ENS 55784
ENS Event | |
|---|---|
06:00 Jan 12, 2022 | |
| Title | Part 21 Report - Temperature Transmitter Failures |
| Event Description | The following is a synopsis of information received via facsimile:
Three defects were identified on an N7030 temperature transmitter, and all sub-models, manufactured by Ultra Energy. The first two defects were identified during product testing and are dependent on component tolerances and fabrication, these may not exist in all units. The third defect was identified during the safety investigation. First, for transmitters configured to indicate a failed resistance temperature device (RTD) via an over-range signal, the transmitter could return an in-range reading when operating at a temperature near the bottom of the specified temperature range. Second, for transmitters configured to indicate a failed RTD via an under-range signal, the transmitter could return an in-range reading when operating near the bottom of the specified loop voltage range. Third, transmitters with a disconnected RTD could output noise in the presence of very high impedance (mega-ohm range) at the input terminals and in specific narrow temperature ranges (less than 10 degrees Celsius). The first two defects could cause a sensor, which had failed, to appear to be functioning, although the reading would likely be obviously false and thereby highly unlikely to result in any risk to safety. The third condition might, depending on sensor noise filtering, result in a false temperature reading which was not obvious. This however requires multiple parameters to be in the correct ranges to trigger the latent defect and is also highly unlikely to result in any risk to safety. Corrective actions include: a reduction in specified operating temperature and loop voltage range, a field fix for the high impedance condition, and supplying impacted facilities with an engineering bulletin. Additionally, devices in the process of being manufactured have been segregated and will be scrapped. Design modifications will be made prior to continuing manufacturing these temperature transmitters. The facilities listed as being impacted are: Oconee Nuclear Station, Quad Cities NPS, and Prairie Island Nuclear Generating Plant. Contact Gary Hawkins , Vice President Engineering, or Diane Steen, Director of Quality, with questions. (512) 434-2800. Ultra Energy 707 Jeffrey Way P.O. Box 300 Round Rock, Texas 78665 |
| Where | |
|---|---|
| Ultra Energy Round Rock, Texas (NRC Region 4) | |
| Organization: | Ultra Energy |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+1401.28 h58.387 days <br />8.341 weeks <br />1.919 months <br />) | |
| Opened: | Gary Hawkins 15:17 Mar 11, 2022 |
| NRC Officer: | Mike Stafford |
| Last Updated: | Mar 11, 2022 |
| 55784 - NRC Website | |
Ultra Energy with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 557842022-01-12T06:00:00012 January 2022 06:00:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 Report - Temperature Transmitter Failures 2022-01-12T06:00:00 | |