We have investigated minimum weight optimum design algorism for Type III Carbon Fiber Reinforced Plastic (CFRP) pressure vessel as accumulator of hydrogen stations, which are indispensable for commercialization of fuel cell vehicles. The minimum weight design is searched for using isotensoid design as a first trial design and successively revising layers thicknesses of aluminum liner, CFRP hoop and helical layers. It is demonstrated that the function of aluminum liner should change drastically for long life use under extremely high pressure.

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Hydrogen susceptibility in fatigue life has been examined using commercial JIS SCM420 steel. The effects of carbon content, austenitizing temperature and tempering temperature have been explored in comparison with JIS SCM435 steel that was given the standard heat treatment. Discussion has been made with the information of hydrogen thermal desorption spectroscopy (TDS) and appearance of carbide precipitation. When the tensile strength of SCM420 steel is adjusted to the normally heat treated SCM435 steel by combining higher austenitizing temperature and lower tempering temperature, fatigue life ratio that is the fatigue life of hydrogen pre-charged specimen divided by that of non-charged one stays almost unaffected. When tempering is further lowered to 448K, the tensile strength reaches almost 1500MPa, but the drop in fatigue life ratio is minute. One of the reasons is the suppressed phosphorus segregation along austenite grain boundary that is brought about by elevating the austenitizing temperature. The other is especially for 448K tempering. It is the reduced hydrogen segregation along prior austenite grain boundary, as the results of scarce carbide precipitation along it.

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On October 29, 2009, a leakage of gasoline occurred on the Indian Oil Corporation's Petroleum Oil Lubricants Terminal at Sanganer in Jaipur, Rajasthan State, India. The leakage which continued for 75 minutes led to a severe vapor cloud. An unconfined vapor cloud explosion occurred and it resulted a massive fire of eleven aboveground oil storage tanks. The fire continued to burn for eleven days. Eleven people lost their lives and 45 others were injured in the incident. The Independent Inquiry Committee of the Ministry of Petroleum and Natural Gas issued the report on the cause of this incident. This paper describes the incident according to the Committee's report.

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