The following information is a synopsis provided by the licensee via email:
An incident involving a Nuclear Gauge #26 (CPN MC1 DR serial# MD60503240) on a job site (#37: 1564-C) at about 1315 EDT on 07/22/22 in SE Washington, DC 20032. The gauge contained the following sealed sources: 370 MBq (10 mCi) Cs-137 01/17/96 and 1.85 GBq (50 mCi) Am-241/Be 03/27/96.
The gauge was damaged by an excavator while it was under the control of an authorized user (AU). The AU went to their car about 50 feet away to grab some paperwork. The operator of the excavator did not see the gauge, and hit it hard enough to crack its plastic shell. The source rod and electronics were not damaged.
The AU informed an ECS field supervisor about the incident immediately and cordoned off the 15 foot radius of an area around the damaged gauge. The back-up radiation safety officer (RSO), was contacted and came to the site to evaluate the damage. The gauge's plastic case was broken due to the impact, but the sources were in the shielded position. Several surveys were made using a survey meter (RADIATION Alert M4, calibrated on 12/22/21) at one meter distance, and the readings were found to be less than 0.4 mR/hr range.
In addition to contacting the NRC Operations Center on 7/22/22, the Virginia Department of Health was informed at 1755 EDT the same day.
All the pieces of the gauge were placed in a box and it was hauled back to the designated storage area in the Chantilly, VA office around 1700 EDT. After performing a leak test and once an all-clear report is received, the damaged gauge will be returned to the authorized distributor in the area, for them to repair it properly.
All authorized users will be informed about the incident immediately, and this will be discussed in detail at our safety meetings to reiterate and stress the importance of maintaining physical control of
gauges when the
gauge is not otherwise secured using two independent physical locking systems to prevent unauthorized access or removal.