05000247/LER-2012-003, Regarding Technical Specification (TS) Prohibited Condition Caused by Through Wall Defects in Reactor Coolant Pressure Boundary Branch Lines

Regarding Technical Specification (TS) Prohibited Condition Caused by Through Wall Defects in Reactor Coolant Pressure Boundary Branch Lines

ML12144A150
Person / Time
Site:	Indian Point
Issue date:	05/09/2012
From:	Ventosa J Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-12-058 LER 12-003-00
Download: ML12144A150 (5)

LER-2012-003, Regarding Technical Specification (TS) Prohibited Condition Caused by Through Wall Defects in Reactor Coolant Pressure Boundary Branch Lines

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2472012003R00 - NRC Website

text

.Entergy Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, N.Y. 10511-0249 Tel (914) 254-6700 John A. Ventosa Site Vice President NL-12-058 May 9, 2012 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop O-P1-17 Washington, D.C. 20555-0001

SUBJECT:

Licensee Event Report # 2012-003-00, "Technical Specification (TS)

Prohibited Condition Caused by Through Wall Defects in Reactor Coolant Pressure Boundary Branch Lines" Indian Point Unit No. 2 Docket No. 50-247 DPR-26

Dear Sir or Madam:

Pursuant to 10 CFR 50.73(a)(1), Entergy Nuclear Operations Inc. (ENO) hereby provides Licensee Event Report (LER) 2012-003-00. The attached LER identifies an event where there was a Technical Specification (TS) prohibited condition due to two through wall defects identified in Reactor Coolant Pressure Boundary branch lines which is not permitted by the TS, that is reportable under 10 CFR 50.73(a)(2)(i)(B). This condition was recorded in the Entergy Corrective Action Program as Condition Report CR-IP2-2012-01733.

There are no new commitments identified in this letter. Should you have any questions regarding this submittal, please contact Mr. Robert Walpole, Manager, Licensing at (914) 254-6710.

Sincerely, JAV/cbr cc:

Mr. William Dean, Regional Administrator, NRC Region I NRC Resident Inspector's Office, Indian Point 2 Mrs. Bridget Frymire, New York State Public Service Commission LER Events@ inpo.org

Abstract

On March 12, 2012, during a scheduled refueling outage (RO) boric acid program walk down inspection, two locations on Reactor Coolant System (RCS) pressure boundary (RCPB) branch piping had boron deposits that appeared not to be due to packing or mechanical joint leakage.

The areas were cleaned and non-destructive surface examinations confirmed that the boric acid deposits were due to through wall defects.

1) Pressure Control Valve PCV-455A Spray Inlet Stop valve 4152 contained a defect on the top of the horizontal leak-off pipe in the base metal approximately one inch from where the pipe connects to the valve bonnet.

2)

The socket weld of a 3/8 inch diameter tubing "tee" fitting down stream of valve 4138 contained a defect.

Technical Specification 3.4.13 does not allow any RCPB leakage.

The apparent cause of defect 1 (leak-off pipe) was stress corrosion cracking due to surface contamination.

The apparent cause of defect 2 was poor quality weld due to insufficient weld reinforcement in part of the weld.

Corrective actions included replacement of the bonnet of valve 4152 containing the leak-off pipe, and replacement of the socket welded "tee" with a Swagelok "tee" eliminating the two field welds that were lacking reinforcement.

An engineering change (EC) and associated work orders (WO) will be prepared to eliminate the capped leak-off pipes on RCS valves at unit 2 and 3.

A visual inspection on 10% (random sampling) of applicable field welds will be performed.

The event had no significant effect on public health and safety.

(If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)

Safety Significance

This event had no significant effect on the health and safety of the public. There were no actual safety consequences for the event because there were no significant failures in the RCPB.

Periodic inspections identify leaks when they are small so that repairs can be performed to prevent RCPB degradation.

TS 3.4.13 has Surveillance Requirement 3.4.13.1 to verify RCS leakage is within limits by performance of RCS inventory balance every 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

This surveillance ensures the integrity of the RCPB is maintained and provides a trend of leakage early before significant degradation.

An early warning of RCPB leakage or unidentified leakage is provided by the systems that monitor containment atmosphere radioactivity and operation of the containment sump.

Failure of a RCPB would be a Loss of Coolant Accident (LOCA).

A LOCA is analyzed in UFSAR Section 14.3.

A minor pipe break (small break) is defined as a rupture of the RCPB with a total cross-sectional area less than 1.0 square foot in which the normally operating charging system flow is not sufficient to sustain pressurizer level and pressure.

The results of analysis in UFSAR Section 14.3.3.4 concluded the limiting break was a 3 inch cold leg break.

The results of the analysis demonstrated that for a small break LOCA, the Emergency Core Cooling System will meet the acceptance criteria contained in 10CFR50.46.

The LOCA analysis of Section 14.3 are bounding for the components reported in this LER.