Systems acceptance and operability testing for rotary mode core sampling in flammable gas tanks

Water hammers, or fluid transients, compress flammable gasses to their autognition temperatures in piping systems to cause fires or explosions. While this statement may be true for many industrial systems, the focus of this research are reactor coolant water systems (RCW) in nuclear power plants, which generate flammable gasses during normal operations and during accident conditions, such as loss of coolant accidents (LOCA’s) or reactor meltdowns. When combustion occurs, the gas will either burn (deflagrate) or explode, depending on the system geometry and the quantity of the flammable gas and oxygen. If there is sufficient oxygen inside the pipe during the compression process, an explosion can ignite immediately. If there is insufficient oxygen to initiate combustion inside the pipe, the flammable gas can only ignite if released to air, an oxygen rich environment. This presentation considers the fundamentals of gas compression and causes of ignition in nuclear reactor systems. In addition to these ignition mechanisms, specific applications are briefly considered. Those applications include a hydrogen fire following the Three Mile Island meltdown, hydrogen explosions following Fukushima Daiichi explosions, and on-going fires and explosions in U.S nuclear power plants. Novel conclusions are presented here as follows. 1. A hydrogen fire was ignited by water hammer at Three Mile Island. 2. Hydrogen explosions were ignited by water hammer at Fukushima Daiichi. 3. Piping damages in U.S. commercial nuclear reactor systems have occurred since reactors were first built. These damages were not caused by water hammer alone, but were caused by water hammer compression of flammable hydrogen and resultant deflagration or detonation inside of the piping.

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STUDY OF GAS FUEL LEAKAGE AND EXPLOSION IN THE ENGINE ROOM OF A SMALL LNG-FUELED SHIP

The International Journal of Maritime Engineering ◽

10.5750/ijme.v161ia3.1096 ◽

2021 ◽

Vol 161 (A3) ◽

Author(s):

Q G Zheng ◽

W Q Wu ◽

M Song

Keyword(s):

Injury Risk ◽

Engine Fuel ◽

Limited Region ◽

Gas Dispersion ◽

Engine Room ◽

Flammable Gas ◽

Gas Fuel ◽

Fuel Leakage ◽

Gas Cloud ◽

The Given

The engine fuel piping in LNG-fuelled ships’ engine room presents potential gas explosion risks due to possible gas fuel leakage and dispersion. A 3D CFD model with chemical reaction was described, validated and then used to simulate the possible gas dispersion and the consequent explosions in an engine room with regulations commanded ventilations. The results show that, with the given minor leaking of a fuel pipe, no more than 1kg of methane would accumulate in the engine room. The flammable gas clouds only exit in limited region and could lead to explosions with an overpressure about 12 mbar, presenting no injury risk to personnel. With the given major leaking, large region in the engine room would be filled with flammable gas cloud within tens of seconds. The gas cloud might lead to an explosion pressure of about 1 bar or higher, which might result in serious casualties in the engine room.

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Cryogenic leakage risk analysis for FLNG and use of brittle crack arresting material as a risk mitigation measure

10.5957/wmtc-2015-105 ◽

2015 ◽

Author(s):

Akio Usami ◽

Naohiko Kishimoto ◽

Hiroki Kusumoto ◽

Fujio Kaneko ◽

Takehiro Inoue

Keyword(s):

Carbon Steel ◽

Risk Analysis ◽

Brittle Fracture ◽

Risk Mitigation ◽

Brittle Crack ◽

Cryogenic Fluid ◽

Mitigation Measure ◽

Flammable Gas ◽

Confined Environment

Leakage of cryogenic fluid can bring diverse consequences within confined environment like FLNG. In particular, leakage from pressurized refrigerant system is expected to form cryogenic pool, which could initiate brittle fracture of the structure as well as violent evaporation of flammable gas. The authors put the series of different leakage scenarios under light and quantitatively analyzed the potential consequences in an attempt to provide overall pictures of this hazard yet to have been made clear so far. Further, use of brittle fracture arresting steel – a new strain of carbon steel produced through special TMCP technology – was explored on its potential to mitigate the risk.

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