NESC0703 ORCENT-2.

1. NAME OR DESIGNATION OF PROGRAM:  ORCENT-2.

3. DESCRIPTION OF PROBLEM OR FUNCTION

ORCENT-2 performs heat and mass balance calculations at valves-wide-open design conditions, maximum  garanteed rating conditions, and an approximation of part-load conditions for steam turbine cycles supplied with throttle steam, characteristic of contemporary light-water reactors. The program handles both condensing and back-pressure turbine exhaust arrangements. Turbine performance calculations are based on the General Electric Company method for 1800-rpm large steam turbine- generators operating with light-water-cooled nuclear reactors. Output includes all information normally shown on a turbine-cycle heat balance diagram.

4. METHOD OF SOLUTION

The turbine performance calculations follow the procedures outlined in General Electric report GET-6020. ORCENT-2 utilizes the 1967 American Society of Mechanical Engineers (ASME) formulations and procedures for calculating the properties of steam, adapted for ORNL use by D.W. Altom.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
   12 feed-water heaters
    5 moisture removal stages in the low-pressure turbine section.
ORCENT-2 is limited to 1800-rpm tandem-compound turbine-generators with single- or double-flow high pressure sections and one, two, or  three double-flow low-pressure turbine sections. Steam supply for LWR cycles should be between 900 and 1100 psia and slightly wet to 100 degrees F of initial superheat. Generator rating should be greater than 100 MVA.

6. TYPICAL RUNNING TIME

Execution time for one valves-wide-open case followed by one maximum guaranteed case is approximately 5 seconds on the IBM 360/91. NESC compiled and executed the sample problems in less than 30 CPU seconds on an IBM 3033.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

The original ORCENT program, prepared by H.I. Bowers of Oak Ridge National Laboratory, for analyzing turbine cycles with large steam turbine-generators operating with saturated or low-superheat throttle steam, utilizes steam properties based on the equations of Keenan and Keyes and turbine performance calculations following the General Electric procedures described in GER-2454A.

10. REFERENCES

- L.C. Fuller:
  User's Instructions for ORCENT II - A Digital Computer Program
  for the Analysis of Steam Turbine Cycles Supplied by Light-Water-
  Cooled Reactors
  ORNL/TM-6525, February l979.
- F.G. Baily, J.A. Booth, K.C. Cotton, and E.H. Miller:
  Predicting the Performance of 1800-rpm Large Steam Turbine
  Generators Operating with Light-Water-Cooled Reactors
  General Electric Company report, GET-6020, February l973.
- R.B. McClintock and G.J. Silvestri:
  Formulations and Iterative Procedures for the Calculation of
  Properties of Steam
  American Society of Mechanical Engineers, New York, 1967.
- ORCENT2, NESC No. 703, ORCENT2 Sample Problem Output
  NESC Note 80-08, December 5, 1979.

11. MACHINE REQUIREMENTS

210K bytes of storage were needed for execution of the sample problems on an IBM 3033.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  OS/360,370.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHOR

L.C. Fuller
Oak Ridge National Laboratory
P. O. Box X
Oak Ridge, Tennessee 37830, U. S. A.

File name	File description	Records
NESC0703_01.001	INFORMATION	36
NESC0703_01.003	SOURCE (EBCDIC)	6531
NESC0703_01.004	S.P. INPUT DATA	49
NESC0703_01.005	S.P. OUTPUT	1008