CCC-0256 TDT.

1. NAME OR DESIGNATION OF PROGRAM:  TDT. Time Dependent TASK.

3. DESCRIPTION OF PROBLEM OR FUNCTION

TDT solves the one-dimensional, time-dependent, multi-group form of the reactor kinetics equations,  allowing an arbitrary number of delayed neutron groups. It can also  solve standard static problems such as eigenvalue problems (trans- port only), distributed source problems and boundary source problems using either diffusion theory or transport theory. The time depend-  ent solution is available only using transport theory. Vacuum and reflected boundary conditions are available.

Convergence problems associated with highly multiplicative media are circomvented. Such problems are readily calculable.

   All data are input using the FIDO format.

4. METHOD OF SOLUTION

The code employs a combination scattering and transfer matrix method to eliminate difficulties that arise in clas- sical finite difference techniques in the spatial domain. Within group (inner) iterations are eliminated and the solution convergence is independent of the spatial or time mesh. A predictor-corrector method is employed to obtain solutions in the temporal domain.

The time mesh can be supplied by the user, or calculated inter- nally. A point kinetics option is available to circomvent the dif- ficulties that arise in calculating the initial transient during rod drops.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

A variable dimen- sioning technique is used to store data, and thus the only restric-  tion is available space.

6. TYPICAL RUNNING TIME

A 10 second rod drop transient problem using  7 regions, 5 groups and an S4 angular quadrature required 5 minutes  CPU time on IBM 360/91. This time is significantly reduced by the point-kinetics option.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

TDT is an extension of TASK (2) (NESC-0558) to solve time-dependent problems.

10. REFERENCES

- E.T. Tomlinson, H.L. Dodds, R.A. Lillie, J.C. Robinson:
  A User's Manual for TDT (Time-Dependent TASK)
  ORNL-TM-4869 (June 1975).
- A.R. Buhl, H.L. Dodds Jr, J.C. Robins, R.A. Lillie, O.W. Hermann,
  R.J. Hinton:
A User's Manual for TASK - A Generalized One-Dimensional Transport    and Diffusion Kinetics Code
  ORNL-TM-3811 (December 1972).

11. MACHINE REQUIREMENTS

TDT requires 178k bytes of storage, plus data block storage, on an IBM 360/91. There is an option to output fluxes to a tape.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  IBM/360 OS.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHOR

E.T. Tomlinson, J.C. Robinson
University of Tennessee
Knoxville, Tennessee, U.S.A.

H.L. Dodds
Savannah River
Charleston, South Carolina, U.S.A.

R.A. Lillie
Neutron Physics Divsion
Oak Ridge National Laboratory
Oak Ridge, Tennessee 37830, U.S.A.

File name	File description	Records
CCC0256_01.001	SOURCE PROGRAM (F4,EBCDIC)	3912
CCC0256_01.002	SAMPLE PROBLEM INPUT DATA (CASE 1)	337
CCC0256_01.003	SAMPLE PROBLEM INPUT DATA (CASE 2)	337
CCC0256_01.004	SAMPLE PROBLEM PRINTED OUTPUT (CASE 1)	1396
CCC0256_01.005	SAMPLE PROBLEM PRINTED OUTPUT (CASE 2)	2211