ENS 45655
ENS Event | |
|---|---|
16:30 Jan 25, 2010 | |
| Title | Unanalyzed Condition - Overflow Of Uranium Bearing Ammoniated Wastewater |
| Event Description | It was reported to the EH&S Management that on January 24, 2010 a spill of approximately 200 gallons of uranium bearing ammoniated (5-7%) wastewater overflowed from the 'Q' tanks into the diked area below the tanks. These tanks are the final filtration prior to transfer of this liquid effluent to the outside treatment facility. Operators received a high level alarm and responded by shutting down the process in accordance with the operational procedure, with the overflow occurring for approximately six minutes. This event was the result of a pump failure in the tank discharge line. Notification was made to the on duty Health Physics (HP) staff and the on duty Incident Commander. Health Physics staff responded within minutes and used a Drager counter to determine the ammonia concentrations present. Readings in the immediate area of the dike were as high as 256 ppm ammonia. Readings in adjacent areas of the facility were approximately 150 ppm ammonia. Non-essential personnel were evacuated and essential personnel were instructed to don PPE-respirators with ammonia cartridges.
Operations cleanup of the area was completed and with normal plant ventilation running the ppm ammonia concentrations were returned to < 25 ppm within approximately two hours. The failed pump has been repaired and returned to service. Based on the quick response of the HP staff, evacuations and appropriate use of PPE, no workers were exposed to significant concentrations and no medical attention was necessary. Notification is made based on 10CFR70 Appendix A (b)(1) 'Any event or condition that results in the facility being in a state that was not analyzed, was improperly analyzed, or is different from that analyzed in the Integrated Safety Analysis, and which results in failure to meet the performance requirements of 10CFR70.61.' The potential for a loss of containment was recognized and evaluated in one of the Process Hazards Analysis (PHA) which constitutes the Integrated Safety Analysis for this system. The PHA identified several initiating events which could lead to a high level and loss of containment event. The appropriate safeguards were identified, including the procedural responses, the evacuation during such an emergency of the workers in the enclosed chemical area, and the use of appropriate PPE. The consequences of the event were identified as a potential for personnel inhalation and exposure hazard from the uranium bearing ammoniated wastewater. However, the PHA did not specifically indentify that the potential existed for the consequences to exceed the Intermediate Consequence criteria for credible events. In accordance with SNM-1107 License Requirements for the Columbia Plant Intermediate Consequences are those that have the potential for a worker to receive greater than or equal to ERPG-2 chemical exposures. (ERPG-2 value for ammonia is 150 ppm.) Since the Q-Tank contains comingled uranium and chemicals, the Intermediate Consequences of 10CFR70.61 apply. Failure to identify that an Intermediate Consequence event was credible led to that event not being included in the Conversion ISA Summary ISA-03 and not designating Items Relied on For Safety (IROFS) for that accident sequence. Corrective Actions: As stated previously, the pump which failed has been repaired and returned to service. Actions taken by the staff to mitigate the event were appropriate and in accordance with approved procedures. Normal ventilation system operation reduced the concentrations to acceptable levels. [These actions are] complete. The safeguards identified in the PHA will be evaluated in the ISA and appropriate selections of IROFS will be made based on that evaluation and included in the ISA summary. [These actions are] in progress.
Time and Date of Event: September 30, 2010, 0800. Previously Westinghouse had reported to the Nuclear Regulatory Commission (NRC) in Licensee Event Report #45655, that the conversion Integrated Safety Analysis (ISA) did not specifically indentify that the potential existed for the consequences of overflows or spills in the conversion wastewater system to exceed the Intermediate Consequence criteria for credible events based on chemical exposure. In accordance with SNM-1107 License Requirements for the Columbia Plant intermediate consequences are those that have the potential for a worker to receive greater than or equal to ERPG-2 chemical exposures. In the required written follow up to that event (LTR-RAC-10-16, February 23, 2010). Westinghouse committed to perform an extent of condition review of other chemical release scenarios and designate necessary Items Relied On For Safety (IROFS). Westinghouse further provided NRC the casual analysis related to that event, (LTR-RAC-10-28, April 6, 2010) which identified the need to quantitatively evaluate chemical release scenarios. Westinghouse has completed the necessary evaluations and determined that additional scenarios exist which have the potential to exceed the performance requirements of 10 CFR 70.61. EH&S Management has now determined that these analyses, the necessary ISA and ISA Summary revisions, and the identification of appropriate IROFS are complete. For these new ISAs the necessary controls, procedures and equipment are in place and the performance requirements are met in a fully compliant manner taking into account the newly identified IROFS. The extent of condition review identified additional areas within the facility where chemical releases have the potential to exceed consequence thresholds for facility workers. There is one area where potential consequences could challenge off-site receptor chemical consequence criteria. The areas covered by the extent of condition review impacted by this updated chemical analysis are Conversion, the Scrap Uranium Processing, the Solvent Extraction System, and the facility Wastewater Tanks. Notification is made based on 10CFR70 Appendix A (b)(1) 'Any event or condition that results in the facility being in a state that was not analyzed, was improperly analyzed, or is different from that analyzed in the Integrated Safety Analysis, and which results in failure to meet the performance requirements of 10CFR70.61.' The potential for a loss of containment was recognized and evaluated in the applicable Process Hazards Analysis (PHA) which constitutes the Integrated Safety Analysis. The PHAs identified initiating events which could lead to loss of containment. The appropriate safeguards were identified, including the procedural responses, the evacuation during such an emergency of the workers in the enclosed chemical area, and the use of appropriate PPE. Failure to identify in the areas mentioned above those chemical release consequences could exceed 10CFR70.61 criteria led to these events not being included in the applicable ISA Summary and not designating Items Relied on For Safety (IROFS) for these accident sequences. Corrective Actions: As stated previously, the associated Integrated Safety Analysis, Integrated Safety Analysis Summaries, and designation of IROFS to ensure the performance requirements are satisfied is complete for the extent of condition reviews previously committed to by Westinghouse. Full implementation of the revised ISA Summaries, to include all required procedure revisions and appropriate training will be completed by October 30, 2010. Notified R2DO (Lesser) and NMSS EO (Rubenstone). |
| Where | |
|---|---|
| Westinghouse Electric Corporation Columbia, South Carolina (NRC Region 2) | |
| License number: | Snm-1107 |
| Reporting | |
| Part 70 App A (B)(1) | |
| Time - Person (Reporting Time:+2.05 h0.0854 days <br />0.0122 weeks <br />0.00281 months <br />) | |
| Opened: | Gerald Couture 18:33 Jan 25, 2010 |
| NRC Officer: | Joe O'Hara |
| Last Updated: | Sep 30, 2010 |
| 45655 - NRC Website | |
Westinghouse Electric Corporation with Part 70 App A (B)(1) | |
WEEKMONTHYEARENS 561992022-11-01T15:29:0001 November 2022 15:29:00
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