The experts at MRG have extensive experience working in nuclear power plants and with nuclear power plant operators. Our team has more than a combined 100 years of experience supporting nuclear power plants with routine fluids analysis (oil and grease), tendon support testing, IR Training, vibration analysis, and ultrasound analysis.
INDUSTRIES SERVES
- Nuclear Power Plants
- Hydro Power Plants
- Coal Power Plants
- Waste to Energy Plants
- Wind Turbines
- Solar Energy
HOW WE SUPPORT POWER GENERATION
- Grease Sampling per ASTM D7718, grease analysis per ASTM D7918
- Oil sampling supplies, including sample fittings, sample bottles (high-temp & UCVD), and the ability to retro-fit sample fittings
- Oil analysis
- HCC – test slate for hydraulics, compressors, and chillers
- PMG – test slate for pumps, motors, and gear boxes
- Diesel Engine Test Slate
- Turbine Oil Test Slate
- Oil Cleanliness Test-Slate
- Coolant Test Slate
- EHC Test-Slate – Electro-hydraulic Control
- Compatibility Studies
- Oil & Grease Compatibility Studies to support lubricant changeovers or inadvertent mixing
- Root Cause Failure Analysis
- Bearings, gears, couplings, belt-drivers, filters, and electrical components
- ICML 55 Lubrication Audit
- Custom lubrication storage solutions and turnkey installations
- Testing MOV regreasing and sample collection
- Electrical signal analysis
- Grease sampling and analysis
- Stem relubrication
NUCLEAR POWER PLANTS
MOV Stem and Stem Nut In-Service Lubrication
To date, the only practical way of relubricating the stem and stem nut of an MOV requires stroking the valve back and forth or disassembly. There is now a more efficient option offered by MRG Labs called the StemThief.
MRG Labs introduced the StemThief at the 2013 MOV User’s Group meeting. A simple and straightforward design, the patent-pending StemThief uses the stem protector mounting threads in the actuator housing to introduce a device that creates a seal against the stem nut. This allows new, fresh grease to be pumped into the stem/stem-nut thread area, purging out the old grease and particulates to establish a new lubricant film for the threads. The relubricator tube section of the Stem Thief is sized to slide over the stem grease sampling without impacting it, and a Zerk fitting mounted on the tube allows the new grease to be introduced with a manual lever grease gun.
MOV Grease Sampling and Analysis
To address the other issues raised in 2010-03, a grease sample can be obtained from the MOV actuator, motor cavity, or the purged grease at the far end of the stem nut. A special kit is available from MRG that follows the guidance of ASTM D7718, “Standard Practice for Obtaining In-Service Samples of Lubricating Grease” to gather a 1 gram sample of the discharged grease. This sample can be analyzed using the Grease Thief.
With this gram of grease, which is approximately the amount that is effectively coating the stem threads in the interface area, analysis can provide insight into particulate levels, both wear and contaminants, consistency changes (hardening or softening from the new fresh grease baseline), and oxidation of the grease. The condition of the grease, as well as wear of the threads, can be monitored in this manner, and the NRC guidance to “assess lubricant performance in MOV application” can be systematically and objectively achieved.
