05000247/LER-2013-004, Regarding Technical Specification (TS) Prohibited Condition Due to an Inoperable Essential Service Water (SW) Header as a Result of Pin Hole Leaks in Code Class 3 SW Piping
| ML13319B082 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 11/12/2013 |
| From: | Ventosa J Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-13-142 LER 13-004-00 | |
| Download: ML13319B082 (5) | |
| 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 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 2472013004R00 - NRC Website | |
text
e-En tergy 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-13-142 November 12, 2013 U.S. Nuclear Regulatory Commission Document Control Desk 11545 Rockville Pike, TWFN-2 F1 Rockville, MD 20852-2738
SUBJECT:
Licensee Event Report # 2013-004-00, "TechnicalSpecification (TS)
Prohibited Condition Due to an Inoperable Essential Service Water (SW)
Header as a Result of Pin Hole Leaks in Code Class 3 SW Piping" 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) 2013-004-00. The attached LER identifies an event where there was a Technical Specification (TS) Prohibited Condition due to an inoperable essential Service Water (SW) header as a result of pin hole leaks in Code Class 3 SW Piping, which 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-IP2-2013-03759.
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.
cc:
Mr. William Dean, Regional Administrator, NRC Region I NRC Resident Inspector's Office Ms. Bridget Frymire, New York State Public Service Commission
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Abstract
On September 11, 2013, during an engineering walkdown of service Water (SW) temperature control valve SWN-TCV-1103, eight pin hole leaks were discovered in SW piping that supports three Radiation Monitors (RM).
All leaks had minor corrosion product buildup as well as staining of the piping and staining of the floor.
Seven leaks were on socket welds and one on an elbow and all located in ASME Section XI Code boundary.
The affected SW piping and the essential SW header were declared inoperable and Technical Specification (TS) 3.7.8 (SW System) was declared not met which required entry into TS 3.0.3.
The leaking piping was isolated restoring operability of the SW header.
The apparent cause was procedure EN-DC-336 (Plant Health Committee) was not followed to document a risk assessment or mitigating (bridging) strategy when the pipe replacement was rescheduled.
The corrective actions are to weld repair the affected piping followed by replacing piping with highly corrosion resistant material (AL6XN).
Full pipe replacement is scheduled for the 2014 refueling outage.
A review and assessment of the Site Integrated Project Database (SIPD) will be performed to identify any additional potential risks for not having documented risk assessments of items meeting the risk criteria.
The Modification Project Review Committee (MPRC),
Engineering Change Review Group (ECRG),
Plant Health Committee (PHC),
and System Engineering staff will be briefed on the need to consider requesting a bridging strategy when required high or medium risk ranked work is rescheduled beyond the operating cycle.
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)
Event Analysis
The event is reportable under 10 CFR 50.73(a)(2)(i)(B).
The licensee shall report any operation or condition which was prohibited by the plant's TS.
This condition meets the reporting criteria because the essential SW header was declared inoperable as a result of discovering pin hole leaks in ISI Class 3 SW piping for the RM system.
TS 3.7.8 LCO requires three pumps and required flow path for the essential header to be operable.
The LCO requires associated piping, valves and instrumentation and controls required to perform the safety related function to be operable.
The piping discovered with through wall leaks is ISI Class 3 piping and is not operable with this condition.
During previous operation for an unknown period of time of up to approximately 6 months the subject piping contained through wall leaks as evidenced by corrosion product buildup at certain welds, staining of the piping directly below the welds, and staining of the floor below the welds.
This previously unrecognized condition required TS 3.0.3 entry and corrective actions to return the piping header to operable.
Failure to comply with the TS LCO and perform required actions is a TS prohibited condition.
There was no safety system functional failure reportable under 10 CFR 50.73(a) (2) (v).
A designated essential header was available and the leaks would not have prevented the SW cooling function for affected heat loads.
A similar condition was discovered in 2008 as a result of a walkdown that identified SW system leaks in RM piping in the SW pipe chase and recorded in CR-IP2-2008-04268 on September 17, 2008.
The 2008 leak was not in the same location.
The plant did not enter TS 3.0.3 as the piping was isolated for ultrasonic examination prior to determining the pipe was inoperable.
The condition was recorded as "no reportability determination required" therefore, past reportability was not assessed and no LER was submitted.
The condition in 2008 would not now require an LER as the past reporting criteria of three years has been exceeded.
CR-IP2-2013-04346 recorded this finding.
Past Similar Events A review was performed of the past three years of Licensee Event Reports (LERs) for events reporting a TS violation due to inoperable SW piping caused by leaks and none were identified.
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 accidents or events during the degraded condition.
No active leaking was identified.
There were no significant potential safety consequences of this event.
The leaks in SW piping were within the capability of the SW system to provide adequate SW flow to SW loads.
The degraded piping was on the discharge of the heat loads therefore any failure would not prevent the SW cooling function.
Any failure of the degraded piping as a result of a transient, accident or event could result in potential flooding.
SW leaking in the PAB area would drain to the PAB sump.
Any flooding condition could be identified and mitigated as the PAB sump has a high level alarm that actuates an alarm on the PAB sump alarm panel in the unit 2 NPO office and at the Waste Disposal Panel (Flood 15 foot Elevation, Flood 68 foot Elevation).
Alarm Response Procedure ARP-014 (PAB Flooding) requires operator acknowledgement of the alarm, notification of the Control Room and initiation of action to eliminate the cause of the flooding.
Procedure 2-ARP-004 (Waste Disposal Panel) also includes actions to respond to WDP PAB Sump Pump Hi level alarm.
The ARP actions include isolation of any source of flooding.
The SW piping leaks were downstream of the isolation valves which would allow operators to isolate the leak once alerted.
In addition to PAB Sump level alarms, periodic operator rounds (Nuclear Rounds) include Waste Disposal Alarm Panel tested/verification thereby providing another means to identify SW piping leakage.