Uncertainty file for FENDL-3/A

1. FENDL Vienna 23-26.3.2010 Uncertainty file for FENDL-3/A J. KopeckyJUKO Research, the Netherlands

2. Scope of the presentation • Introductory remarks on EAF uncertainties (Reminder of background) • FENDL-3/A status • Conclusions

3. Remarks on EAF/FENDL uncertainties • Previous FENDL activation libraries (FENDL-1/A and FENDL-2/A) did not have any uncertainty information. • Important assumption in this action is that the coming FENDL-3/A library shall be based on one of the two last versions of EAF series, EAF-2007 or EAF-2010. • The content of the FENDL-/A uncertainty file can be adopted to the chosen content (e.g. no actinide data).

4. Remarks on EAF/FENDL uncertainties • The first uncertainty file (in the ENDF-6 MF = 33 format) was a part of EAF-3 (1992).The uncertainty values adopted correspond to the error factorf = 1 + , where  is the relative error (2 is actually stored in the file) in the cross section . In this case the best estimate of the cross section uncertainty is /f <  < f. • This file underwent many improvements and extensions during the last 18 years up to EAF-2007. They are documented in EAF manuals and were in detail discussed in two latest presentations : J. Kopecky and R.A. Forrest, Update of uncertainty file in EAF project, FENDL-3 CRP meeting, Vienna, 2-5.12. 2008 and J. Kopecky ad R.A. Forrest, Uncertainty file in EAF libraries, EAF workshop, Prague, 25-29.3.2009,

5. Threshold reactions with exp. data New consistent rules have been introduced for the determination of uncertainties for threshold reactions with experimental information. They are sensitive to the position of the experimental data on the excitation function and thus give a better representation of the adopted uncertainty with respect to the energy dependence (see next slide). A new treatment has been introduced for data with split cross-section to isomeric states, if only one of the uncertainties is known experimentally. All changes and improvements have been included in the SAFEPAQ-II uncertainty data base and have been used for processing of EAF-2010 library

6. Region = 1 D = 0.3 Region = 2 D = 0.2 Regions = 1 + 2 D = 0.2 Region = 3 D = 0.1 Region = 3 + others D = 0.1 Region = 4 D = 0.2 Region = 5 D = 0.3 Uncertainty ranges1,2 – weak arguments 3,4,(5) – strong arguments for D 3 4 2 1 5

7. Threshold reactions with exp. data • Several additional rules are applied for error factors based on TALYS validations, SACS analysis and comparison against experimental data. • If D(Eth-20 MeV) < 0.1 the value has been increased to 0.1. • If D(Eth-20 MeV) < 0.2 the value of D(20 - 60 MeV) is specially treated for excitation curves with dominant cross section part above 20 MeV. • Further the starting energy of the last energy group (20 MeV) has been made free, in order to better cover the the shape of the excitation curve. The use of C/E (integral data) for cross section improvements is added.

8. Uncertainty rangesCombination of sources smax SACS Visual estimate EXP SACS Emaxsmax D1/2x TALYS predictive power From SACS

9. Non-threshold reactions with exp. data • The major revision of the EAF-2010 uncertainty file has taken place for non-threshold reactions. This action covered all (n,g), (n,f) and a part of (n,p) and (n,a) reactions. Contrary to threshold reactions, for which the uncertainty estimates are based on educated visual comparison (empirical approach) of the cross section data against the experimental information (Score = 1-6 targets) or against the cross section systematic (Score = 0 targets), the non-threshold reaction use for two energy groups (< EH) a semi-quantitative treatment. • In this rather novel approach the experimental errors of recommended experimental markers (thermal cross sections or resonance integrals) are together with C/E values of the adopted cross section data propagated in a common uncertainty factor for these two pertinent energy regions.

10. Non-threshold reactions (Resonance integral) Resonance integral (RI) from 0.5 eV → 100 keV is a integral experimental quantity, which covers a part of 1/v, resolved resonance and unresolved regions. C/E (I) calculated from EAF data and stored in parameter database. Used together with the experimental RI error to quantify the fit of EAF data to this experimental information adopting for reactions with RI

11. Non-threshold reactions DIg or 0.5 EH EL Dexpor 0.5 20MeV (C/E,DIg)infoor > 0.5 Ds(th) 60MeV EL

12. EAF-2010 status (no exp.) • Error factors with no experimental data (based on s(14.5 MeV) systematic - These factors quantify how well the systematic of s(14.5 MeV) fits the experimental data. They are used in the generation of the uncertainty file if no experimental data are available and the adopted library data agree with s(14.5 MeV). They are assumed to be representative for the whole energy range above Eth and the conservative values are applied and are tabulated and stored in Safepaq. • Error factors f without systematic - If no cross section systematic is available, the results of graphical treatment of calculations or adopted data (e.g. SACS analysis) and the educated conservative guess of the accuracy of the calculation (upper limit) are applied. • Error factors f > 20 MeV - If no experimental data are available to estimate f, the same uncertainty is adopted as the uncertainty of the energy group just below 20 MeV.

13. Error factors EAF-2010 (no exp)

14. FENDL-3/A Uncertainty file status and Conclusions • The uncertainty file to use for FENDL-3 activation library is ready to be included. It is based on the recent uncertainty file of EAF-2010, the only uncertainty file for activation data. • For reactions supported with experimental data it includes high quality (realistic) variances, estimated visually from the data scatter around the library excitation curve or from growing data base of experimental integral validations. Semi-quantitative approach is applied for non-threshold reactions. • For reactions with no experimental data the educated conservative guess of the accuracy of the calculation (upper limits) are applied based on several testing. • The eventual modifications will depend on the choice of the data source for FENDL-3/A and its data content (chosen targets).

15. FENDL-3/A Uncertainty file status and Conclusions The starter FENDL-3/A file is ready for testing. The detailed documentation of actions and applied tools can be found in references: • RA Forrest, J Kopecky, Statistical analysis of cross sections, Fusion Eng. and Design, 82(2007) 73. • RA Forrest, J Kopecky, AJ Koning, Detailed analysis of (n,p) and (n,a) reactions in the EAF-2007 and TALYS-generated libraries, Fusion Eng. and Design, 83(2007) 614. • RA Forrest et al., Validation of EASY-2007 using integral experiments, UKAEA FUS 547 (April 2008). • RA Forrest, J Kopecky, AJ Koning, Revisions and improvements of neutron capture cross sections for EAF-2009 and validation of TALYS calculations, UKAEA FUS 546 (March 2008). • J Kopecky, Revisions and improvements of neutron uncertainty file for EAF-2010, EAF-Doc-52 (December 2009) and private communication.