05000269/FIN-2014007-05
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Potential Unanalyzed Condition Associated with Emergency Power System |
| Description | During a review of Oconees engineered safeguards protection system (ESPS) emergency power start control for the KHUs, the team noted that the 125Vdc control cables for train A of the ESPS and cables for supervisory control of both KHUs were recently modified. The team also noted that these 125Vdc control cables were installed in the same underground concrete raceway systems as the 4160Vac auxiliary power cables, 13.8kVac power cables for both emergency power and protected service water (PSW), and were in close proximity to these power cables. The team was concerned that a short circuit (which the licensee considered outside their design basis) in the 13.8kVac cables could induce voltage and currents in the dc control system which could potentially impact the functionality of the emergency power system which is required to mitigate certain design basis events. A similar issue exists in Manhole 6 of the PSW underground raceway where the new power supply to the PSW (adjacent to the 125Vdc control emergency power system) could short circuit or fault to ground. The licensee had not performed an analysis to determine the effects of such failures on the ability of the emergency power system to perform its safety function, thus the team questioned whether the plant was in an unanalyzed condition. Although the licensee did not agree that these failures were part of their licensing basis, they reported this as an unanalyzed condition to the NRC in accordance with 10 CFR 50.73(a)(2)(ii)(B) in Licensee Event Report 269/2014-01. In response to the teams concerns, the licensee entered this issue into their corrective action program, and performed immediate and prompt determinations of operability in which they concluded a reasonable expectation of operability exists. The team has requested assistance from subject matter experts in the Office of Nuclear Reactor Regulation via a Task Interface Agreement1 to review the emergency power system licensing basis to determine the acceptability of the licensees design. If the design is found to be noncompliant with the licensing basis, the licensee will be required to implement corrective actions to restore compliance. This issue is being tracked as URI 05000269/2014007-05, 05000270/2014007-05, 05000287/2014007-05, Potential Unanalyzed Condition Associated with Emergency Power System. |
| Site: | Oconee  |
|---|---|
| Report | IR 05000269/2014007 Section 1R21 |
| Date counted | Jun 30, 2014 (2014Q2) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | G Nicely J Eargle R Nease R Williams S Pindale S Sanchez T Fanelli T Tinkel W Monkj Riveram Riley N Childs T Fanelli W Loo B Collins E Crowe G Croon G Mccoy |
| INPO aspect | |
| ' | |
Finding - Oconee - IR 05000269/2014007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Oconee) @ 2014Q2
Self-Identified List (Oconee)
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||