ENS 46554
ENS Event | |
|---|---|
22:02 Jan 6, 2011 | |
| Title | Foreign Material Found in Spare Heat Exchanger |
| Event Description | {{#Wiki_filter:Part 21 reportable defect foreign material (FM) was discovered in a spare heat exchanger (HX) when visually inspected on 10/19/10 as part of contingency planning for potential installation of the HX during the 3EOC�25 refueling outage.
Visual inspections with a video probe (fiberscope) were being performed on the inlet/outlet channels and the tubes of a spare HX to verify that no FM was present. However, when performing these inspections, a problem was encountered in that maintenance was unable to disassemble and remove the bonnet from the lower (inlet) pressure seal connector on the HX. Subsequently, on 10/19/10 a fiberscope inspection was performed of the "back side" of the pressure seal bonnet by inserting a fiberscope thru the inlet nozzle access. A foreign object that appeared as a u-shaped piece of thin wire was seen just behind the pressure seal bonnet, laying in the bottom of the body. Due to the inability to disassemble the pressure seal connector, the affected HX was not installed, The FM was retrieved from the spare HX on December 27,2010 and its size and material type confirmed. The "U-shaped" material is type 304 stainless steel and appears to be a metal shaving. It is about 1-1/2" in length if the "u" was stretched out, 3/32" wide and less than 1/64" thick. The HX was intended for use as a Reactor Coolant System Letdown Cooler. It was ordered in 2006 and was supplied by Energy Steel Supply Company (ESSC), Catalog 10 350952, SIN N32389-1, Purchase Order No. DP 19279. Initial Safety Significance: This event has no actual significance since the issue was discovered prior to installation of the component and the component was not installed. However, Part 21 requires evaluation based on the assumption that the component was installed in the as-found condition. On 1/6/2011, Oconee Engineering concluded that, in some low probability scenarios, this FM could constitute a Substantial safety hazard. Per the postulated scenarios, the FM would be flushed out of the cooler when placed in service. A low potential exists that the FM could be trapped in a downstream valve and damage the seat, resulting in leakage. The cooler outlet valve and the next valve in series are containment isolation valves. If the FM caused leakage in one of those valves and the other was affected by a postulated single failure, any resultant leakage would constitute containment leakage. Also, in some event scenarios, unacceptable leakage past the cooler outlet valve seat could render the Oconee Standby Shutdown Facility (SSF) Reactor Coolant Make-up System inoperable. Therefore, Oconee concludes this issue meets the Part 21 definition as a reportable defect. Corrective Action(s): The affected spare cooler was not installed. Subsequently, the FM was removed. A second spare cooler was inspected, no similar FM was found, and the second cooler was installed. The NRC Resident Inspector will be notified. }} |
| Where | |
|---|---|
Oconee  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+307.7 h12.821 days <br />1.832 weeks <br />0.421 months <br />) | |
| Opened: | Randy Todd 17:44 Jan 19, 2011 |
| NRC Officer: | Joe O'Hara |
| Last Updated: | Jan 19, 2011 |
| 46554 - NRC Website
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Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Oconee with 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | |
WEEKMONTHYEARENS 469552011-06-07T15:52:0007 June 2011 15:52:00
[Table view]10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Nonconservative Valve Actuator Program Software ENS 465542011-01-06T22:02:0006 January 2011 22:02:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Foreign Material Found in Spare Heat Exchanger ENS 463752010-10-28T16:40:00028 October 2010 16:40:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Defect Discovered in Tube Steel That Could Be Used in Various Safety Related Structual Applications ENS 443122008-06-16T18:13:00016 June 2008 18:13:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Replacement Breaker Charging Motors Failed Minimum Voltage Test ENS 428932003-01-02T04:00:0002 January 2003 04:00:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Part 21 Notification - Voids in Plate Steel 2011-06-07T15:52:00 | |