Despite millions of dollars spent on upgrades, the 60-year-old production hub at the Y-12 nuclear weapon plant remains seismically vulnerable and could be severely damaged or disabled by a major earthquake.
Sections of the 9212 complex, where the nation’s bomb-grade uranium is processed, were built during World War II, and a federal spokesman at Y-12 said it’s not possible to bring the old facility up to today’s seismic standards. He said that’s one of the reasons why the government wants to build a new Uranium Processing Facility, which is projected to cost as much as $6.5 billion and won’t be available for at least another decade.
The National Nuclear Security Administration initially declined to answer questions about 9212’s structural integrity and whether it could withstand a major earthquake, but spokesman Steven Wyatt later issued this statement by email:
“Safety analyses show that a major earthquake could result in significant structural damage and process failure.”
Process failure means the uranium operations would no longer function, Wyatt said.
The spokesman confirmed that an earthquake could potentially compromise the safety measures in place to prevent a nuclear criticality — an event involving an uncontrolled nuclear chain reaction and release of radiation. “We have analyzed this very carefully and have not identified any scenarios that would have an impact beyond a few meters from the facility,” he said.
No information, however, was released on the potential impacts to workers at 9212 from collapsing walls, falling items, radiation and other earthquake-related hazards.
Wyatt said Y-12’s seismic analyses are based on the “anticipated maximum horizontal ground surface accelerations” for this area, with a range of 0.006 to 0.30 on the Modified Mercalli Intensity Scale. That correlates roughly to an earthquake between 5.0 and 6.0 on the Richter scale, he said.
The latest evaluation was done in 2005, and that report is not releasable to the public, Wyatt said.
A 1987 report, which was obtained years ago through a Freedom of Information Act request, identified more than 500 plausible scenarios for significant earthquake damage at 9212 — each of which would lead to at least one of the “consequences of interest.” Those consequences were serious injury or death of personnel; loss of plant capability; and criticality. At that time, the E-wing of 9212 was considered the most vulnerable because it would collapse with the lowest ground acceleration (0.14), with 20 of the top 50 scenarios involving serious injuries or deaths. Thirteen of the 18 criticality scenarios also were at E-wing, where manufacturing work with highly enriched uranium is conducted. It’s not immediately clear if E-wing today is in better shape or worse shape than it was 20 years ago.
The 9212 complex is a sprawling network of inter-connected process buildings, many of which were added during Y-12’s burgeoning work on nuclear weapons during the Cold War 1950s. Concerns about its safety and the structural soundness are not new.
In 1989, a structural engineer at Lockwood Greene Engineers, a Department of Energy contractor, said he was fired after his study concluded that 9212 would collapse during a major earthquake. The engineer, Paul Nestel, said his study was later revised by other engineers to show that the Y-12 building could withstand an earthquake.
A DOE investigation concluded that Nestel’s firing was inappropriate, although not directly tied to his seismic study of the Y-12 facility. He was later offered his job back, but declined, and reportedly received a $33,000 financial settlement.
The report, meanwhile, brought new scrutiny to 9212 complex, which contains numerous chemical processes for recycling highly enriched uranium used in nuclear weapons. At least one of the building’s wings is used to cast, fabricate and machine uranium metal in various shapes.
In early 1990, a DOE nuclear safety panel headed by John Ahearne, a former chairman of the Nuclear Regulatory Commission, reviewed the seismic issues while holding a session in Oak Ridge and called for additional studies.
There have been other evaluations since then, including regular reports by the Defense Nuclear Facilities Safety Board. The DNFSB has called for more aggressive upgrades at 9212 as the schedule for UPF keeps getting delayed. In a 2005 letter to NNSA, the board’s then-chairman A.J. Eggenberger wrote that the Y-12 contractor recommended that some modifications to address structural deficiencies not be made “because of the facility’s limited life, given the planned construction and start-up of a replacement facility by 2013.”
In a September 2010 letter to Congress, the safety board wrote, “The Department of Energy continues to rely on aging facilities to carry out hazardous production missions.” The board cited the 9212 complex at Y-12 as an “acute” example, along with a plutonium operation at Los Alamos National Laboratory in New Mexico.
“These two facilities are structurally unsound and are unsuitable for protracted use,” said the report signed by the safety board’s five members. “The board is especially concerned as schedules for replacement facilities continue to slip . . . ”
The Oak Ridge situation is complicated by the Y-12 facility’s reportedly essential role in the nuclear weapons program. The current plan is to operate the 9212 complex until the Uranium Processing Facility comes online. However, construction of UPF isn’t scheduled to start until 2012 and won’t’ be completed until 2020, at the earliest, and the new facility won’t be fully operable until 2024.
Wyatt said the government has invested millions of dollars and made “numerous modifications” to 9212 over the past 20 years, “taking seismic design into consideration.”
Those modifications included “efforts to fortify walls and roofing to strengthen the structural integrity of the facility by adding building cross bracing, modifications to equipment and piping,” and the addition of seismic shut-off valves for some processes, he said.
There also is a continuing effort to minimize the quantity of nuclear material at risk, thus reducing the consequences in the event on earthquake or other problem.
Y-12 is just getting started on a $100 million, multi-year program known as the Nuclear Facilities Risk Reduction, which would include improvements to 9212 to extend its lifetime, and Wyatt said an unspecified amount of that money would address seismic-related issues.
While not identifying specific risks to workers, the Y-12 spokesman said the plant tries to prepare for the worst.
“We strive to do everything that we possibly can to ensure the safety and well being of our employees in all potential emergency situations,” Wyatt said. “This includes performing hazard analyzes of all production facility areas in order to determine what personal protective equipment is needed in normal and emergency situations, and training is done to ensure proper usage of it. Workers also participate in emergency management exercises throughout the year to stay prepared for any unforeseen incidents.”