Computer hypermedia technologies offer significant possibilities for integrating data, information, and multifaceted knowledge resources abounding in existing and next-generation nuclear plant operations. A hypermedia system may be viewed as a set of nodes and links allowing nonlinear access to plant information residing in computers regardless of format. The process of accessing information in hypermedia systems is known as navigation. After a review of the state of the art, quantitative criteria are presented for the development of hypermedia databases and a fuzzy graph-based methodology for navigating the large information spaces involved in nuclear plant operations. In the developed methodology, membership functions embodying context-dependent criteria provide application-specific tools for navigation. The methodology is illustrated through numerical examples and a Hyper-Card-based prototypical system for monitoring special material in a next-generation nuclear reactor.