6.4.11.8

for a package in isolation, it shall be assumed that water can leak into or out of all void spaces

of the package, including those within the containment system. however, if the design incorporates

special features to prevent such leakage of water into or out of certain void spaces, even as a

result of error, absence of leakage may be assumed in respect of those void spaces. special

features shall include either of the following:

(a) multiple high standard water barriers, not less than two of which would remain watertight if

the package were subject to the tests prescribed in 6.4.11.13 (b), a high degree of quality

control in the manufacture, maintenance and repair of packagings and tests to demonstrate the

closure of each package before each shipment; or

(b) for packages containing uranium hexafluoride only, with maximum enrichment of 5 mass percent

uranium-235:

(i) packages where, following the tests prescribed in 6.4.11.13 (b), there is no physical

contact between the valve and any other component of the packaging other than at its original point

of attachment and where, in addition, following the test prescribed in 6.4.17.3 the

valves remain leaktight; and

(ii) a high degree of quality control in the manufacture, maintenance and repair of packagings

coupled with tests to demonstrate closure of each package before each shipment.