ENS Event | |
|---|---|
18:28 Oct 18, 2013 | |
| Title | Potential for High Energy Line Break on Letdown System Outside Containment |
| Event Description | A postulated High Energy Line Break (HELB) between the Letdown Heat Exchanger and its containment penetration has been identified in the Fort Calhoun Station calculation FC07885, Rev. 0, Stress Analysis of Small Bore Piping on Isometric CH-4106 High Energy Line Break Assessment.
Based on this, there is a potential for a HELB on the inlet of the Letdown Heat Exchanger that may adversely impact the upstream piping and the outboard containment isolation valve. Assuming a single failure of the inboard isolation, this condition has the potential to degrade a principal safety barrier by bypassing the containment building. The licensee has notified the NRC Resident Inspector. |
| Where | |
|---|---|
Fort Calhoun  Nebraska (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded | |
| Time - Person (Reporting Time:+1.17 h0.0488 days <br />0.00696 weeks <br />0.0016 months <br />) | |
| Opened: | Amy Burkhart 19:38 Oct 18, 2013 |
| NRC Officer: | John Shoemaker |
| Last Updated: | Oct 18, 2013 |
| 49452 - NRC Website
Loading map... | |
Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |
WEEKMONTHYEARENS 512702015-07-22T18:30:00022 July 2015 18:30:00
[Table view]10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Condition Due to Reactor Coolant System Leak ENS 497102014-01-10T05:17:00010 January 2014 05:17:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Fittings Connected to Containment Penetration ENS 494522013-10-18T18:28:00018 October 2013 18:28:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Potential for High Energy Line Break on Letdown System Outside Containment ENS 481112012-07-17T15:00:00017 July 2012 15:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Degraded Charging Line Socket Welds Based on Thermal Fatigue Analysis ENS 479532012-05-23T21:00:00023 May 2012 21:00:00 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Crack Identified in Pressurizer Heater ENS 457242010-02-24T17:40:00024 February 2010 17:40:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(A), Seriously Degraded Auxiliary Feedwater Pumps May Experience Runout at Low Steam Pressures 2015-07-22T18:30:00 | |