1. NAME AND TITLE

LEPRICON: PWR Pressure Vessel Surveillance Dosimetry Analysis System.

AUXILIARY ROUTINES:

DOTSOR: Represent Neutron Source Distribution in LWR Cores.

DOTSYN: Synthesize 3-D Fluxes.

TIMEPATCH: Evaluate Effects of Time-Dependent Source Distributions in PWR Surveillance Dosimetry.

FLUENS: Obtain Weighted Spectral Fluences and Uncertainties.

LEPRICON: (ADJUSTMENT Module) Generalized Least Squares Data Analysis Module with Application to PWR Surveillance Dosimetry.

DATA LIBRARY:

ELXSIR: 56-Group Neutron Cross-Section Library for LWR Pressure Vessel Irradiation Studies.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 3033. (P00277/I3033/01) and Fortran 77; IBM RS/6000 (P00277/IRISC/00).

4. NATURE OF PROBLEM SOLVED

The LEPRICON system provides state-of-the-art routines to prepare input for and process results from the discrete ordinates codes CCC-484/DORT and CCC-254/ANISN to determine best estimates with uncertainties of group fluences in pressure vessels of pressurized water reactors. The system anticipates availability of results of dosimetry measurements performed in the reactor as well as sources operating during the time of exposure.

No source files were modified in the June 1994 update to the IBM 3033 version, but the binary flux files were converted to ASCII, and BCD to binary conversion programs were added. The IBM RS/6000 version was released in May 1995.

5. METHOD OF SOLUTION

Effects of time-dependent core source spatial distributions, when necessary, are treated by the use of an adjoint function coupled with a scaling technique. Sources are generated by combining the results of the diffusion theory code PDQ-7 pin-wise calculations with in-core assembly-wise instrumentation and are converted from X-Y to R-theta geometry. Fluxes calculated by the discrete ordinates codes are then synthesized to form 3-D distributions, and the resulting calculated dosimeter responses compared with the measurements, and adjustments performed in a generalized linear least-squares combination procedure. Through correlations generated from the input, adjustments to the originally calculated group fluxes at a selected point in the pressure vessel are then made, and the best estimates of the fluences accumulated during the time period analyzed are output along with their reduced uncertainties.

6. RESTRICTIONS OR LIMITATIONS

Much of the input data to the adjustment routine may be defaulted to "built-in" values by proper choice of the input options. However, these values may not apply to every reactor, and a caveat must be issued that the user might have to alter some of the definitions of the flux bias factors to describe additional uncertainties peculiar to his own reactor. One may also override any default input if other values are judged more appropriate.

The ISOPLOT4 source, sample input and output files are included on the IBM 3033 tape but were not tested by RSIC. Users who wish to run ISOPLOT may request PSR-155/DOGS from RSIC to obtain source and additional I/O routines required. ISOPLOT is omitted in the IBM RS/6000 package.

7. TYPICAL RUNNING TIME

On the IBM 3033 sample problem running times vary from 1 second for FLUENS to approximately 5 minutes for the LEPRICON ADJUST module. On the IBM RS/6000 520H, the make-lepricon script runs in 15-20 minutes and builds the entire system and runs sample problems.

8. COMPUTER HARDWARE REQUIREMENTS

LEPRICON runs on the IBM 3033 or the IBM RS/6000.

9. COMPUTER SOFTWARE REQUIREMENTS

On the IBM 3033 the sample cases were executed under OS/VS2 using the IBM VS Fortran compiler (Level 2.2.0). The language level flag must be set to 66. The LEPRICON source (file 23) should be compiled with OPT=1. The IBM RS/6000 version was ported using the XLF 2.3 compiler. Sample problems were also executed using XLF 3.2 under AIX 3.2.5.

10. REFERENCES

a. Included in documentation:

M. L. Williams, "DOTSOR: A Module in the LEPRICON Computer Code System for Representing the Neutron Source Distribution in LWR Cores," EPRI Research Project 1399-1 Interim Report (Dec. 1985).

M. L. Williams, P. Chowdhury, B. L. Broadhead, "DOTSYN: A Module for Synthesizing Three- Dimensional Fluxes in the LEPRICON Computer Code System," Prepared by ORNL for EPRI.

R. E. Maerker, M. L. Williams, B. L. Broadhead, "TIMEPATCH: A Module in the LEPRICON Computer Code System for Evaluating Effects of Time-Dependent Source Distributions in PWR Surveillance Dosimetry," EPRI Research Project 1399-1 Interim Report (Dec. 1985).

R. E. Maerker, "FLUENS: A Module in the LEPRICON Computer Code System for Obtaining Weighted Spectral Fluences and Their Uncertainties," EPRI Research Project 1399-1 Interim Report (Oct. 1985).

B. L. Broadhead, R. E. Maerker, J. J. Wagschal, "LEPRICON Adjustment Module: A Generalized Linear Least Squares Data Analysis Program with Application to PWR Surveillance Dosimetry," EPRI Research Projects 1399-1, 1399-2 Interim Report (March 1985).

R. E. Maerker, W. E. Ford III, C. C. Webster and M. L. Williams, "The ELXSIR Cross-Section Library for LWR Pressure Vessel Irradiation Studies: Part of the LEPRICON Computer Code System," EPRI NP-3654, Research Project 1399-1 Interim Report (Sept. 1984).

J. A. Bucholz, "make-lepricon," unix script (July 1994).

b. Background information:

R. E. Maerker, B. L. Broadhead, and J. J. Wagschal, "Theory of a New Unfolding Procedure in Pressurized Water Reactor Pressure Vessel Dosimetry and Development of an Associated Data Base," Nuclear Science and Engineering 91, 369-392 (1985).

R. E. Maerker, B. L. Broadhead, B. A. Worley, M. L. Williams, and J. J. Wagschal, "Application of the LEPRICON Unfolding Procedure to the Arkansas Nuclear One-Unit 1 Reactor," Nuclear Science and Engineering 93, 137-170 (1986).

R. E. Maerker, "LEPRICON Analysis of Pressure Vessel Surveillance Dosimetry Inserted into H. B. Robinson-2 During Cycle 9," Nuclear Science and Engineering 96, 263-289 (1987).

R. E. Maerker, M. L. Williams and B. L. Broadhead, "Accounting for Changing Source Distributions in LWR Surveillance Dosimetry Analysis," Nuclear Science and Engineering 94, 291-308 (1986).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents (in 10a) and 5 3.5-inch (1.4 MB) diskettes including the source codes, ELXSIR data library, sample input and output written in DOS format; for the IBM 3033 package. The IBM RS/6000 version is available on either DC 6150 (150 MB), 4 mm DAT (8 GB), or 8 mm (2.3 GB) cartridge tapes in tar format.

12. DATE OF ABSTRACT

March 1990, August 1994, June 1995.