EVALUATION OF LEAK SEAL ADDITIVES – COOLING WATER PIPE IN NUCLEAR WASTES

摘要

Commercial leak seal products were evaluated for remote, short-term repair of leaks in water pipe in tanks containing radwaste. A liquid glass metallic product was identified for extensive testing after initial screening of four candidates. Testing was performed with manufactured holes and slits in sample pipe at ～50 psig nominal field pressure (.345 Mpa), immersed in water or simulated waste. The maximum leaks sealed under field test conditions were a slit, 0.016 × 0.291 in. at leak rate 1.34 gpm (.406 × 7.39 mm, 5.07 L/min) and a 0.046 inch diameter hole at 0.63 gpm (1.17 mm hole, 2.38 L/min). Actual geometry and locations of facility leaks could not be determined. Degradation of seals and of constituent fibers was studied for radiation, water and simulated waste exposures. Seals withstood 1.66E7 R, equivalent to 2 years in a nuclear waste tank. A seal functioned for 50 days in simulated waste at 75-80 °C, internal water at 27-35 °C, and several salt/desalt (thermal) cycles. A small leak at 23 days self-healed. The limited results provided confidence that small coil leaks could be repaired. A simple deployment system was designed to introduce sealant to the coil pipe assemblies. The coils have operated for three years with only one reapplication necessary.