Explosions on a cryo-pump for LH2 transfer

The incident occurred when filling a gaseous tube trailer from a liquid hydrogen stationary storage system. The liquid hydrogen cryogenic pump shaft malfunctioning caused a series of explosions and a fire.

The target pressure of the tube trailer was 2400 psi (180 bar). After approximately 30 minutes of filling, when the pressure in the tubes was approximately 1800 psi (125 bar) the operators heard first a loud explosion and saw then flames and ripples from heat generation near the ground in the hydrogen fill area.

They quickly actuated the emergency alarm system that shut down the cryogenic pump and closed the air-actuated valves on the cryogenic pump supply line. After this shutdown, three smaller explosions were heard as well as the sound of gas releasing from a safety relief valve.

There were no injuries from this incident and negligible property damage.

INITIATING CAUSE: a leak at the cold end packing of the LH2 pump was determined to be the source of the hydrogen.
The IGNITION SOURCE was most likely static electricity or frictional energy on the cryogenic pump shaft.
H2TOOLS identified as PROBABLE ROOT CAUSES shortcomings in maintenance, incomplete procedures and lack of hydrogen detection equipment. Evidences for these attributions were however not provided, but probably contained in the original inspection report.

tube trailer

There were no injuries from this incident and only a small amount of equipment damage with some floor charring.

The fire department was called to the scene and participated in the final shutdown of the hydrogen system as the fire was extinguished prior to their arrival. The partially filled tube trailer was disconnected and moved away from the incident area to a safe location.

A Notice of Violation was issued by the fire department that prevents the start-up of the liquid hydrogen system until all necessary safeguards are in place to re-start the system.