wpec sub group 34 “coordinated evaluation of 239 pu in the · icsbep and irphep. for the time...

WPEC Sub group 34“Coordinated evaluation of 239Pu in the

resonance region”

Coordinator C. De Saint Jean / Monitor R. D. McKnig ht

Subgroup report

Contributions : ORNL, CEA Cadarache, IAEA

2011, May 12, NEA Headquarters

History

• Sub-group proposition by McKnight/Dunn/Chadwick on June 2009 at previous WPEC meeting

• Justification :– General discrepancies on Pu-SOL-THERMAL assemblies and

Pu-INTER assemblies– JEFF 3.1.1 thermal part– New Derrien/Leal ENDF resonance files :

• With covariances• Using new microscopic data sets

• Goal � obtain an improved 239Pu resonance evaluation :– including covariances– consistent with our fundamental cross section data, – leading to improvements in calculations of integral data

Time Schedule & Deliverables

• June, 2010 Review of SG Proposal by WPEC; initiate Subgroup activities

• From June to September 2010, Define a list of participants and corresponding activities (evaluation, benchmark, various,..)

• December 2010, Report on Benchmarks with fine analysis of sensitivities to 239Pu nuclear data files

Change in Initial Schedule • End 2011/ Beginning 2012 Preliminary revised resonance evaluation• June, 2012 Report on 239Pu fission spectra breakthrough • End 2012 Present Final Report of Subgroup activities, including :

– documentation and recommendation of a new resonance evaluation for 239Pu

– benchmark performance for Pu-fuelled thermal and intermediate energy systems with the recommended evaluation

– motivation for new 239Pu measurements, if needed.

Effective Work

• « Classical » Benchmarking :ALL Members – Define a set of public Benchmarks related to 239Pu nuclear data:

ICSBEP and IRPhEP.

For the time being �Common Benchmarks : ICSBEP 239Pu benchmark systems

Water-Reflected and bare spheres of plutonium nitrate solutionsIntermediate and fast Benchmarks will be added

ORNL/CEA– Calculations of these benchmarks with various evaluations (ENDF,

JEFF) with Monte-Carlo and Deterministic codes

Effective Work

• Feed-back Benchmarking :ORNL/CEA– Use of sensitivity analysis (combine Microscopic and

Integral experiments) to help improvement of nuclear data

• KENO/TSUNAMI/TSURFER Code at ORNL• ERANOS/SNATCH/CONRAD Code at CEA

ORNL/CEA– Calculate effects of using Maslov PNFS

Effective Work

• Evaluation :ORNL/CEA separately for time being – On going re-evaluation (CEA in progress / ORNL

advanced)– Covariance evaluations on Xs – On going work also on URR (consistency)� Two/Three weeks (full time) to test possible

convergence

Covariance Work 239Pu ORNL fission/capture estimation

Pu-239(n,f)preliminary results

Propagation of nuisance parameter uncertainties with marginalization techniques

Pu-239(n,γ)preliminary results

15 energy groups15 energy groups

Covariance Work 239Pu CEA fission/capture estimation

Benchmarking/Integral Data feed-back 239Pu Data Sensitivity and Adjustment at ORNL

� 239Pu resonance evaluation including covariance was done at ORNL� Evaluation was processed with the AMPX/PUFF code system to generate group cross sections and covariance�44-neutron group structure of the SCALE system was used� 15 ICSBEP 239Pu benchmark calculations- Thermal water reflected benchmark experiments were used� Sensitivity calculations were done with the TSUNAMI code� Data adjustments were done with the TSURFER code

ORNL 239Pu sensitivity calculations of the cross section to keff (TSUNAMI)


ORNL 239Pu data adjustment for the fifteen benchmark experiments (TSURFER)


12

�Maslov 239Pu prompt fission spectra replacement in 239Pu JEFF-3.1.1 evaluation file

• Personal communication June 2009

�ICSBEP PU-SOL-THERM 001 and Pu-MET-FAST benchmarks

• MCNP data file automatic conversion

• TRIPOLI-4 – MCNP4C3 keff calculations checks

� Calculations performed with TRIPOLI-4 Release 4.6

Benchmarking/Integral Data feed-back CEA work ��Effect Of 239Pu PNFS on Benchmarks

13

�PU-SOL-THERM 001

Water reflected 11.5 inch diameter spheres of plutonium nitrate solutions


14

�PU-MET-FAST

Bare spheres of Pu (001, 002) �

Reflected spheres of Pu (005 W, 008 Th, 009 Al, 010 U , 011 Water, 018 Be) �

Reflected arrays of Pu (012 U, 013 Cu, 014 Ni, 015 Fe ) �


Intermediate Conclusions

� Benchmark experiments sensitive to the fission, capture cross sections, nu-bar and prompt neutron fission spectrum (PNFS)

� A right combination of capture-to-fission ratio (alpha) may lead to an improvement on the keff;

�Further studies are needed using new PNFS evaluations;

Scheduled Work

� Finalize a document related to Benchmark list and calculations

� 3 weeks of intensive work between CEA/ORNL in 2011 on the evaluation itself

�New PNFS evaluations to be tested (JEFF/ENDF)

� Additional Contributions are welcomed

wpec sub group 34 “coordinated evaluation of 239 pu in the · icsbep and irphep. for the time...

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