NL-13-142, LER 13-004-00 for Indian Point, Unit 2, 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: | Docket Number  |
| Issue date: | 11/12/2013 |
| From: | Ventosa J A Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-13-142 LER 13-004-00 | |
| Download: ML13319B082 (5) | |
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
~Z~L NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES: (9-2007) 10/31/2013 Estimated burden per response to comply with this mandatory collection request: 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry.
Send comments regarding burden LICENSEE EVENT REPORT (LER) estimate to the Records and FOIA/Privacy Service Branch (T-5 F52), U.S.Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME: INDIAN POINT 2 2. DOCKET NUMBER 3. PAGE 05000-247 1 OF 4 4.TITLE: 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 5. EVENT DATE 6. LER NUMBER 7. REPORT DATE 8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL REV, MONTH DAY YEAR 05000 NUMBER NO.FACILITY NAME DOCKET NUMBER 09 11 2013 2013- 004 -00 11 12 2013 05000 9. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)EL 20.2201(b)
E] 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 1 El 20.2201(d)
[E 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
[E 50.73(a)(2)(viii)(A)
El 20.2203(a)(1) 0l 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 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)
El 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
- 10. POWER LEVEL El 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71 (a)(4)100% El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71 (a)(5)El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi)
Z 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A 12. LICENSEE CONTACT FOR THIS LER NAME TELEPHONE NUMBER (Include Area Code)Joe Lafferty, Engineer, Equipment Reliability Engineering (914) 254-6612 13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT MANU- REPORTABLE MANUFACTU REPORTABLE CAUSE SYSTEM COMPONENT FACTURERCAUSE SYSTEM COMPONENT ER TO EPIX A BI PSP Y 14. SUPPLEMENTAL REPORT EXPECTED 15. EXPECTED MONTH DAY YEAR El YES (If yes, complete 15. EXPECTED SUBMISSION DATE) [ NO SUBMISSION DATE 16. ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced type written lines)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.
NRC FORM 366AU.S. NUCLEAR REGULATORY COMMISSION (9-2007)LICENSEE EVENT REPORT (LER)FACILITY NAME (1) DOCKET (2) LER NUMBER (6) PAGE (3)1SEQUENTIAL REVISION YEAR NUMBER NUMBER Indian Point Unit 2 .05000-247 2013 -004 00 2 OF 4 NARRATIVE (if more space is required, use additional copies of NRC Form 366A) (17)Note: The Energy Industry Identification System Codes are identified within the brackets 01.DESCRIPTION OF EVENT On September 11, 2013, during an engineering walkdown of Service Water (SW){BIj temperature control valve SWN-TCV-1103
{TCV}, eight pin hole leaks were discovered at approximately 17:30 hours, in the Primary Auxiliary Building {NF} pipe chase in SW piping (PSP} that supports three Radiation Monitors (RM) (IL}. 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 was on an elbow with all located in the 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 at 17:30 hours, which also required entry into TS 3.0.3. SW valves SWN-61 and SWN-55A were closed isolating the leaking piping restoring operability of the SW header and TS 3.7.8 declared met at 17:54 hours. The tagout boundary for leak isolation required placing Radiation Monitor (R) R-49, R-46, and R-53 to standby rendering them non-functional and required that compensatory action be taken. TS 3.0.3 was exited on September 11, 2013, at 17:57 hours. Radiation Monitor R-49 monitors the liquid blowdown from the secondary side of the steam generators (SGs). Samples from the bottoms of all four SGs are mixed in a common header and the common sample is monitored.
R-46 and R-53 monitor the SW return from all five containment fan cooler units. The condition was recorded in the Indian Point Energy Center (IPEC) Corrective Action Program (CAP) as Condition Report CR-IP2-2013-03759.
An investigation revealed that the original SW pipe serving R-46, R-53 and R-49 was cement lined carbon steel (CS) small bore piping. The CS piping experienced general corrosion pitting at socket weld locations where protective cement lining could not be applied leaving susceptible material exposed to the corrosive Hudson River water that is used for SW. The CS piping was replaced with 300 series Stainless Steel (SS) in the late 1980's. Pin hole leaks were first identified in the replacement SS SW piping in 2008 as part of an extent of condition of ASME Code piping with 300 series SS material.The pitting corrosion of SS series 300 SS pipe material is well understood by the industry and at Indian Point and generally does not challenge the structural integrity of the pipe. Series 300 SS is susceptible to general corrosion pitting in a brackish water (chloride) environment.
A walkdown on September 11, 2013 identified eight pin hole leaks in SW piping serving monitors R-46, R-53 and R-49. The leaks were at the following locations; at the second elbow upstream of valve SWN-57, first elbow downstream of valve SWN-944, second elbow upstream of valve SWN-944, upstream pipe fitting of valve SWN-658, second elbow downstream of valve SWN-61, first elbow downstream of valve SWN-61, second elbow in overhead where piping penetrates the SW pipe chase ceiling, and the horizontal elbow in overhead prior to the vertical run down to the mixing nozzle. There was no active leakage identified.
The leak locations would not allow for Ultrasonic Testing (UT) or to obtain thickness readings.
Without the ability to characterize the flaw size, structural evaluations could not be performed in accordance with code case requirements and the piping was declared inoperable.
All ASME Section XI Code SS piping weld deficiencies identified in 2008 were weld repaired and a corrective action prepared to track replacement of the 300 series SS pipe with highly corrosion resistant material (AL6XN). Pipe replacement was scheduled for the spring 2010 outage but was deferred to 2012 because of higher risk work and inspections had not identified any degraded conditions.
The pipe replacement scheduled for 2012 was again deferred to 2014 for higher risk work. No mitigation strategy was documented.
Procedure EN-DC-336 (Plant Health Committee)
Revision 4 had a requirement to document the evaluation of risk and required interim actions for high priority long term projects.
Revision 4 became effective December 15, 2011.
NRC FORM 366AU.S. NUCLEAR REGULATORY COMMISSION (9-2007)LICENSEE EVENT REPORT (LER)FACILITY NAME (1) DOCKET (2) LER NUMBER (6) PAGE (3)1 SEQUENTIAL REVISION YEAR NUMBER NUMBER Indian Point Unit 2 05000-247 2013 -004 00 3 OF 4 The pipe replacement deferral was made by the Modification Project Review Committee (MPRC) based on having no leaks and the need to perform other higher risk work for the SW system. The piping is typically walked down every six months because of dose considerations.
A more frequent targeted inspection plan was not developed.
The SW System (SWS) is designed to supply cooling water from the Hudson River to various heat loads in both the primary and secondary portions of the plant. The design ensures a continuous flow of cooling water to those systems and components necessary for plant safety during normal operation and under abnormal or accident conditions.
The SWS consists of two separate, 100% capacity, safety related cooling water headers. Each header is supplied by 3 pumps to include pump strainers, with SWS heat loads designated as either essential or non-essential.
The essential SWS heat loads are those which must be supplied with cooling water immediately in the event of a Loss of Cooling Accident (LOCA) and/or Loss of Offsite Power (LOOP). The essential SWS heat loads can be cooled by any two of the three SW pumps on the essential header.Either of the two SWS headers can be aligned to supply the essential heat loads or the non-essential SWS heat loads.An extent of condition (EOC) review assessed the amount of Section XI series 300 SS small bore piping remaining in the SW system. The review determined that with the exception of the SW piping for the RMs scheduled for replacement in the spring of 2014, no additional small bore series 300 SS piping exists in the SW Systems at units 2 and 3. Therefore, pitting corrosion in SS piping is expected to be fully mitigated by the outage of 2014 when the piping for the RMs is replaced.Cause of Event 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 from the 2R20 outage. A bridging strategy would document the risk of deferring pipe replacement and identify interim actions that could be taken (more frequent targeted inspections).
The direct cause of pin hole leaks in the SW piping is because Series 300 SS piping is susceptible to corrosion pitting in a brackish water (chloride) environment.
In 2008 pin hole leaks due to crevice crack corrosion was identified and a modification developed to replace the piping with material immune to brackish water corrosion.
In 2008, the Unit Reliability Team (URT) appropriately ranked the risk for replacement in 2010. Subsequently, the piping replacement was de-scoped from the 2010 outage and rescheduled to 2012, and then rescheduled again to 2014 due to no indication of leakage and higher risk work.Corrective Actions The following corrective actions have been or will be performed under Entergy's Corrective Action Program to address the cause and prevent recurrence:
- The affected piping will be weld repaired and returned to operable.* Full pipe replacement with highly corrosion resistant material (AL6XN) 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.
NRC FORM 366AU.S. NUCLEAR REGULATORY COMMISSION (9-2007)LICENSEE EVENT REPORT (LER)FACILITY NAME (1) DOCKET (2) LER NUMBER (6) PAGE (3)1 SEUENTIAL REVISION YEAR NUMBER NUMBER Indian Point Unit 2 05000-247 2013 -004 -00 4 OF 4 NARRATIVE (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.