NEA-0125 NRN.

1. NAME OR DESIGNATION OF PROGRAM:  NRN.

3. NATURE OF PHYSICAL PROBLEM SOLVED

A system of programmmes using the NRN shield design method.
NRN consists of the following programmes

   1) Data preparation programme NECO.
   2) Multigroup removal programmes REBOX for box geometry and REMC for spherical and cylindrical geometries.
   3) Multigroup diffusion - and slowing down programme NEDI.

4. METHOD OF SOLUTION

The NRN method presents a new approach in the formulation of removal-diffusion theory. The removal cross section is redefined and the slowing down between the multi-group diffusion  equations is treated with a complete energy-transfer matrix rather than in an age theory approximation.

6. TYPICAL RUNNING TIME

With suitably optimized programmes the method  leads to relatively short running times, a typical first run of a problem (including a data preparation run) taking approximately 2 minutes and repeated runs with a ready macroscopic data tape 1 minute on a CDC 6600 computer.

7. UNUSUAL FEATURES OF THE PROGRAM

The aim has been to produce a method that required the minimum amount of manual input data, mainly the specifications for the materials, configuration and sources in question. This has been possible to arrange by letting the output magnetic tape of one programme serve as an input tape to the next programme etc.

8. RELATED OR AUXILIARY PROGRAMS: RELATED AND AUXILIARY PROGRAMS

- L. Hjarne:
  A Users Manual for the NRN Shield Design Method
  AE-145, AB-Atomenergi (1964).
- E. Aalto et al:
  A Users Manual for the CDC Version of the NRN Shield Design Method
  AE-RF-73-462 AB-Atomenergi (1973).
- E. Aalto et al:
  A Preliminary Users Manual for the NRN Shield Design Method in
  FORTRAN IV Language
  AE-FFA-673, RFN-213, AB-Atomenergi (1965).
- L. Hjarne, M. Leimdorfer:
  A Method for Predicting the Penetration and Slowing Down of
  Neutrons in Reactor Shields
  Reprint from Nucl. Sci. and Eng.. 24, p. 165 - 174 (1966).
- E.Aalto et al:
The Fine Adjustment of the Neutron Penetration in the NRN Method
Nucl.Sci.Eng., 24(2),165-174 (1966)

11. MACHINE REQUIREMENTS:  64k words or less.

13. OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED: IBJOB (IBM 7044).
SCOPE (CDC 3400 and CDC 6600).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

15. NAME AND ESTABLISHMENT OF AUTHOR

       G. Olson
       AB-Atomenergi
       Studsvik, Nykoping
       Sweden.

CDC 3400 version was offered by Tesperhude (Gesellschaft fuer
Kernenergieverwertung in Schiffbau und Schiffahrt MBH., Germany).

File name	File description	Records
NEA0125_01.001	NECO SOURCE PROGRAM (F4)	2277
NEA0125_01.002	REBOX SOURCE PROGRAM (F4)	499
NEA0125_01.003	REMC SOURCE PROGRAM (F4)	603
NEA0125_01.004	NEDI SOURCE PROGRAM (F4)	1193
NEA0125_01.005	NRN DATA LIBRARY (BCD)	7083
NEA0125_01.006	NECO SAMPLE PROBLEM INPUT DATA	75
NEA0125_01.007	REBOX SAMPLE PROBLEM INPUT DATA	53
NEA0125_01.008	REMC SAMPLE PROBLEM INPUT DATA	36
NEA0125_01.009	NEDI SAMPLE PROBLEM INPUT DATA	93
NEA0125_01.010	RECO SAMPLE PROBLEM PRINTED OUTPUT	2720
NEA0125_01.011	REBOX SAMPLE PROBLEM PRINTED OUTPUT	1240
NEA0125_01.012	REMC SAMPLE PROBLEM PRINTED OUTPUT	1280
NEA0125_01.013	NEDI SAMPLE PROBLEM PRINTED OUTPUT	1140