Overview of the Spallation Neutron Source and affiliated facilities on Chestnut Ridge. Click on pic to enlarge. (ORNL photo)
Big Science sometimes brings big headaches, further evidenced by events of early Friday morning at the Spallation Neutron Source.
At about 1:30 a.m., the SNS experienced a “significant power disturbance.” According to Kevin Jones, director of Oak Ridge National Laboratory’s Research Accelerator Division, the problem was related to a storm passing through the area, with lightning probably striking an overhead transmission line at the research center atop Chestnut Ridge.
“The disturbance lasted long enough to trip off the majority of the accelerator systems,” Jones said in an email message Friday evening. “The accelerator was restored to operation at about noon, but we have to do a complete warm up and cool down cycle for the cryogenic moderator system to ensure that full performance is recovered.”
Jones said the SNS folks expect the moderator system to be ready for operations by late Saturday afternoon. If that’s the case, the overall impact on research activities will be approximately 40 hours — not incredibly long, but hurtful nonetheless.
“This will affect up to 22 experiments and 65 users, and we will be working with them to re-plan their experiments if they cannot successfully bring them to conclusion this weekend,” Jones said.
As noted recently following an equally unsettling problem at the High Flux Isotope Reactor, a sister neutron facility, there’s more at stake this month than the operating experiments.
Beginning tomorrow (Sunday, June 21), ORNL will be hosting students taking part in the annual ORNL/Argonne Neutron and X-ray School. That will continue through Friday, June 26, and the Oak Ridge National Laboratory neutron sciences group would like to have both of its major neutron sources up and running for students to gain how-to experience.
The SNS has had some notable disruptions over the past year, but Jones said that before the stormy events of Friday morning the systems had been operating “quite well” at a power level of about 1.15 megawatts. The availability for users has been about 95 percent, he said.
The spring research season at SNS is about to come to a close, with plans to turn off the system for the annual six-week summer maintenance outage on June 28. The plan is to resume operating on Aug. 14.
Addendum: I asked Jones this morning about the above-ground transmission lines. He noted that the on-site lines are underground, but the site power delivered by TVA is via overhead 165kV lines — so that’s where the problem may have occurred. He said the recovery is on schedule and operations should resume this afternoon.
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