NEA-0539 ASCOT-1.

ASCOT-1, Thermohydraulics of Axisymmetric PWR Core with Homogeneous Flow During LOCA

NAME OR DESIGNATION OF PROGRAM, COMPUTER, NATURE OF PHYSICAL PROBLEM SOLVED, 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 OR MONITOR UNDER WHICH PROGRAM IS EXECUTED, OTHER RESTRICTIONS, AUTHOR, MATERIAL, CATEGORIES

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1. NAME OR DESIGNATION OF PROGRAM: ASCOT-1.

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2. COMPUTERS

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Program name	Package id	Status	Status date
ASCOT-1	NEA-0539/01	Tested	01-NOV-1978

Machines used:

Package ID	Orig. computer	Test computer
NEA-0539/01	IBM 360 series	IBM 360 series

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3. NATURE OF PHYSICAL PROBLEM SOLVED

ASCOT-1 is used to analyze the thermo-hydraulic behaviour in a PWR core during a loss-of-coolant accident.

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4. METHOD OF SOLUTION

The core is assumed to be axisymmetric two-dimensional and the conservation laws are solved by the method of characteristics. For the temperature response of fuel in the annular regions into which the core is divided, the heat conduction equations are solved by an explicit method with averaged flow conditions.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM: Axi-symmetric
two-dimensional homogeneous flows.

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6. TYPICAL RUNNING TIME: About 1.3 msec per mesh point per time step.

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7. UNUSUAL FEATURES OF THE PROGRAM

(1) Two-dimensional flow, namely, axial flow and radial flow can be solved.
(2) The method of characteristics has the advantage of being accurate and stable and of being able to give well-posed boundary conditions.

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8. RELATED AND AUXILIARY PROGRAMS

The SPADE program is used to calculate the steam tables with pressure and density as independent variables and the APLOT program is used to plot the result calculated by ASCOT-1.

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9. STATUS

Package ID	Status date	Status
NEA-0539/01	01-NOV-1978	Tested at NEADB

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10. REFERENCES

- K. Sato et al:
SCOPE of the Code Development in JAERI for the LOCA-ECCS Evaluation of Light Water Reactors.
Seminar on Reactor Safety, OECD, NEA

NEA-0539/01, included references:

- K. Kobayashi and K. Sato:
  ASCOT-1: A Computer Program for Analyzing the Thermo-Hydraulic
  Behaviour in a PWR Core during a LOCA
  JAERI-M 7917 (September 1978)

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11. MACHINE REQUIREMENTS: About 160k words of memory.

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12. PROGRAMMING LANGUAGE(S) USED

Package ID	Computer language
NEA-0539/01	FORTRAN-IV

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13. OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED: FACOM230-75 monitor 7.

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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 AUTHORS: NAME AND ESTABLISHMENT OF AUTHOR

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16. MATERIAL AVAILABLE

NEA-0539/01

File name	File description	Records
NEA0539_01.001	SOURCE PROGRAM (F4,EBCDIC)	7563
NEA0539_01.002	SAMPLE PROBLEM INPUT DATA	31
NEA0539_01.003	SAMPLE PROBLEM PRINTED OUTPUT	1405

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17. CATEGORIES

G. Radiological Safety, Hazard and Accident Analysis

Keywords: flow rate, heat transfer, hydraulics, loss-of-coolant accident, pwr reactors, reactor safety, thermodynamics, two-dimensional.