Investigation on Transient Characteristics of High Pressure Vessel Water Level Measurement

An experimental study was conducted on the characteristics of high pressure vessel water level systems at both fast and slow depressurization states. The swollen and collapsed water levels were observed experimentally. The test results show that the swollen water level has a relatively fixed difference compared to the collapsed one for the transient of both high and low depressurization rates. Under the conditions of steady and heat up, the differences between the swollen and collapsed water levels are acceptable. For the transients of depressurization, the outputs from the three channels of the inside vessel double-reference-tube water level system have a great deal of differences between each other because of the thermal inertia of the two reference tubes and the water levels in the cistern. In view of nuclear power plant safety and operation, the outside vessel single-reference-tube water level system used in the current pressurizer is adequate and the inside vessel double-reference-tube water level system is suggested as an additional reference to monitor the water level in the steam generator.

Stress–strain and burst failure analysis of fiber wound composite material high-pressure vessel

Composite material high-pressure storage vessel has been increasingly applied in the hydrogen storage industry. This study aims to establish parametric analysis of fiber wound composite vessel and investigate the stress distribution, failure mechanism as well as the burst strength. Based on the maximum strain criterion and Tsai-Wu failure criterion, the burst strength of the vessel and the failure mechanism of the cylinder segment were evaluated and studied. The stresses of the cylinder were much higher than those of the dome. The cylindrical part of the vessel is its weakest area. Matrix failure initiated at the spiral wound layer, then the accumulation of matrix failure resulted in the stiffness becoming degraded and hence fiber failure happened on the hoop wound layers. The fiber failure leaded to the ultimate failure of the vessel. The wound scheme of the outer layers also plays an important role on the load-bearing ability of the vessel. The burst strength of vessel with case-A wound was 122 MPa, while it was 91 MPa for case-B wound, about 25.4% decrease. The numerical results were compared with the burst mode studied in experiments on composite vessels and a good agreement was obtained. This study provides a theoretical foundation for safe design and utilization of composite material high-pressure vessel in the fields of hydrogen storage.

Technical Progress in Chinese Standard of Ultra-High Pressure Vessels

GB/T 34019-2017 “Ultra High Pressure Vessels” is the most important national standard that applies to pressure vessel which design pressure value is greater than or equal to 100MPa (14.5ksi). There is no standard for Ultra-high Pressure Vessel, Then this standard fills the gap in the standard system of pressure equipment in China. This paper mainly introduces the concept and main content of the new national standard, including the materials, design methods and nondestructive testing of ultra-high pressure vessel.