IAEA1418 ZZ-INDL/TSL.

1. NAME OR DESIGNATION:  ZZ-INDL/TSL.

3. DESCRIPTION

Format: ENDF-6 and ACE
Materials: H2O, D2O and ZrHx
Temperatures: 293.6 K up to 1200 K
Energy range: 9.031 eV-1 up to 19.34 eV-1 (Desye-Waller Integral)
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The objectives were to produce an improved library of thermal scattering law data for hydrogen bound in water, hydrogen bound in zirconium hydride, and deuterium bound in heavy water.

4. METHODS

New and re-evaluations were carried out for the three thermal moderator materials: hydrogen bound in light water (H2O), deuterium bound in heavy water (D2O) and hydrogen in ZrH (zirconium hydride). The calculations for a variety of temperatures were made with the LEAPR module of NJOY to obtain new evaluated thermal neutron scattering files that are accurate over a wider range of energy and momentum transfer than existing files. The IKE physics models and the inputs to LEAPR were used.
  
Detailed comparisons with a significant number of measurements of differential and integral neutron cross sections and other relevant data are reported (for the validation of the generated Scattering Law data files S(alpha,beta,T)). Experimental data were reproduced. In addition, thermal MCNP data sets for use in the continuous Monte Carlo codes MCNP and MCNPX were generated from these evaluations. Calculated neutron spectra agree rather well with measurements.
  
Details are also given of the updates to the NJOY modules LEAPR, THERMR, and ACER necessary in generating and processing the thermal neutron scattering data.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

- H in H20
H bound in H2o is given for the calculation of S (alpha, beta) in incoherent approximation for 8 temperatures from 293.6 K up to 647.2 K according to the IKE model.
- H in ZrH
H bound in ZrH is tabulated for the calculation of S (alpha, beta) in incoherent approximation for 8 temperatures from 293.6 K up to 1200 K according to the IKE physics model.
- D in D2O
D bound in D2O is tabulated for the calculation of S (alpha, beta) in incoherent approximation for 293.6 K. D-D interference is not included as this is not treated in LEAPR.

8. RELATED OR AUXILIARY PROGRAMS:  NJOY-99.90 (modules THERMR, LEAPR, ACER).

- M. Mattes and J. Keinert:
Thermal Neutron Scattering Data for the Moderator Materials H2O, D2O and ZrHx
in ENDF-6 Format and as ACE Library for MCNP(X) Codes(INDC(NDS)-0470 April 2005)
- Dermott E. Cullen et al.:
How accurately can we calculate thermal systems?
INDC(USA)-107  UCRL-TR-203892 (May 2004)
- A. Trkov and M. Mattes:
On the Thermal Scattering Law Data for Reactor Lattice Calculations
International Conference Nuclear Energy for New Europe 2004 (Portoroz, Slovenia
September 6-9)
- M. Mattes and J. Keinert:
Status of Thermal Neutron Scattering Data for Graphite
INDC(NDS)-0475 (July 2005)

15. NAME AND ESTABLISHMENT OF AUTHORS

Margarete Mattes and J. Keinert
Institut fuer Kernenergetik
Universitaet Stuttgart
Pfaffenwaldring 31
D-70550 Stuttgart
GERMANY
  
For the IAEA, Vienna (Austria)

ENDF library
ACE library
Documentation
NJOY99 Updates