NESC0733 RELAP3B/MOD110

1. NAME OR DESIGNATION OF PROGRAM:  RELAP3B/MOD110.

3. DESCRIPTION OF PROBLEM OR FUNCTION

RELAP3B describes the behaviour of water-cooled nuclear reactors during postulated accidents or power transients, such as large reactivity excursions, coolant losses or pump failures. The program calculates flows, mass and energy inventories, pressures, temperatures, and steam qualities along with variables associated with reactor power, reactor heat transfer, or control systems. Its versatility allows one to describe simple hydraulic systems as well as complex reactor systems.

4. METHOD OF SOLUTION:

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

RELAP3B allows a maximum of 75 volumes connected by a maximum of 100 junctions, with no restrictions as to the order of these connections. However, these maxima may be increased to far greater limits on a large computer.

6. TYPICAL RUNNING TIME

NESC executed the sample problem in less than 1 second of CP time on a CDC 7600.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

RELAP3B/MOD110 is a modification of the RELAP3/MOD62 code developed by the Aerojet Nuclear Company for use on an IBM360. The additions to and/or modifications of RELAP3/MOD62 include:
(1)  Doppler feedback dependence on moderator density;
(2)  extended restart capability;
(3)  capability to trip individual pumps on independent signals;
(4)  automatic time-step selection;
(5)  improved definition of the average fuel temperature; (6)  option to allow the fuel-rod gap size to vary during a transient; (7)  capability to modify the steam table mesh; (8)  inclusion of realistic steam generator models; (9)  calculation of reactivity weight factors; (10)  option to specify new fill curves at restart; and (11)  option to specify new feedback coefficients at restart.

10. REFERENCES:

- User's Manual for RELAP3B-MOD110, A Reactor System Transient Code
  BNL-NUREG-22011.

11. MACHINE REQUIREMENTS:  65K (decimal) words of central memory are required.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  SCOPE.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

   
For best results RELAP3B/MOD110 should be compiled with OPT= and ROUND=+-*/.

15. NAME AND ESTABLISHMENT OF AUTHOR

                 A. Aronson
                 Thermal Reactor Safety Division
                 Brookhaven National Laboratory
                 Upton, Long Island, New York  11973

File name	File description	Records
NESC0733_01.001	INFORMATION	1
NESC0733_01.002	SOURCE PROGRAM	22834
NESC0733_01.003	JCL	9
NESC0733_01.004	SAMPLE PROBLEM INPUT DATA	119
NESC0733_01.005	SAMPLE PROBLEM PRINTED OUTPUT	1034