Dangerous Goods by Road
For accident conditions of carriage a number "N" shall be derived, such that two times "N" packages
shall be subcritical for the arrangement and package conditions that provide the maximum neutron
multiplication consistent with the following:
(a) Hydrogenous moderation between packages, and the package arrangement reflected on all
sides by at least 20 cm of water; and
(b) The tests specified in 6.4.15 followed by whichever of the following is the more limiting:
(i) the tests specified in 6.4.17.2 (b) and, either 6.4.17.2 (c) for packages having a mass not
greater than 500 kg and an overall density not greater than 1 000 kg/m3 based on the
external dimensions, or 6.4.17.2 (a) for all other packages; followed by the test specified
in 6.4.17.3 and completed by the tests specified in 6.4.19.1 to 6.4.19.3; or
(ii) the test specified in 6.4.17.4; and
(c) Where any part of the fissile material escapes from the containment system following the tests
specified in 6.4.11.13 (b), it shall be assumed that fissile material escapes from each package in
the array and all of the fissile material shall be arranged in the configuration and moderation
that results in the maximum neutron multiplication with close reflection by at least 20 cm of
water.
The criticality safety index (CSI) for packages containing fissile material shall be obtained by dividing
the number 50 by the smaller of the two values of N derived in 6.4.11.12 and 6.4.11.13 (i.e. CSI =
50/N). The value of the criticality safety index may be zero, provided that an unlimited number of
packages is subcritical (i.e. N is effectively equal to infinity in both cases).
Test procedures and demonstration of compliance
Demonstration of compliance with the performance standards required in 2.2.7.2.3.1.3, 2.2.7.2.3.1.4,
2.2.7.2.3.3.1, 2.2.7.2.3.3.2, 2.2.7.2.3.4.1, 2.2.7.2.3.4.2, and 6.4.2 to 6.4.11 must be accomplished by
any of the methods listed below or by a combination thereof:
(a) Performance of tests with specimens representing LSA-III material, or special form
radioactive material, or low dispersible radioactive material or with prototypes or samples of
the packaging, where the contents of the specimen or the packaging for the tests shall
simulate as closely as practicable the expected range of radioactive contents and the
specimen or packaging to be tested shall be prepared as presented for carriage;
(b) Reference to previous satisfactory demonstrations of a sufficiently similar nature;
(c) Performance of tests with models of appropriate scale incorporating those features which are
significant with respect to the item under investigation when engineering experience has
shown results of such tests to be suitable for design purposes. When a scale model is used,
the need for adjusting certain test parameters, such as penetrator diameter or compressive
load, shall be taken into account;
(d) Calculation, or reasoned argument, when the calculation procedures and parameters are
generally agreed to be reliable or conservative.
After the specimen, prototype or sample has been subjected to the tests, appropriate methods of
assessment shall be used to assure that the requirements for the test procedures have been fulfilled in
compliance with the performance and acceptance standards prescribed in 2.2.7.2.3.1.3, 2.2.7.2.3.1.4,
2.2.7.2.3.3.1, 2.2.7.2.3.3.2, 2.2.7.2.3.4.1, 2.2.7.2.3.4.2, and 6.4.2 to 6.4.11.
All specimens shall be inspected before testing in order to identify and record faults or damage
including the following:
(a) Divergence from the design;
(b) Defects in manufacture;
(c) Corrosion or other deterioration; and
(d) Distortion of features.
The containment system of the package shall be clearly specified. The external features of the
specimen shall be clearly identified so that reference may be made simply and clearly to any part
of
such specimen.
Testing the integrity of the containment system and shielding and evaluating criticality safety
After each of the applicable tests specified in 6.4.15 to 6.4.21:
(a) Faults and damage shall be identified and recorded;
(b) It shall be determined whether the integrity of the containment system and shielding has been
retained to the extent required in 6.4.2 to 6.4.11 for the package under test; and
(c) For packages containing fissile material, it shall be determined whether the assumptions and
conditions used in the assessments required by 6.4.11.1 to 6.4.11.14 for one or more packages
are valid.
Target for drop tests
The target for the drop tests specified in 2.2.7.2.3.3.5 (a), 6.4.15.4, 6.4.16 (a), 6.4.17.2 and 6.4.20.2
shall be a flat, horizontal surface of such a character that any increase in its resistance to displacement
or deformation upon impact by the specimen would not significantly increase the damage to the
specimen.
Tests for demonstrating ability to withstand normal conditions of carriage
The tests are: the water spray test, the free drop test, the stacking test and the penetration test.
Specimens of the package shall be subjected to the free drop test, the stacking test and the penetration
test, preceded in each case by the water spray test. One specimen may be used for all the tests,
provided that the requirements of 6.4.15.2 are fulfilled.
The time interval between the conclusion of the water spray test and the succeeding test shall be such
that the water has soaked in to the maximum extent, without appreciable drying of the exterior of the
specimen. In the absence of any evidence to the contrary, this interval shall be taken to be two hours if
the water spray is applied from four directions simultaneously. No time interval shall elapse, however,
if the water spray is applied from each of the four directions consecutively.
Water spray test: The specimen shall be subjected to a water spray test that simulates exposure to
rainfall of approximately 5 cm per hour for at least one hour.
Free drop test: The specimen shall drop onto the target so as to suffer maximum damage in respect
of
the safety features to be tested.
(a) The height of drop measured from the lowest point of the specimen to the upper surface of the
target shall be not less than the distance specified in Table 6.4.15.4 for the applicable mass.
The target shall be as defined in 6.4.14;
(b) For rectangular fibreboard or wood packages not exceeding a mass of 50 kg, a separate
specimen shall be subjected to a free drop onto each corner from a height of 0.3 m;
(c) For cylindrical fibreboard packages not exceeding a mass of 100 kg, a separate specimen
shall be subjected to a free drop onto each of the quarters of each rim from a height of 0.3 m.
Table 6.4.15.4: Free drop distance for testing packages to normal conditions of carriage
|
Free drop distance (m) |
|
|
Package mass < 5 000 |
1.2 |
|
5 000 Package mass < 10 000 |
0.9 |
|
10 000 Package mass < 15 000 |
0.6 |
|
15 000 Package mass |
0.3 |
Stacking test: Unless the shape of the packaging effectively prevents stacking, the specimen shall be
subjected, for a period of 24 h, to a compressive load equal to the greater of the following:
(a) The equivalent of 5 times the maximum weight of the package; and
(b) The equivalent of 13 kPa multiplied by the vertically projected area of the package.
The load shall be applied uniformly to two opposite sides of the specimen, one of which shall be the
base on which the package would typically rest.
Penetration test: The specimen shall be placed on a rigid, flat, horizontal surface which will not move
significantly while the test is being carried out.
(a) A bar of 3.2 cm in diameter with a hemispherical end and a mass of 6 kg shall be dropped and
directed to fall, with its longitudinal axis vertical, onto the centre of the weakest part of the
specimen, so that, if it penetrates sufficiently far, it will hit the containment system. The bar
shall not be significantly deformed by the test performance;
(b) The height of drop of the bar measured from its lower end to the intended point of impact on
the upper surface of the specimen shall be 1 m.