scope:

This TR documents guidance for the inspection, assessment, and repair of heavy wall reactor vessels (nominally considered a wall thickness of 50 mm (2 in.) and greater) in high-pressure hydrogen service operating at temperatures below 455 °C (850 °F). It provides industry practices dealing with reactor vessels after construction and exposure to operating conditions. It focuses on reactor vessels fabricated from 2¼Cr-1Mo, 3Cr-1Mo, 2¼Cr-1Mo-¼V, and 3Cr-1Mo-¼V steels. It also offers some guidance for heavy wall reactor vessels fabricated from 1Cr-½Mo and 1¼Cr-½Mo steels, but specifically does not pertain to C-½Mo steel vessels. However, guidance included in this document can be used for C-½Mo steel reactor vessels at the owner's discretion and with modifications as appropriate.

This document does not address damage found in hot wall catalytic reforming reactors, fluid catalytic cracking unit (FCCU) reactors, and delayed coking drums as they generally operate at higher temperatures and have thinner walls.

Since this is a technical report, it does not provide recommendations, but instead presents industry experience with case histories of repairs and recognized practices, much of which was documented as part of a Joint Industry Program (JIP) on Aging Reactor Vessels, conducted in two phases between 1995 and 2004.