Thanks to artefact for posting this video that was published on August 31, 2018 by Brilliant Light Power on their YouTube Channel titled ‘World’s First Closed SunCell’. It’s quite short and from the description below BLP stat that it was destroyed during subsequent testing due to a power surge.
The description for the video is:
“World’s First Closed SunCell: Batch, hydrogen-inventory-limited testing with predominantly noble gas with some hydrogen having a total pressure slightly over atmospheric. Engineering and low power testing successful. Ignition with higher H2 inventory resulted in a power surge. The World’s First Closed SunCell is no more. Subsequent slow motion (0.25 real time) videos are of sequential runs of the World’s Second Closed SunCell that was tested with limited, reduced hydrogen inventories.”