NESC0898 OCTAVIA.

1. NAME OR DESIGNATION OF PROGRAM:  OCTAVIA.

3. DESCRIPTION OF PROBLEM OR FUNCTION

OCTAVIA (Operationally Caused Transients and Vessel Integrity Analysis) calculates the probability of pressure vessel failure from operationally-caused pressure transients which can occur in a pressurized water reactor (PWR). For specified vessel and operating environment characteristics the program computes the failure pressure at which the vessel will fail  for different-sized flaws existing in the beltline and the probability of vessel failure per reactor year due to the flaw. The  probabilities are summed over the various flaw sizes to obtain the total vessel failure probability. Sensitivity studies can be performed to investigate different vessel or operating characteristics in the same computer run.

4. METHOD OF SOLUTION

The analysis approach involves calculation of vessel failure pressures using fracture mechanics methods and estimation of pressure-transient characteristics using historical nuclear data.
The pressure vessel is described by input data, such as vessel wall thickness, inside radius, copper and phosphorus content, residual stress, flaw sizes, fluence, and temperature. The failure pressure for a given flaw is calculated using linear-elastic and elastic-plastic methods. After obtaining the failure pressure for a  given flaw size, the probability evaluation is performed. The probabilities for the different flow sizes are then summed to obtain the total probability of pressure vessel failure from the various flaws which might exist in the vessel.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
   100 temperatures
    12 fluences
     8 flaw sizes
with the program's current dimensioning. Only failure oriented flaws in the vessel beltline are considered.

6. TYPICAL RUNNING TIME

The sample problem requires approximately 7 CPU seconds for execution on an IBM370/195 or 3033.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- J.G. Merkle, G.D. Whitman, and R.H. Bryan,
  An Evaluations of the HSST Program Intermediate Pressure Vessel
  Test in Terms of Light-Water-Reactor Pressure Vessel Safety,
  ORNL-TM-5090, November 1975.

- W.E. Vesely, E.K. Lynn and F.F. Goldberg:
  The OCTAVIA Computer Code: PWR Reactor Pressure Vessel Failure
  Probabilites due to Operationally Caused Pressure Transients.
  NUREG-0258 R1  (March 1978)

11. MACHINE REQUIREMENTS

OCTAVIA requires approximately 170K bytes of  storage for execution of the sample problem on an IBM370/195 or 3033

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

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

In
addition to use of the standard input and output units, the program  uses logical unit 10 for scratch storage. OCTAVIA graphical output is produced using proprietary CalComp plotter software. Subroutine LOGRID, which plots logarithmic-scaled grid lines, and the dummy MESSAG subroutine were supplied by NESC for completeness.

15. NAME AND ESTABLISHMENT OF AUTHOR

             W.E. Vesely, E.K. Lynn, and F.F. Goldberg*
             Office of Nuclear Regulatory Research
             U.S. Nuclear Regulatory Commission
             Washingron, D.C. 20555
* Contact

File name	File description	Records
NESC0898_01.001	INFORMATION	33
NESC0898_01.002	JOB CONTROL	62
NESC0898_01.003	OCTAVIA FORTRAN SOURCE	1247
NESC0898_01.004	DUMMY PLOTTING ROUTINES	24
NESC0898_01.005	SAMPLE PROBLEM INPUT	21
NESC0898_01.006	SAMPLE PROBLEM OUTPUT	661