Understanding Site Hazards

Transcription

1 Springfield, Illinois - City Water, Light and Power - Dallman Unit 31 Nov. 10, 2007 Westinghouse Unit trips. Throttle and control valves close but not completely. Blue Blush issues causes pilot valves not to seat, Throttle valve remained open.016 when valves showed closed. #1 control valve doesn t seat due to a jamming #2 valve stem. Generator breaker opens. Within 30 seconds of unit trip, machine accelerates to an estimated 6,000 RPM Within 39 seconds, major damage to the turbine, the complete destruction of the generator, a hydrogen explosion, significant damage to building structures, and the destruction of three transformers takes place. 6

2 Around Units Operating Hot Pipes/valves: Hot instrument sensing lines (GE or station). If the pressure transmitter has a small leak on a steam line, there will be no water leg and the sensing line will be extremely hot. Skin burns. Water Hammer causing pipes to shift position violently. Damage to piping, hangars. X-rays: If welding is being done then they may be taking x-rays. Ask and stay away. We had an incident where the x-ray areas were not roped off. Steam leaks, piping leaks, spills Fatigue, Heat Exhaustion : Temperatures at the DA level of over 120F on the handrails. Many times well over 100F on the turbine deck. Rotating BOP Equipment, Energized Equipment Thermowells: Incident where compressed air was used to clean out a TW on a hot, operating unit. The cold air weakened the TW and it failed large steam leak, could have killed someone. Never inject cold air into a hot TW best to do TW work when unit is cold and offline. Witness Points: Asbestos insulation. Don t disturb insulation of unknown composition. Pressure Transmitters: Station pressure transmitter sensing line compression fittings (i.e. 1/2" Swagelok connections). An incident occurred where the compression fitting on station HP FW transmitter (~1500psia) was not seated correctly. When our IS attempted to tap into the drain to install our pressure transmitter the line blew apart. Isolation: Valve packing can blow out when tightening valves. Never stand in front of the valve, always to the side. Make sure the operator tightening the valve does not stand over the valve head. We do NOT open or close any station valves! Remote location: The ST engineers are always out on our own for isolation reviews (top of boiler, under condenser, etc). Could be very easy to get hurt and no one being able to find you for hours. Make sure people know the general location of where you will be working. We don't travel with 2 way radio's but we can get these at most plants. 7

3 Southern Company Yates #7 - January 2003 During outage the left side MS inlet piping was found to have bulged. 8

4 Texas - WAP Unit #8 July 2003 Piece of RH pipe traveled over Admin Building an estimated 400+ yards, before hitting and bringing down two (2) 345 kv transmission lines and falling in parking lot. 9

5 Ghent Unit #1 January 2009 Westinghouse unit, blows the lid off a Intercept valve. Note the valve is sitting on top of the turbine. The unit ran a year with the wrong size nuts on the studs. 10

6 Around Unit Disassembled Cranes, Rigging, Cribbing & Equipment Racks: Heavy lifts have occurred over head with no warning. Diaphragm racks have failed with a LP diaphragm falling on a worker. What are others doing around you? There can be a lot of activities that can affect you. Welding, Grinding, Open Flames, Fumes, Rotor being rolled, Hi-pot of generator. Fall hazards: Open Holes in turbine decks such as for MSV access. Horizontal Joints openings when unit is on the half shell. Don t immediately trust condenser cover plating. Trip hazards: Air hoses, power cords. Limited floor space in many powerhouses lead to a cluttered turbine deck full of disassembled components. Air Hoses can break and whip, Machine Tools may be operating nearby. Cuts, Abrasions, Burns, Hearing, Eyes, Toes, Clothing. Always bring proper PPE. Plant may not have items such as ear plugs or hard hats available to borrow. Rotating BOP Equipment, Energized Equipment, Confined Spaces, LOTO Nuclear Plants: Hot components have been found in the disassembly of steam turbines at PWRs plants with steam generator leaks. Asbestos: I may be in steam piping insulation, generator insulation. Breaking steam flanges and joint bolting may disturb and become friable. Cutting into generator insulation can make airborne. Atmosphere: Blast Cleaning is an extremely noisy operation. If tent does not have negative pressure, blast media can escape to atmosphere and be very dirty. Coal dust can be everywhere and easily disturbed during an outage. Fatigue, Heat Exhaustion : Temperatures can be well over 100F on the turbine deck. High humidity environment, outdoor units in hot climate. Long working hours on tight schedule. When we get fatigued, we don t always think clearly. 11

7 Los Barrios Station June 2008 Diaphragm racks of poor design. No lateral support, only a bolt in bottom holding the diaphragm is place. Bolt pulled out of threads and diaphragm fell and severely injured a worker. 12

8 St. Clair Station January 2006 Cast Iron Hood broke when rigging through the manway holes. 13

9 Tools Available in an Emergency Crisis Management 19

10 Hey!!!! Lets be CAREFUL out there!