05000352/LER-2012-007, Regarding Condition Prohibited by Technical Specifications Due to Inoperable Primary Containment Isolation Valves

Regarding Condition Prohibited by Technical Specifications Due to Inoperable Primary Containment Isolation Valves

ML12293A100
Person / Time
Site:	Limerick
Issue date:	10/19/2012
From:	Dougherty T Exelon Generation Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
LER 12-007-00
Download: ML12293A100 (6)

LER-2012-007, Regarding Condition Prohibited by Technical Specifications Due to Inoperable Primary Containment Isolation Valves

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii)(A) 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
3522012007R00 - NRC Website

text

10CFR50.73 October 19, 2012 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353

Subject:

LER 2012-007-00, Condition Prohibited by Technical Specifications due to Primary Containment Isolation Valves Design This Licensee Event Report (LER) addresses a condition prohibited by Technical Specifications.

Multiple primary containment isolation valves were declared inoperable due to a design deficiency in the valve closing circuit.

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

10CFR50.73(a)(2)(ii)(A), 10CFR50.73(a)(2)(ii)(B), 10CFR50.73(a)(2)(v)(C) and 10CFR50.73(a)(2)(vii).

There are no 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 5

4. TITLE Condition Prohibited by Technical Specifications due to Inoperable Primary Containment Isolation Valves

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 Limerick Unit 2 DOCKET NUMBER 05000353 08 20 2012 2012 - 007 - 00 10 19 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 operated PCIVs in series with the affected PCIVs. The air operated PCIVs were not affected.

Two additional normally closed CAC 2-inch penetrations used for primary containment venting to the reactor enclosure equipment compartment exhaust were affected. Each of the two lines use air operated PCIVs in series with the affected PCIVs. The air operated PCIVs were not affected.

Two additional normally closed CAC 1-inch penetrations used for primary containment nitrogen makeup were affected. The lines use two inboard solenoid valve PCIVs in series with the one affected PCIV. The inboard solenoid valve PCIVs were not affected.

4. The instrument gas compressor suction line is a normally open one-inch penetration. The inboard PCIV was affected. The outboard PCIV is an air operated PCIV which was not affected.

5. The suppression pool clean-up pump suction line is a normally closed 6-inch penetration. Both the inboard and outboard PCIVs were affected.

Cause of the Event

The original design for certain PCIVs contained a design flaw that could potentially prevent the equipment from performing the intended safety function.

Corrective Action Completed Following the identification of the design deficiency a design change was implemented on 24 affected PCIVs. The design change installed a jumper which removed the LS-8 contact feature. This eliminated the dead zone on these PCIVs. In addition, three Unit 1 affected CAC drywell purge PCIVs' stroke times were reduced to remove the vulnerability.

Corrective Action Planned Three inoperable Unit 2 affected CAC drywell purge PCIVs' stroke times will be reduced to remove the vulnerability.

Previous Similar Occurrences There were no previous similar conditions in the prior 5 years of PCIVs being declared inoperable due to electrical design deficiencies.