ENS Event | |
|---|---|
20:31 Mar 27, 2010 | |
| Title | Potentially Degraded Pressurizer Level Tap Identified |
| Event Description | Arkansas Nuclear One Unit 1 is currently shut down in Mode 6 for refueling outage 1R22.
On March 27, 2010 at 1531 CDT a visual examination of Unit 1 pressurizer level tap 1-RC-1001 A/B indicated evidence of past leakage from the nozzle bore. The leakage is indicated by a small trail of what appears to be dry boron on the lower portion of the nozzle bore accompanied by rust stains on the stainless steel nozzle. The licensee notified the NRC Resident Inspector.
Update per 10CFR50.72(c). During the visual examination of the bore of T1 pressurizer level tap nozzle RC-1001 after the inconel nozzle removal, it is evident that corrosion of the carbon steel base material is present. This nozzle location was identified as leaking during the bare metal visual examination. The licensee notified the NRC Resident Inspector. Notified R4DO (O'Keefe). |
| Where | |
|---|---|
Arkansas Nuclear  Arkansas (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+0.02 h8.333333e-4 days <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) | |
| Opened: | David Thompson 20:32 Mar 27, 2010 |
| NRC Officer: | Pete Snyder |
| Last Updated: | Mar 31, 2010 |
| 45797 - NRC Website
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WEEKMONTHYEARENS 573692024-10-08T19:31:0008 October 2024 19:31:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition ENS 555062021-10-04T19:33:0004 October 2021 19:33:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Discovered on Reactor Vessel Head Penetration ENS 534562018-06-12T20:00:00012 June 2018 20:00:00 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Pressure Boundary Leakage Identified While Shutdown ENS 457972010-03-27T20:31:00027 March 2010 20:31:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Potentially Degraded Pressurizer Level Tap Identified ENS 414732005-03-09T11:37:0009 March 2005 11:37:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Pressurizer Heater Sleeve Leakage ENS 407212004-04-30T19:38:00030 April 2004 19:38:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded "on 4/30/2004, During Refueling Outage 1 R18, Ultrasonic Testing of the Reactor Vessel Head Identified Two Axial Indications on Control Rod Drive Mechanism, Nozzle 61. the Indications Were Located on the Outside Diameter of the Nozzle on the Lower Hillside. One of the Flaws Was at the Toe of the Fillet Weld and Extended Below the Fillet Weld Cap. the Second Flaw Extended the Full Length of the Weld and Just Below the Toe of the Fillet Weld. ENS 402162003-10-02T22:15:0002 October 2003 22:15:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Rcs Boundary Leakage Due to Small Crack on Drain Line Welded Cap 2024-10-08T19:31:00 | |