Friday, May 9, 2003 | 11:14 a.m.
WASHINGTON -- The Baltimore train tunnel fire burned at peak temperatures up to 1,800 degrees Fahrenheit during its first three hours, a fire expert who studied the blaze said Thursday. That's higher than the average 1,475-degree temperature rating nuclear waste shipping containers need to withstand for 30 minutes, required by the Nuclear Regulatory Commission.
But despite the skepticism of Nevada experts, independent fire experts and NRC officials at a meeting Thursday said radiation would not have leaked from the hulking metal waste containers if waste had been aboard the train.
Both the state of Nevada and the NRC have been analyzing the July 2001 Howard Street Tunnel fire in Baltimore as part of the high-stakes preparations in the development of the Yucca Mountain project. NRC consultants explained some of their findings at a meeting with Nevada consultants at NRC headquarters in Rockville, Md.
The Yucca project aims to construct a national repository for high-level nuclear waste at the Nevada site 90 miles northwest of Las Vegas, and state officials have challenged whether waste can be shipped there safely. The NRC would be responsible for licensing and regulating the site. The agency also regulates the waste containers.
As part of the NRC's analysis of the Baltimore fire, which has not yet been documented in a full report, experts examined materials from the blaze, including aluminum-coated, cast-iron train car air brakes and train car roof plating, as well as paint and rail-bed sand samples.
Fire experts from the National Institute of Standards and Technology also conducted extensive modeling based in part on baseline statistics gathered at a monitored fire test in a decommissioned West Virginia highway tunnel in the 1990s.
The revelation by NIST's Kevin McGraffan that the fire may have reached 1,800 degrees sparked a line of questions from five Nevada consultants. Nevada officials have challenged the theory that radiation would not have leaked from the casks in the Baltimore fire.
The consultants also raised a few concerns about NIST's modeling.
"All of your modeling is based on a limited amount of tunnel fire testing," Nevada waste transportation consultant Bob Halstead said during McGraffan's presentation. Halstead also decried some "unjustifiably sweeping" generalizations in the NRC's analysis.
Both the NRC and the NIST put the spent fuel in an extra container, adding a layer of protection that the state's analysis did not take into account, Fred Dilger, Clark County Nuclear Waste Division transportation expert, said. A truck shipment of spent reactor fuel would not be packed in an extra container, because the load would weigh too much, he said.
Other experts have noted that the NRC failed to examine the "re-radiation" of heat from the walls of the tunnel, which would intensify the fire, Dilger said.
"The point is really bad accidents happen and really bad accidents can cause containers to fail," Dilger said.
Further, there is a question about how comprehensive the model is, Dilger said.
"The lesson is, we should consider the extra protection for truck shipments of nuclear waste," Dilger said.
Yucca project managers have joined NRC officials in saying that waste containers are robust and would survive conceivable fires.
Still, the NRC is planning a new series of impact and fire tests on full-scale models of the steel waste-shipping containers.
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