Chase Environmental Group employees discovered an abnormally high radiation reading on contact with a sealed source
gauge at approximately 8:30 a.m. EST. Contact readings were 150 mR/hr with the window of the
gauge. The shutter indicator light on the C-Frame indicated that the shutter was closed. Cycling the shutter controls did not change the radiation measurements on contact with the window, however the indicator lights cycled from closed to open to closed again.
The manufacturer was notified and the manufacturer advised that air pressure should be disconnected to cause the shutter to close. After removing air, no changes to radiation levels were found. Nucor employees are arranging for the manufacturer to come on site to repair the gauge as soon as possible.
Because the shutter will not close, Nucor has locked out air and electrical power to the device to prevent inadvertent operation, and cordoned off the area to prevent anyone from accessing the gauge. Measurements at one foot from the window of the gauge were less than 2 mR/hr. The area is posted as a Radiation Area. Chase Environmental Group employees made all radiation measurements and were wearing dosimetry. No overexposures are expected.
The gauge involved is at the Nucor Steel company in Crawfordsville, IN. The Nucor NRC License number is 13-25975-01 and the RSO is Dave Sulc. The gauge is a DMC Am-5A, serial# BS21645. The source is Am-241, activity of 1 Ci, and serial# 1979LQ. This is a C-frame thickness gauge to measure steel in a pickling process in the Cold Mill facility of Nucor Steel. The previous leak test of the gauge was August of 2011.
Chase Environmental Group (licensed in the state of TN, R-01108-E19) is a contractor to Nucor for consulting, training, and leak testing.
- * * UPDATE FROM CHRIS ECHTERLING TO JOE O'HARA AT 1608 EST ON 02/09/12 * * *
The following was received via e-mail.
On February 8th, 2012, a sealed source gauge abnormal event was reported, event# 47645. Today, a representative from Advanced Gauging Technologies, LLC arrived at Nucor Steel Crawfordsville and was able to repair the gauge successfully. The shutter and indicator lights are now operating appropriately.
Notified R3DO(Giessner) and
FSME EO(Michalak).