The following report was received from the Commonwealth of
Kentucky via fax:
KY RHB [Kentucky Radiation Health Branch] was notified by telephone on 2/12/2019 at 1315 EST by a representative from a specifically licensed facility, North American Stainless, that on Sunday, 2/10/2019, North American Stainless encountered a 'breakout' when molten steel escaped and poured onto billet caster molds located below a 'tundish' filled with molten steel. One of the molds attached to a Berthold Model No. LB300ML Mold Level Control fixed gauging device, serial number 9415, containing 1 mCi (37 MBq) Co-60 (source serial number 1819-11-15) was covered with the liquid steel encapsulating the source holder. After the steel and mold had cooled, it was freed on 2/12/2019 and segregated. The encapsulating steel rendered the device on-off mechanism (shutter) inoperable. Initial readings taken with a Ludlum 2241-3 survey instrument measured 6.25 mR/hr measured 12 inches directly in front of the window, and 1.25 mR/hr measured 90 degrees from the line of the window measured at a distance of 12 inches. Readings at the back of the source holder were 132 microR/hr measured at a distance of 12 inches. No overexposures have been reported. On 2/12/2019, Radiametric Technologies, a service provider located in Lorain, Ohio, requested reciprocal approval and was granted reciprocity on 2/13/2019 in order to assess and remediate the situation.
The fixed gauging device involved in the incident was recently leak tested (test conducted on 7/31/2018) by Suntrac Services, League City TX. Radiametric Technologies, Lorain OH, recently tested the source holder on-off mechanism (1/31/2019) and it was found to be in good working order. North American Stainless is reviewing the incident to avoid future incidents involving 'tundish' failures. A full report will be provided once the remediation is complete.
Reporting criteria in 10 CFR 30.50(b)(2).
KY Report #KY190001