NESC0548 CEBUG

1. NAME OR DESIGNATION OF PROGRAM:  CEBUG

3. DESCRIPTION OF PROBLEM OR FUNCTION

The    transient    hydraulic
behavior of the sodium in a sodium-heated steam generator in which
a  sodium-water reaction  occurs  due to  a  large  water leak  is
calculated for flows in up to three dimensions.

4. METHOD OF SOLUTION

The  method of  finite  elements  is used  to
calculate  the pressures  in the  multi-dimensional bubble  growth
region.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
   140 elements in 3-D region (including transition elements)
    30 channels
    30 channel nodes
     5 transition elements
     1 cover gas space
    28 connections to finite elements for each transition element
     4 connections to channels for each transition element
   200 time-steps saved in plot output array
In general, the following assumptions also apply -
     A single water leak occurs instantaneously.
     The chemical reaction is instantaneous.
     All water reacts to form NA2O and H2 at 1800 degrees F.
     The hydrogen bubble expands isothermally.
     The sodium is incompressible.
     The steam generator does not deform.
     The analysis stops when the hydrogen bubble reaches a cover
     gas space or completely fills a flow channel.

6. TYPICAL RUNNING TIME

This is highly problem dependent. The sample  problem with 130 finite elements, 1 transition element, and 1 channel is used as an example. This was a 5-tube leak which took 0.39 seconds for the hydrogen bubble to reach the transition element.
     Computer                CPU time
     6400                    435 seconds
     6600                    188 seconds
     7600                     20 seconds

7. UNUSUAL FEATURES OF THE PROGRAM

(a) Leak rate - User specification of water leak rate allows any  desired situation to be modeled (all leaks must be in one  finite element). Any axial and radial location of the leak is  possible. Back pressure effects on the leak rate are calculated      automatically.
(b) Model - Up to 3 dimensions may be modeled in the finite element   region. One-dimensional lumped-parameter channels may be used  to model remainder of system. A cover gas may be modeled. Form,      frictional, and inertial flow resistances may be used.
(c) Pressure relief system - Triggered by pressure above user-set      threshold.  Two-component compressible flow is modeled.
(d) General - Any l/d steam generator may be modeled. Bubble  pressure, sodium pressure and sodium flow throughout the system  are calculated. Relief system flow and material inventory are  calculated. Selected pressures and flows are retained for an      automated plotting package.

8. RELATED AND AUXILIARY PROGRAMS

This program is a major extension
of the APDA  program BUG3.  A plotting package specific  to C-E is
called by CEBUG.  A dummy subroutine,  GRAPH, is provided in place
of it and  can be replaced by a local  equivalent with appropriate
calls.

10. REFERENCES:

- P.K. Doherty and D.W. Stuteville:
  CEBUG - A Code for Steam Generator Sodium-Water Reaction Analysis
  CEND-368 (December 21, 1972).
- P.K. Doherty:
  Double Precision  Version of  CEBUG
  CEND Note (May 17, 1973).

11. MACHINE REQUIREMENTS

21,000 word  memory (CDC6400,6600),  17,000
word memory (CDC7600)

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:     SCOPE    3.3
(CDC6400,6600), SCOPE 2.0 (CDC7600).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

   For
computers with word length less than 60 bits, double precision may
be necessary.  See reference on double precision use with CEBUG.

15. NAME AND ESTABLISHMENT OF AUTHORS

                 P. K. Doherty and D. W. Stuteville
                 Combustion Engineering, Inc.
                 1000 Prospect Hill Road
                 Windsor, Connecticut  06095

File name	File description	Records
NESC0548_01.001	SOURCE PROGRAM (F4)	1299
NESC0548_01.002	SAMPLE CASE INPUT DATA	146
NESC0548_01.003	SAMPLE CASE PRINTED OUTPUT	2565