ESTS0054 SPIRT.

1. NAME OR DESIGNATION OF PROGRAM:  SPIRT.

3. DESCRIPTION OF PROGRAM OR FUNCTION

The SPIRT (Stress-strains from  Pressures Instigated by Reactor Transients) program was developed to predict the pressure generated by the rapid dispersal of molten UO2  from power-reactor-type fuel rods into the coolant water. This rapid dispersal of molten fuel results from very high-power excursions initiated by the rapid insertion of reactivity. SPIRT was used in the safety analyses of the ATR and ETR. The program can analyze the response of one-dimensional plane, cylindrical, and spherical geometric configurations to pressure-generating heat sources with free-surface or fixed-surface boundary conditions. SPIRT can calculate the response of systems to the dispersal of hot  fuel particles as a function of the following variables: enthalpy of fuel at time of dispersal, rate at which fuel is dispersed, size of  dispersed fuel droplets, dispersal density of fuel (grams of fuel dispersed per cc of water), quality of water at time of fuel, enthalpy of water at time of fuel dispersal, system pressure at time of fuel dispersal, and the size and constituency of the medium enveloping the dispersed fuel. By holding all but one of  the listed variables constant, and varying that one, the program computes the relative effect of that variable upon the response of systems to the dispersal of hot fuel. SPIRT exists as two releases one, written for UO2 fuel is called SPIRTU; the second, for uranium-aluminide fuel is identified as SPIRTA.

4. METHOD OF SOLUTION

Both SPIRTU and SPIRTA predict the pressure histories which might be expected when fuel rods fail and calculate  the strain responses on both the capsule and the capsule hold down system.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:

6. TYPICAL RUNNING TIME

Typical running time is two to three minutes. In NESC testing of the sample problem, SPIRTU required approximately 87 CPU seconds for execution, including creation of the plot file on a CYBER175; SPIRTA required approximately 93 seconds.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

A formatted water properties library and an auxiliary program WATER to convert the formatted library into a binary file (TAPE15) for SPIRT use are included in the package. The SPIRT program makes use of the Integrated Software  Systems Corporations's (ISSCO) proprietary software product, DISSPLA.

10. REFERENCES

- RELAP4/MOD5
  A Computer Program for Transient Thermal-hydraulic Analysis of
  Nuclear Reactors and Related Systems,
  User's Manual, Volume II: Program Implementation
  ANCR-NUREG-1335 (September 1976).
- Mark L. Wilkins,
  Calculation of Elastic-Plastic Flow,
  Methods in Computational Physics, Vol. 3, pp. 211-263,
  Academic Press, New York (1964).

- L.J. Siefken and G.H. Hanson:
  SPIRT Computer Program (Stress-Strains from Pressures Instigated
  by Reactor Transients)
  RE-A-78-189
- L. Reed:
  SPIRT Tape Description, Implementation Information, and Excerpts
  from ANCR-NUREG-1335 Vol. II (1976) pp. 265-275.

11. MACHINE REQUIREMENTS

SPIRTU and SPIRTA require approximately 173K  (octal) words for execution under NOS 1.3.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  SCOPE 2.1 (CDC CYBER76) ; NOS 1.3 (CDC CYBER175).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

The
subroutines STH20I, STH201, and STH203 which calculate thermodynamic properties of water are copies of those supplied with the RELAP4/MOD6 package.

15. NAME AND ESTABLISHMENT OF AUTHORS

- Siefken, L.J.
  EG and G Idaho, Inc.,
  Idaho Falls, ID,
  United States

source program   mag tapeSPIRTU FORTRAN Source                      SRCTP
test-case data   mag tapeSPIRTU Sample Problem Input                DATTP
source program   mag tapeSPIRTA FORTRAN Source                      SRCTP
test-case data   mag tapeSPIRTA Sample Problem Input                DATTP
source program   mag tapeSTH20 WATER Routines FORTRAN Source        SRCTP
source program   mag tapeWATER FORTRAN Source                       SRCTP
symb data lib    mag tapeWATER Property Data Library                LBSTP
report                   RE-A-78-189                                REPPT
prog. note               NESC Note 82-83 (1982) + Attachment        NOTPT