The radiation safety officer (
RSO) for the licensee reported that he discovered a mass thickness measuring
gauge (
NDC Model # 1107 containing an 80 milliCurie
Am-241 sealed source) removed from its normal location with its shutter open and people working in the vicinity. The
gauge is normally mounted on machinery and used to measure paper thickness for the licensee's pulp mill operations. The mill operation was apparently shut down at approximately 0730 a.m. on 11/09/04 for maintenance. Evidently, the radioactive
gauge shutter was not closed when the operation was shut down. Furthermore, the
gauge was then moved from its mounted location an placed near a walkway as part of the maintenance activities.
The licensee's RSO discovered the condition at approximately 3:30 pm on 11/09/04 and immediately closed the shutter on the gauge. The RSO stated that the shutter on the gauge is opened and closed procedurally without any automatic safety closure when not in operation. The RSO also stated that there are numerous signs and postings that alert personnel to inform and involve the RSO when any activities take place that are in the vicinity of the gauge.
The RSO stated that investigation is just beginning and that details or estimates on potential exposures have not yet been determined. The RSO noted that the maintenance crew in the area consisted of 10 (or less) people. Based on preliminary discussions, it is estimated that the maximum exposure to the gauge was less than 0.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> at a distance of 6 to 12 inches. None of the maintenance personnel were wearing dosimetry so all exposures will have to be estimated.
The
RSO reported this event without a specific CFR report category.