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NESC0326 AIROS2A

AIROS-2A, Space-Independent Reactor Kinetics and Space-Dependent Heat Transfer, Mass Transfer

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1. NAME OR DESIGNATION OF PROGRAM:  AIROS2A
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2. COMPUTERS
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Program name Package id Status Status date
AIROS-2A NESC0326/01 Tested 01-MAY-1972

Machines used:

Package ID Orig. computer Test computer
NESC0326/01 IBM 360 series IBM 360 series
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3. DESCRIPTION OF PROBLEM OR FUNCTION

AIROS2A solves   the   space-
independent  reactor  kinetics  equations  and  provides  for  the
determination of reactivity by solving in addition the discretized
equations that represent the spatial  heat and mass transfer model
for several  fuel channels.   In addition,  variation of  the film
coefficient with  flow is accounted  for along with  the provision
for flow decay and afterglow heating.   Scrams can be initiated by
delayed  signals   from  instruments   that  sense   any  quantity
calculated,   e.g.,   power,  inverse   period   or   temperature.
Generalized feedback equations are used  to provide flexibility in
the  models that  represent multichannel  heat transfer  including
conduction and  convection, energy, pressure and  other phenomenon
such as fuel  melting, coolant boiling and  voiding burn-out.  The
reactivity equation is also  generalized.  The reactivity feedback
coefficients  can  be constant  or  vary  as  the square  root  or
reciprocal of temperature.  Furthermore, any feedback variable can
be used to  initiate a reactivity scram, each with  a unique delay
time.  An input  generator computes the conduction  and convection
coefficients for an n x m  nodal, multichannel system using built-
in tables  of specific heat,  density, conductivity  and viscosity
for the common fuel, structure and coolant materials, and performs
an initial temperature calculation.  The  film coefficients may be
specified or  calculated  using  Lyon's equation  or  the  Dittus-
Boelter equation.
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4. METHOD OF SOLUTION

The numerical technique used to integrate the
neutron and feedback  differential equations is that  developed by
E. R.  Cohen as previously used  in the AIREK codes.   An improved
interval  switching  technique  allows   rapid  calculations  with
predetermined accuracy.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
    15 delayed neutron precursor groups
   400 feedback variables
    90 feedback variables printed out
Any number of channels and nodes per channel within the limitation
above are allowed.
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6. TYPICAL RUNNING TIME

1 to 2  minutes are required for  a problem
with 6 delayed neutron precursor  groups and 50 feedback variables
(including CRT).
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7. UNUSUAL FEATURES OF THE PROGRAM

   (a)  A special provision is made for reactor startup problems
        resulting in a large reduction in running time.
   (b)  Many of the required input data are pre-set but can be
        changed if desired.
   (c)  Addressable input data are used so that on multiple cases,
        only changes need be specified.
   (d)  A restart feature is provided wherein restart cards are
        punched upon abnormal problem termination and/or on an
        input option.
   (e)  Extensive printed and graphical displays are provided as
        follows - power, inverse period, reactivity and any 90
        feedback variables.  Printing and display of feedback
        variables is under the user's control and the latter can
        be grouped on CRT frames as desired.
   (f)  Conduction and convection coefficients may be input and/or
        calculated by means of an input generator which in addi-
        tion performs an initial temperature calculation.
   (g)  Phenomenological models for change of phase are incorpo-
        rated.
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8. RELATED AND AUXILIARY PROGRAMS:
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9. STATUS
Package ID Status date Status
NESC0326/01 01-MAY-1972 Tested at NEADB
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10. REFERENCES

- R.A. Blaine:
  AI Environment Report (May 1967).
- R.A. Blaine:
  Modifications to Airos II-A
  W00048, AI Computing Notice No. 118 (April 4, 1968).
NESC0326/01, included references:
- R.A. Blaine and R.F. Berland:
  Simulation of Reactor Dynamics, Volume I - A Description of
  AIROS IIA
  NAA-SR-12452 (September 1967).
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11. MACHINE REQUIREMENTS

256K byte  IBM360 and an  SC-4020 graphical
display device
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0326/01 FORTRAN+ASSEMBLER
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:   OS/360.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

   Two
new features have been added to  the latest version of AIROS2A.  A
contact resistance term  has been added in the  calculation of the
overall heat transfer coefficients, UA.  A new subroutine has been
added to simulate setback or controller action of a single bank of
control  rods.  If  an  SC-4020 graphical  display  device is  not
available, the  AICRT 3 display routine  can be rewritten,  or all
routines but TAPOUT  and PRINT can be deleted from  the last link.
The NAA SC-4020 (OS) subroutine package is available through -
                  UAIDE Librarian
                  c/o Stromberg-Carlson
                  P. O. Box 2449
                  San Diego, California  92112
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15. NAME AND ESTABLISHMENT OF AUTHOR

                 A. N. Nickols
                 Codes Coordinator
                 Atomics International
                 P. O. Box 309
                 Canoga Park, California  91304
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16. MATERIAL AVAILABLE
NESC0326/01
File name File description Records
NESC0326_01.001 SOURCE PROGRAMME 4470
NESC0326_01.002 OVERLAY,DD CARDS+INPUT DATA 83
NESC0326_01.003 PRINTED OUTPUT 3068
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17. CATEGORIES
  • E. Space-Independent Kinetics
  • H. Heat Transfer and Fluid Flow

Keywords: Cohen equation, computer graphics, delayed neutron precursors, feedback, reactivity, reactor kinetics.