At 1355
CDT on 10/3/18, the
Nebraska Office of Radiological Health was notified by the Corporate Radiation Safety Officer (
RSO) that a licensed
moisture density gauge was run over by a large piece of construction equipment on a construction site in Omaha, NE. At the time of the notification to the State, the Corporate
RSO did not know which of the licensee's
gauges was involved in the incident, nor the device model number, isotope, or quantity.
Staff from the Nebraska Office of Radiological Health were dispatched and are enroute to the event site to meet the licensee's Assistant RSO to assess the possible damage to the gauge and obtain further information. No injuries related to the event were reported to the State and no offsite emergency services support were requested.
- * * UPDATE ON 10/5/2018 AT 0945 EDT FROM HOWARD SHUMAN TO ANDREW WAUGH * * *
Contamination swipes verified the source of the gauge to be intact. The gauge's source rod was broken during the event and the source had to be manually retracted into the shielded position. The gauge is currently at Terraco.
The moisture density gauge is a Troxler Model 3440 (serial number: 30122).
Notified R4DO (Farnholtz) and NMSS Event Notifications (email).
- * * UPDATE ON 10/5/2018 AT 1725 EDT FROM LARRY HARISIS TO DONG PARK * * *
The following was received via email from the State of Nebraska:
Nebraska Department of Health and Human Services, Office of Radiological Health was notified on October 3, 2018, by the Radiation Safety Officer (RSO) from Terracon, Inc (Nebraska license 01-58-01) that a portable nuclear moisture density gauge was damaged at a temporary job site. [The licensee authorized user] said that he arrived on the jobsite in Omaha, NE to perform moisture density measurements for Peter Kiewit Construction (general contractor) that was going to be pouring concrete later that afternoon by JR Barger & Sons Concrete Contractors (subcontractor). When [the licensee authorized user] arrived, he parked his vehicle near the work area and assessed the work area. He noticed that there were trucks and other heavy machinery working in the area. [The licensee authorized user] proceeded to take the Troxler portable nuclear moisture density gauge (model 3440, serial number 30122 containing 9 mCi of Cs-137 and 44 mCi of Am-241:Be) out of his vehicle and placed it on the ground where moisture density measurements were to be made. While performing a moisture density measurement with the Cs-137 source deployed from the protective housing, a skid loader backed up and hit the portable gauge. Fortunately, [the licensee authorized user] was able to dive out of the way with the back of the skid loader hitting the back of [the licensee authorized user's] arm. The extent of [the licensee authorized user's] injury is unknown.
[The licensee authorized user] indicated he then proceeded to inform the skid loader to stop but said he continued without acknowledgement. [The licensee authorized user] was then able to get the attention of [the construction project supervisor] to inform him what just transpired. [The licensee authorized user] said that [the construction project supervisor] was not interested in stopping work for the damaged gauge and proceeded to tell [the licensee authorized user] [profanity] or we will call your boss . At this time, [the licensee authorized user] indicated that [an employee] picked up the damaged gauge and threw it to an area outside the work location. An assumption was made of the [the employee's] whole body dose of 571.1 millirem, assuming that he carried the gauge at one centimeter from the trunk of the body and that it took him one minute to move the gauge.
[The licensee authorized user] said he then called [the Omaha RSO] and informed him of what just happened. [The Omaha RSO] then called the Corporate RSO. [The Omaha RSO] was then dispatched to the area with a survey meter and to assist [the licensee authorized user]. [The Corporate RSO] informed [the Nebraska Department of Health and Human Services (DHHS), Office of Radiological Health Manager]. [The Nebraska DHHS, Office of Radiological Health Manager] dispatched [personnel] to the scene.
Meanwhile at the jobsite, [the licensee authorized user] maintained surveillance of the gauge and informed personnel to stay away from where the gauge was located. [The Omaha RSO] said that when he arrived, a radiation survey of the surveillance area and gauge was made. Radiation levels at the surveillance area was about 0.5 mR/hr and the gauge was 10 mR/hr, nearest to the extended Cs-137 source and the source was stuck into the ground to provide additional shielding. Calculations indicated that the exposure rate at the 15 foot exclusion boundary would have been 0.04 mR/hr.
When Nebraska DHHS, Office of Radiological Health staff arrived, another confirmatory radiation survey of the gauge was completed with a result of 10.5 mR/hr. The gauge was also observed to have the source rod extended into the ground and part of the trigger mechanism was broken and sheared off. A wipe test was performed on the source rod with nip tongs and was reading the same as background. The portable gauge was then manipulated to place the Cs-137 source rod assembly back into the shielded position. After an unsuccessful attempt was made, the sliding spring lock was still open and was emitting 385 mR/hr on contact of the port hole. [The Omaha RSO] was able to clear off the excess mud and dirt on the port hole using the nip tongs and the sliding spring lock was shut. Another wipe test was completed and read at background. A radiation survey of the portable gauge confirmed that the Cs-137 source was in the shielded position and measured 20.8 mR/hr.
[The Omaha RSO] placed the portable gauge back in the shipping container and duct tape was applied to prevent any movement of the source rod from the shielded position. A radiation survey of the transport case was performed with the portable gauge inside and the highest was 8.9 mR/hr on contact and 0.4 mR/hr at 3 feet. The listed TI [Transportation Index] of the package was labeled as 0.6 mR/hr. [The Omaha RSO] stated that he will contact InstroTek to either repair or dispose of the gauge upon their return to the Omaha office.
An investigation is currently underway and the event is not closed.
Notified R4DO (Farnholtz) and NMSS Event Notifications (email).
- * * UPDATE ON 10/9/2018 AT 1624 EDT FROM HOWARD SHUMAN TO OSSY FONT * * *
The State of Nebraska submitted the full report. The detailed information was previously provided via email. The item is still open pending a reconstruction of the dose received by the employee who picked up the damaged gauge.
Incident Report No: NE180006
Notified R4DO (Gepford) and
NMSS Event Notifications (email).