Title: VACUUM PUMP EXPLOSION.

At 2:38 p.m., on July 8, 1977, the Alyeska Pipeline Service Company's pump station No. 8, located 17 miles southeast of Fairbanks, Alaska, exploded and then burned. As a result of this accident, one person was killed, five persons were injured slightly, pump station No. 8 was rendered inoperable, and the entire pipeline from Prudhoe Bay to Valdez was shut down. Damage was estimated to be $35 million. The National Transportation Safety Board determines that the probable cause of the accident was the failure of the poorly coordinated and inadequately supervised personnel at pump station No. 8 to follow preciselymore » the written procedures for performing maintenance work and starting the pumps. Contributing to the accident was the absence of a sole authority or station manager in complete control of all activities within the pump station during this critical startup period. Contributing to the amount of crude oil spilled, to the explosion, and to the fire were the inability of the control room personnel to see the activities going on in the pump room, and the lack of controls in the pump room to enable personnel in that location to close or override the valves and to shut down the pump.« less

The experimental and computational investigations of nanosecond electrical explosion of thin Al wire in vacuum are presented. We have demonstrated that increasing the current rate leads to increased energy deposited before voltage collapse. Laser shadowgrams of the overheated Al core exhibit axial stratification with a {approx}100 {micro}m period. The experimental evidence for synchronization of the wire expansion and light emission with voltage collapse is presented. Two-wavelength interferometry shows an expanding Al core in a low-ionized gas condition with increasing ionization toward the periphery. Hydrocarbons are indicated in optical spectra and their influence on breakdown physics is discussed. The radial velocitymore » of low-density plasma reaches a value of {approx}100 km/s. The possibility of an overcritical phase transition due to high pressure is discussed. 1D MHD simulation shows good agreement with experimental data. MHD simulation demonstrates separation of the exploding wire into a high-density cold core and a low-density hot corona as well as fast rejection of the current from the wire core to the corona during voltage collapse. Important features of the dynamics for wire core and corona follow from the MHD simulation and are discussed.« less

The hydrodynamic blast created by the initiation of a 1 kev X-ray source from an arc-induced ionized gas column, involves density and temperature ratios of such magnitude that the strong shock theory of propagation from continuum fluid mechanics does not apply. Because these simulations occurs in a near vacuum, the continuum equations of motion break down and become invalid during the expansion process as the wavefront density decreases. This report summarizes an approximate treatment of the hydrodynamics of a strong explosion followed by an expanding wavefront in a near vacuum. The analysis was performed in support of the Saturn programmore » to assist the test engineers in the design of a shroud which is optimized to receive the maximum cold X-ray radiation through its aperture while minimizing the hydrodynamic damage to the rest specimens. The analytical treatment uses mass conversion and the assumption of a liner velocity profile to assess the dynamic behavior of the developing wavefront. This technique provides a first estimate of the gas motion and pressure pulse and indicates some general trends of the hydrodynamic phenomenon. 9 refs., 16 figs., 1 tab.« less