The following information was received from ALLWEST Testing & Engineering, Inc. via email:
On October 29, 2020, an ALLWEST employee [the authorized user] was testing the density of freshly placed asphalt on Painted Sky Street in the Spring Hollow Ranch subdivision in Nampa, Idaho using a CPN MC-1 portable nuclear densometer (SN 9216). At approximately 1115 Mountain Daylight time, the gauge was damaged by a Cat CCS9 combination roller under the direction of Nampa Paving.
[The authorized user] was in the process of running a density test in AC mode when the roller backed up and impacted the gauge. The roller moved off of the gauge after impact. After impact, the handle was oriented at a 45-degree angle from the base of the gauge and the case was detached from the base. [The authorized user] moved away from the damaged gauge and cordoned off the area to prevent anyone from approaching the damaged gauge.
[The authorized user] immediately contacted the Meridian office assistant RSO [radiation safety officer] who contacted the Corporate RS. [The assistant RSO] and another ALLWEST employee [the employee] responded to the accident and initiated ALLWEST's emergency protocol. [The assistant RSO] used a survey meter to obtain readings around the damaged gauge. The readings indicated the nuclear sources were not exposed and the shielding was intact. The handle was placed back in the case, and the handle, case and base were placed in the transport box. The transport box was then placed in an overpak barrel and transported back to the ALLWEST office.
Additional readings were taken using the survey meter around the gauge at the ALLWEST office. All readings were consistent with the sources being in a shielded condition.
[The assistant RSO] contacted lnstrotek and discussed the condition of the gauge and the readings obtained from the survey meter. lnstrotek representatives indicated it was acceptable to ship the damaged gauge to them for disposal in the transport box. As an additional precaution, [the assistant RSO] and [the employee] wrapped the damaged gauge in lead sheeting and placed the wrapped gauge in the transport box. The transport box with the damaged gauge was then shipped to lnstrotek for disposal.
ALLWEST sent the personal dosimetry badges for [the authorized user], [the assistant RSO], and [the employee] to Landaeur for immediate evaluation. The radiation dosimetry report from Landauer indicated minimal exposure to all three individuals.
The
gauge contained 10 mCi
Cs-137 source and a 50 mCi
Am-241 source.