A Simplified Analysis of the Regulatory Puncture Test

Among the prescribed tests in the Nuclear Regulatory Commission safety standards in Title l 0 of the Code of Federal Regulations, Part 71, Subpart F ( l 0 CFR 71.73) for packagings of radioactive materials is a puncture test, which must follow a 9-m (30-ft) drop event and precede an 8000C thermal event in the hypothetical-accident test sequence. The specific conditions of the puncture test involve a free drop of the specimen through a distance of l m (40 in.) in a position for which maximum damage is expected, onto the upper end of a solid, vertical, cylindrical, mild-steel bar mounted on an essentially unyielding, horizontal surface. The bar must be 15 em (6 in.) in diameter, with the top horizontal and its edge rounded to a radius of not more than 6 mm ( 1/4 in.) and of a length as to cause maximum damage to the package, but not less than 20 em (8 in.) long. The long axis of the bar must be vertical. A packaging user must demonstrate in the Safety Analysis Report for Packaging, either by test or analysis, that the packaging can withstand the puncture test without loss or dispersal of radioactive contents, with no significant increase in external radiation levels, and no substantial reduction in the effectiveness of the packaging, including the assurance of subcriticality.