Container Design Concept - std301320000042

DOE-STD-3013-2000

4. Pressure indication, such as a pressure deflectable lid or bellows observable by

radiography, will permit early detection of inner container pressurization prior to

potential failure. The pressure detection threshold [set at 790 kPa (100 psig) in this

Standard] balances the need to minimize "false positives" with the need to eliminate

"false negatives." Pressure buildup in the container is expected to yield internal

pressures less than 790 kPa (100 psig) from all known pressurization mechanisms.

An internal pressure indication of 790 kPa (100 psig) is therefore adequately

indicative of unexpected pressurization, yet far below the design pressure for the

outer container (Criterion 6.2.1.5 requires the design pressure to be at least

4927 kPa, or 699 psig).

5. Specifying a minimum design pressure provides compatibility with the safety

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.