05000455/LER-2013-003, Regarding Unit 2 A-Train Diesel Generator Ventilation Fan Not Reset
| ML13326B065 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 11/22/2013 |
| From: | Kearney F Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 1.10.0101, BYRON 2013-0149 LER 13-003-00 | |
| Download: ML13326B065 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(B), System Actuation 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4552013003R00 - NRC Website | |
text
Exelon Generation November 22, 2013 LTR:
BYRON 2013 -0149 File:
1.10.0101 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
Subject:
Licensee Event Report (LER) 455-2013-003-00, Unit 2 A-Train Diesel Generator Ventilation Fan Not Reset Byron Station, Unit 2 Facility Operating License No. NPF-66 NRC Docket No. STN 50-455 Enclosed is an LER concerning the Byron Station Unit 2 Emergency Diesel Generator credit for manual actions that occurred on August 17, 2011. This condition is reportable to the NRC in accordance with 10 CFR 50.73(a)(2)(iv)(B)
Any Operation or Condition Prohibited by the Plant Technical Specifications.
Should you have any questions concerning this submittal, please contact Mr. Steven Gackstetter, Regulatory Assurance Manager, at (815) 406-2800.
FAK/GC/sg
Enclosure:
LER 455-2013-003-00 cc:
Regional Administrator NRC Region Ill NRC Senior Resident Inspector Byron Nuclear Power Station Respectfully, Faber A. Kearn Site Vice President Byron Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-01 04 EXPIRES: 10/31/2013 (10-2010)
, the NRC may
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information collection.
- 3. PAGE Byron Station, Unit 2 05000455 1
OF 3
- 4. TITLE Unit 2 A-Train Diesel Generator Ventilation Fan not Reset
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED FACILITY NAME MONTH DAY YEAR YEAR SEQUENTIAL 1 MONTH DAY YEAR N/A N/A FACILITY NAME DOCkET NUMBER 08 15 2011 2013 003 00 11 25 2013 N/A N/A
. OPERATING MODE
- 11. THIS REPORT IS UBMITJED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Checkalithat apply) 0 20.2201(b) 0 20.2203(a)(3)(i) 0 50.73(a)(2)(i)(C) 0 5073(a)(2)(vii) 1 0 20.2201(d) 0 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(A) 0 50.73(a)(2)(viii)(A) 0 20.2203(a)(1) 0 20.2203(a)(4) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B)
C 20.2203(a)(2)(i)
C 50.36(c)(1)(i)(A)
C 50.73(a)(2)(iii)
C 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL Q 20.2203(a)(2)(ii)
C 50.36(c)(1)(ii)(A)
C 50.73(a)(2)(iv)(A)
C 50.73(a)(2)(x) c:j 20.2203(a)(2)(iii)
C 50.36(c)(2)
C 50.73(a)(2)(v)(A)
C 73.71(a)(4) 100 C 20.2203(a)(2)Ov)
C 50.46(a)(3)(ii)
C 50.73(a)(2)(v)(B)
C 73.71 (a)(5)
EJ 20.2203(a)(2)(v)
C 50.73(a)(2)(i)(A)
C 50.73(a)(2)(v)(C)
C OTHER EJ 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B)
C 50.73(a)(2)(v)(D)
Specify in Abstract below or in Operations personnel inappropriately credited HELB analysis to justify past operability for the two days the 2A DG Ventilation Fan auto start was defeated. This assumption resulted in an LER for this issue not being submitted at the time of the event.
D. Safety Significance
There is reasonable expectation that the 2A DG was capable of performing its design function as discussed under the Updated Final Safety Analysis Report (UFSAR) without the fan auto start function being operable.
UFSAR Section 8.3.1.1.2.2 states, Short term unavailability of the diesel-generator room ventilation fans and dampers is bounded by the HELB analysis (See Subsection 9.4.5.2.1.3.e). UFSAR 9.4.5.2.1.3.e provides the following Safety Evaluation: Loss of diesel-generator room ventilation in the event of a HELB in the Turbine Building will not affect the safe shutdown capability of the unit for the short duration of the transient. These rooms are exposed to elevated temperatures until operator action is taken to restore room ventilation.
The 1A, 1 B and 2B DG Ventilation Fans had previously been modified with this same time delay modification and these fans were verified to have their High D/P trip interlocks properly reset outside the PMT work instructions. Each of these DGs was operable and available to support Unit 2 operations for the entire period during which the auto start interlock was not operable on the 2A DG.
Reviews concluded there were no cross-train instances of equipment being inoperable that would constitute a loss of safety function during the period that the 2A DG was inoperable Based the analyses above, the significance of this issue is considered low.
E. Corrective Actions
On August 17, 2011 Reactor Operators took the Main Control Board (MCB) control switch for the 2A DG ventilation fan to Pull-to-Lock (PTL) position and back to the After-Trip position and verified that the fan started.
Each Byron Station work group responsible for generating or reviewing PMT work instructions (Engineering, Operations, and Maintenance Work Planning) communicated and reinforced the need to ensure the as-left condition of components/systems being tested is proper to meet its design function.
Operations performed reviews of pending critical modifications to ensure that PMT5 specified via work instructions provide sufficient guidance to test and properly restore systems or components to the correct as-found condition.
F.
Previous Occurrences
There have been no previous occurrences of this nature in the previous three years.