A column I wrote earlier this week, "Was Los Alamos weak link on SNS?" attracted a bit of attention -- including a posting on a blog known as LANL: The Rest of the Story.
An anonymous commenter on the blog said the SNS wasn't the success story it's been built up to be and raised some technical issues about the neutron-producing facilities. I thought they were interesting enough to pursue, and so I asked Ian Anderson -- associate lab director at ORNL and the SNS chief -- to respond to them.
Anderson is currently in Europe and didn't have immediate internet access, but he provided responses via his Blackberry.
Here they are:
Allegation: "The linear accelerator has serious beam loss problems that lead to activation of the items in the accelerator tunnel."
Answer: Linac beam losses at the recent 340 kW are within a factor of 2 of design expectations, which is a roaring success by any measure.
Allegation: "The spallation neutron target can only operate at the specified power for a few weeks before it has to be replaced, a two-month effort."
Answer: Per the SNS design, the system has been designed to rapidly replace targets. The operation should take 1 week, which is built in to the operations schedule.
Allegation: "The superconducting cryomodules provided by the Jefferson Laboratory will ALL have to be totally reworked in order to meet their performance specifications."
Answer: Half the cryomodules exceed their performance specifications by approximately 30%. The other half are lower than their performance specifications by approximately 15%. The performance will be improved by in-situ methods. There is no plan to "totally rework" all cryomodules.
Allegation: "The entire system was designed and built with no consideration of the reliability..."
Truth: Our present availability of 86% is world-class. ISIS 10-year average availability is 88%, Lujan is 80%, PSI is 85-90%.