NEA-0397 FRANCESCA-BWR.

FRANCESCA-BWR, 2 Phase Flow Dynamic for BWR Cooling Channel

NAME OR DESIGNATION OF PROGRAM, COMPUTER, NATURE OF PHYSICAL PROBLEM SOLVED, METHOD OF SOLUTION, RESTRICTIONS, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, AUXILIARIES, STATUS, REFERENCES, REQUIREMENTS, LANGUAGE, OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED, OTHER RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHOR, MATERIAL, CATEGORIES

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1. NAME OR DESIGNATION OF PROGRAM: FRANCESCA-BWR.

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2. COMPUTERS

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Program name	Package id	Status	Status date
FRANCESCA-BWR	NEA-0397/01	Tested	01-MAY-1974

Machines used:

Package ID	Orig. computer	Test computer
NEA-0397/01	IBM 370 series	IBM 370 series

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3. NATURE OF PHYSICAL PROBLEM SOLVED

The steady state and transient problem of a number of parallel BWR coolant channels are solved by the finite difference method. The two-phase flow model includes subcooled boiling and vapour recondensation in the subcooled region.

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4. METHOD OF SOLUTION

The heat transmission in a cylindrical fuel element and cladding is considered at each axial level, with neglect of axial heat conduction. Heat transmission from cladding surface to coolant is governed by Colburn and Jeans & Lottes correlations in convective and boiling transmission, respectively. The subcooled boiling inception point is determined by an original method and vapour production in the subcooled region is evaluated essentially by Bowring's method. DNB correlations are not included and film boiling is not considered. The power distribution is freely specified in input, as well as power evolution during time. The coolant flow redistribution among the different groups of channels is evaluated by the program both in steady state and transients.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM. Pressure drop inside channels must be small compared to the general pressure level. The pressure variation must be slow. No acoustic waves are considered.

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6. TYPICAL RUNNING TIME: One minute.

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7. UNUSUAL FEATURES OF THE PROGRAM

The kinematic model is essentially that of Zuber and Findlay and includes the average effect of local vapour drift as well as that of velocity and concentration distributions.

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8. RELATED OR AUXILIARY PROGRAMS: RELATED AND AUXILIARY PROGRAMS

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9. STATUS

Package ID	Status date	Status
NEA-0397/01	01-MAY-1974	Tested at NEADB

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10. REFERENCES

NEA-0397/01, included references:

- G. Forti:
'FRANCESCA BWR, A Numerical Programme for the Steady State and Dynamic
Calculation of Parallel Coolant Channels for BWR Nuclear Reactors'
Preprint (to be published).

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11. HARDWARE REQUIREMENTS: MACHINE REQUIREMENTS

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12. PROGRAMMING LANGUAGE(S) USED

Package ID	Computer language
NEA-0397/01	FORTRAN-IV

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13. OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED: IBM 370/O.S.

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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

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15. NAME AND ESTABLISHMENT OF AUTHOR: G. Forti
J.R.C. EURATOM
Ispra Establishment, Italy

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16. MATERIAL AVAILABLE

NEA-0397/01

File name	File description	Records
NEA0397_01.001	SOURCE PROGRAM (F4)	1606
NEA0397_01.002	SAMPLE INPUT	32
NEA0397_01.003	OUTPUT LIST OF SAMPLE PROBLEM	905

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17. CATEGORIES

F. Space - Time Kinetics, Coupled Neutronics - Hydrodynamics - Thermodynamics
H. Heat Transfer and Fluid Flow

Keywords: BWR reactors, finite difference method, fuel elements, heat transfer, hydrodynamics, loss-of-coolant accident, steady-state conditions, two-phase flow.