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Panel ensures safe operation of the $94 million NSTX Upgrade

Like a new passenger jet or power plant, the National Spherical Torus Upgrade (NSTX-U) must be certified safe to operate. At the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), the task of evaluating the safety of the $94 million upgrade belongs to the Activity Certification Committee (ACC), whose work remains ongoing. “This is a critical group,” said Adam Cohen, deputy director for operations at the Laboratory. “When you have a complex activity like the upgrade you need a standing committee to guarantee that it will run safely.”

For nearly two years the ACC has reviewed key components of the upgrade, which is scheduled for completion in March and will make the NSTX-U the most powerful spherical fusion facility on Earth. The group conducts hands-on inspections — or “walkdowns” — of all systems and subsystems and reviews training and pre-operational test procedures. “It’s very vital and reassuring when the ACC says we’re ready to go,” said Mike Williams, director of engineering and infrastructure and associate director of the Laboratory.

“Defense in Depth”

The committee’s work augments detailed design reviews and safety checks that engineers and other staffers have undertaken. “Even though the Lab has a lot of processes, we go into the field to give added assurance that the upgrade will be safe,” said Charles Gentile, chair of the ACC, whose eight members represent the PPPL safety, engineering and research departments and the DOE site office. The committee provides “defense in depth,” he said.

For example, the ACC checks to make sure that all procedures are followed, all potential hazards identified and all safety issues addressed. “We get into the weeds,” Gentile said. The group asks about not only what works, he noted, but about what didn’t work at first and how it was fixed.

The ACC is free to recommend changes. Gentile led the group that evaluated the original NSTX, which operated from 1999 to 2011 before work began on the upgrade. When that ACC called for installation of more emergency stop buttons and an additional stairway in the NSTX test cell, both recommendations were rigorously followed.

Safety certificate 

The current committee is to deliver a report that recommends issuance of a safety certificate that authorizes the NSTX-U to operate and describes the terms under which the facility is to run. This report will go to the PPPL Environment, Safety and Health (ES&H) Executive Board , the Laboratory’s advisory board for ES&H issues, for review. Final approval of the safety certificate and subsequent operations must then come from Cohen, who chairs the executive board, with concurrence from the DOE site office.

The current ACC evaluation is going well, said committee member Jerry Levine, who heads the Environment, Safety, Health & Security Department and will draft the safety certificate for Cohen to approve with site-office concurrence. While the final report may recommend changes, “we haven’t found any showstoppers,” Levine said.

Committees don’t disband once a certificate is issued. They remain on call throughout the life of a facility to evaluate any changes that could affect safety and to recommend any amendments that may be required. The ES&H Executive Board amended the certificate of the original NSTX several times, on the advice of the committee, after the Laboratory installed new plasma control equipment and modified other parts of the machine.

The painstaking work of such committees makes them invaluable — if largely unsung —  contributors to the research at PPPL. Their scrutiny, says Cohen, “underlies the extremely solid design and construction that produces the equipment and results that outsiders to the Laboratory find incredible.”

U.S. Department of Energy
Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

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