Feb. 9, 2001

MA and PA buses almost ready to roll into NIF



By Sue Stephenson
Newsline correspondent

At the end of January, the first pair of amplifier buses was produced in the high bay of Bldg. 381 and shipped to Bldg. 493, a storage area for the National Ignition Facility (NIF).

These massive enclosures will house the first bundle of NIF amplifiers. The main amplifier, MA, is the larger one, and the power amplifier, PA, is the smaller one. This spring these amplifier buses will be installed into Bldg. 581, NIF.

This effort involved not only the NIF Amplifier Assembly team and Flashlamp Window Assembly team, it also required the assistance of Plant Engineering/NIF riggers to operate the overhead crane, straddle lifter and tugs, and Security Police Officers to control traffic on Outer Loop.

"I’m amazed when I think of all the problems this team overcame due to good planning and hard work. It’s a credit to their talent and dedication that a job this complicated was accomplished safely and on such an aggressive schedule," says Amplifier Associate Project Manager Doug Larson.

One difficulty the Amplifier Assembly team overcame was to assemble these school bus-size amplifiers with the great alignment accuracy required by NIF. Parts inside the amplifiers were aligned and fixed within one fourth of a millimeter.

Some of the parts, 72 flashlamp window assemblies, were put together in the Optics Processing Lab (OPL) in Bldg. 391. Then they were carefully transported to the high bay in Bldg. 381 where they were inserted into the amplifier bus.

"All of the large NIF optics will pass through Bldg. 391’s OPL," said Gina Bonanno, associate project manager for Assembly, Installation and Refurbishment, "and this is the first production run performed in that facility. Jim Fair the OPL manager and the two production leads, Guy Robitaille and Sue Frieders led the team that worked very hard to make this happen."

"This is the first step. A total of 1,728 flashlamp window assemblies will be required for NIF. Typically, the Lab does not produce large quantities of anything," Bonanno said, "so we’ve been challenged to not only build complex opto-mechanical assemblies, but to do it in large quantities while meeting strict standards of quality. I’m impressed with how well the team has performed."

Once the amplifier is assembled it will not be cleaned again. So all of the assembly work is done in Class 100 clean rooms: Bldg. 381 high bay and the Optics Processing Lab in Bldg. 391. A Class 100 clean room refers to the quality of air: no more than 100 particles greater in size than half a micron per cubic foot of air.

In addition to working in a clean environment, the assembly teams must keep the surfaces of the various parts with which they work at Level 83 cleanliness. This means there are no more than 900 particles per square foot that are greater in size than five microns on the surface of the items. It is difficult to see a spec of dust that is five microns. The diameter of a human hair is 100 microns.

These super clean requirements are necessary while building, moving and attaching the amplifiers to the NIF system. Even the transport container that stores the massive frames for the amplifiers is specially designed to keep them clean, temperature controlled and precisely aligned while they wait their turn to be placed in NIF.

"This is the culmination of five years of planning and hard work by many people," said Buzz Pedrotti, lead engineer of NIF amplifier mechanical systems. "The responsible engineer, Ernie Moor, production manager Tom Kohut, and their teams of engineers, designers, coordinators, technicians, buyers and suppliers have done a remarkable job of satisfying many difficult requirements for these large structures.

"They have created a production line that safely produces clean, electrically isolated, leak-free enclosures assembled to very tight tolerances. We are proud of our team and delighted that the factory is producing," he said.