INDEN - International Nuclear Data Evaluation Network
Network managed by the International Atomic Energy Agency

This is WORK IN PROGRESS.
The main updates to the U-235 evaluation include

• Detailed shape of the fission cross section that follows better the measured data in the unresolved resonance range and above..
• Spurious cross-reaction covariance elements between the resonance and the fast energy ranges were removed because they gave rise to negative eigenvalues.
• Cross-covariances between nu-bar and fission cross section were removed for the same reason.

Additional work was performed on the resonance analysis to improve agreement with the measurements of the fission and capture cross sections below 20 eV. This work resulted in version "zt". Note that the integral of the fission cross section from 7.8 to 11 eV in this version is higher than the recommended standard value. ST10 includes high-resolution fission evaluation data in the URR. Recommended version ST25 includes LANL evaluated nubar (above 200keV) and PFNS (above thermal), as well as changes in nubar from 40eV up to 500eV.

Data files available for downloading:

This is WORK IN PROGRESS.
Recommended Pu-239,240,241 files combined with recommended U-238 (u238e80u8V03i4) solve the burnup problem.
Updtaed Pu and U-238 evaluations lead to a similar criticality to B71 library at 50GWD/uT.

Data files available for downloading:

The main updates to the ENDF/B-VIII.0 Pu-239 evaluations (suffix "p16", "p17", "p29", "p38/p39", "p55", and "p57") include

• RRR (ORNL/IAEA/JSI led by M. Pigni): Adjustment of thermal cross sections and nubar to agree with TNC from IAEA Standards 2017.
• RRR (ORNL/IAEA/JSI led by M. Pigni): Increase of the capture-to-fission ratio near and below the first resonance of Pu-239 to decrease the criticality in high leakage PST (ATLF>0.4).
• Fast: A rigid-rotor RIPL 2408 neutron potential with extended coupling was used in EMPIRE calculations.
• Fast: New EMPIRE calculation in the fast neutron range tuned to describe ENDF/B-VIII.0 fission and capture cross section; (n,2n) well reproduced.
• Capture cross section in the fast range adopted from ENDF/B-VIII.0.
  
• p16: LANL (D. Neudecker) Pu-239 PFNS evaluation that include thermal, ChiNu and CEA data (preliminary). The thermal PFNS average energy of Eav=2.08 MeV agrees with the one of the IAEA PFNS evaluation (ENDF/B-VIII.0 value ~2.12 MeV). (n,f) from IAEA STD 2017.
• p17: IAEA Pu-239 PFNS for thermal neutrons with average energy Eav=2.08 MeV (ENDF/B-VIII.0 value ~2.12 MeV). The PFNS for neutron incident energies of 500 keV and above is taken from Talou et al evaluation (IAEA PFNS CRP). (n,f) from IAEA STD 2017.
• p29: IAEA Pu-239 PFNS for thermal neutrons with average energy Eav=2.08 MeV (ENDF/B-VIII.0 value ~2.12 MeV). The PFNS for neutron incident energies of 500 keV and above is taken from updated LANL (D. Neudecker) Pu-239 PFNS evaluation that include ChiNu and Marini CEA data (20210501). Updated GMA fit of (n,f) by Neudecker. IAEA nubar tweak.
• p38/p39: IAEA Pu-239 PFNS for thermal neutrons with average energy Eav=2.08 MeV (ENDF/B-VIII.0 value ~2.12 MeV). The PFNS for neutron incident energies of 500 keV and above is taken from updated LANL (D. Neudecker) Pu-239 PFNS evaluation that include ChiNu and Marini CEA data (20210501). Updated GMA fit of (n,f) by Neudecker. (n,2n) cross section adopted from ENDF/B-VIII.0. LANL nubar evaluation (p38 - digitized, p39 exact numbers)
• p55: (recommended) IAEA Pu-239 PFNS for thermal neutrons with average energy Eav=2.08 MeV (ENDF/B-VIII.0 value ~2.12 MeV). The PFNS for neutron incident energies of 500 keV and above is taken from updated LANL (D. Neudecker) Pu-239 PFNS evaluation that include ChiNu and Marini CEA data (20210501). Updated GMA fit of (n,f) by Neudecker. (n,2n) cross section adopted from ENDF/B-VIII.0. LANL nubar evaluation. Corrected inelastic below 80keV (Empire interpolation problem). IAEA fitted capture and n2n using GANDR with Empire model prior. Capture data derived from alpha measurements plus Mosby data.
• p57: = p55, but nubar renormalized by +0.1% from 1 up to 2 MeV to get Jezebel Keff=1.00004(3).

The p16 and p17 evaluations only differ in the PFNS used. The criticality dependence on ATLF for PST benchmarks (see SG34 report) is preserved using the new IAEA thermal PFNS combined with updated resonance parameters (ORNL/IAEA/JSI). Additional work may be required in capture cross sections above 10 eV (renormalization of Mosby et al data by 1.074). This evaluation increases a RTC (Reactivity temperature coeff) to about -1.5pcm/K; further changes in cross sections in the sub-thermal/near-thermal region may be needed. See unpublished technical report by A. Trkov on criticality performance pdf on "Analysis of the Plutonium Thermal Solution Benchmarks from the ICSBEP Handbook (Rev2)".

This is WORK IN PROGRESS.
The main updates to the U-238 evaluation ("u238e80u8V03i3") include

• (V03i4) The ENDF/B-VIII.0 RRR is replaced by JENDL-5 RRR evaluation (=B8 below 100eV, increased capture from 100 eV up to 20keV).
• (V03i4) The u238 nubar was reevaluated by LANL with improved UQ and also by JENDL-5. INDEN file adopted JENDL-5 evaluaion from 1 up to 5 MeV, new LANL evaluation above 5 MeV.
  An improvement is seen in main fast benchmarks (BigTen, Jemimas, Flaptops) compared to ENDF/B-VIII.0. The JENDL-5 RRR allowed for better performance in LEU lattices compared to B8 and previous u238 version V02b. See the comparison of criticality results that includes all INDEN recommended files.
• (V02b) The ENDF/B-VIII.0 RRR is replaced by ENDF/B-VII.1 RRR evaluation.
• (V02b) The ENDF/B-VIII.0 fission background (MF3/MT18) in the RRR is preserved to increase the (very small) average fission cross section from 1 up to 20 keV (u238e80u8V02b).
• (V02b) The ENDF/B-VIII.0 URR is also preserved.
• (V02b) This update was tested in pin-cell burnup calculations. The change in criticality from ENDF/B-VII.1 is less than 200 pcm.
• RRR reevaluation is required using all new experimental data (n_TOF, Kim et al) and transmission experiments. Averaged capture cross sections up to 100 eV is expected to be equal or larger than in ENDF/B-VII.1.

Data files available for downloading:

This is WORK IN PROGRESS.
See IAEA report INDC(SLO)-0004 on "On the Analysis of Benchmarks with 233U fuel and Be or Polyethylene reflectors".
The main updates to the ENDF/B-VIII.0 U-233 evaluation include

• Use of the IAEA U-233 PFNS for thermal neutrons with average energy Eav=2.030 MeV (ENDF/B-VIII.0 value ~2.074 MeV). Talou et al PFNS evaluation (IAEA PFNS CRP) is used in the fast region.
• Adjustment of thermal cross sections to agree with TNC from IAEA Standards 2017.
• Introduction of energy dependence for nubar below 30eV from Reed et al data.
• Introduction of energy dependence for nubar from 500eV up to 300keV from Gwin et al data measured relative to Cf-252(sf).
• Resonance parameters were completely refitted (M. Pigni) adding new experimental data (Berthomieux, Calviani, Tarrio, Leal-Cidoncha). Capture resonance yields renormalized to be close to Weston data.

Criticality was improved compared to ENDF/B-VIII.0 (see solution benchmarksas a function of FEPIT, Mosteller U-233 benchmarks, and UCT (LWBR) benchmarks).

Data files available for downloading:

The recommended files are the best files (post-CIELO) as of 22 December 2023.

Fe-57:
Fe-57 update (fe57e80m) was related to the increase in the average inelastic cross section in the RRR, and the use of thick-target transmission data measured at n_ELBE (Dresden Germany) by R. Beyer, A. Junghans and collaborators. The total Fe-57 cross section above the resonance range (above ~200keV) was taken from Pandey (EXFOR entry “13872002[4]”) up to 850 keV. The elastic cross section was calculated as the difference between the total and the non-elastic cross section. This change is critical to achieve good performance in comparison with Beyer et al very recent transmission measurements on very thick samples undertaken in HZR Dresden.

Fe-56:
The resonance range was adopted from the JEFF-3.1 (=JEFF-3.3). The Gg of the 27.7keV resonance is 30% lower than in CIELO evaluation as proposed by Froehner (1995). The 1/v background below the first resonance was changed to match ZPR/9-34 (hmi006) within integral uncertainties. A new Cf-252(sf) neutron leakage experiment performed at Rez is documented in ALARM-CF-steel-SHIELD-001-final and was submitted to IRPhEP benchmark database.
Fe-56 latest iterations (r48 and higher) were validated above 1.5 MeV by new Rez neutron leakage measurement in Cf-252(sf) source documented above. Quasi-differential iron measurements published by RPI (Daskalakis et al) shows an improved performance of the IAEA CIELO evaluation adopted in ENDF/B-VIII.0 from 500 up to 850 keV compared to INDEN fe-56 file. The issue was traced to an unintended change of fitted Perey angular distributions by Kinney fitted data below the 850 keV that happended in version r39. The Fe-56 r61 file corrects the problem, which was present in all recent INDEN evaluations including the one validated for the FENDL-3.2 library before version r61. The recommended Fe-56 r61d improves the transmission near the 137 keV and 311 keV total XS minima.

Data files available for downloading:

The main change compared to the original Fe-56 CIELO evaluation (adopted by ENDF/B-VIII.0) is the reduction of the inelastic cross section by 10-15% compared to Negret et al data adopted in ENDF/B-VIII.0. There is small but very impactful change in Fe-57 total and inelastic cross sections.

Specific features:

"Fe56 r67d" (recommended) r67 with (n,p)-MT103 and Cr-50 production reconstructed. 0.12 barn background added to Fe-56 elastic cross section near 137 keV and 311 keV minima.
"Fe56 r67b" r67 with (n,p)-MT103 and Cr-50 production reconstructed.
"Fe56 r67" JEFF-3.3 (=JEFF-3.1 RRR evaluation -Gg 27.7=1.0005) with RRR angular distributions from Perey below 850keV. 1/v background close to JENDL-5 direct capture used to reproduce hmi006 (ZPR-9/34) - the iron benchmark. Kinney fit changed to tune11.
"Fe56 r61" CIELO RR evaluation (including Perey RRR angular distributions below 850keV) was restored for Fe-56. ENDF/B-VIII.0 1/v background reduced more than 50% to reproduce hmi006 (ZPR-9/34) - the iron benchmark. Kinney fit changed to tune11. The added (smaller) background is in excellent agreement with the direct capture cross section estimated by Japanese colleagues and included into the JENDL-5 evaluation.
"Fe56 r50" CIELO RR evaluation was restored for Fe-56 but Kinney AD used from 500 to 850 keV. ENDF/B-VIII.0 1/v background reduced more than 50% to reproduce hmi006 (ZPR-9/34) - the iron benchmark. Kinney fit changed to tune11. The added (smaller) background is in excellent agreement with the direct capture cross section estimated by Japanese colleagues and included into the JENDL-5 evaluation.
"Fe56 r48" CIELO RR evaluation was restored for Fe-56 but Kinney AD used from 500 to 850 keV. ENDF/B-VIII.0 1/v background reduced more than 50% to reproduce hmi006 (ZPR-9/34) - the iron benchmark. Adopted by FENDL.
"Fe56 r44" CIELO RR evaluation was restored for Fe-56 but Kinney AD used from 500 to 850 keV.
"Fe56 r41" Thermal capture in Fe-56 was increased from 2.39 barn in r39 (Firestone et al value) to 2.577 barn (JEFF-3.1.1 value) as the lower value was rejected in CEA MINERVE benchmarking.
"Fe56 r39" Fe-56: Standard angular distribution fit of Kinney (above 0.85 MeV) and Smith (from 2.5 to 4 MeV) was adopted. "fe54e80p" Adding background to fit Allen 1977 Fe-54(n,g) data up to 500 keV, ENDF/B-VII.1 (n,g) above. Expected to improve agreement with RPI natural iron data. See Fe-54(n,g) in B8 and B71 vs Allen data
"fe54e80o" ENDF/B-VIII.0 with reduced capture above 500 keV. Adopted for FENDL-32.
"fe57e80o" ENDF/B-VIII.0 in the RRR. Pandey (n,tot) data used up to 800 keV.
"fe57e80m" ENDF/B-VIII.0 with additional background in the RRR inelastic. Pandey (n,tot) data used up to 800 keV.

RRR was changed in all isotopes to include new fits and estimated direct capture using the CUPIDO code as documented in the technical report ORNL/LTR-2018/1044 (M. Pigni et al., 2018) on "EVALUATION AND VALIDATION OF 28,29,30SI CROSS SECTIONS IN THE RESOLVED RESONANCE REGION". Thermal capture of the major Si-28 nucleus was increased up to 186(3) mb to agree with the recommended IAEA EGAF value (IAEA 2007).

Data files available for downloading (updated on April 26, 2023 to correct a missing capture background in the RRR):

See IAEA report INDC(NDS)-0810 on "Evaluation of thermal capture gamma spectra".

Data files available for downloading:

Technical paper describing the new chromium evaluation to be submitted to Nuclear Data Sheets in September 2020. New evaluations both in the resonance and fast regions for Cr-50,51,52,53,54 isotopes. Additional changes done to increase the MACS in Cr-52 evaluation after the publication (see Cr-52 v2.3.4c) Resonances parameters adopted from BROND-3.1 for the 1.6, 22.9, 27.6, 33.92, 47.95, 78.8, 94.9, 106.4, and 122.9 keV resonances. This change reduces the pmi002 criticality by 300pcm and improves the lattice criticality gradient compared to B8.

Data files available for downloading:

New evaluation of copper isotopes (Cu-63 and Cu-65). ENDF/B-VIII.0 evaluation was taken as the starting point below 5 MeV, and JENDL-4 evaluation above. Further improvement of angular distributions, elastic and inelastic cross sections undertaken to improve the criticality performance of fast assemblies and the Cf neutron leakage experiment undertaken at Rez, Czech Republic (ALARM-CF-CU-SHIELD-001-FINAL). A new neutron leakage experiment performed at Rez is documented in ALARM-CF-CU-SHIELD-001-FINAL and was submitted to IRPhEP benchmark database.
This shielding benchmark played a key role in testing the elastic/inelastic cross sections and elastic angular distributions. For the ENDF/B-VIII.1 proposed files a new resonance region was fitted on Jan-25-2024. The reactivity of the IMF020 cases is over-predicted by +250pcm, but we suspect there is a bias in the IMF020,IMF022 benchmarks since the IMF021 benchmark that uses exactly the same fuel, but contains no copper is similarly over-predicted. - ENDF/B-VIII.0 evaluation was taken as the starting point below 5 MeV - Elastic angular distributions from Popov below 300 keV and Smith from 300 keV up to 1100 keV were used. - Cu-63 Weigand data for capture, reduced by 5 percent was adopted above 50keV (both in the RRR and in the fast region) - Double differential inelastic continuum distributions (MF6MT91) were adopted from JENDL-4.0 above 7 MeV. - Discrete and continuum inelastic and (n,np) cross sections from JENDL-4.0/HE were adopted above 6 MeV - Total cross section from JENDL-4.0/HE was adopted above 2.7 MeV, elastic was adjusted for consistency.

Data files available for downloading:

This is WORK IN PROGRESS.
The O-16 cross sections below 20 MeV are an active area of investigation. JENDL/HE cross sections are recommended above 20 MeV.
The O-16 evaluation (o16j4HE_e) was adopted from JENDL/HE (JENDL-3.2) that showed an improved agreement with recent measurements of the C-13(a,n)O-16 inverse reaction (see Febbraro et al, PRL, 2020). The O-16 evaluation (o16j4HE_e) was adopted from JENDL/HE (JENDL-3.2) that showed an improved agreement with recent measurements of the C-13(a,n)O-16 inverse reaction (see Febbraro et al, PRL, 2020). Elastic and capture cross sections at the thermal point were fitted to ENDF/B-VIII.0 values. Cross-section differences between ENDF/B-VIII.0 and updated evaluations are shown in this comparison.
An improved integral performance is demonstrated for the updated O-16 evaluation in ICSBEP LCT benchmarks LCT049, LCT079, and LCT096.
An alternative evaluation (O16-B8-JENDL-above20, D. Lopez Aldama, IAEA) is to keep ENDF/B-VIII.0 below 20 MeV and take elastic from JENDL/HE above 20 MeV.

Data files available for downloading:

Updated transport evaluation of B-10 and B-11. Adapted from ENDF/B-VIII.0 to correct double counting of two alpha-emission (D. Lopez Aldama, IAEA). Used IRDFF-II to reproduce production cross sections. Evaluations adopted for FENDL-3.2
A new boron evaluation is being produced at LANL within the IAEA Neutron standards project.

Data files available for downloading:

La-139 was adopted from TENDL-2014. Issues identified by C. Konno (Japan) in the unresolved resonance region were corrected by D. Lopez Aldama (IAEA). The updated file was adopted for FENDL-3.2.

Data files available for downloading:

This is WORK IN PROGRESS.
* 15 December 2022 A final update was made available. The ENDF/B-VIII.0 evaluation was used as starting point to have gamma emission data available which is in good agrement with measured data. Morgan/Dickens inelastic data were considered below 1.4 MeV (EXFOR entries 10583003 and 10583004). Double differential cross sections measured at 92deg were assumed isotropic to derive the inelastic cross section as a simple multiplication by 4pi of measured data. Angular distributions below 2 MeV were replaced by a fit of Elwyn data (EXFOR 11441, Nucl. Phys.59(1964)113).

* 29 November 2022 A new update f19j50_zq_ENDF made, JENDL-5.0 used as starting point. The JENDL-5.0 evaluation was updated to consider Morgan/Dickens inelastic data listed as EXFOR entries 10583003 and 10583004 below 1.4 MeV. Double differential cross sections measured at 92deg were assumed isotropic to derive the inelastic cross section as a simple multiplication by 4pi of measured data. Angular distributions below 2 MeV were replaced by a fit of Elwyn data (EXFOR 11441, Nucl. Phys.59(1964)113).

* INDEN evaluation adopted the JENDL-4.0/HE evaluation as ENDF/B-VIII.0 inelastic shows an unphysical behavior as identified by ML studies led by D. Neudecker and colleagues. The JENDL-4.0 evaluation was updated to consider Morgan/Dickens inelastic data listed as EXFOR entries 10583003 and 10583004 below 1.4 MeV. Double differential cross sections measured at 92deg were assumed isotropic to derive the inelastic cross section as a simple multiplication by 4pi of measured data. This replacement led to a significant decrease of the evaluated inelastic cross section below 1.4 MeV (see the cross-section comparison to the original JENDL evaluation (INDEN26z0) and the updated evaluation (INDEN26zc) in the F19_j4HE-INDEN26zc.pdf document). Morgan data was trusted as he concurrently measured the Li(n,ng) cross section which became a reference n,ng cross section (see Carlson et al, NDS163(2018) 253). Additionally, elastic angular distributions below 1 MeV were also updated following Elwyn data.

The criticality performance of fluorine benchmarks was dramatically improved by these changes, but still overestimates measured criticality. A new fluorine compound TSL is needed. Performance vs CURIE (cases 1-6), HMF007 (cases 32-34) and HST039 (cases 1-6) benchmarks can be seen in icsbep_Teflon and icsbep_hst039 documents, respectively.

Data files available for downloading: