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CCC-0405 SENSIT.

SENSIT, Integral Response Sensitivity from Neutron Cross-Sections, Gamma Cross-Sections Errors

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1. NAME OR DESIGNATION OF PROGRAM:  SENSIT.
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2. COMPUTERS
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Program name Package id Status Status date
SENSIT CCC-0405/01 Tested 21-SEP-1981

Machines used:

Package ID Orig. computer Test computer
CCC-0405/01 IBM 3033 IBM 3033
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3. DESCRIPTION OF PROBLEM OR FUNCTION

SENSIT computes the sensitivity and uncertainty of a calculated integral response (such as a dose rate) due to input cross sections and their uncertainties.
Sensitivity profiles are computed for neutron and gamma-ray reaction cross sections (of standard multigroup cross-section sets) and for secondary energy distributions (SED's) of multigroup scattering matrices. In the design sensitivity mode, SENSIT computes changes in an integral response due to design changes and gives the appropriate sensitivity coefficients. Cross-section uncertainty analyses are performed for three types of input data uncertainties:
(a) cross-section covariance matrices for pairs of multigroup reaction cross sections, (b) spectral shape uncertainty parameters for secondary energy distributions (integral SED uncertainties), and (c) covariance matrices for energy-dependent response functions.
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4. METHOD OF SOLUTION

For all three types of data uncertainties, SENSIT computes the resulting variance and expected deviation in an  integral response of interest, based on generalized perturbation theory.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

SENSIT uses one-, two-, and three dimensional arrays to manage the large amount of numerical data involved in the execution. Core storage is reserved for a particular dimensional array only during the time the corresponding data are required to be in-core; at other times, the space is made available for the storage of other data. In order to alleviate bookkeeping chores associated with such dynamic storage allocation techniques, Argonne National Laboratory developed a collection of subroutines, called the BPOINTR package, which is incorporated in SENSIT.
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6. TYPICAL RUNNING TIME

A typical execution time on the CDC-7600 for a standard cross-section sensitivity analysis, together with an  SED uncertainty analysis is about 4 seconds CPU (central processor units) time. Here a coupled neutron/gamma group structure of 30 x 12 groups, P3 cross-sections, and 137 spatial intervals was used. A typical vector cross-section sensitivity and uncertainty analysis with 30 x 30 covariance matrices requires about 2 seconds of CPU time per case.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS

SENSIT uses angular-flux files from one-dimensional discrete-ordinates codes like ONETRAN, ANISN and DTF and reads multigroup cross-section sets in three different formats.  For covariance data input a convenient ENDF-like input format is adopted which is identical to the output format from the cross- section processing code system NJOY.
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9. STATUS
Package ID Status date Status
CCC-0405/01 21-SEP-1981 Tested at NEADB
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10. REFERENCES

- S.A.W. Gerstl, R.J. LaBauve, and P.G. Young:
  "A Comprehensive Neutron Cross-Section and Secondary Energy Dis-
   tribution Uncertainty Analysis for a Fusion Reactor",
   Los Alamos Scientific Laboratory report LA-8333-MS (May 1980).
CCC-0405/01, included references:
- S.A.W. Gerstl:
  SENSIT: A Cross Section and Design Sensitivity and Uncertainty
  Analysis Code
  LA-8498-MS UC-32 (August 1980).
- BPOINTER + POINTER Description of Subroutines.
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11. MACHINE REQUIREMENTS

Due to the variable dimensioning as described above, large flexibility exists to adjust the storage requirements for a specific problem to the available machine core. On a CDC-7600  all of the 8 sample problems and the realistic applications could be executed within a maximum of 24000 words of fast (SCM) core and 80000 words of extended-core (ECM) memory.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
CCC-0405/01 FORTRAN+ASSEMBLER
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  SCOPE 2.1 ,
IBM/OS 370.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHOR

S.A.W. Gerstl
Theoretical Division
Los Alamos Scientific Laboratory
Los Alamos, New Mexico 87545, U.S.A.
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16. MATERIAL AVAILABLE
CCC-0405/01
File name File description Records
CCC0405_01.001 SENSIT MAIN PROGRAM (F4) 697
CCC0405_01.002 COMPUTATIONAL SUBROUTINES 2647
CCC0405_01.003 BPOINTR FORTRAN ROUTINES 1580
CCC0405_01.004 BPOINTR ASSEMBLER ROUTINES 314
CCC0405_01.005 ANISN FORWARD SAMPLE PROBLEM 35
CCC0405_01.006 ANISN ADJOINT SAMPLE PROBLEM 37
CCC0405_01.007 ANISN OUTPUT FORWARD PROBLEM 472
CCC0405_01.008 ANISN OUTPUT ADJOINT PROBLEM 473
CCC0405_01.009 SENSIT S.P. 1 INPUT 42
CCC0405_01.010 SENSIT S.P. 2 INPUT 30
CCC0405_01.011 SENSIT S.P. 1 OUTPUT 330
CCC0405_01.012 SENSIT S.P. 2 OUTPUT 252
CCC0405_01.013 TAPE4 CROSS SECTION FOR S.P. 20
CCC0405_01.014 JCL AND INFORMATION 149
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17. CATEGORIES
  • B. Spectrum Calculations, Generation of Group Constants and Cell Problems

Keywords: cross sections, dose rates, gamma radiation, multigroup, neutron reactions, perturbation theory, response functions, sensitivity.