RSICC CODE PACKAGE CCC-677

1. NAME AND TITLE

MESORAD1.4: Code System for Emergency Response Dose Assessment.

2. CONTRIBUTORS

Pacific Northwest Laboratory, Richland, Washington, through the Energy Science Technology Software Center, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran 77 and DEC Vax Fortran Extensions; DEC VAX11/780 (C00677/DOVAX/00).

4. NATURE OF PROBLEM SOLVED

A dose assessment model for emergency response applications. Dose pathways represented in the model are those that are most likely to be important during and immediately following a release (hours) rather than over an extended time frame (days or weeks). The doses computed include: external dose resulting from exposure to radiation emitted by radionuclides in the air and deposited on the ground, internal dose commitment resulting from inhalation, and total whole-body dose. Three preprocessors are included. RSFPREP generates the MESORAD run specification (input) file, METWR creates the meteorological data file, and RELPREP prepares the release definition file. PRNT is a postprocessor for generating printer or screen-compatible output. All four programs run interactively. MESORAD was developed from version 2.0 of the MESOI atmospheric dispersion model (NESC 9862) retaining its modular nature.

5. METHOD OF SOLUTION

External doses from airborne material are computed using semi-finite and finite cloud approximations. When the dimensions of the puff become large in comparison with the mean free paths of gamma radiation emitted from radionuclides in the puff, the semi-finite cloud model is used. Otherwise, the finite puff model is applied. The finite puff model is an approximation to the point-kernel integration technique which reduces dose computation times. Atmospheric processes are represented by a combination of Lagrangian puff and Gaussian plume dispersion models, a source depletion (deposition velocity) dry deposition model, and a wet deposition model using washout coefficients based on precipitation rates. Dose assessment calculations occur simultaneously with the atmospheric dispersion and deposition calculations.

6. RESTRICTIONS OR LIMITATIONS

MESORAD is designed to accommodate up to 50 radionuclides.

7. TYPICAL RUNNING TIME

Model execution proceeds at a nominal rate of approximately 1 minute per hour simulated for a continuous release. The two sample problems required about 8 and 9 CPU seconds, respectively, on a DEC VAX6220 when executed by NESC October 1990 on a DEC VAX6220.

8. COMPUTER HARDWARE REQUIREMENTS

The programs run on DEC Vax computers.

9. COMPUTER SOFTWARE REQUIREMENTS

MESORAD 1.4 was developed under NRC sponsorship at Pacific Northwest Laboratory in Richland, Washington, and was first distributed by NESC in October 1990. The code was executed at the NEA Data Bank in March 1995 on a VAX 6000/510 computer running Open VMS V6.1. It was not retested nor were any changes made to the package when it was contributed to RSICC and released in 2002. The RSICC distribution is a duplicate of the NEA Data Bank ESTS0331/01 package.

MESROAD1.4 reads input from a file named MESOR.RSP. File MROUT.FMT, which describes the MESORAD output format, was created using a text editor and is read by subroutine OUT2 in PRNT. Volume 3 of the reference report, which was intended to describe the auxiliary programs, was never written.

10. REFERENCES

a) Included in documentation:

R.I. Scherpelz, T.J. Bander, G.F. Athey, and J.V. Ramsdell, "The MESORAD Dose Assessment Model Volume 1: Technical Basis," NUREG/CR-4000 (PNL-5219) (January 1986).

b) Included only in electronic format:

J.V. Ramsdell, G.F. Athey, T.J. Bander, and R.I. Scherpelz, "The MESORAD Dose Assessment Model Volume 2: Computer Code," NUREG/CR-4000 (PNL-5219) Vol.2 (September 1988).

11. CONTENTS OF CODE PACKAGE

Included are the referenced Volume 1 document and a CD which contains the Vax source files, test cases and Volume 2 document transmitted in a self-extracting, compressed Windows file.

12. DATE OF ABSTRACT

January 2002.

KEYWORDS: AIRBORNE; EXTERNAL DOSE; GAUSSIAN PLUME MODEL; INTERNAL DOSE; NUCLIDE TRANSPORT; RADIOACTIVITY RELEASE; RADIOLOGICAL SAFETY.