1. NAME AND TITLE

EMERALD-NORMAL: Calculation of Activity Releases and Potential Doses from the Normal Operation of a Pressurized Water Reactor Plant.

EMERALD-NORMAL incorporates most of the capabilities of an earlier PG&E version (1971) EMERALD (Engineering Model for the Evaluation of Reactor Activity Leakage Doses, Argonne Code Center Abstract 546), and provides extensive new features.

2. CONTRIBUTOR

Pacific Gas and Electric Company, San Francisco, California.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

EMERALD-NORMAL is designed to make a reasonably accurate prediction of the radioactivity buildup and release to the environment from a large pressurized water reactor plant under normal operating conditions. The plant is assumed to be base loaded, and assumed average equipment and component leakage parameters and process flow rates are used. Shutdown periods are approximated by using a plant capacity factor, and whole body offsite radiation doses are calculated by using a semi-infinite cloud approximation with no downwind decay from the plant.

5. METHOD OF SOLUTION

The approach used in EMERALD-NORMAL is similar to an analog simulation of a real system. Each component or volume in the plant which contains a radioactive material is represented by a subroutine which keeps track of the production, transfer, decay and absorption of radioactivity in that volume using simple first-order differential equations with constant coefficients. During the course of operation, activity is transferred from subroutine to subroutine in the program as it would be transferred from place to place in the plant. For example, the primary coolant subroutine uses as input the activity leakage rate from the reactor core subroutine and calculates the equilibrium primary coolant activity for the time period chosen, the activity leakage rates to the secondary system, the auxiliary building, and the containment sump, and the activity removals due to decay, demineralizer cleanup, and chemical shim control letdown. These calculated quantities are then used as input for other subroutines describing the secondary system, and the radwaste system. The rates of transfer, leakage, production, cleanup, decay, and release are read in as input to the program, and are assumed to be constant during the period of operation.

Subroutines are also included which calculate the off-site doses from the gaseous and liquid discharges at various distances, for individual isotopes and sums of isotopes. The program contains a variety of physical data for the forty isotopes of most interest in licensing calculations, and other isotopes can be added or substituted.

6. RESTRICTIONS OR LIMITATIONS

The program can handle a maximum of 50 isotopes and 47 volumes. Using 50 isotopes requires approximately 530 K of core space on an IBM 370 computer. Using 40 isotopes and reducing DIMENSION parameters accordingly reduces core requirements to approximately 425 K.

7. TYPICAL RUNNING TIME

The central processing time for running an EMERALD-NORMAL case on an IBM 360 computer is less than 40 seconds.

8. COMPUTER HARDWARE REQUIREMENTS

EMERALD-NORMAL is operable on the IBM 360/370 computers. It is said to have been run successfully on a CDC 6600 and on a CDC 6400 with some modifications to reduce the required core space.

9. COMPUTER SOFTWARE REQUIREMENTS

A FORTRAN IV compiler is required.

10. REFERENCE

S. G. Gillespie and W. K. Brunot, "EMERALD-NORMAL: A Program for the Calculation of Activity Releases and Potential Doses from the Normal Operation of a Pressurized Water Reactor Plant," Revision 1, Volume IProgram Description (December 1974).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source code and sample problem input and output.

12. DATE OF ABSTRACT

August 1975; revised December 1982.