NEA-0587 UTSG.
UTSG, Steady-State and Transients of Vertical U-Tube Steam Generator
NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROBLEM OR FUNCTION, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED, OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHOR, MATERIAL, CATEGORIES
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| Program name | Package id | Status | Status date |
|---|---|---|---|
| UTSG | NEA-0587/01 | Tested | 01-MAR-1980 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NEA-0587/01 | IBM 3033 | IBM 3033 |
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3. DESCRIPTION OF PROBLEM OR FUNCTION
The code is based on a non- linear theoretical model describing the steady-state and transient behaviour of a vertical natural-circulation U-tube steam generator together with its main steam system. The steam generator is con- sidered to consist of a heat exchange section, a top plenum, a down- comer region and a main steam system (with a sequence of relief and/ or safety valves, isolation, bypass, turbine-trip and turbine- control valves and a steam turbine). Possible perturbations from outside can be: inlet water temperature, inlet water mass flow and system pressure on the primary side, feedwater temperature, feed- water mass flow and outlet steam mass flow disturbed by actions of the different valves within the main steam system on the secondary side.
The code is based on a non- linear theoretical model describing the steady-state and transient behaviour of a vertical natural-circulation U-tube steam generator together with its main steam system. The steam generator is con- sidered to consist of a heat exchange section, a top plenum, a down- comer region and a main steam system (with a sequence of relief and/ or safety valves, isolation, bypass, turbine-trip and turbine- control valves and a steam turbine). Possible perturbations from outside can be: inlet water temperature, inlet water mass flow and system pressure on the primary side, feedwater temperature, feed- water mass flow and outlet steam mass flow disturbed by actions of the different valves within the main steam system on the secondary side.
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4. METHOD OF SOLUTION
The theoretical model consists of a set of ana- lytical state and nonlinear ordinary differential equations of first order:
- The steady state (= starting) values are determined by putting in the set of equations the time derivatives equal to zero and sol- ving the resulting set of nonlinear algebraic equations by using the solution method of a linear algebraic equation system in a recursive way.
- Eliminating the steady state parts from the differential equation system and regarding the variables as (absolute) difference values (with respect to its steady state) the calculation of the transient behaviour of the system is performed in a normal- precision way, thus avoiding the more capacity and time-consuming double-precision procedure. The solution of the non-linear ordinary differential equation system of first order is obtained by applying the digital DIFSYS method, an explicit integration procedure based on a method established by Bulirsch and Stoer.
The theoretical model consists of a set of ana- lytical state and nonlinear ordinary differential equations of first order:
- The steady state (= starting) values are determined by putting in the set of equations the time derivatives equal to zero and sol- ving the resulting set of nonlinear algebraic equations by using the solution method of a linear algebraic equation system in a recursive way.
- Eliminating the steady state parts from the differential equation system and regarding the variables as (absolute) difference values (with respect to its steady state) the calculation of the transient behaviour of the system is performed in a normal- precision way, thus avoiding the more capacity and time-consuming double-precision procedure. The solution of the non-linear ordinary differential equation system of first order is obtained by applying the digital DIFSYS method, an explicit integration procedure based on a method established by Bulirsch and Stoer.
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10. REFERENCES
- A. Hoeld:
A Theoretical Model for the Calculation of Large Transients in
Nuclear Natural-Circulation U-Tube Steam Generators (Digital Code
UTSG)
Nucl. Eng. and Design 47, 1-23 (1978).
- A. Hoeld:
A Theoretical Model for the Calculation of Large Transients in
Nuclear Natural-Circulation U-Tube Steam Generators (Digital Code
UTSG)
Nucl. Eng. and Design 47, 1-23 (1978).
NEA-0587/01, included references:
- A. Hoeld:USTG - A Digital Code for Calculating the Nonlinear Transient
Behaviour of a Natural-Circulation U-Tube steam Generator with ITS
Main Steam System. Program Description.
GRS-A-426 (March 1980).
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NEA-0587/01
| File name | File description | Records |
|---|---|---|
| NEA0587_01.001 | INFORMATION | 9 |
| NEA0587_01.002 | SOURCE | 6401 |
| NEA0587_01.003 | INPUT FOR S.P. | 31 |
| NEA0587_01.004 | OUTPUT OF S.P. | 193 |
| NEA0587_01.005 | JCL | 11 |
Keywords: heat exchangers, ordinary differential equations, steady-state conditions, steam generators, steam turbines, transients.