ENS 45640
ENS Event | |
|---|---|
06:00 Jan 18, 2010 | |
| Title | Agreement State Report - Potential Gauge Shielding Failure |
| Event Description | The following information was received via e-mail:
On January 20, 2010, the Agency [Texas Department of State Health] was notified by the licensee that while conducting routine surveillance on a Texas Nuclear Model 5192 level gauge, dose rates were measured to be greater than 200 millirem per hour (mr/hr). This is the highest reading obtainable with the instrument they [licensee] used. The initial survey for this device was done in November 1981 and indicated a reading of 40 mr/hr at the same location on the gauge. The licensee measured the highest dose rates in any area that could be occupied by company personnel at 0.3 mr/hr. On the ground below the gauge was measured at 0.02 mr/hr. The gauge is located 15 feet above the ground and is attached to the side of the vessel. The dose rates were taken on the outside of the gauge on the top of the gauge casing. The licensee stated that the gauge does not pose any additional exposure risk to their workers. The gauge contained an initial activity of 100 millicuries of cesium (Cs) - 137. The current decay corrected activity is 52.2 millicuries. The licensee has contacted the manufacturer and requested assistance in repairing or replacing the gauge. This is not a shutter failure, but appears to be a shielding failure. The licensee stated that the gauge is not used in an area where temperatures are elevated. "The Agency will perform an onsite investigation on January 21, 2010. The Agency will provide a dose rate instrument capable of measuring the dose rate at the gauge. Texas Incident Number: I-8703.
The following information was received via e-mail: On 1/21/10 an Agency [Texas Department of State Health] inspector met with the RSO at the licensee's security office to perform an on-site investigation. He found that the gauge is located below a large tank, which normally contains hydrofluoric acid. There is very limited space between the top of the gauge and the bottom of the vessel. The gauge did not have any buildup of material on it nor were there any streaks on it that would indicate that liquids had leaked on to it. The RSO stated that the gauge is not subjected to high temperatures and that on the day of the event, the temperature at the gauge was about 110 degrees Fahrenheit. The area where the gauge is located requires special training in addition to special protective clothing and monitoring devices to enter. A licensee employee took an Eberline RO-2 instrument provided by the Agency into the area to perform a radiation survey. The dose rate on the top of the gauge was measured at 120 mr/hr. The instrument could not be placed on the very top of the gauge due to the space limitation. The dose rate taken on the side of the gauge was 10 mr/hr. A dose rate taken at the side of the road next to the boundary chain was <0.2 mr/hr. It appears that there may be some type of degradation of the shielding in the gauge. The RSO stated that he was trying to contact the manufacturer for assistance on determining the cause for the increase in dose rates on the gauge. The licensee has been instructed to notify this Agency when the arrangements are completed for the inspection of the gauge. Notified R4DO (Werner) and FSME (Camper). |
| Where | |
|---|---|
| Diamond Shamrock Refining Company Three Rivers, Texas (NRC Region 4) | |
| License number: | 03699 |
| Organization: | Texas Department Of Health |
| Reporting | |
| Agreement State | |
| Time - Person (Reporting Time:+56.87 h2.37 days <br />0.339 weeks <br />0.0779 months <br />) | |
| Opened: | Art Tucker 14:52 Jan 20, 2010 |
| NRC Officer: | Vince Klco |
| Last Updated: | Jan 22, 2010 |
| 45640 - NRC Website | |
Diamond Shamrock Refining Company with Agreement State | |
WEEKMONTHYEARENS 459422010-05-21T05:00:00021 May 2010 05:00:00
[Table view]Agreement State Agreement State Report - Stuck Open Shutter on Ronan Gauge ENS 456402010-01-18T06:00:00018 January 2010 06:00:00 Agreement State Agreement State Report - Potential Gauge Shielding Failure 2010-05-21T05:00:00 | |