Total Monte Carlo and related applications of the TALYS code system Arjan Koning NRG Petten, the...
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Transcript of Total Monte Carlo and related applications of the TALYS code system Arjan Koning NRG Petten, the...
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