Studying of Thermal and Shielding Properties of PVDF(PolyVinyliDene Fluoride) Pipes used in Aqueous Solution Sectorof the Nuclear Fuel Fabrication Facility

Abstract

As a result of a fire or explosion in nuclear fuel fabrication facilities two risks to health and safety. Mitigation of fire hazards and radioactive release necessitates the use of fire-resistant and appropriate shielding materials, specifically plastic tubes used in chemical reactions during the conversion process. This paper aims to study the thermal stability, flammability, and shielding properties of polyvinylidene fluoride (PVDF) tubes used in the aqueous solutions sector of the Egypt Fuel Manufacturing Pilot Plant (FMPP), to can replacement the consumed one by another from the local market with the same property. For this purpose, PVDF samples were tested by Energy Dispersive X-ray spectroscopy (EDX) and X-ray direction (XRD). Thermal analysis tests as thermogravimetric analysis (TGA) as well as the derivative of thermogravimetric analysis (DTGA). The ignition test was applied using a limiting oxygen index (LOI), flame chamber (UL/94). 137Cs radioactive source of 5mCi activity was used for gamma shielding properties measurement. Shielding parameters of fast neutrons like removal cross-section and mean free path was calculated. Results of (TGA), showed that PVDF has good thermal stability, where weight loss (about1%) is observed at a temperature above 422ºC. PVDF sample successfully passed the UL-94 H-0 rating with a Limiting Oxygen Index (LOI) of about % 44.8. Also, it has appropriate shielding properties due to the high content of fluorine atoms. PVDF containing Al metal in their composition is more effective for the attenuation of fast neutrons.