Problems of JENDL-3.2

(Updated on 2007/02/28)

We are recognizing the following problems in JENDL-3.2.

4-Be- 9

• One benchmark test [Oy95] indicated that the secondary neutron spectrum is too high at forward angles, and other two benchmark tests [Ta95, Ma95] said that it is in good agreement with experimental data.

6-C - 12

• NK of (MF14,MT102), which is the number of discrete phoyons, is not correct. It should be 10.

7-N - 14

• The (n,p) reaction cross section (MF3,MF103) : The cross section might be too small, because the evaluation was based on the experimental data to the C-14 ground state.

7-N - 15

• The capture cross section (MF3,MT102) is probably too large above a few tens keV.

8-O - 16

• The (n,2n) reaction cross section (MF3,MT16) is 10 times larger than correct one.

9-F - 19

• There are discrepancies among the leakage spectra from a 60-cm diameter sphere calculated from JENDL-3.2 and measured at OKTAVIAN (Osaka University, Japan) for the 14 MeV neutrons.

22-Ti

• There are discrepancies among the leakage spectra from a 40-cm diameter sphere calculated from JENDL-3.2 and measured at OKTAVIAN (Osaka University, Japan) for the 14 MeV neutrons.
• There are discrepancies among the gamma-ray spectra from a sphere calculated from JENDL-3.2 and measured at OKTAVIAN (Osaka University, Japan) for the 14 MeV neutrons.

24-Cr

• There are discrepancies among the gamma-ray spectra from a sphere calculated from JENDL-3.2 and measured at OKTAVIAN (Osaka University, Japan) for the 14 MeV neutrons.

26-Fe

• The total cross section (MF3,MT1) and inelastic scattering cross section (MF3,MT4) in the energy range from 800 keV to several MeV: inconsistent with ASPIS and FNS integral experiments. There are discrepancies the total cross section and measured data at GEEL.
• The elastic scattering cross section (MF3,MT2) around 14 MeV might be too small.
• In the gamma-ray production data in the energy range from several hundred keV to 2.5 MeV, energy balance is not kept.
• In the gamma-ray production data around 14 MeV, energy balance is not kept, because GNASH calculation was normalized to experimental data. This problem has been solved in the JENDL Fusion File.

Cr, Fe, Ni

• Reinvestigation is needed for the resonance parameters. In the case of Cr, the parameters are largely different from other evaluations. For Fe, large background cross sections are given.

27-Co- 59

• There are discrepancies among the leakage spectra from a 40-cm diameter sphere calculated from JENDL-3.2 and measured at OKTAVIAN (Osaka University, Japan) for the 14 MeV neutrons.

28-Ni

• The Q-value of the capture cross section (MF3,MT102) is not correct. The current value of 10.598 MeV must be 8.485 MeV. According to this modification, the gamma-ray multiplicity in the thermal neutron region has to be decreased by 0.8 %.
• The (n,alpha) reaction cross section (MF3,MT107) should be 0.0 below about 100 keV.
• In the gamma-ray production data around 14 MeV, energy balance is not kept, because GNASH calculation was normalized to experimental data. This problem has been solved in the JENDL Fusion File.

29-Cu

• The resonance parameters around a few hundred keV are possibly too large.

41-Nb-93

• There are discrepancies among the gamma-ray spectra from a sphere calculated from JENDL-3.2 and measured at OKTAVIAN (Osaka University, Japan) for the 14 MeV neutrons.

44-Ru-99

• There are resonance levels whose total spin is not physically correct.

52-Te-127m

• Inadequate interpolation is specified to MF=3, MT=4, 51 and 52. The current interpolation of 5 should be replaced with 3.

62-Sm-147

• The unresolved resonance parameters (MF2,MT151) in the energy range from several ten keV to 100 keV cannot reproduce the capture cross section. The capture cross section calculated from the parameters is too large.

72-Hf-180

• The level energy of (MF12,MT51) should 93.32 keV.

73-Ta-181

• The (n,alpha) reaction cross section (MF3,MT107) is not correct.

74-W

• The discrete gamma rays are not considered in the neutron energy range above 400 keV. They should be considered up to 2.5 or 3.0 MeV.

82-Pb

• The benchmark test results for a lead cooled fast reactor is worse than JENDL-3.1.

90-Th-232

• In the angular distributions of elastically scattered neutrons (MF4,MT2), the value at 2 MeV and cos(theta)=-1.0 is 1/100 of the correct one.
• The delayed neutron spectra (MF5,MT455) is not correct [modified to the update file, 1996/12].

91-Pa-231

• The fission cross section (MF3,MT18) above 100 keV is quite smaller than the new experimet made at the Research Reactor Institute of Kyoto University[Ko98].

92-U -233

• The delayed neutron spectra (MF5,MT455) is not given [modified to the update file, 1996/12].

92-U -235

• In the comment (MF1,MT451) for MF=2 (resonance parameters):
  
  AVERAGE CAPTURE WIDTH OF 0.035 EV WAS INCREASED TO 0.0385 EV
  IN THE ENERGY REGION ABOVE 300 EV.
  
  This modification was made in the whole energy range up to 500 eV. (2007/02/28)
• The capture cross section in the resolved resonance region (MF2,MT151) is probably too small.
• The delayed neutron spectra (MF5,MT455) is not correct [modified to the update file, 1996/12].

92-U-238

• In the comment (MF1,MT451),
  
  1) RESOLVED RESONANCE PARAMETERS FOR MLBW FORMULA
  (RESOLVED RESONANCE REGION = 1.0E-5 EV TO 10 KEV)
  
  "MLBW" (Multilevel Breit Wigner) is not correct. It should be "RM" (Reich-Moore).
• The delayed neutron spectra (MF5,MT455) is not correct [modified to the update file, 1996/12].

94-Pu-236

• The fission cross section (MF3,MT18) is not consistent with experimental data in the whole energy range.

94-Pu-239

• The delayed neutron spectra (MF5,MT455) is not correct [modified to the update file, 1996/12].

94-Pu-240

• The delayed neutron spectra (MF5,MT455) is not correct [modified to the update file, 1996/12].

94-Pu-241

• The delayed neutron spectra (MF5,MT455) is not correct [modified to the update file, 1996/12].

95-Am-241

• In the resonance region (MF2,MT151), 22 - 140 eV, the fission cross section calculated from the resonance parameters is smaller than experimental data[Ko96].

General problems

• Some secondary neutron spectra are given in the form of simple evaporation spectrum. This shape is not adequate in the case of inelastic scattering to the continuum, (n,2n) reaction, etc.
• In the case of table type representation of spectra, we do not have suitable representation method at the threshold energy. For JENDL-3.2, the same spectrum as that at the second neutron incident energy was adopted at the threshold energy. Therefore, emitted neutron energy is larger than incident in the energy range from the threshold to the second energy point.
• The data of natural elements are not consistent with those of their isotopes. For example, the total cross section of natural elements has been measured well, and no data exit for isotopes. In such cases, the data of natural element was evaluated on the basis of the experimental data, and the data of isotopes were calculated with theoretical codes. In JENDL-3.2, the use of natural element data is strongly recommended.
• In the natural element data, upper boundaries of the resolved resonance region are different from isotope to isotope. Some processing codes cannot treat such data. The elements having this problem are Mg, S, K, Ca, Cr, Fe, Ni, Zr, Mo, Cd, Sb, Eu, Hf and W.

References

[Ko96] Kobayashi, K., et al.: "Measurement of Fission Cross Section with Pure Am-241 sample using Lead Slowing-Down Spectrometer," JAERI-Conf 96-008, p.117 (1996).

[Ko98] Kobayashi, K.,et al: "Measurement of Fission Cross Section of Pa-231 using Lead Slowing-down Spectrometer," 1998 Symposium on Nucl. Data, JAERI Tokai, Nov.19-29, 1998, to be published as JAERI-Conf.

[Ma95] Makita Y. et al.: AESJ 1995 Spring Meeting D21 (1995).

[Oy95] Oyama Y. et al.: AESJ 1995 Spring Meeting, D18 (1995).

[Ta95] Tayama R. et al.: AESJ 1995 Spring Meeting D22 (1995).