covariances +Covariances
+(Co)variances
+Covariances
+Covariances
TASMAN
Monte Carlo: 1000 TALYS runs
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ResonanceParameters
.TARES
Experimental data
(EXFOR)
Nucl. model parameters TALYS
TEFAL
Output
Output
ENDFGen. purpose
file
ENDF/EAFActiv. file
NJOY
PROC.CODE
MCNP
FIS-PACT
Nuclear data scheme: Total Monte Carlo
-K-eff
-Neutron flux
-Etc.
- activation
- transmutation
Determ.code
Othercodes
+Uncertainties
+Uncertainties
+Covariances
+Covariances
TASMAN Monte Carlo: 1000 runs of all codes
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Application: criticality benchmarks
Total of 60000 random ENDF-6 files
Sometimes deviation from Gaussian shape
Rochman, Koning, van der MarckAnn Nuc En 36, 810 (2009)
Yields uncertainties on benchmarks
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Covariance versus Total Monte Carlo
Advantages: Advantages:- Relatively quick - Exact- Use in sensitivity study - Requires only “main” software- Easier release (TENDL)Disadvantages: Disadvantages:- Approximative (cross-correlations) - (Computer) time consuming- No covariance for gamma production, - Backward (sensitivity) route DDX (MF36), etc. not obvious- Requires special processing- Requires covariance software for application codes
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Application: SFR void coefficient
• KALIMER-600 Sodium Fast Reactor (Korea)
• Total Monte Carlo with MCNP and FISPACT
• Uncertainties due to transport libraries only, but for all materials
• Sensitivity profiles with MCNP
• K-eff, void coefficient, burn-up and radiotoxicity using TMC
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The total uncertainty is underestimated. Uncertainties for:• Activation cross sections• Fission yield data• Decay dataAre not (yet) taken into account.
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TMC: Other possibilities
• Random thermal scattering data libraries (?)
• Random decay data libraries
• Random fission yield libraries
• Normalization to experimental data or other nuclear data libraries at the basic input level (TENDL-2010)
• Optimization to integral benchmarks using e.g. simulated annealing (“search for the best random file”)
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Optimization of Pu-239
• Select 120 ICSBEP benchmarks
• Create 630 random Pu-239 libraries, all within, or closely around, the uncertainty bands
• Do a total of 120 x 630 =75600 MCNP criticality calculations
• Do another 120 x 4 calculations:
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Optimization of Pu-239
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Optimization of Pu-239
• 6% of libraries have lower chi-2 than JEFF-3.1
• Library #307 has the lowest
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Conclusions
• To improve evaluated libraries, TMC is an easier tool than covariances + perturbation + sensitivity
• However, the world wants covariances, and they get covariances (TENDL)
• With a reproducible automated system, almost anything is possible. After some years of serious software development we can now fork into various branches:- TALYS Evaluated Nuclear Data Library (TENDL)
including complete covariance data (MF31-35)- Total Monte Carlo uncertainty propagation- Nuclear data library optimization- Other applications (not discussed here)
The results of all improvements in uncertainly handling (UMC, model uncertainties, etc.) will be directly visible
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