NIF transport amplifies success
On the evening of Sept. 26, as part of an integrated test of the transport system, the first amplifier slab line-replaceable-unit (LRU) was installed into the National Ignition Facility.
"There was a proud moment when the LRU was inserted," said Gina Bonanno, associate project manager for NIF Assembly, Installation and Refurbishment (AIR), "and even more so when it was retracted. The next day the measurements confirmed that we met our cleanliness requirements as well."
"This test required the collaboration and integration of many different groups and many years effort," said Arlen Rowe, responsible engineer for the bottom-loading slab canister, "and this test occurred seven months ahead of schedule."
In mid August, Ed Moses, NIF Project Manager, asked Bonanno what it would take to demonstrate an LRU insertion into the beamline sooner than scheduled. According to Bonanno, Jacobs was in the process of completing enough of the beampath so it could be pressurized for an LRU insertion into the main amplifier. Pressurization is necessary to maintain cleanliness when the beamline is opened up to the LRU canister, which is pressurized slightly less than the beamline. This positive pressure of clean air keeps particulates out of the beamline during LRU insertion.
Bonanno told Moses she thought they could do it. "It’s important to have a schedule that shows you doing things in a methodical and logical manner, but if the technical work and supporting facility is ahead of schedule, why not take advantage of the situation?" Bonanno said.
An integrated effort of many years
In mid-August, an integrated team started planning how they would insert the first LRU into the system. This team drew upon experts from across the NIF organization. In addition to the AIR team, two other key groups involved were the Beampath Infrastructure System (BIS/Jacobs organization) and the Amplifier Group. These organizations provide the beamline and the amplifier slab LRU. The large optics and the optics processing organizations provided non-production laser glass used in the LRU. The Cleanliness and Contamination Control Group monitored the beamline cleanliness and the Assurances Office made sure integrated safety management was fully embraced through the timeline of activities.
Recently, NIF introduced the Integrated Product Team (IPT) concept to the organization. Brian Felker is the IPT leader for the amplifier system. His job is to coordinate and manage everything required to bring the amplifiers together: utilities, amplifier beam line, LRU, laser glass, and the amplifier assembly team.
"The IPT approach really paid off during this test because so many interfaces were involved — Brian did a terrific job managing them," Bonanno said.
The laser bay-bottom loading delivery system was used to install the amplifier slab LRU. It consists of two components, the bottom-loading canister and the laser bay transporter. The LRU is carried inside the clean environment of the canister. The canister is carried from the optics assembly building (OAB) to the laser bay using the laser bay transporter. The laser bay transporter is an automated guided vehicle that will eventually move automatically to 530 different parking locations in the laser bay. This delivery system required three years of software development, 14,000 lines of code, close to 3,000 point-to-point connections, 150 monitored control points, 11 cameras, and an automated optical alignment system.
It took four years for AIR’s OAB special equipment group – engineers, designers and technicians – to develop and build the equipment used to clean and assemble the LRU used in this test: optic insertion devices, amplifier LRU assembly stands, slab LRU insertion carrier, bottom-loading vertical lifts, the OAB transporter, mechanical cleaners, and docking ports.
"We’re working very well with Jacobs and the trades," Moses said.
"Jacobs did a great job getting the beamline ready for us," Bonanno said, "and clearing the way for us to get in to insert the LRU." Also, to minimize the AIR team’s impact on Jacobs’ other construction efforts, they worked in the laser bay during the swing shift (after 5:30 p.m.) for several weeks leading up to the actual test.
"This test broke the ice, " Bonanno said. "We discovered what it took to get an LRU in the beamline." The steady hand of lead engineer for AIR’s Transport and Handling Group, Steve Yakuma, manually drove the transporter in the laser bay (target sensors for automated operation have not yet been installed) and throughout the procedure to dock the canister with the main amplifier. The transporter has less than one-inch clearance as it turns corners and comes in under the main amplifier.
Inserting an LRU into the beamline forced the team to deal with a lot of issues: cleanliness, safety, off-normal conditions (e.g., what do you do if the LRU gets stuck).
"We took a very rigorous approach to preparing for this test," Bonanno said. "We wanted to be sure we had considered and mitigated all the technical risks. So, we planned it thoroughly."
Three phases of the test
There were three phases to inserting the LRU into the beamline: docking, cover removal and bottom loading the amplifier slab canister into the main amplifier.
On the evening of Sept. 5, the laser bay transporter Defiant moved under the main amplifier and docked for the first time, physically engaging the canister with the beamline, but not inserting the LRU into the beamline.
During the week of Sept. 17, the team performed "cover removal" simulations to make sure that every part of the sequence worked. "This requires us to understand all the details of removing the beamline covers," Bonanno said.
Prior to starting the test on Sept. 26, amplifier group technicians manually removed the covers and swiped the inside of the beamline for cleanliness. They activated the beam purge system, flowing clean dry air through the beamline. "Cleanliness results on the LRU before and after were virtually unchanged," Bonanno said. "The LRU came out very clean, less than level 50 on the glass."
On Wednesday night, Sept. 26, after the team carbo-loaded on a spaghetti dinner prepared by Yakuma, they went out and successfully inserted and removed the LRU into and out of Cluster 3, Bundle 34 of the main amplifier.
The process of moving the LRU from the OAB to the laser bay took a total of five and a half hours. This early test has changed the group’s focus from cleanliness, because they’ve demonstrated they can do it cleanly, to mechanical, physical and alignment items that need to be worked through.
In addition, conducting this LRU insertion and removal test early "gives us confidence that if we plan, coordinate, and work together well, we can do more in that facility than we originally planned," Bonanno said.