Evaluation of Polymeric Spray-in-Place Pipe Liners under Elevated Temperature Conditions for Nuclear Industry Applications

Polymeric Spray-In-Place Pipe (SIPP) lining has emerged as a promising trenchless renewal method in the nuclear power industry, often serving as a stand-alone structural solution. A critical challenge for polymeric SIPP linings is their qualification under extreme conditions, including exposure to elevated temperatures that may exceed the material's glass transition temperature (Tg) during transient operations. This study presents a full-scale experimental evaluation of polymeric SIPP performance under such conditions. Experimental testing was conducted on buried and bare SIPP subjected to loading and cyclic temperatures far above their Tg using a Soil-Box setup with a 330-kipf (1,467.9 kN) Mechanical Testing Systems (MTS) compression actuator that simulated soil loading. High-temperature airflow and appropriate instrumentation, including high-temperature-rated Linear Variable Differential Transformers (LVDTs), were used to monitor deflection and structural behavior under direct soil loading. Results demonstrate that polymeric SIPP pipes retained structural integrity and stiffness at temperatures approximately 85°F above Tg, while surrounded by compacted backfill material. The findings support SIPP qualification for nuclear safety applications.