Yes. It is a historical source you are using, not a commentary on a source. The primary/secondary/tertiary definitions are about your relationship to the source, not the source's relationship to history or truth or anything like that.

Primary sources are any sources you are taking as examples of evidence in and of themselves. Them being "primary" does not make them more accurate or anything like that. It just means you are considering them to be a piece of evidence you will be directly examining.

A secondary source is a piece of scholarly commentary, e.g., something that a learned analyst is writing about a primary source. Note that there are things that start out as secondary sources but can easily become primary sources again (e.g., if it was a commentary on the Bible written in the 15th century and you were interested in 15th century commentaries on the Bible, then you'll be regarding such commentaries as primary sources).

Tertiary sources are works that are built up from secondary sources, like encyclopedia articles. Though again, if you were writing a paper on the development of encyclopedia articles, they'd be primary sources again.

So for your paper, the Bible might be your primary source, a scholarly paper on flood narratives might be your secondary source, and a pop culture reference might be a modern song about Noah. Or something like that.

The bible is a group of very diverse documents that would be hard to generalize in this context. However, almost all of the bible used in almost any responsible context would need to be considered to be a primary source in an academic context.

A primary source, as the term is most commonly used in academia and outside of journalism, can be a much more diverse kind of document than just a first hand account of an event written by someone who witnessed the event. It can be functionally any kind of information that was created at the time under study in the context being studied. At least in an academic context, a primary source exist in contrast o a secondary or tertiary source, which are documents that are created to collate and analyze primary sources while citing them. Thus, as the distinction is temporal and contextual rather than authorial exactly, the same document could be either a primary or a secondary source depending on the questions that you are asking of it.

For example, much of Tolkien's scholarship on the history of language was intended to be used as a secondary source, and is still used as such, but those same documents can also be considered a primary source on Tolkien's perspective on language - which is itself a field of study. In the same way, the apostle Paul's epistles constantly cite information he has received second hand about events in cities he was not in. However, almost no one really uses his letters as a secondary source of information about those events - the point of reading his letters is almost always for his perspective on those events, which they are a primary source of information for.

That many of the later letters attributed to Paul are probably pseudepigraphic, also has at least a complex relationship to whether they become secondary rather than primary sources. These are letters written in the voice of Paul by people who clearly at least knew him well but injected their own distinct perspectives into them. If you are reading the letters as a way to gain insight into Paul's perspective, you would probably have to consider these specific letters as at least in some sense secondary sources, but if you are reading them to gain insight into their authentic author's perspective they would be obviously primary.

In your context, so long as you are using the Genesis account of the flood narrative as a source for the Genesis account of the flood narrative, it would be obviously a primary source.

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