1. NAME AND TITLE

RIVER-RAD: Code System for Simulating the Transport of Radionuclides in Rivers.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran 77; IBM PC and compatibles. (C00626MNYPC00)

4. NATURE OF PROBLEM SOLVED

RIVER-RAD assesses the potential fate of radionuclides released to rivers. The model is simplified in nature and is intended to provide guidance in determining the potential importance of the surface water pathway, relevant transport mechanisms, and key radionuclides in estimating radiological dose to man.

5. METHOD OF SOLUTION

A compartmental linear transfer model is used in RIVER-RAD. The river system model in the code is divided into reaches (compartments) of equal size, each with a sediment compartment below it. The movement of radionuclides is represented by a series of transfers between the reaches, and between the water and sediment compartments of each reach. Within each reach (for both the water and sediment compartments), the radionuclides are assumed to be uniformly mixed. Upward volatilization is allowed from the water compartment, and the transfer of radionuclides between the reaches is determined by the flow rate of the river. Settling and resuspension velocities determine the transfer of absorbed radionuclides between the water and sediment compartments. Radioactive decay and decay-product buildup are incorporated into all transport calculations for all radionuclide chains specified by the user. Each nuclide may have unique input and removal rates. Volatilization and radiological decay are considered as linear rate constants in the model.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

Approximately 20 seconds on a Northgate 486/66 was required to run the sample problem.

8. COMPUTER HARDWARE REQUIREMENTS

An IBM PC or compatible with 640K of RAM; no hard disk is required.

9. COMPUTER SOFTWARE REQUIREMENTS

DOS 3.2 or higher is required to run on a personal computer. The Ryan MacFarlane V2.4 compiler was used to create executables included in package. RIVER-RAD was also tested on a VAX 600-420 running VMS 5.5 using VAX Fortran V5.9 and on an IBM RISC 6000 running AIX 3.2.4 using AIX XL Fortran V2.4. Run times on the VAX and RISC using the included sample problem were 44 and 11 seconds respectively.

10. REFERENCES

D. M. Hetrick, L. M. McDowell-Boyer, A. L. Sjoreen, D. J. Thorne, M. R. Patterson, "RIVER-RAD: A Computer Code for Simulating the Transport of Radionuclides in Rivers," ORNL/TM-12169 (November 1992).

11. CONTENTS OF CODE PACKAGE

The referenced document and one DS/HD 3.5-inch (1.44 MB) diskette are included written in self-extracting compressed DOS files. The code package contains sample input and output, the author's executable, and the RIVER-RAD source file.

12. DATE OF ABSTRACT

February 1994.