Container Construction - std3028

DOE-STD-3028-2000

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

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

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 during

storage.

Finally, it should be noted that the pressure estimates derived in Appendix B using

the pressure equation are highly conservative bounding estimates. Current data

indicate that it is unlikely that container pressures will exceed 207 kPa (30 psia)

under normal storage conditions during a 50-year storage period [Icenhour et al.

2000].

A.6.2.2

Container Construction

1. Corrosion-resistant material should be used for the containers. Use of 304L and

316L stainless steels are recommended, with 316L being preferable to 304L

because of its greater corrosion resistance. Both materials are justified based on

extensive experience in this and similar types of service. Stainless steels 301, 302,

and 303 are not recommended due to their relatively low concentrations of alloying

additions. The use of any corrosion resistant alloy recognized as suitable pressure

vessel material under the criteria of the ASME Boiler and Pressure Vessel Code or

equivalent recognized safety standards is permissible. To reduce the chance of

galvanic corrosion, contact between different metals should be minimized as much

as practical.

2. Polyethylene and polyvinyl chloride (PVC) have been used as bagging materials.

Both deteriorate under heat and radiation and generate undesirable gaseous

products [Kazanjian et al. 1985]. Experiments show that low-density polyethylene

can be used to temperatures as high as 300C (572F) without excessive

degradation to form hydrogen. The maximum service temperature for PVC is ~85C

(185F). In addition to H2, thermal degradation of this plastic produces gaseous HCl,

which corrosively reacts with other materials to form hydrogen. Radiolysis of the two

plastics yields large amounts of the same gaseous products. The radiolysis rate is a