1. NAME AND TITLE

HYACINTH: Fast Heavy Isotope Point Burnup and Decay Code System - Analytical Solution.

DATA LIBRARY

HLD: Seventy-four isotopes from stable ²⁰⁶Pb up to ²⁵³Es are included.

2. CONTRIBUTOR

Central Electricity Generating Board, Berkeley Nuclear Laboratory, United Kingdom.

3. CODING LANGUAGE AND COMPUTER

FORTRAN IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

HYACINTH replaces NUC-022/HYLAS for predicting the heavy isotope content of reactor fuel during and after irradiation for any reactor design and any irradiation history. Seventy-four isotopes, from the stable ²⁰⁶Pb up to ²⁵³Es, are included which allow comprehensive studies of the re-irradiation of wastes and their decay on geological time scales. New mathematical methods used in solving the set of seventy-four coupled differential equations which describe the system have led to improved execution times in dealing with irradiation periods, and an analytical solution may be used to obtain results for cooling periods ranging from a fraction of a second to millions of years. Output consists of isotope number densities, activities and spontaneous fission rates, the hazard associated with each isotope, total and energy release rate, and a 15-group spectrum.

5. METHOD OF SOLUTION

The system of burnup equations is said to be stiff, that is, it involves a wide range of time constant values. Straight-forward methods of solution require a large number of small time steps for accuracy. To avoid long execution times, the method of Chambers was adapted. This method uses an implicit trapezoidal rule for integration and Aitken's formula to accelerate the convergence.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

No study has been made by RSIC of typical running time for HYACINTH.

8. COMPUTER HARDWARE REQUIREMENTS

HYACINTH is operable on the IBM 360/370 computers.

9. COMPUTER SOFTWARE REQUIREMENTS

A FORTRAN IV compiler is required.

10. REFERENCES

G. A. Harte, "A Heavy Isotope Point Burnup and Decay Code," RD/B/N3564 (February 1976).

G. A. Harte, "The Numerical Integration of a Stiff System of Linear Differential Equations," RD/B/N3693 (June 1976).

11. CONTENTS OF CODE PACKAGE

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

12. DATE OF ABSTRACT

January 1984, updated August 1991.