05000266/FIN-2007005-07
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Finding | |
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| Title | September 2007 Maintenance Activities Associated with TURBINE-DRIVEN Auxiliary Feedwater Pump 2P-29 |
| Description | The elevated moisture content in the outboard bearing for the 2P-29 turbine was present since the last ten-year overhaul was performed in November 2006. However, while the moisture content levels in the oil from November 2006 until the September 21, 2007, overhaul were elevated, the levels were below the 5,000 ppm value documented as acceptable in EPRI and vendor guidance. Steam leakage from the gland seal or turbine casing joints prior to the September overhaul would not have been vented away from the bearing housing since the turbine insulation extended over the top of the gland seal casing and up to the bearing housing. In addition, original cement-based insulation also blocked the gland seal area vent holes. The licensee concluded, based on test data, that the 2P-29 turbine overhaul that was completed on September 23, 2007, significantly increased the moisture content in the outboard bearing oil. A silicone seal applied at the gland casing to turbine casing joint failed upon initial service resulting in a steam leak in the area of the outboard bearing housing. The failure of the sealant could not be attributed to one factor; however, the licensee did conclude one of the root causes was its maintenance procedures did not address the special requirements needed when applying sealants, and, therefore, site personnel did not have adequate instruction or training on the use of sealants. In addition, the licensee identified that the September 2007 maintenance did not allow for the proper cure time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for the sealant and exceeded the process time of 30 minutes from when the sealant was applied and the joint was torqued. In a review of the site maintenance procedures, the licensee also identified an additional root cause that the site continued to lack adequate guidance on specific assembly details of the turbine, specifically for the oil deflector ring on the turbine shaft: the tightening of the oil deflector ring set screw was not discussed; and acceptable clearances between the turbine shaft and the inner diameter of the oil deflector ring were not specified. The licensee identified three additional contributing causes: receipt and installation of a gland casing from the vendor that had incorrect critical dimensions; previous insulation work blocked the gland seal vents; and plant personnel did not have adequate guidance on the installation of insulation. At the end of the inspection period, the licensee continued to develop and implement corrective actions to address the issues documented in CAP 01115748. At the conclusion of the inspection, the licensee continued to assess the impact of the water ingress on the availability of the Unit 2 TDAFW pump to perform its design and augmented quality functions. There is no current safety concern because the pump was adequately tested and the current low ingress of water into the bearing housing indicated that the pumps functionality is currently maintained for all licensing and design basis events. This issue is an Unresolved Item (URI 05000301/2007005-07) until the NRC reviews the licensees past availability assessment. |
| Site: | Point Beach  |
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| Report | IR 05000266/2007005 Section 4OA5 |
| Date counted | Dec 31, 2007 (2007Q4) |
| Type: | URI: |
| cornerstone | No Cornerstone |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | K Walton M Jones C Zoia R Ruiz R Winter N Valos W Slawinski M Kunowski P Higgins S Burton R Krsekm Kunowskir Krsek S Ghasemian M Jones R Langstaff R Ruiz R Winter J Jandovitz T Bilik W Slawinski C Brown |
| INPO aspect | |
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Finding - Point Beach - IR 05000266/2007005 | |||||||||||||||||||||
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Finding List (Point Beach) @ 2007Q4
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