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NESC0467 HRG3

HRG-3, Slowing-Down Neutron Spectra Using P1 and B1 Approximation with Average Cross-Sections Calculation

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1. NAME OR DESIGNATION OF PROGRAM:  HRG3
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2. COMPUTERS
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Program name Package id Status Status date
HRG-3 NESC0467/01 Tested 01-JUN-1975

Machines used:

Package ID Orig. computer Test computer
NESC0467/01 IBM 370 series IBM 370 series
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3. DESCRIPTION OF PROBLEM OR FUNCTION

The code computes the slowing down spectrum over the energy range 10 MeV to 0.414 eV in either the B1 or P1 approximation, using 68 groups of neutrons with a constant  group width of delta u = 0.25. The calculated flux and current spectra are used to reduce the original 68-group cross section data  to average values over as many as 33 broad groups. Output is printed and may also be punched in formats for input to any of several spatial multigroup codes.
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4. METHOD OF SOLUTION

The 68 fine-group fluxes and currents are calculated by one sweep through the group structure, starting from a specified source distribution. The source may be selected from among the eight available on the data tape or may be input. The multigroup model uses a full downscattering matrix, with inelastic, (n,2n), and P0 and P1 components of elastic scattering explicitly included. Macroscopic fine-group parameters are constructed from input nuclide concentrations and microscopic parameters, available on the data tape for more than 200 individual nuclides. There is no restriction, other than availability, on the number of nuclides usable in a case. A special calculation is made in the resonance range for certain nuclides, using an adaptation of the Adler, Hinman, and Nordheim method to obtain an intermediate resonance approximation for both the absorber nuclide and an admixed moderator. The resonance contribution is allocated to the fine-groups in a consistent manner  providing self-shielding in both space and energy. Additional self-  shielding factors may be read in for any nuclide, if desired. The fine-group fluxes and currents are used as weighting functions in averaging macroscopic and microscopic parameters over the specific option, the neutron age in an infinite medium may be calculated by the moments method.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The maximum number of broad groups is 33. Broad-group boundaries are adjusted internally to coincide with one of the 68 fine-group boundaries.
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6. TYPICAL RUNNING TIME

For 10 nuclides, including four with resonance calculation and no punched output, 40 seconds are required for the first case in a run, and 20 seconds for each succeeding case.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS

NUTAPE2 updates and/or prints the HRG3 data tape. BINHDT converts a BCD library to the binary format used by HRG3.
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9. STATUS
Package ID Status date Status
NESC0467/01 01-JUN-1975 Tested at NEADB
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10. REFERENCES

J.  L. Carter,  HRG3  - A  Code  for Calculating  the
Slowing-down Spectrum in  the P1 or B1  Approximations, BNWL-1432,
June 1970.
             HRG-3 Changes in Conversion to IBM 360/370, TVA Note,
1973.
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11. MACHINE REQUIREMENTS

64K memory, normal input, output, program, and punch units, 1 unit for library, 1 to 4 scratch units or their equivalent on drum (UNIVAC1108); 200K memory, standard I/O units, 1 unit for library, and 1 scratch unit (IBM360).
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0467/01 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  CSCX
(UNIVAC1108), OS/360 (IBM360).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

A few special features of CSCX are used by the UNIVAC1108. Their functions are described in the reference report BNWL-1432.
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15. NAME AND ESTABLISHMENT OF AUTHORS

   1108          J. L. Carter
                 Reactor Physics Department
                 Pacific Northwest Laboratories
                 Battelle
                 P. O. Box 999
                 Richland, Washington  99352
   360           G. W. Perry
                 Tennessee Valley Authority
                 303 Power Building
                 Chattanooga, Tennessee  37401
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16. MATERIAL AVAILABLE
NESC0467/01
File name File description Records
NESC0467_01.001 INFORMATION 1
NESC0467_01.002 BINHDT JCL 12
NESC0467_01.003 BINHDT SOURCE PROGRAM (F4) 286
NESC0467_01.004 BINHDT SAMPLE PROBLEM DATA 2
NESC0467_01.005 BINHDT BCD LIBRARY READ FROM UNIT 11 17635
NESC0467_01.006 BINHDT BCD LIBRARY READ FROM UNIT 13 19530
NESC0467_01.007 BINHDT SAMPLE PROBLEM PRINTED OUTPUT 1080
NESC0467_01.008 NUTAPE SOURCE PROGRAM (F4) 858
NESC0467_01.009 HRG-3 JCL 8
NESC0467_01.010 HRG-3 SOURCE PROGRAM (F4) 2116
NESC0467_01.011 HRG-3 SAMPLE PROBLEM DATA 21
NESC0467_01.012 HRG-3 SAMPLE PROBLEM PRINTED OUTPUT 597
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17. CATEGORIES
  • B. Spectrum Calculations, Generation of Group Constants and Cell Problems

Keywords: cross sections, elastic scattering, group constants, inelastic scattering, slowing-down.