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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 44890 | 4 March 2009 19:40:00 | Part 70 App A (C) 10 CFR 70.74 APP. A | Glovebox Overflow Drains May Be Inadequate to Perform Their Safety Function | Many gloveboxes in the processing areas are equipped with overflow drains to prevent solution from exceeding an unsafe depth. These overflow drains are sized to accommodate the credible flow rates into the associated gloveboxes. During the generation of set-point analyses for overflow drains in a new process area, questions arose regarding how the drain discharge flow rates are calculated. To resolve these questions, NFS performed field tests using a glovebox on 2/26/2009 and 2/27/2009. Initial results of these tests indicated that the discharge flow rates are sensitive to drain weir height and glovebox floor flatness. This caused NFS to question the ability of the drains to perform their intended function. NFS, therefore, generated a plant-wide list of all potentially affected gloveboxes and suspended operations in them on 2/27/2009. Uranium-bearing materials were removed from the gloveboxes and all of the affected gloveboxes were tagged out of service. Engineering evaluations of the affected gloveboxes were performed and proceeded through 3/4/2009. As a result of Engineering evaluations, it was determined that in some instances a single drain alone was not capable of maintaining a solution depth to within design parameters in some localized areas within the glovebox. Modifications are being made to the drains to restore their functionality. There were no actual or potential safety consequences to the public or the environment. The potential criticality consequences to the workers were low due to the conservatisms included in the analyses. The licensee has notified the NRC Resident Inspector.
The licensee will issue a press release to summarize the results of NRC Special Inspection Report No. 2009-007. The licensee will inform the NRC Resident Inspector. Notified R2DO (Ernstes), NMSS (Bjorkman) and Fuels Grp via email. | ||
| ENS 44579 | 17 October 2008 20:15:00 | 10 CFR 70.74 APP. A | Inadvertent Transfer of Unsampled Discard Solution | Transfer of low uranium concentration discard solution from Tank WF03 to Waste Water Treatment Facility (WWTF) Tank 29 without final sample and analysis due to inadvertently opening incorrect valve. There were no actual or potential safety consequences to workers, the public, or the environment. Solution from discard Tank WF04 had been sampled and analyzed and was approved for transfer to WWTF Tank 29. An incorrect valve was opened and low uranium concentration solution was transferred from discard Tank WF03 to WWTF Tank 29 without final sample and analysis. All sources into the discard tanks (WF03 and WF04) are routed through an in-line uranium concentration monitor. Remaining SSC's were available and reliable. Solution in discard Tank WF03 had passed through an in-line uranium concentration monitor which would have stopped the transfer if a high uranium concentration was present. Solution in discard Tank WF03 and WWTF Tank 29 were sampled. Both uranium concentration results are low. The solution in discard Tank WF03 would have met sample analysis requirements. The safety significance is low due to the low mass and concentration of U-235. In-line monitor was also present which would have prevented transfer of high concentration solution into discard Tank WF03. The control is to sample and analyze solution prior to transfer to WWTF. The deficiency in this case is the failure to perform those actions prior to discard. Event was identified and entered into Problem Identification, Resolution and Correction System (PIRCS) - PIRCS #15829. Investigation is underway. Both the discard Tank WF03 and the WWTF Tank 29 were sampled. The licensee notified the NRC Resident Inspector. | ||
| ENS 41274 | 18 December 2004 03:30:00 | 10 CFR 70.74 APP. A |
| THIS IS NOT A NEW REPORT. This event report was originally withheld from public release under the NRC's policy for protecting sensitive unclassified information. The NRC has reevaluated this policy and is now making this event report available to the public with suitable redactions. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * CRITICALITY CONTROL Sequence of occurrences: On December 17, 2004, materials were transferred to a storage area without being transferred thru a particular device as required by the Standard Operating Procedure (SOP). This device prevents a more reactive/incorrect material type from being transferred. Prior to the addition of materials to the system, operations personnel verify that the correct materials are added to the system. The device prevents a more reactive/incorrect material type from entering the storage area. Remaining activities relied on: The remaining activities relied on to prevent potential accidents are available and reliable to perform their function. Operations personnel verified that the correct material type was added to the system. Also, the addition of a more reactive/incorrect material type was specifically evaluated and determined to be subcritical. Actions taken in response to the event: A root cause investigation was initiated as a result of the event. Transfers were suspended until compensatory measures can be put in place. Safety significance of event: The safety significance was low for the event given the very low likelihood of adding a more reactive/incorrect material type to the system. A more reactive/incorrect material type was not added to the system and the addition of a more reactive/incorrect material type was specifically evaluated and determined to be subcritical. Brief scenario of how a criticality could occur: In order for a criticality to occur, multiple occurrences of an excessive amount of a more reactive/incorrect material type would have to be added to the system; and, the material would have to be transferred without use of the particular device. What are the controls or control systems and the failures or deficiencies? The controls were limitations on material types input into the system and the use of a particular device when transferring materials to a storage area. Materials were transferred to the storage area without being transferred thru the particular device as required by the Standard Operating Procedure (SOP). The Nuclear Criticality Safety Evaluation (NCSE) for the area credited the device as a passive control device. The act of transferring the materials thru the device should have been credited as an administrative control since operations personnel have the ability to bypass the device if the procedure is not followed correctly. What are the corrective actions taken and when was each implemented? A root cause investigation was initiated on December 21, 2004 after discovery of the event. Material transfers were suspended on December 21, 2004 until compensatory measures can be implemented. Actual or potential health and safety consequences: There were no actual health and safety consequences to workers, the public, or the environment. There were also no personnel exposures to radiation, radioactive materials, or hazardous chemicals produced from licensed materials. The potential Nuclear Criticality Safety (NCS) consequences for workers were low given the actual materials involved and the very low likelihood of adding a more reactive/incorrect material type to the system. A more reactive/incorrect material type was not added to the system and the addition of a more reactive/incorrect material type was specifically evaluated and determined to be subcritical. The licensee notified the NRC Resident Inspector.
THIS IS NOT A NEW REPORT. This event report was originally withheld from public release under the NRC's policy for protecting sensitive unclassified information. The NRC has reevaluated this policy and is now making this event report available to the public with suitable redactions. | ||
| ENS 41197 | 15 November 2004 23:15:00 | 10 CFR 70.74 APP. A |
| THIS IS NOT A NEW REPORT. This event report was originally withheld from public release under the NRC's policy for protecting sensitive unclassified information. The NRC has reevaluated this policy and is now making this event report available to the public with suitable redactions. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * WET OFFGAS (WOG) LINE CALCULATION WAS NOT PERFORMED. Raffinate column WOG Vent (DELETED) is not sized appropriately to handle flow in the event of overflowing of (DELETED) combined with a loss of DI water pressure and a failure of DI water valve when transferring SNM material from sump columns ((DELETED) or (DELETED) using (DELETED)). This would prevent transferring SNM material into an unfavorable geometry tank. The WOG line is specified as IROFS (DELETED) and is listed as (DELETED) in the Recovery Deionized Water Nuclear Criticality Safety Evaluation Risk Indexing Supplement. Setpoint analysis was believed to be completed on all Recovery WOG lines. It was determined that this WOG line calculation was not performed at November 15, 2004. As such, IROFS (DELETED) was not reliable and available on (DELETED) and (DELETED) transfers to (DELETED) which occurred on October 28, November 2 and November 11, 2004. (DELETED) has been taken out of service. A follow-up memo to Operations will be provided to prevent the use of the pump and (DELETED). Defense in-depth measures that were available are as follows: 1. Pumping operations did not overflow (DELETED). 2. Deionized water line to (DELETED) was pressurized (DELETED). 3. Administrative Control listed in the NCSE specified that the operator shut valve (DELETED) upon a loss of DI water pressure. This control is flowed down into the operating procedure. 4. Valve (DELETED) listed as a configuration controlled item was available to be closed upon a loss of pressure in the DI water line. 5. The WOG line was positioned lower than the DI water input line and listed as a configuration controlled item as such. There are no actual potential health and safety consequences to workers, the public or the environment due to defense in depth and configuration control items in place. In additional, overflow (DELETED) did not occur (DELETED). What is the safety significance of the event? Not in compliance with 10CFR70.61. However criticality was not a concern due to defense-in-depth controls and configuration control equipment installed at the time. Brief scenario(s) of how criticality could occur: Transfer of SNM during a backflow scenario into DI water line and subsequent unfavorable geometry tankxx-001. What is the control(s) or control system(s) and the failure(s) or deficiencies? IROFS(DELETED) WOG line on (DELETED). What are the corrective actions taken and when was each implemented? (DELETED) has been taken out of service on 11/15/04. The NRC Resident Inspector was notified of this event by the licensee.
THIS IS NOT A NEW REPORT. This event report was originally withheld from public release under the NRC's policy for protecting sensitive unclassified information. The NRC has reevaluated this policy and is now making this event report available to the public with suitable redactions. |