Abstract

This practice details the recommended method for calculating the equivalent boron content (EBC) values of nuclear elements and materials that are of potential significance as thermal neutron poisons. EBC factors are determined from the atomic weight of elements and the thermal neutron absorption cross section in barns. These may be used depending upon the actual neutron energy characteristics of the applicable reactor system. The elements aluminum, fluorine, rubidium, barium, lead, silicon, beryllium, neon, tin, bismuth, oxygen, zirconium, carbon, magnesium, cerium, and phosphorus are not required to be included in the EBC calculations as their contribution to the total poison effect is not considerably significant.

This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

1. Scope

1.1 This standard details a recommended practice for the calculation of the Equivalent Boron Content (EBC) for nuclear materials. The EBC is used to provide a measure of the macroscopic neutron absorption cross section of a nuclear material. EBC factors for the natural elements are determined from their atomic their masses and thermal neutron absorption cross sections. This practice is illustrated by using EBC factors that are based on thermal neutron (2200 m/s) absorption cross sections. Other EBC factors may be used depending upon the actual neutron energy spectrum.

1.2 The EBC is a characteristic of a homogeneous material. Characterization of inhomogeneous materials and calculation of neutron multiplication factors require techniques that are beyond the scope of this practice.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

C696 Test Methods for Chemical, Mass Spectrometric, and Spectrochemical Analysis of Nuclear-Grade Uranium Dioxide Powders and Pellets

C698 Test Methods for Chemical, Mass Spectrometric, and Spectrochemical Analysis of Nuclear-Grade Mixed Oxides ((U, Pu)O2)

C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium Hexafluoride

C799 Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Nuclear-Grade Uranyl Nitrate Solutions

Keywords

boron; neutron absorption; nuclear materials; nuclear poisons; Boron content--nuclear-grade materials; Boron equivalents; EBC (equivalent boron contents); Neutron absorbing materials; Nuclear applications/materials; Nuclear poisons;

ICS Code

ICS Number Code 27.120.30 (Fissile materials and nuclear fuel technology)

DOI: 10.1520/C1233-09

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ASTM C1233