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Blackness coefficients, effective diffusion parameters, and control rod worths for thermal reactors - Methods

Abstract

Simple diffusion theory cannot be used to evaluate control rod worths in thermal neutron reactors because of the strongly absorbing character of the control material. However, reliable control rod worths can be obtained within the framework of diffusion theory if the control material is characterized by a set of mesh-dependent effective diffusion parameters. For thin slab absorbers the effective diffusion parameters can be expressed as functions of a suitably-defined pair of 'blackness coefficients'. Methods for calculating these blackness coefficients in the P1, P3, and P5 approximations, with and without scattering, are presented. For control elements whose geometry does not permit a thin slab treatment, other methods are needed for determining the effective diffusion parameters. One such method, based on reaction rate ratios, is discussed. (author)
Authors:
Bretscher, M M [1] 
  1. Argonne National Laboratory, Argonne, IL 60439 (United States)
Publication Date:
Jul 01, 1985
Product Type:
Conference
Report Number:
ANL/RERTR/TM-6; CONF-8410173; INIS-XA-C-019
Resource Relation:
Conference: 1984 international meeting on Reduced Enrichment for Research and Test Reactors, Argonne, IL (United States), 15-18 Oct 1984; Other Information: 8 refs; PBD: Jul 1985; Related Information: In: Proceedings of the 1984 international meeting on Reduced Enrichment for Research and Test Reactors. Base technology, 529 pages.
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; CONTROL ELEMENTS; CONTROL ROD WORTHS; MESH GENERATION; NEUTRON ABSORBERS; NEUTRON DIFFUSION EQUATION; NEUTRON FLUX; NUCLEAR REACTION KINETICS; P1-APPROXIMATION; P3-APPROXIMATION
Sponsoring Organizations:
U.S. Department of Energy, Assistant Secretary for Nuclear Energy, Office of Spent Fuel Management and Reprocessing Systems (United States)
OSTI ID:
20571774
Research Organizations:
Argonne National Laboratory, Argonne, IL (United States)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
TRN: XA04C1480023781
Availability:
Available from INIS in electronic form
Submitting Site:
INIS
Size:
page(s) 388-397
Announcement Date:

Citation Formats

Bretscher, M M. Blackness coefficients, effective diffusion parameters, and control rod worths for thermal reactors - Methods. IAEA: N. p., 1985. Web.
Bretscher, M M. Blackness coefficients, effective diffusion parameters, and control rod worths for thermal reactors - Methods. IAEA.
Bretscher, M M. 1985. "Blackness coefficients, effective diffusion parameters, and control rod worths for thermal reactors - Methods." IAEA.
@misc{etde_20571774,
title = {Blackness coefficients, effective diffusion parameters, and control rod worths for thermal reactors - Methods}
author = {Bretscher, M M}
abstractNote = {Simple diffusion theory cannot be used to evaluate control rod worths in thermal neutron reactors because of the strongly absorbing character of the control material. However, reliable control rod worths can be obtained within the framework of diffusion theory if the control material is characterized by a set of mesh-dependent effective diffusion parameters. For thin slab absorbers the effective diffusion parameters can be expressed as functions of a suitably-defined pair of 'blackness coefficients'. Methods for calculating these blackness coefficients in the P1, P3, and P5 approximations, with and without scattering, are presented. For control elements whose geometry does not permit a thin slab treatment, other methods are needed for determining the effective diffusion parameters. One such method, based on reaction rate ratios, is discussed. (author)}
place = {IAEA}
year = {1985}
month = {Jul}
}