【国外标准】 Standard Test Method for Determination of Effective Boron-10 Areal Density in Aluminum Neutron Absorbers using Neutron Attenuation Measurements

5.1 The typical use of this test method is determination of 10B areal density in aluminum neutron absorber materials used to control criticality in systems such as: spent nuclear fuel dry storage canisters, transfer/transport nuclear fuel containers, spent nuclear fuel pools, and fresh nuclear fuel transport containers.5.2 Areal density measurements are also used in the investigation of the uniformity in 10B spatial distribution.5.3 The expected users of this standard include designers, suppliers, neutron absorber users, testing labs, and consultants in the field of nuclear criticality analysis.5.4 Another known method used to determine areal density of 10B in aluminum neutron absorbers is an analytical chemical method as mentioned in Practice C1671. However, the analytical chemical method does not measure the “effective” 10B areal density as measured by neutron attenuation.1.1 This test method is intended for quantitative determination of effective boron-10 (10B) areal density (mass per area of 10B, usually measured in grams-10B/cm2 ) in aluminum neutron absorbers. The attenuation of a thermal neutron beam transmitted through an aluminum neutron absorber is compared to attenuation values for calibration standards allowing determination of the effective 10B areal density. This test is typically performed in a laboratory setting. This method is valid only under the following conditions:1.1.1 The absorber contains 10B in an aluminum or aluminum alloy matrix.1.1.2 The primary neutron absorber is 10B.1.1.3 The test specimen has uniform thickness.1.1.4 The test specimen has a testing surface area at least twice that of the thermal neutron beam’s surface cross-sectional area.1.1.5 The calibration standards of uniform composition span the range of areal densities being measured.1.1.6 The areal density is between 0.001 and 0.080 grams of 10B per cm2.1.1.7 The thermalized neutron beam is derived from a fission reactor, sub-critical assembly, accelerator or neutron generator.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.