1. NAME AND TITLE

DOSE-SGTR: Code System to Calculate the Integrated Iodine Release to the Environment During a Steam Generator Tube Rupture in a PWR.

2. CONTRIBUTOR

Idaho National Engineering Laboratory, Idaho Falls, Idaho.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; IBM PC's and compatibles (C00624/IBMPC/00).

4. NATURE OF PROBLEM SOLVED

The Nuclear Regulatory Commission requires utilities to determine the response of a pressurized water reactor to a steam generator tube rupture (SGTR) as part of the safety analysis for the plant. The SGTR analysis includes assumptions regarding the iodine concentration in the reactor coolant system (RCS) due to iodine spikes, primary flashing and bypass fractions, and iodine partitioning in the secondary coolant system (SCS). Experimental and analytical investigations have recently been completed wherein these assumptions were tested to determine whether and to what degree they were conservative (i.e., whether they result in a calculated iodine source term/dose that is at least as large or larger than that expected during an actual event). The current study has the objective to assess the overall effects of the results of these investigations on the calculated iodine dose to the environment during an SGTR. DOSE-SGTR was written to assist in this study.

5. METHOD OF SOLUTION

DOSE-SGTR uses a simple, non-mechanistic model to calculate the iodine source term to the environment during a steam generator tube rupture as a function of water mass inventories and flow rates and iodine concentrations in the reactor coolant system and secondary coolant system.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

Cumulative execution time for all the DOSE-SGTR sample problems on a Northgate 486/66 was approximately five seconds.

8. COMPUTER HARDWARE REQUIREMENTS

The system runs on an IBM PC or compatible equipped with a math co-processor running MS DOS 3.1 or higher. A hard disk is not required.

9. COMPUTER SOFTWARE REQUIREMENTS

Lahey F77L 5.1 was used to create the executable included in the package.

10. REFERENCE

J. P. Adams, "Assessment of DOSE During a SGTR," EGG-NRE-10644 (January 1993).

11. CONTENTS OF CODE PACKAGE

The referenced document and one 5.25-inch (1.2MB) diskette written in DOS format are included. The code package contains sample input and output, the author's executable, and the DOSE-SGTR source file.

12. DATE OF ABSTRACT

March 1994.