NESC9493 DATING.

1. NAME OR DESIGNATION OF PROGRAM:  DATING.

3. DESCRIPTION OF PROGRAM OR FUNCTION

DATING (Determining Allowable Temperature in Inert and Nitrogen Gases) calculates allowable initial temperatures for dry storage of light-water-reactor spent fuel and the cumulative damage fraction of Zircaloy cladding for specified initial storage temperature and stress and cooling histories. It is made available to ensure compliance with NUREG 10CFR Part 72, Licensing Requirements for the Storage of Spent Fuel  in an Independent Spent Fuel Storage Installation (ISFSI). Although  the program's principal purpose is to calculate estimates of allowable temperature limits, estimates for creep strain, annealing  fraction, and life fraction as a function of storage time are also provided. Equations for the temperature of spent fuel in inert and nitrogen gas storage are included explicit in the code; in addition, an option is included for a user-specified cooling history in tabular form, and tables of the temperature and stress dependencies  of creep-strain rate and creep-rupture time for Zircaloy at constant temperature and constant stress or constant ratio of stress/modulus  can be created.
DATING includes the GEAR package for the numerical solution of the rate equations and DPLOT for plotting the time-dependence of the calculated cumulative damage-fraction, creep strain, radiation damage recovery, and temperature decay.

4. METHOD OF SOLUTION

The calculations are based on the life fraction rule using both measured data and mechanistic equations as reported  by Chin et al. The cumulative life-fraction model assumes that the creep-rupture limit during temperature and stress transients can be  estimated by summing damage which occurs in increments of time. The  fraction of life consumed at the temperature and stress during each  time increment is calculated and summed. The creep-rupture limit is  assumed to be achieved when the sum of the incremental life fractions equals unity. DATING uses this model to evaluate cladding  integrity during dry storage of spent fuel.
The maps of creep-strain and creep-rupture time included in the DATING model allow the rupture lifetime to be calculated using the appropriate limiting creep mechanism (fastest creep) and limiting rupture mechanism (usually, the least time). The mechanistic equations have been adjusted to fit published creep-rate and rupture-time experimental data. Similary, the annealing kinetics for radiation damage are based on published annealing kinetics experimentally determined by Steinberg, Weidinger, and Schaa.
Analytical integration of the life fraction cannot be obtained because of the complicated forms of equations for temperature decay, creep rate, rupture lifetime, and radiation-damage annealing. Therefore, DATING uses the variable time-step method of the GEAR numerical software.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

DATING calculates limiting conditions for dry storage of spent fuel based on creep- strain limits for fuel cladding and does not include other failure mechanisms such as those related to hydrogen. The temperature must be below the alpha/beta transition temperature of 800 degrees C for  Zircaloy and the stress below the yield stress.
Maximum of 50 entries in the user-specified temperature or temperature and stress history input file.

6. TYPICAL RUNNING TIME

One temperature limit can be calculated in 15 seconds on an IBM PC with a math coprocessor and in 5 minutes without a math coprocessor.

NEA-DB ran the test case specified in the input data file DATING.INP on a PC/80486 (66MHz) in less than a second.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- B.A. Chin, M.A. Khan, and J.Tarn:
  Deformation and Fracture Map Methodology for Predicting Cladding
  Behavior During Dry Storage
  PNL-5998 (September 1986).
- E. Steinberg, H.G. Weidinger, and A. Schaa:
  Analytical Approaches and Experimental Verification to Describe
  the Influence of Cold Work and Heat Treatment on the Mechanical
  Properties of Zircaloy Cladding Tubes, Zirconium in the Nuclear
  Industry: Sixth Internal Symposium, American Society for Testing
  Materials
  STP 824, pp. 106-122 (1984).

- E.P. Simonen and E.R. Gilbert:
  DATING - A Computer Code for Determining Allowable Temperatures
  for Dry Storage of Spent Fuel in Inert and Nitrogen Gases
  PNL-6639 (December 1988).
- M. Birgersson:
  DATING Flexible Disk Cartridge Descriptions
  NESC Note 89-45 (March 31, 1989).

11. MACHINE REQUIREMENTS:

The program was installed by the NEA-DB on a DELL/466L  PC/80486 (66MHz). The file sizes of the executables produced with the compiler options: with and without math processor are 127 and 221 Kbyes, respectively.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  MS-DOS.

The program was installed at the NEA-DB under MS-DOS Version 6.2. The executable was generated using the Microsoft FORTRAN Version 5.10 compiler and linker Version 5.15.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

Two
releases of DATING are included - one for use without a math coprocessor (A) and the other with a math coprocessor (M). DPLOT is  written in Advanced BASIC.

15. NAME AND ESTABLISHMENT OF AUTHORS

          E.P. Simonen
          Pacific Northwest Laboratory

File name	File description	Records
NESC9493_01.001	DATING Information File	219
NESC9493_01.002	Batch file to create the DATING executable	42
NESC9493_01.003	Source file with the DATING Main program	798
NESC9493_01.004	Source file with rate equations subroutines	188
NESC9493_01.005	Source file with GEAR subroutines	711
NESC9493_01.006	Source file with Gthe COMMON blocks	28
NESC9493_01.007	Executable of program DATING	0
NESC9493_01.008	Batch file to execute DATINGM.EXE	6
NESC9493_01.009	Sample input file (test case parameters)	8
NESC9493_01.010	Sample output file	32
NESC9493_01.011	User specified temp./stress history file	6
NESC9493_01.012	Advance Basic source file of program DPLOT	176
NESC9493_01.013	Screen message to wait while loading DATING	3
NESC9493_01.014	Batch file to display README.DOC	1
NESC9493_01.015	Machine readable documentation	79
NESC9493_01.016	Source file with the DATING Main program	798
NESC9493_01.017	Source file with the rate equations routines	188
NESC9493_01.018	Source file with the GEAR subroutines	711
NESC9493_01.019	File with the COMMON blocks	28
NESC9493_01.020	Executable of program DATING	0
NESC9493_01.021	Batch file to execute DATINGA.EXE	6
NESC9493_01.022	DATING output file	29
NESC9493_01.023	User specified temp./stress history file	6
NESC9493_01.024	Advanced Basic source of program DPLOT	170
NESC9493_01.025	Screen message to wait while loading DATING	3
NESC9493_01.026	DOS file-names	25