Contamination found at DOE’s North Las Vegas complex

Thursday, Nov. 11, 1999 | 10:34 a.m.

Department of Energy workers on a routine inspection discovered radioactive contamination more than 10 times the limit allowed for drinking water in a 15-gallon pool of water inside a storage vault at the government's North Las Vegas building complex, officials said Wednesday.

It's the second time in four years that radioactive contamination has been found on the site. Three workers were exposed to radioactivity in 1995 after one scientist opened a container with the nuclear element tritium.

The recent contamination, discovered Oct. 28 and confirmed Tuesday, did not endanger workers or the environment, the DOE said.

That contamination also came from tritium, which emits a low level of radiation, DOE spokesman Darwin Morgan said Wednesday. The contamination may have come from the 1995 contamination incident in the same building, he said.

The radioactive water is in at basement vault at 2621 Losee Road. The DOE complex is secured behind a chain link fence in an industrial area.

Water sampled from the vault on Oct. 28 contained 10 times the drinking water limit worth of radiation, and a second sample on Nov. 9 contained an equally high amount confirming the contamination, Morgan said.

"It is not an environmental hazard at the levels found at DOE, but it is clearly not a natural source of radiation," UNLV nuclear engineer Anthony Hechanova said.

Bechtel Nevada scientists first found the water in the storage vault in the basement of building A-1 during a weekly survey on Oct. 28. The 8-foot-deep by 1_frac1/2-foot-wide vault was built below the basement's floor. Its sides are lined with concrete and it has a gravel bottom open to the subsurface.

Minor changes in the water level inside the vault were noted during the first weekend in November.

Bechtel Nevada, the manager of the DOE's Nevada operations, has assembled a team of engineers and scientists to investigate the extent of the contamination and to find out where the water is coming from.

First, scientists have to collect more samples and analyze them for a range of radioactive and nonradioactive elements to help track possible sources of both the water and the tritium.

From the information they gather, scientists will develop and evaluate cleanup options and any intermediate steps.

Tritium can occur in air or in water, usually in trace amounts. Most of the tritium in the environment has occurred as a result of above-ground nuclear weapons experiments. The radioactive source is used by the DOE to calibrate radiation detectors used for projects such as surveying government and industrial nuclear sites.

The latest radiation incident may be a legacy of previous contamination that occurred in the same building in 1995. In that incident, in which three workers were exposed to tritium, the DOE shut down the laboratory for almost two months.

It took about four months to clean up three rooms of the A-1 building in 1995.

The DOE discovered three workers with tritium in their urine. A total of 75 workers were then tested by an independent medical laboratory for tritium traces, but no one else was contaminated.

Each of the three exposed workers received a dose less than 100 millirems, compared with the average 300 millirems of everyday background radiation in the United States that includes cosmic rays, soils and radon gas from certain rocks. Nuclear workers are limited to 5,000 millirems exposure to radiation a year.

So far the workers have remained healthy, DOE officials say.