ENS 41256
ENS Event | |
|---|---|
05:00 Dec 13, 2004 | |
| Title | Containment Penetrations Not Closed During Fuel Handling Operations |
| Event Description | Event:
During refueling operations, containment penetrations providing direct access from the containment atmosphere to the outside atmosphere, closed by manual valves, was not maintained during fuel movement. - On 12/4/04 the five containment closure valves in question were verified closed during the initial establishment of conditions to perform refueling. - On 12/7/04 a steam drain valve checklist was performed in preparation for establishing vacuum which opened the five valves required to be closed by containment closure for fuel handling. - On 12/12/04 during performance of the 100 hour0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> refueling containment closure checklist five containment closure valves were found in the OPEN position. These five valves are to be tagged closed during the time when refueling containment closure is required. - On 12/12/04 at approx 2100 a question as to if refueling containment closure was established on the steam generators was raised. It was investigated. And determined at 1245 on 12/13/04 that refueling containment closure was not established on the inside or outside of containment for the steam generators. Initial Safety Significance: This event is being reported as a condition which could have prevented the fulfillment of the safety function of structures that are needed to control the release of radioactive material. The requirements on containment penetration closure ensure that a release of fission product radioactivity within containment will be restricted from escaping to the environment. Section 15.11.2.2 of the Oconee UFSAR addresses a Fuel Handling Accident inside Containment. The 1977 analysis concludes that the worst case release is appropriately within 10 CFR 100 limits but does not take any credit for containment. For this event the potential flow rate would be restricted due to the size of the open valves, the diameter of the piping from one open 3/4 inch valve in the Containment building to the four open 2 inch valves and one 3 inch valve in the Turbine Building, and the absence of a significant differential pressure. Oconee wishes to note that a TS amendment incorporating Alternate Source Terms has been approved, but is currently awaiting implementation, which would only require refueling containment closure during movement of recently irradiated fuel (i.e. fuel moved within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of criticality). This event began on day 59 of the current refueling outage. Thus the potential for a significant release of radioactive material as a result of a postulated fuel handling accident during this time period was greatly reduced. Corrective Actions: At the time of discovery fuel handling operations were no longer in effect. On 12/13/2004 at 1245 it was determined that refueling containment closure was not established, fuel handling operations were complete at 0358 on 12/13/2004. The licensee has notified the NRC Resident Inspector. |
| Where | |
|---|---|
Oconee  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | |
| Time - Person (Reporting Time:+12.6 h0.525 days <br />0.075 weeks <br />0.0173 months <br />) | |
| Opened: | Michael Dunton 17:36 Dec 13, 2004 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Dec 13, 2004 |
| 41256 - NRC Website
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