IAEA0884 TRIVENI.

1. NAME OR DESIGNATION OF PROGRAM:  TRIVENI.

3. DESCRIPTION OF PROBLEM OR FUNCTION

The program has been developed  to follow up the operation of pressurized heavy water reactors. It solves three-dimensional two-group diffusion theory equations and calculates reactivity, two-group fluxes and fuel channel and fuel bundle power distributions and fuel bundle burnup distribution. It can take into account the refuelling of fuel channels with multi- bundle shifting and also generates data useful for fuel scheduling.

4. METHOD OF SOLUTION

TRIVENI accepts lattice parameters from the code MURLI-CLUSTER (CLIMAX) (Abstract IAEA0892)in which an integral  transport equation is solved by the collision probability method and ring homogenization is carried out to treat the fuel rod cluster. It can also take lattice parameters from codes based upon the conventional four-factor formalism.

The three-dimensional simulation is done by solving the two-group diffusion equations by the method of finite differences. A
successive overrelaxation technique is used for faster convergence.  
For the follow-up of the reactor operation, burnup calculation is done assuming constant flux over small time steps. The constants for the solution of the diffusion equations are obtained by interpolating into the lattice constant tables provided by a code like MURLI-CLUSTER (CLIMAX) (Abstract IAEA0892).

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The present version  has the following restrictions, but these could be easily relaxed depending upon availability of main storage.

     Number of mesh points                    5800
     Number of fuel points                    3600
     Number of mesh types                       10
     Number of entries in the fuel tables       15
     Number of boundary points                1800

6. TYPICAL RUNNING TIME

      PRIME-450   CYBER-170
Time per print iteration:    2 msec     0.43 msec

The two test cases included in the packages have been executed by NEA-DB on CDC CYBER 740. The following execution times were required:
  test case 1:  1714 CPU seconds
  test case 2:   121 CPU seconds, using the flux values of test
                                  case 1 as as  initial guess

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

TRIVENI takes lattice parameters from the program MURLI-CLUSTER (CLIMAX) (Abstract IAEA0892).

10. REFERENCES

- Tin E.S.Y. and P.C. Loken:
  POWDERPUFS-V, Physics Manual, Part 1 of 3,
  TDAI 31, AECL - Engineering Co. (July 1979)
- A.N. Nakra and K.R. Srinivasan:
  DUMLAC - A Program to Calculate Lattice Properties of Heavy Water
           Lattices
  Note No. RED/TRP/50 (1965)
- H.C. Huria:
  MURLI-CLUSTER, Multiregion Collision Probability Code for PHWR
  BARC Report (to be published)

- K.R. Srinivasan and H.D. Purandare:
  TRIVENI - Three Dimensional Simulator for PHWR.
- In-Core Fuel Management Programs for Nuclear Power Reactors
  IAEA-TECDOC-314  (October 1984)

11. MACHINE REQUIREMENTS:  60K words of main storage are sufficient.

242,616 (octal) words of main storage were required to  run the test cases on CDC CYBER 740.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:
PRIMOS (PRIME-450).

The test cases were executed on CDC CYBER 740 under NOS 1.4-531.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHOR

This code system has been included in the Coordinated Research Programme (CRP) on  "Codes Adaptable  to Small and  Medium-Size
Computers Available in Developing Countries for In-Core Fuel
Management" of the International Atomic Energy Agency.

       K.R. Srinivasan and H.D. Purandare
       Bhabha Atomic Research Centre
       BOMBAY - 400 085, India

File name	File description	Records
IAEA0884_01.003	INFORMATION FILE	44
IAEA0884_01.004	SOURCE PROGRAM (FORTRAN)	1791
IAEA0884_01.005	JCL TO RUN THE TEST CASES	27
IAEA0884_01.006	TEST CASE 1 INPUT FROM UNIT 5	93
IAEA0884_01.007	TEST CASE 1 INPUT FROM UNIT 6	6
IAEA0884_01.008	TEST CASE 1 PRINTED OUTPUT	2105
IAEA0884_01.009	TEST CASE 2 INPUT FROM UNIT 6	8
IAEA0884_01.010	TEST CASE 2 PRINTED OUTPUT	1888