**1. NAME AND TITLE**

SWANLAKE: Cross Section Sensitivity Analysis Code System for One-Dimensional Discrete
Ordinates Calculations.

**AUXILIARY ROUTINE**

INTRIGUE II-L CALCOMP Plotting Package.

CCC-254/ANISN or other comparable code is needed for input data generation. It is not
included in this package.

**2. CONTRIBUTOR**

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV and Machine Language; IBM 360/91.

**4. NATURE OF PROBLEM SOLVED**

SWANLAKE determines the sensitivity of a calculated quantity or result to microscopic cross
section data utilized in the calculation.

**5. METHOD OF SOLUTION**

A particular sensitivity function, which represents an application of earlier perturbation
approaches, is determined for the cross sections which were utilized in the discrete ordinates
calculation.

**6. RESTRICTIONS OR LIMITATIONS**

The discrete ordinates calculations to be analyzed by this version of SWANLAKE must be
time-dependent and one-dimensional. The sensitivity function only allows for energy downscatter,
does not include the effects of fission cross sections, and cannot evaluate the sensitivity of the
calculated quantity or response to the response function itself.

**7. TYPICAL RUNNING TIME**

The infinite air sample problem included in the code package required 2.5 minutes for the
ANISN forward calculation, 2.5 minutes for the ANISN adjoint calculation, and 1.8 minutes for
the SWANLAKE calculation.

**8. COMPUTER HARDWARE REQUIREMENTS**

Designed for the IBM 360/91, SWANLAKE is also operable on the IBM 360/75. Maximum core requirement for the sample problems discussed in the code manual is 848K bytes, minimum size is 290 K bytes.

Auxiliary storage requirements, in addition to standard input and output devices, are 2 scratch
devices and 3 storage devices. If cross sections are not read from cards, an additional tape or disk
will be required, and if the CALCOMP plotting routine included in the package is to be used,
another tape unit is required.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A FORTRAN IV compiler is required. A CALCOMP plotting package, INTRIGUE-II (PSR-54), is included in the SWANLAKE package.

**10. REFERENCES**

D. T. Ingersoll, "Availability of SWANLAKE," memo (October 1978).

D. E. Bartine, F. R. Mynatt, and E. Oblow, "SWANLAKE, A Computer Code Utilizing ANISN Transport Calculations for Cross Section Sensitivity Analysis," ORNL-TM-3809 (May 1973).

M. B. Emmett, "INTRIGUE-II: An IBM 360 Subroutine Package for Making Linear,
Logarithmic and Semilogarithmic Graphs Using the CALCOMP Plotter," ORNL-4664 (March
1971).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents and one (1.2MB) DOS diskette which contains the
source code and sample problem input and output.

**12. DATE OF ABSTRACT**

August 1975; reviewed February 1983.

**KEYWORDS:** NEUTRON; GAMMA-RAY; SENSITIVITY ANALYSIS; CROSS-SECTION
ANALYSIS; ONE-DIMENSION