The State of
Texas provided this information via email:
On May 3, 2010, the licensee discovered that the shutter of a nuclear gauge mounted on the Ryton Quench Salt Solution Tank was stuck in the 'Open' position. The gauge is an Ohmart-Vega Model SH-F1 serial #6966CN, with a 20 mCi Cesium (Cs)-137 source. Initial efforts were made to free the shutter mechanism with penetrating oil and hand pressure, with no results. The shutter mechanism has been tagged out and the manufacturer has been contacted. The gauge is stuck in the open position which is its normal operating position. The source does not present an increased exposure risk to personnel as there are no identified needs for entry/opening of the vessel which would require lockout of the gauge.
The licensee is working with the manufacturer to arrange for a field service engineer to evaluate/repair/replace the stuck shutter. This shutter had previously failed in October 2009 (EN45399, I-8675.) Repairs had been made and a protective cover for the gauge was installed at that time.
Texas Incident Report # I-8737