Paragraph 6, Pressure Safety Requirements, of Attachment 1 to DOE O 440.1

DOE-STD-3013-2004

envelopes for current and planned storage facilities. The specified design pressure of

4927 kPa (699 psig) is sufficient to contain the pressure generated by the mass of

oxide specified in Section 6.3.2 under "worst case" conditions of 0.5 wt% moisture,

19 w heat generation, and 211C (412F) gas temperature. It thus accommodates

bounding storage conditions at most, if not all DOE facilities where plutonium-

bearing materials might be stored.

6. Paragraph 6, Pressure Safety Requirements, of Attachment 1 to DOE O 440.1,

requires that the ASME code or an alternative design code equal or superior to the

intent of the ASME code be used for pressure vessels. Since the outer can qualifies

as a pressure vessel, but cannot be hydrostatically tested when loaded because of its

contents, and the final weld is not performed by the manufacturer, it will not be

ASME stamped. However, there is precedence in the shipping container qualification

process for less than literal adherence to the code. In this Standard, the pressure

containment vessel is designed to ASME requirements and the fabricator

manufactures the vessel according to code but does not stamp the vessel as

complying with the code. This approach should be used in application of this

Standard by designing and manufacturing the outer storage container to ASME

specifications (for example, ASME VIII) with exceptions documented to show safety

equal to or superior to the intent of the ASME code.

The container may be designated as "Safety Class" in Safety Analysis Reports or

other Authorization Basis documents because it provides primary containment.

It should be noted that designation as a pressure vessel can arise simply because of

the need to contain the internal pressure generated by radioactive decay and by

operation at a temperature higher than that at which it was filled and sealed. Beyond

that, its function as the primary containment requires that it be able to contain the

pressures that might conceivably be generated by all credible processes.

Finally, it should be noted that the pressure estimates are considered to be highly

conservative bounding estimates. Current data indicate that it is unlikely that

container pressures will exceed 790 kPa (100 psig) under normal storage conditions

during a 50-year storage period. It should also be noted that the container

atmosphere may include appreciable percentages of hydrogen in the total gas at the

time of opening, and appropriate precautions should be taken.