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| Program name | Package id | Status | Status date |
|---|---|---|---|
| ZZ-GROUPSTRUCTURES | NEA-1344/01 | Tested | 15-JAN-1991 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NEA-1344/01 | IBM 3090 | DEC VAX 8810 |
Within the International Evaluation Cooperation, four energy group structures for multigroup cross section libraries were defined and adopted. The main purpose is to facilitate the inter-laboratory benchmarking of the evaluated files: ENDF/B-VI, JEF-2, JENDL-3. These group structures are:
VITAMIN-J, a 175 neutron and 42 photon group structure aimed at fission and fusion reactor shielding and for fusion blanket shielding (based on VITAMIN-J and -D group structures).
XMAS, a 172 neutron group structure, based on group structures formerly used with APOLLO and WIMS. This group structure is aimed at thermal and intermediate spectra cell calculations.
ECCO-33, a 33 neutron group structure forming a subset of the VITAMIN-J structure. It is aimed at benchmarking fast reactor criticality calculations.
ECCO-2000, a 1968 neutron fine group structure based on a lethargy grid of 1/120. It contains all the energy boundaries of the group structures VITAMIN-J, XMAS, and ECCO-33.
A computer program is provided for producing a weighting spectrum for group averaging purposes. This spectrum is the one adopted for the VITAMIN-J group cross section libraries and consists of
temperature dependent thermal Maxwellian
1/E slowing down spectrum
fission spectrum
fusion spectrum.
The computer produces a table which is linearly interpolable to a specified tolerance.
| File name | File description | Records |
|---|---|---|
| NEA1344_01.001 | Information File | 83 |
| NEA1344_01.002 | VITAMIN-J (175) Neutron Group Boundaries | 31 |
| NEA1344_01.003 | VITAMIN-J (42) Gamma Group Boundaries | 9 |
| NEA1344_01.004 | XMAS (172) Neutron Group Boundaries | 30 |
| NEA1344_01.005 | ECCO-33 (33) Neutron Group Boundaries | 7 |
| NEA1344_01.006 | ECCO-2000 (1968) Neutron Group Boundaries | 330 |
| NEA1344_01.007 | VITAMIN-J Spectrum Generation Program | 459 |
| NEA1344_01.008 | Dummy plotting routines | 22 |
| NEA1344_01.009 | JCL for running spectrum generation program | 23 |
| NEA1344_01.010 | Sample Problem output spectra | 1013 |
| NEA1344_01.011 | Sample Problem printed output | 10 |
| NEA1344_01.012 | Group Structures Comparison | 1976 |
Keywords: group constants, neutrons, photons, spectra.
