Section 178.358-4 - Construction of Specification 21PF-1B overpacks(a) Each Specification 21PF-1 overpack for which construction began after March 31, 1989, must meet the requirements of Specification 21PF-1B, in conformance with drawings E-S-31536-J-P, and S1E-31536-J2-B of DOE CAPE-1662, Rev. 1, Supplement 1 (IBR, see §171.7 of this subchapter).(b) With the exception of the closure nuts and bolts, all metal parts of the Specification 21PF-1B must be of stainless steel as shown on the drawings referred to in paragraph (a) of this section.Amdt. 178-90, 53 FR 36551, 9/20/1988. Redesigntated by Amdt. 178-97, 55 FR 52716, 12/21/1990; 68 FR 75757, 12/31/2003