PIGs Inspect Oil Pipeline.

From BotPop:

Today’s dramatic shutdown of the BP Alaskan oilfield was actually due to the work of inspection robots that, according to the Times Online, detected “signs of 16 anomalies, and areas where the pipeline wall had thinned by more than 70 per cent.”

The robots are known as intelligent PIGs, or pipeline inspection gauges. The PIGs are sent down pipelines, propelled by oil pressure, and employ a variety of tools including magnetic flux leakage, ultrasonics, and calipers to measure the internal state of the pipeline. The results of a recent inspection (”pigging”) were severe enough to merit today’s shutdown of the Prudhoe Bay oilfield, which supplies 8% of US crude.

Link | Pipeline Inspection Gauge [wiki] | USA Today Article on the shutdown