WC Monitor
8/7/2015
Hanford Workers Test Clean After Possible Radiological Contamination
Three workers appear to be in the clear following potential exposure to airborne radiological contaminants in June at the Hanford Site’s Plutonium Finishing Plant (PFP0, the Defense Nuclear Facilities Safety Board said in a report released this week. “Bioassay evaluations directed due to a potential uptake that occurred when workers disturbed dust in the 242-Z tank room … were returned and activity levels were less than detectable,” DNFSB site representatives said in a report dated July 10.
In a prior site report, the DNFSB officials said all three workers were wearing protective suits while working on a glove box as part of the PFP decontamination and dismantlement process. “Contamination of 1 dpm was measured on one nasal smear and the reading from the lapel air sampler filter of the same individual showed greater than 1DAC-hr after correcting for the respirator protection factor,” according to the June 26 report.
One worker underwent decontamination after a “split” was found in the fabric of the protective suit near the foot. Work on the glove box was also suspended.
However, both DNFSB and DOE said errors were made in calculating the level of airborne radiological material. “Upon further review, an employee made a mistake in the calculations to determine airborne radiological contamination levels; the actual levels were approximately 100 times less than originally thought,” DOE contractor CH2M Plateau Remediation said in an email statement Thursday to Weapons Complex Monitor. “The employee involved received additional training to reduce the likelihood of recurrence.”
The company added that workers “have been retrained on evaluating lapel air sample results. In addition to working with the manufacturer to resolve issues with the suits, employees are adding reinforcing tape to the feet areas of the suits, in line with safety protocols and procedures.”
The size reduction project for the glove box has also resumed, according to CH2M Plateau Remediation.
