Nuclear Engineering ETDs

Publication Date

Summer 7-28-2026

Abstract

Licensing efforts for Fluoride-Salt-Cooled High-Temperature Reactors (FHRs) are dependent on passive safety systems designed for decay heat removal, yet no prior study has evaluated an air-based Reactor Cavity Cooling System (RCCS) for this role. This thesis addresses that gap by determining whether an air-cooled RCCS can be designed to passively remove post-shutdown decay heat from the Mk 1 FHR. An RCCS configuration was developed and sized using a one-dimensional lumped-parameter design methodology, then evaluated through system-level thermal-hydraulic modeling in RELAP5-3D under a conservative, lower-bound post-shutdown transient. The analysis characterizes the radial heat-transfer pathways from the FHR core to the RCCS and assesses whether core thermal inertia is sufficient to drive passive natural circulation cooling. RELAP5-3D results verify the design methodology, with peak convective heat removal agreeing to within 1.0%. These results demonstrate the feasibility of passive, air-cooled RCCS performance for the Mk 1 FHR and contribute to the technical basis supporting licensing readiness for FHR safety systems.

Keywords

FHR, Safety system, RCCS, passive decay heat removal

Document Type

Thesis

Language

English

Degree Name

Nuclear Engineering

Level of Degree

Masters

Department Name

Nuclear Engineering

First Committee Member (Chair)

Dr. Minghui Chen

Second Committee Member

Dr. Amir Ali

Third Committee Member

Dr. Cassiano Endres de Oliveira

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