1. Comparison of deterministic and Monte Carlo sensitivity analysis including SAD/SED Ivo Kodeli, SG39 Meeting, NEA, Dec. 4, 2015

2.  eff sensitivity comparison SUSD3D/SERPENT SG39, NEA, Dec. 4, 2015

3.  eff sensitivity SUSD3D/SERPENT

5.  eff SAD sensitivity SUSD3D/SERPENT

6. SNEAK-7A & -7B sensitivity code benchmark exercise (UAM project) SG39, NEA, Dec. 4, 2015

7. V. Mastrangelo, I. Kodeli, E. Sartori, Proposal of a Benchmark for Stochastic and Deterministic Analyses of Nuclear Data Sensitivities and Uncertainties, UAM Workshop, Pisa, April 2006 Fast reactor benchmarks SNEAK-7A & 7B (Karlsruhe Fast Critical Facility), re-evaluated using detailed 3-D models in the framework of the International Reactor Physics Benchmark Experiments (IRPhE) project, were proposed to test and compare state-of-the-art cross section sensitivity and uncertainty codes. Reference: NEA/NSC/DOC(2006)1 March 2009 Edition – IRPhE Handbook (Evgeny Ivanov, IRSN, CNAM, IPN) http://irphep.inl.gov/handbook/hbrequest.shtml  Calculate the sensitivity of k eff and  eff to the nuclear cross sections and the corresponding uncertainties.  Compare and analyse results from different methods and codes for consistency and identify and explain discrepancies. SG39, NEA, Dec. 4, 2015

8. SNEAK-7A and -7B fast critical experiments (detailed&simplified 3D models). SNEAK-7A core unit cell consisted of one PuO 2 -UO 2 pellet (26,6% PuO 2 and 73,4% UO 2 ) and one graphite platelet. Radial and axial blankets were loaded with metallic depleted UO 2 plates. In SNEAK-7B the graphite platelets were replaced by U nat O 2 platelet. The effective core radii of SNEAK-7A & 7B were 28.63 cm and 37.84 cm. SG39, NEA, Dec. 4, 2015

9. Model SNEAK 7ASNEAK 7B k eff  k eff k eff  k eff 1 Detailed 3D model with stretched platelets 1.0010 (a) 0.0029 (b) 1.0016 (a) 0.0035 (b) 2 3D simplified model with homogenized core regions of fuel elements 0.9998 (c) 0.00291.0001 (c) 0.0035 3 RZ two-dimensional model 1.0038 (c) 0.00291.0028 (c) 0.0035 (a) Measured k eff. (b) Combined experimental uncertainty (c) Equal to experimental value + (calculated simplified model – calculated more detailed model) SNEAK 7ASNEAK 7B  eff - 252 Cf source measurements 0.00395 ± 5%0.00429 ± 5%  eff – noise analysis 0.00413±6%0.00450±6%  eff – benchmark values 0.00395±5% 0.00429±6% SG39, NEA, Dec. 4, 2015

10. Contributed solutions Winfried Zwermann: XSUSA Manuele Aufiero: SERPENT2 GPT extended Victor Mastrangelo/W. Zwermann: TSUNAMI 3D Yannick Peneliau, Cyrille De Saint Jean: PARIS & ERANOS Evgeny Ivanov: MCNP6 Ivo Kodeli: SUSD3D SG39, NEA, Dec. 4, 2015

11. k eff and  eff sensitivity: Winfried Zwermann, GRS: XSUSA/TWODANT, direct perturbation method, 2D Cross sections: ENDF/B-VII Manuele Aufiero, LPSC/CNRS: SERPENT2 with extended GPT option, 2D, Cross sections: JEFF 3.1.1, probability tables Ivo Kodeli, IJS Ljubljana Neutronic and sensitivity code: SUSD3D with PARTISN/TWODANT/THREEDANT Cross sections: 33-group ENDF/B-VII.0, S 8 P 3, processed by NJOY99 2D and 3D models Evgeny Ivanov, IRSN (ongoing) MCNP6 k eff sensitivity: Victor Mastrangelo (retired from CNAM and IPN-Orsay) Neutronic and sensitivity code: TSUNAMI-3D; Cross sections: 238-group ENDF/B-VII, P 5 S 8 Yannick Peneliau, Cyrille De Saint Jean, CEA Cadarache Neutronics & sensitivity codes: ERANOS and PARIS; 2D model Cross sections: Ecco+Sn2d with JEFF 3.1.1 and ENDF/B-VII (33 groups) Sensitivities to cross-sections, total nu-bar and fission spectra Computational Methods and Procedures SG39, NEA, Dec. 4, 2015

12. SNEAK-7A & -7B (SUSD3D–TSUNAMI3D- PARIS/ERANOS-XSUSA–SERPENT-MCNP5) Model SNEAK 7ASNEAK 7B k eff - directk eff - adjointk eff - directk eff - adjoint SUSD3D (simplified 3D) 1.00659 (0.99839) SUSD3D (2D, P 5 ) 1.006911.006901.006301.00628 TSUNAMI3D (3D) 1.00848 ±8pcm 1.0120 ±400pcm 1.00666 ±2pcm 1.0019 ±100pcm SERPENT (2D) 1.00724 ±3pcm not needed MCNP6 (detailed 3D) 1.00237 ±2pcm not needed1.00330 ±1pcm not needed Measured 1.0010 ±290pcm 1.0016 ±350pcm SG39, NEA, Dec. 4, 2015

14. SNEAK-7A SAD/SED Sensitivity (k-eff)

15. CONCLUSIONS Validation of beta-eff sensitivities calculated by SUSD3D and SERPENT: excellent/good agreement for Jezebel, Flattop-Pu and SNEAK-7A, including SAD/SED sensitivities. SNEAK-7A & 7B inter-comparison exercise of XS sensitivity and uncertainty codes (UAM project). Several solutions were received using deterministic and stochastic codes (SUSD3D, XSUSA, SERPENT, ERANOS, PARIS, TSUNAMI, MCNP6), different modelisation of the geometry (2D/3D). Good consistency between the sensitivities, both integral values and sensitivity profiles. Constrained PFNS sensitivity depends on spectra used, unconstrained should be provided to be used in adjustment Berenice – in cooperation with CEA. SG39, NEA, Dec. 4, 2015

16. Analysed benchmarks from ICSBEP and IRPhE SNEAK-7A & -7B: MOX fuel reflected by metallic depleted U. Jezebel: bare sphere of 239 Pu metal, 6.385-cm radius Skidoo (Jezebel-23): bare ~98.1% 233 U sphere; Popsy (Flattop-Pu): ~20-cm natural U reflected 239 Pu sphere; Topsy (Flattop-25): ~20-cm natural U reflected 235 U sphere; Flattop-23: ~20-cm natural U reflected 233 U sphere; Big Ten: 10% enriched U with U-reflector, cylinder r=41.91cm, h=96.428cm; ZPPR-9: MOX core with sodium cooling, depleted U blanket. -I. Kodeli, Sensitivity and uncertainty in the effective delayed neutron fraction (β eff ), Nuclear Instruments and Methods in Physics Research A 715 (2013)70-78 WPEC SG39, NEA, Issy-les-Moulineaux, May 19, 2015