Once removed and decommissioned, any spent fuel from naval reactors is usually reprocessed to extract usable nuclear fuel for civilian generation and the remaining radioactive waste concentrated.

Source: https://www.theguardian.com/australia-news/2023/mar/19/spectre-of-maralinga-hangs-over-aukus-nuclear-waste-for-indigenous-communities

When the product reaches the end of its life, its materials will be reprocessed and kept within the economy to be used for other purposes.

Source: https://www.chartattack.com/how-to-promote-the-use-of-reusable-materials/