The TREAT facility suspended operations in 1994 after decades of highly successful operation. The TREAT facility began operations in 1958 with a hazards summary report that met the safety-basis regulatory requirements at that time. The TREAT safety basis was later updated in the early 1980s to include a Final Safety Analysis Report (FSAR) and Technical Specifications (TSs) that met the U.S. Department of Energy (DOE) regulatory requirements at that time. The last substantial update of the TREAT safety-basis documents was performed in 1988 prior to suspension of operations in 1994. After the last update, significant changes in DOE regulatory foundation occurred with nuclear safety rule codification in 10 CFR 830, “Nuclear Safety Management.”

To support resumption of transient testing operations, a complete modernization and a significant rewrite of the TREAT safety-basis documents were required to meet 10 CFR 830, Subpart B, “Safety Basis Requirements.” In addition, a completely updated nuclear safety accident analysis was required to support the current operating strategy and a modern safety posture, as well as bound the safe operations of future experiments.

No one clear regulatory format and content template or guide exists for the FSAR and TS for a pulse-type, air-cooled, graphite-moderated DOE reactor such as TREAT. This paper discusses the unique challenges with (1) updating the TREAT safety basis to current DOE regulatory requirements to support the resumption of transient testing operations; (2) documenting that the TREAT design, safety analysis, and operations ensure that the facility is operated safely; and (3) providing an analysis that supports future experiment operations.

The successful approval of the updated TREAT safety basis was a key milestone in the Resumption of Transient Testing Program.