last modified: 01-FEB-1984 | catalog | categories | new | search |

NEA-0865 SCRIMP.

SCRIMP, Steady-State Thermohydraulics of HTGR Subchannel

top ]
1. NAME OR DESIGNATION OF PROGRAM:  SCRIMP.
top ]
2. COMPUTERS
To submit a request, click below on the link of the version you wish to order. Only liaison officers are authorised to submit online requests. Rules for requesters are available here.
Program name Package id Status Status date
SCRIMP NEA-0865/01 Tested 01-FEB-1984

Machines used:

Package ID Orig. computer Test computer
NEA-0865/01 CDC CYBER 740 CDC CYBER 740
top ]
3. DESCRIPTION OF PROBLEM OR FUNCTION

SCRIMP is a thermal hydraulic subchannel analysis code which calculates the steady state pressure  drops, flow rates, heat transfer rates and temperatures in gas- cooled thermal reactors. It is not designed to model fast reactor conditions, but can be used if the power gradient across a fuel element is not too large.
top ]
4. METHOD OF SOLUTION

A lumped parameter type of calculation is applied using averaged values for each sub-flow-area or subsurface.  The same pressure drop is assumed to exist along each subchannel, and no net cross flow is allowed between them in any one axial step. Turbulent eddy, momentum exchange between adjacent subchannels is, however, calculated.

Four heat transfer modes are considered:
1)  Surface to coolant convection.
2)  Intersurface radiation exchange.
3)  Intersurface conduction.
4)  Surface to ambient heat loss.

Axial variation of physical properties and the redistribution of mass flow between subchannels can be accounted for by dividing the problem into a series of axial steps. The outflow properties of one  step are used to compute the inflow properties of the next.
top ]
5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

There is a maximum of 28 characteristic flow channels and 74 characteristic surfaces.
However, the total number of channels and surfaces is limited only by the available memory space.
top ]
6. TYPICAL RUNNING TIME

32 seconds of CP time on a CDC 6500 were required for a sample problem consisting of a 37 rod hexagonal bundle divided into 4 axial sections. 1% iteration accuracy was requested, and radiation exchange was neglected.
top ]
7. UNUSUAL FEATURES OF THE PROGRAM

SCRIMP incorporates a new sub- routine to calculate friction factors and stanton numbers in terms of subchannel boundary conditions. Thus, individual heat transfer coefficients are computed for each subsurface; the earlier SCEPTIC code calculated only one value per subchannel.

The program is suitable for a wide range of geometries.
top ]
8. RELATED AND AUXILIARY PROGRAMS

SCRIMP is an extended version of SCEPTIC, itself a modification of HECTIC-II.
top ]
9. STATUS
Package ID Status date Status
NEA-0865/01 01-FEB-1984 Tested at NEADB
top ]
10. REFERENCES:
NEA-0865/01, included references:
- M. Huggenberger:
  SCRIMP: A Subchannel Analysis Code - Short Description and User's
  Guide.  TM-IN-635  September 1976.
- M. Huggenberger:
  SCRIMP: A Thermal-Hydraulic Subchannel Analysis Computer Code.
  EIR-Bericht Nr. 322  June 1977.
top ]
11. MACHINE REQUIREMENTS

140,000 octal words on a CDC 6500. In addition, one subroutine requires a buffer of 20,000 octal words of  extended core storage.
top ]
12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NEA-0865/01 FORTRAN-IV
top ]
13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  Standard.
top ]
14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
top ]
15. NAME AND ESTABLISHMENT OF AUTHOR

          M. Huggenberger
          Eidg. Institut fuer Reaktorforschung
          5303 Wuerenlingen
          Switzerland
top ]
16. MATERIAL AVAILABLE
NEA-0865/01
File name File description Records
NEA0865_01.003 SCRIMP INFORMATION FILE 35
NEA0865_01.004 SCRIMP SOURCE PROGRAM (FORTRAN-4) 2076
NEA0865_01.005 SCRIMP INPUT DATA FOR TEST CASE 220
NEA0865_01.006 SCRIMP JCL FOR TEST CASE EXECUTION 14
NEA0865_01.007 SCRIMP PRINTED OUTPUT OF TEST CASE 2316
top ]
17. CATEGORIES
  • G. Radiological Safety, Hazard and Accident Analysis
  • H. Heat Transfer and Fluid Flow

Keywords: HTR reactors, flow rate, gas cooled reactors, heat transfer, hydrodynamics, hydrothermal systems, pressure, pressure gradients, steady-state conditions, thermal reactors, thermodynamics.