In the UK Generic Design Assessment (GDA) process, there are very few firm requirements. Through the ALARP process, you determine the optimal approach through consideration of safety significance, relevant good practice, and the claims/argument/evidence (CAE) approach.
If you're using ASME...
EPRI is an abbreviation for Electric Power Research Institute. It is a collaborative organization where utilities jointly fund research initiatives that have common interest in the industry. Many of their reports have been released to the public.
Ah, you're looking for the concrete consumption amounts (effectively, amount of bulk commodities used during construction).
Your best bet on this might be searching for publically-available EPRI reports. Most such reports for actual projects will be proprietary.
I may have some pouring charts for basemats and structural modules (nuclear island, non-containment) laying around that are public-space. Is this what you're looking for? Or are you looking for an example of a concrete containment building pouring chart?
What are you actually trying to do? In...
US NRC RG 1.136 is the relevant US NRC regulatory guidance on concrete containments.
Other countries will have different rules - most likely wherever you're at will accept the US requirements after reconciliation with your local rules.
https://www.nrc.gov/docs/ML0703/ML070310045.pdf
Lots of great design information about nuclear power plants is provided to the public as part of plant licensing in the US and United Kingdom. As an example, the design certification documents (DCD) for new plants are a good source (https://www.nrc.gov/reactors/new-reactors/design-cert.html) or...
In my experience, you will have appropriate isolation features between the safety and non-safety portion of your system (e.g., two safety-related fuses). If the modification is occurring entirely "downstream" of your isolation features and does not require changes to the design of the safety...
It's probably easier to assess your question if you indicate what the proposed alternative is?
My general understanding is that you are relying on the cable raceway to perform a safety function (structural integrity), so it should be similarly classified as the cable that runs it.
