NESC9710 TOXRISK.

1. NAME OR DESIGNATION OF PROGRAM:  TOXRISK.

3. DESCRIPTION OF PROGRAM OR FUNCTION

TOXRISK is an interactive program developed to aid in the evaluation of nuclear power plant control room habitability in the event of a nearby toxic material release. The program uses a model which is consistent with the approach described in the NRC Regulatory Guide 1.78. Release of the  gas is treated as an initial puff followed by a continuous plume. The relative proportions of these as well as the plume release rate  are supplied by the user. Transport of the gas is modeled as a Gaussian distribution and occurs through the action of a constant velocity, constant direction wind. Great flexibility is afforded the user in specifying the release description, meteorological conditions, relative geometry of the accident and plant, and the plant ventilation system characteristics.
Two types of simulation can be performed: multiple case (parametric) studies and probabilistic analyses. Upon execution, TOXRISK presents a menu, and the user chooses between the Data Base  Manager, the Multiple Case program, and the Probabilistic Study Program.
The Data Base Manager provides a convenient means of storing, retrieving, and modifying blocks of data required by the analysis programs. The Multiple Case program calculates resultant gas concentrations inside the control room and presents a summary of information that describes the event for each set of conditions given. Optimally, a time history profile of inside and outside concentrations can also be produced. The Probabilistic Study program provides a means for estimating the annual probability of operator incapacitation due to toxic gas accidents on surrounding transportation routes and storage sites.

4. METHOD OF SOLUTION

Dispersion or diffusion of the gas during transport is described by modified Pasquill-Gifford dispersion coefficients.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:

6. TYPICAL RUNNING TIME:

NEA-DB compiled the program on a CRAY-XMS computer and  ran the three sample cases included in this package. The following execution times were required (in seconds): 0.5 (ESTDATA); 0.61 (PUNDATA); 0.94 (TOXRISK).

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- U.S. Nuclear Regulator Commission, Office of Standards
Development, Regulatory Guide 1.78, Assumptions for Evaluating the    Habitability of a Nuclear Power plant Control Room During a
  Postulated Hazardous Chemical Release, June 1974.

- D.I. Chanin, A.W. Shiver, and D.E. Bennett:
  Toxic Gas Accident Analysis Code User's Manual
  NUREG/CR-3685 (SAND84-0367), (August 1984).

11. MACHINE REQUIREMENTS:

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:

  UNICOS 6.1 with FORTRAN-77 compiler CFT 5.0.1.0.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

A skeleton database, which contains weather data for 29 cities, is included along with two auxiliary programs which convert the database from card-image to random-access format for use by TOXRISK  and vice versa.
Substantial effort would be required for conversion of the program to a non-CDC computer due to the strong dependence of the Data Base Manager on the CDC mass storage file system.
   Program size - 7518 lines.

15. NAME AND ESTABLISHMENT OF AUTHORS

          D.E. Bennett, D.I. Chanin, and A.W. Shiver
          Sandia National Laboratories
          P.O. Box 5800
          Alburquerque, New Mexico 87185

File name	File description	Records
NESC9710_01.001	Information file	68
NESC9710_01.002	JCL to run TOXRISK (NEADB)	12
NESC9710_01.003	ESTDATA FORTRAN source	345
NESC9710_01.004	Input data file in card-image format	258
NESC9710_01.005	PUNDATA FORTRAN source	383
NESC9710_01.006	TOXRISK FORTRAN source	7589
NESC9710_01.007	CCL proc. to exec. TOXRISK on CDC computer	105
NESC9710_01.008	CCL proc. to comp. TOXRISK on CDC computer	50
NESC9710_01.009	ESTDATA FORTRAN source (by author)	343
NESC9710_01.010	PUNDATA FORTRAN source (by author)	358
NESC9710_01.011	TOXRISK FORTRAN source (by author)	7518
NESC9710_01.012	ESTDATA differences	121
NESC9710_01.013	PUNDATA differences	207
NESC9710_01.014	TOXTISK differences	1015
NESC9710_01.015	ESTDATA tape 7 sample problem output	247
NESC9710_01.016	PUNDATA tape 7 sample problem output	32
NESC9710_01.017	PUNDATA tape 9 sample problem output	255
NESC9710_01.018	TOXRISK tape 7 sample problem output	259