A second fluid leak has occurred at a Maunakea telescope.
The University of Hawaii’s 88-inch telescope, also called UH88, was discovered in January to have sprung a leak in its coolant system some time between mid-December and Jan. 10, spilling an unknown amount of anti-freezing agent ethylene glycol.
Subsequent investigations determined that some of the chemical might have spilled into a partially blocked pipe that deposits outside the building, although fluid samples from the pipe later showed no significant levels of the substance.
Greg Chun, director of UH’s Center for Maunakea Stewardship, told the board of the Maunakea Stewardship and Oversight Authority on Thursday that plans to transition UH88’s coolant system to propylene glycol — another cooling agent which he said is safer than ethylene — have been finalized and that UH has secured price quotes for replacing the leaky tank and disposing the remaining ethylene glycol.
Those plans, Chun said, are being reviewed by the state Department of Health and the UH Environmental Health and Safety Office. Until those plans are approved and the transition begins, it will remain unclear how much fluid is left in UH88’s coolant system — and, correspondingly, how much leaked. The telescope’s cooling system has an estimated capacity of roughly 480 gallons.
However, Chun told the board Thursday that another ethylene glycol leak was reported April 6 at Subaru Telescope.
“The leak occurred from a small piece of equipment that’s used to pressurize the mirrors,” Chun said.
“This particular piece of equipment had not been operational or turned on since July of last year.”
The Subaru leak, which evidently was caused by the failure of an O-ring filter seal, spilled an estimated 6 liters of fluid over an eight-month period until it was discovered.
Chun said there is no indication that any of the spilled coolant at Subaru escaped the observatory building.
However, he added that Subaru — “on (UH’s) advice” — notified the Department of Health of the leak and is preparing a report about the incident.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
