2. A package must be so designed that, under the ambient conditions specified in paragraphs 4 and 5, heat generated within the package by the radioactive contents must not, under normal conditions of transport, as demonstrated by the tests in paragraphs 7 – 12 of Part IV of Schedule 9, adversely affect the package in such a way that it would fail to meet the applicable requirements for containment and shielding if left unattended for a period of one week. Particular attention is to be paid to the effects of heat which may—
(a)alter the arrangement, the geometrical form or the physical state of the radioactive contents or, if the radioactive material is enclosed in a can or receptacle (for example, clad fuel elements), cause the can, receptacle or radioactive material to deform or melt; or
(b)lessen the efficiency of the packaging through differential thermal expansion or cracking or melting of the radiation shielding material; or
(c)in combination with moisture, accelerate corrosion.