ASME Codes for Non-Nuclear Pumps

Have you tried a search in their digital library section?

http://www.asme.org/

You will likely need to use the name of the specific type of pump (such as "centrifugal") to narrow down the search.

Either that or you could try a Google search using the search parameters above including "pressure boundary design".

If you get desperate (or need more specific details applicable to a specific code or standard) you could buy the relevant pump standard, but you should be able to find general information on the ASME or internet.

You may be better off looking toward the Hydraulic Institute publications or the API (American Petroleum Institute ) for guidance. ASME would probably refer to it under "Pressure Vessels" as opposed to pump design standards.