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PublisherNACE InternationalLanguageEnglish
Document ID 05604
Content TypeConference Paper
TitleEvaluation of Leak Seal Additives - Cooling Water Pipe in Nuclear Wastes
AuthorsCharles Francis Jenkins, Gregory T. Chandler, and John I. Mickalonis, Westinghouse Savannah River Company; David A. Wilson, Savannah River National Laboratory
SourceCORROSION 2005, April 3 - 7, 2005 , Houston, Tx
Copyright2005. NACE International
Keywordsinhibited water, high level waste, salt deposits, deployable cooling coils, leak seals
PreviewABSTRACT
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.

INTRODUCTION
At the Savannah River Site (SRS) and other nuclear facilities for the Department of Energy, waste from the processing of nuclear material is stored in large carbon steel tanks. Some of these tanks have closed-loop cooling coils for temperature control. At SRS, a receipt tank for evaporator concentrate developed leaks in its cooling loops. Commercial leak seal products were evaluated as a short-term repair to recover some of the cooling coil capacity.

The waste tanks require cooling to remove the radioactive decay heat and other sources of heat (i.e. steam heat loads, ventilation heat loads, or mechanical heat loads from pumping/mixing operations). Cooling at SRS is provided to the waste tanks by a closed loop chromate cooling water (CCW) system. This system has centrally located supply and return headers on the top of the waste tank, which can be individually isolated from the main distribution system. Cooling coil inlet and outlet valves are connected to the supply and return headers, respectively.
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