05000352/LER-2012-004, Regarding Common-cause Inoperability of Independent Channels Due to Pipe Leak

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Regarding Common-cause Inoperability of Independent Channels Due to Pipe Leak
ML12255A027
Person / Time
Site: Limerick Constellation icon.png
Issue date: 09/10/2012
From: Dougherty T
Exelon Generation Co
To:
Office of Nuclear Reactor Regulation, Document Control Desk
References
LER 12-004-00
Download: ML12255A027 (5)


LER-2012-004, Regarding Common-cause Inoperability of Independent Channels Due to Pipe Leak
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability

10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications

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
3522012004R00 - NRC Website

text

10CFR50.73 September 10, 2012 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 1 Facility Operating License No. NPF-39 NRC Docket No. 50-352

Subject:

LER 2012-004-00, Common-cause Inoperability of Independent Channels This Licensee Event Report (LER) addresses a common-cause inoperability of two independent channels in the reactor protection system and a condition prohibited by Technical Specifications. The inoperability was due to a steam leak on an instrument line shared by two instruments which is used to measure main turbine first stage pressure.

This LER is being submitted pursuant to the requirements of 10CFR50.73(a)(2)(vii) and 10CFR50.73(a)(2)(i)(B).

There are no regulatory commitments contained in this letter.

If you have any questions, please contact Robert B. Dickinson at (610) 718-3400.

Respectfully, Original signed by Thomas J. Dougherty Vice President - Limerick Generating Station Exelon Generation Company, LLC cc: Administrator Region I, USNRC USNRC Senior Resident Inspector, LGS

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (10-2010)

LICENSEE EVENT REPORT (LER)

(See reverse for required number of digits/characters for each block)

APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013

, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

1. FACILITY NAME Limerick Generating Station, Unit 1
2. DOCKET NUMBER 05000352
3. PAGE 1 OF 4
4. TITLE Common-cause Inoperability of Independent Channels Due to Pipe Leak
5. EVENT DATE
6. LER NUMBER
7. REPORT DATE
8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO.

MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 05000 07 11 2012 2012 - 004 - 00 09 10 2012 FACILITY NAME DOCKET NUMBER 05000

9. OPERATING MODE 1
10. POWER LEVEL 100
11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)

OTHER 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)

Specify in Abstract below or in LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET The "Turbine Control Valve/Stop Valve Scram Bypassed" alarm response procedure was revised to direct a power reduction if trip unit status can not be determined within 15 minutes.

Corrective Action Planned A modification will be installed to address vibration induced fatigue on the affected instrument piping.

Previous Similar Occurrences There were no previous similar occurrences of RPS instrument pipe failures in the past 3 years.

Component data:

System:

JC (Plant Protection System)

Component:

PIS (Switch, Indicating, Pressure)

Manufacturer:

R369 (Rosemount Nuclear Instruments Inc.)

Model:

710DU0TT