- List
- NSG – Trigger List (Part 1) – INFCIRC/254/Rev.15/Part 1 (21 April 2026)
Graphite having a purity level better than 5 ppm (parts per million) boron equivalent
3 and with a density greater than 1.50 g/cm for use in a nuclear reactor as defined in paragraph 1.1. above, in quantities exceeding 1 kg.
EXPLANATORY NOTE
Boron Equivalent (BE) may be determined experimentally or is calculated as the sum of BE_(z) for impurities (excluding BE_(carbon) since carbon is not considered an impurity) including boron, where:
BE_(z) ppm = CF x concentration of element Z (in ppm); CF is the conversion factor: (σ_(z) x A_(B)) divided by (σ_(B) x A_(z));
σ_(B) and σ_(z) are the thermal neutron capture cross sections (in barns) for naturally occurring boron and element Z respectively; and
A_(B) and A_(z) are the atomic masses of naturally occurring boron and element Z respectively.
3 and with a density greater than 1.50 g/cm for use in a nuclear reactor as defined in paragraph 1.1. above, in quantities exceeding 1 kg.
EXPLANATORY NOTE
Boron Equivalent (BE) may be determined experimentally or is calculated as the sum of BE_(z) for impurities (excluding BE_(carbon) since carbon is not considered an impurity) including boron, where:
BE_(z) ppm = CF x concentration of element Z (in ppm); CF is the conversion factor: (σ_(z) x A_(B)) divided by (σ_(B) x A_(z));
σ_(B) and σ_(z) are the thermal neutron capture cross sections (in barns) for naturally occurring boron and element Z respectively; and
A_(B) and A_(z) are the atomic masses of naturally occurring boron and element Z respectively.