**1. NAME AND TITLE**

RACC-PULSE: RACC Code System for Computing Radioactivity-Related Parameters for Fusion Reactor Systems Modified for Pulsed/Intermittent Activation Analysis.

**AUXILIARY ROUTINE**

CONVERTFLUX: Routine to convert ONEDANT and TWODANT flux data.

**DATA LIBRARIES**

raccdlib Decay constant data

raccxlib Transmutation cross section data

**2. CONTRIBUTOR**

University of Wisconsin, Madison, Wisconsin.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN 77; UNICOS Cray 2, DEC 5000 and HP 7000 series workstations (C00639/MNYWS/00).

**4. NATURE OF PROBLEM SOLVED**

CCC-388/RACC was specifically developed to compute the radioactivity and radioactivity-related parameters (e.g., afterheat, biological hazard potential, etc.) due to neutron activation within Inertial Fusion Energy and Magnetic Fusion Energy reactor systems. It can also be utilized to compute the radioactivity in fission, accelerator or any other neutron generating and neutron source system. This new version designated RACC-PULSE is based on CCC-388 and has the capability to model irradiation histories of varying flux levels having varying pulse widths (on times) and dwell periods (off times) and varying maintenance periods. This provides the user with the flexibility of modeling most any complexity of irradiation history beginning with simple steady state operating systems to complex multi-flux level pulse/intermittent operating systems.

**5. METHOD OF SOLUTION**

The solution method implemented within the RACC-PULSE code is a matrix based method which relies on the evaluation of the Matrix Exponential for the pulse period (on period), dwell period (off time) and post shutdown periods. For the pulsed and dwell periods, the Matrix Exponential was evaluated using the squaring and scaling technique outlined in a review article by Molar and Van Loan entitled "Nineteen Dubios Ways to Compute the Exponential of a Matrix"5. A balanced binary tree method utilized for parameter storage in information systems was employed to evaluate the linear chains constructed for the post shutdown period. The RACC-Pulse code retains the capability of modeling the standard slab, cylinder, sphere and torus geometries in multidimensions as well as the point or zero-dimension geometry for Monte Carlo code interfacing. It provides easy interfacing with many of the standard multigroup, multidimensional neutron/photon transport code systems currently employed by the fusion community and implemented on the UNICOS Cray 2 System at NERSC. An auxiliary code is provided to interface between the Los Alamos National Laboratory CCC-547/DANTSYS transport codes for users running on UNIX workstations. RACC-Pulse retains the FIDO formatted style of data input.

**6. RESTRICTIONS OR LIMITATIONS**

The user of the code is encouraged to update the transmutation library as it contains only a subset of reactions from the USACT 93 library. The library lacks the gamma photon emission intensity data required for the generation of the gamma source output.

**7. TYPICAL RUNNING TIME**

The typical run time is one half to one hour for simple 1-dimensional 15 zone, 600 fine mesh problems. Large detailed 2-dimensional problems are projected to run for one to several hours. The actual run time depends on the operating history of the reactor being modeled. The more complex the operating history the longer the run time.

**8. COMPUTER HARDWARE REQUIREMENTS**

RACC-PULSE runs on the CRAY 2 UNICOS computer and DEC 5000 and HP 7000 series UNIX workstations. The code is memory intensive, hence workstation systems containing 32 MB of RAM or more are required for large problems.

**9. COMPUTER SOFTWARE REQUIREMENTS**

A FORTRAN 77 compiler is required. RACC-PULSE was tested at RSIC using the included sample input files on an IBM RS/6000 Model 590 running AIX 3.2.5 using XL FORTRAN v3.2.2.3. It was also tested at RSIC on a DEC5000 running Ultrix 4.5 using DEC FORTRAN for RISC/Ultrix v.3.2.

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**10. REFERENCES**

**a. included in package:**

M. E. Newman, "README.RSI," (April 1995).

Q. Wang and D. L. Henderson, "RACC-Pulse: A Version of the RACC Radioactivity Code for Pulsed Intermittent Activity Analysis," UWFDM-980 (May 1995).

J. Jung, "Theory and Use of the Radioactivity Code RACC," ANL/FPP/TM-122 (May 1979).

**b. background information:**

SIAM Review, 20, 801 (October 1978).

Q. Wang and D. L. Henderson, "Summary Report for ITER Design Task DIO: Updating the Activation Code RACC for ITER Design Analysis," UWFDM-977 (January 1995).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents in (10.a) and distribution media which includes FORTRAN source for the code and for the flux interfacing auxiliary program, sample input and output as a compressed tar file. The package is transmitted in a Unix compressed tar file on one of these media: CD-ROM, DC 6150 (150 MB), 4mm DAT (8 GB), or 8 mm (2.3 GB) cartridge tape.

**12. DATE OF ABSTRACT**

April 1996.

**KEYWORDS:** NEUTRON; SLAB; SPHERICAL GEOMETRY; TOROIDAL GEOMETRY;
CTR; ACTIVATION; RADIONUCLIDES; ISOTOPE INVENTORY; WORKSTATION