05000249/LER-2010-002, MSIV Leakage Exceeds Technical Specifications Allowable Limits
| ML110060165 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 12/29/2010 |
| From: | Hanley T Exelon Nuclear, Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| SVPLTR# 10-0055 LER 10-002-00 | |
| Download: ML110060165 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 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 |
| 2492010002R00 - NRC Website | |
text
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Exelon Generation Company, LLC www.exeloncorp.coM Nuclear Dresden Nuclear Power Station 6500 North Dresden Road Morris, IL 60450-9765 10 CFR 50.73 SVPLTR # 10-0055 December 29, 2010 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 3 Renewed Facility Operating License No. DPR-25 NRC Docket No. 50-249
Subject:
Licensee Event Report 249/2010-002-00, "MSIV Leakage Exceeds Technical Specifications Allowable Limits" Enclosed is Licensee Event Report 249/2010-002-00, MSIV Leakage Exceed Technical Specification Allowable Limits for Dresden Nuclear Power Station, Unit 3. This event is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B), Any operation or condition which was prohibited by the plant's Technical Specifications" and 10 CFR 50.73(a)(2)(v)(C), Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material.
The causal analysis for this event has not been completed at this time. Therefore a supplemental Licensee Event Report will be submitted upon completion of the analysis.
There are no regulatory commitments contained in this submittal.
Should you have any questions concerning this letter, please contact Mr. Dennis Leggett at (815) 416-2800.
Respectfully, Tim Hanley Site Vice President Dresden Nuclear Power Station Enclosure cc:
Regional Administrator - NRC Region III NRC Senior Resident Inspector - Dresden Nuclear Power Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Dresden Nuclear Power Station, Unit 3 05000249 1 OF 3
- 4. TITLE MSIV Leakage Exceeds Technical Specifications Allowable Limits
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MYATFACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR N/A 05000
~NUMBER NO.
FACILITY NAME DOCKET NUMBER 11 01 2010 2010 002 00 12 29 2010 N/A 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
[1 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 4 [E 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
[I 50.73(a)(2)(viii)(B)
E] 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
[I 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
[I 20.2203(a)(2)(iii) 0l 50.36(c)(2) 0l 50.73(a)(2)(v)(A)
El 73.71(a)(4) 000 El 20.2203(a)(2)(iv)
[I 50.46(a)(3)(ii)
[I 50.73(a)(2)(v)(B)
E0 73.71(a)(5)
[I 20.2203(a)(2)(v)
[E 50.73(a)(2)(i)(A) 0 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B)
[E 50.73(a)(2)(v)(D)
Specify in Abstract below or in Inadequate guidance of the plug is a known issue that has caused previous failures due to localized seat wear. It is likely that the same design characteristic could also cause the valve plug to not fully self-align during closure, resulting in a specific leak path due to the misalignment.
This LER is being submitted based on preliminary results of the investigation. Following completion of the investigation, a supplemental report is scheduled to be submitted.
D.
Safety Analysis
The safety significance of this Condition is low. Three MSIVs exceeded the allowed limits for leakage as specified by the plant's Technical Specifications. The combined leakage of all main steam lines was 96.4 scfh. The allowed limit (0.6La) for overall primary containment leakage is 810.5 scfh. The combined MSIV leakage was within the allowed leakage limits for overall primary containment.
Therefore, health and safety of the public was not compromised as a result of this condition.
E.
Corrective Actions
The three MSIVs that exhibited excessive leakage were repaired and successfully retested.
F.
Previous Occurrences
A review of DNPS Licensee Event Reports (LERs) for the last three years did not identify any LERs associated with failures of MSIVs during LLRTs.
G.
ComDonent Failure Data:
Manufacture Model Component Isolation Valve Crane Nuclear, Inc YPATTERN