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On July 4, 2017 at 1533 (EDT) it was identified that two desiccant filters serving a dry train ventilation system on a uranium processing glovebox line contained a uranium compound. The two containers were located within close proximity to one another, but were separated during maintenance activities associated with the equipment prior to knowledge of the uranium mass presence. This was assumed to be a non-uranium-bearing system and there were no documented controls in the Integrated Safety Analysis to prevent accumulations. The system was not included in typical duct surveys to identify such accumulations. Uranium processing operations were shut down and the plant is in the summer shutdown outage. There was no immediate risk of criticality or threat to the safety of workers or the public as a result of this event. Security is controlling access to the area and the area will remain shutdown. The initial 10 CFR 70 Appendix A(a)(4) 1 hour report notification was made at 1630 EDT. While making that telephone notification, at approximately 1646 EDT, the licensee communicator notified the Headquarters Operations Officer that the licensee had declared an Alert at 1556 EDT. The Alert declaration was based on a loss of control of all parameters preventing criticality for which control cannot be immediately re-established per the site's Emergency Plan. There is no release and a release is not projected. The licensee's Emergency Operations Center has been activated. The licensee will notify the NRC Resident Inspector. The licensee notified the Commonwealth of VA and local agencies. Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, DHS NICC, USDA Ops Center, EPA EOC via conference call. Notified FDA EOC, FEMA NWC, Nuclear SSA and FEMA NRCC SASC via email.

• * * UPDATE AT 0231 EDT ON 07/05/17 FROM CHRIS TERRY TO S. SANDIN * * *

The licensee has completed preliminary NCS (Nuclear Criticality Safety) calculations based on conservative theoretical analysis and concluded that vessel no. 1, which has the higher loading of material, could achieve a k-effective >1 if conditions were changed, Vessel no. 2 would remain sub-critical under all conditions. The licensee will reconvene their technical staff in the morning to determine what controls could be applied to the higher loaded vessel to evaluate two possible options; the first option is to characterize the material in the sub-critical vessel no. 2 for a better informed NCS analysis of the higher loaded vessel no.1 and the second option is to poison the higher loaded vessel no. 1. The situation remains stable and the licensee continues to restrict access to the RTR Processing Area. Notified R2DO (Heisserer), NMSS (Moore), IRD (Stapleton) and NMSS Events Notification and Fuels Group via email.

• * * UPDATE AT 0938 EDT ON 07/05/17 FROM ROBERT JOHNSON TO S. SANDIN * * *

The licensee is still reviewing the NCS calculations to identify the appropriate course of action and will reconvene the technical staff at 1300 EDT. Following this meeting, additional surveys of the area will be performed. Notified R2DO (Heisserer), NMSS (Moore), IRD (Stapleton) and NMSS Events Notification and Fuels Group via email.

• * * UPDATE AT 1437 EDT ON 7/5/17 FROM ROBERT JOHNSON TO JEFF HERRERA * * *

The Licensee is reporting no change in status they are still in an Alert condition. The licensee reported that the density of the desiccant is being re-evaluated. It is expected that actual density is less than initial assumed density which is favorable. The net effect should be to reduce the estimated grams inside the unit. Reduced estimated grams will improve the safety margin and assist the recovery process. Additional calculations and modeling is being conducted and more information is expected at a licensee discussion meeting at 1600 EDT. The Emergency Operations Center remains staffed at this time. The NRC Resident Inspector has been notified. Notified R2DO (Heisserer), NMSS (Moore), IRD (Grant) and NMSS Events Notification and Fuels Group via email.

• * * UPDATE AT 1954 EDT ON 7/5/2017 FROM ROBERT JOHNSON TO MARK ABRAMOVITZ * * *

On July 5, 2017 at 1857 (EDT) BWXT LOG-Lynchburg downgraded form an Alert status. Based on a conservative estimate of U-235 mass and an accurate characterization of the desiccant material involved, Nuclear Criticality Safety (NCS) has determined that a criticality is highly unlikely. Updated evaluations based on as-found conditions and technical information provided by the system manufacturer demonstrated the maximum amount of U-235 in system #1 and system #2. Current NCS controlled parameters in place are mass, moderation, spacing, and container geometry. NCS has determined that the worst case K-adjusted is below the normal license limit. Based on this information, there was no immediate risk of criticality or threat to the safety of workers or the public as a result of the event. Access to the area remains restricted under the control of Security and the Emergency Operations Center. The licensee will notify the NRC Resident Inspector. Notified R2DO (Heisserer), NMSS (Moore), IRD (Grant) and NMSS Events Notification, Fuels Group (via email). Notified DHS SWO, DOE Ops Center, FEMA Ops Center, HHS Ops Center, DHS NICC, USDA Ops Center, EPA EOC via conference call. Notified FDA EOC, FEMA NWC, Nuclear SSA and FEMA NRCC SASC via email.