05000251/LER-2004-003, Regarding Bearing Oil Leak Causes High Head Safety Injection Pump to Be Inoperable Longer than Allowed by Technical Specifications

Regarding Bearing Oil Leak Causes High Head Safety Injection Pump to Be Inoperable Longer than Allowed by Technical Specifications

ML043010237
Person / Time
Site:	Turkey Point
Issue date:	10/15/2004
From:	Jones T Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2004-190 LER 04-003-00
Download: ML043010237 (7)

LER-2004-003, Regarding Bearing Oil Leak Causes High Head Safety Injection Pump to Be Inoperable Longer than Allowed by Technical Specifications

Event date:
Report date:
Reporting criterion:	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)(vii), Common Cause Inoperability 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 10 CFR 50.73(a)(2)
2512004003R00 - NRC Website

text

FPL 10 CFR § 50.73 L-2004-190 10/15/2004 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Re:

Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 2004-003-00 Date of Event: August 3, 2004 Bearing Oil Leak Causes High Head Safety Injection Pump to be Inoperable Longer Than Allowed by Technical Specifications The attached Licensee Event Report 251/2004-003-00 is being submitted pursuant to the requirements of 10 CFR 50.73(a)(2)(i)(B) to provide notification of the subject event.

If there are any questions, please call Mr. Walter Parker at (305) 246-6632.

Very truly yours, Terry O. Jnes Vice President Turkey Point Nuclear Plant Attachment cc:

Regional Administrator, USNRC, Region II Senior Resident Inspector, USNRC, Turkey Point Nuclear Plant an FPL Group company

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004)

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 estimate to the Records and FOIAPrivacy Service Branch (T-5 F52), U.S. Nuclear Regulatory Commission, LICENSEE EVENT REPORT (LER)

Washington, DC 20555-0001, or by Internet e-mail to lnfocollects~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 0MB control (See reverse for required number of number, the NRFC may not conduct or sponsor, and a person Is not required to digits/characters for each block) respond to. the Information collection.

3. PAGE Turkey Point Unit 4 05000251 1 OF 6

4. TITLE Oil Leak Causes High Head Safety Injection Pump to be Inoperable Longer Than Allowed by Technical Specifications

5. EVENT DATE

6. LER NUMBER l

7. REPORT DATE

8. OTHER FACILITIES INVOLVED SEUNILRVFACILrTY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBERL NE MONTHIl DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 8

3 2004 2004 - 003 - 00 10 15 2004 05000

9. OPERATING MODE 11.THIS REPORTIS SUBMITTED PURSUANTTO THE REQUIREMENTS OF 10CFR§: (Checkallthatapply) o 20.2201(b)

E 20.2203(a)(3)(i) 0 50.73(a)(2)(i)(C)

El 50.73(a)(2)(vii) 10 20.2201(d) 0 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(A)

Cl 50.73(a)(2)(viii)(A)

O 20.2203(a)(1) 0 20.2203(a)(4) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B) o 20.2203(a)(2)(i) 0 50.36(c)(1)(i)(A) 0 50.73(a)(2)(iii)

El 50.73(a)(2)(ix)(A)

10. POWER LEVEL 0 20.2203(a)(2)(ii)

El 50.36(c)(1)(ii)(A) 0 50.73(a)(2)(iv)(A)

El 50.73(a)(2)(x) o 20.2203(a)(2)(iii) 0 50.36(c)(2) a 50.73(a)(2)(v)(A) a 73.71(a)(4) o 20.2203(a)(2)(iv) 0 50.46(a)(3)(ii) 0 50.73(a)(2)(v)(B) 0 73.71(a)(5) 100 0 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A) 0 50.73(a)(2)(v)(C)

LI OTHER o 20.2203(a)(2)(vi)

ED 50.73(a)(2)(')(B) 0 50.73(a)(2)(v)(D)

Specify In Abstract below or In NRC Form 366A

12. LICENSEE CONTACT FOR THIS LER NAME TELEPHONE NUMBER (Incluce Area Code)

Paul F. Czaya - Licensing Engineer 305-246-7150CAUSE SYSTEM l COMPONENT MVANU-REPORTABLE lll

CAUSE

SYSTEM ICOMPONENT MANU-REPORTABLE jFACTURER TO EPIX j jFACTURER TO EPIX

14. SUPPLEMENTAL REPORT EXPECTED

15. EXPECTED MONTH DAY YEAR SUBMISSION El YES (If yes. complete 15. EXPECTED SUBMISSION DATE) 0D NO DATE I

ABSTRACT (Limit to 1400 spaces, I.e., approximately 15 single-spaced typewritten lines)

The outboard bearing oiler for high head safety injection (HHSI) pump 4B was found empty on August 3, 2004.

Subsequent investigation determined that the previously identified minor outboard bearing oil leak experienced a step change in leak rate rendering the pump inoperable on or about June 6, 2004. Therefore, the 4B HHSI pump was unavailable for 60 days due to the oil leak, which exceeds the Technical Specification allowed outage time of 30 days. Any one of the three remaining HHSI pumps was capable of performing the intended HHSI safety function.

The cause of the oil leak was due to human performance deficiencies during the last pump overhaul assembly of the bearing housing. A contributing cause was insufficient guidance in the maintenance procedure for bearing housing work. Plant procedures have been revised to provide additional guidance in performing HHSI pump bearing maintenance. All other plant safety-related pumps have been inspected to ensure that no other similar oil leakage conditions exist. Oil addition program enhancements and trend plan development guidance for oil leak monitoring have been developed under the corrective action program to address generic implications. It was concluded that the health and safety of the public were not affected by this event.

NRC ORM 86(-200)

PINTE ON ECYLED APE NRC FORM 366 (6-2004)

PRINTED ON RECYCLED PAPER

INRC FRM365A I&NUCLEAB REGULATORY COMMISSION U-20011 LICENSEE EVENT REPORT (LEH)

TEXT CONTINUATION FACIITY NAME ID0 DOCKETNUMBER LED NUMBEJI 161 PAGE 131 YER SEQUENTIAL REVISION YEA NUMBER NEUVMBER Turkey Point Unit 4 05000251 N

N Page 2 of 6 2004 -003-00 lTr (IIIUOeSprsckaCsIIItI sDolhflDSpleoolNsfARCFro1m35W1Tm DESCRIPTION OF THE EVENT The outboard bearing oiler [EHC: LU] for 4B high head safety injection [EIIS: BQJ (HHSI) pump [EIIC: P]

was found empty on August 3, 2004. Subsequent investigation determined that the previously identified minor outboard bearing oil leak experienced a step change in leak rate rendering the pump inoperable on or about June 6, 2004. Therefore, the 4B HHSI pump was considered inoperable due to the oil leak from June 6, 2004 until it was repaired on August 5, 2004. This 60-day period exceeds the Technical Specification allowed outage time of 30 days. The plant (Unit 4) was operating in Mode 1 at 100 percent power at the time the oiler was found empty on August 3, 2004. Unit 3 was also operating in Mode 1.

After a thorough Engineering and Maintenance evaluation, this condition was determined to be reportable on August 18, 2004 in accordance with 10 CFR 50.73(a)(2)(i)(B).

BACKGROUND Emergency core cooling is provided by the Safety Injection System (which constitutes the Emergency Core Cooling System). The primary purpose of the Safety Injection System (SIS) is to automatically deliver coolant to the reactor core [EIIS: AC] in the event of a loss-of-coolant accident. The SIS limits fuel clad temperature and thereby ensures that the core will remain intact with its heat transfer geometry preserved.

The principal components of the SIS are the accumulators [EHC: ACC] (one for each loop), four safety injection (high head) pumps and two residual heat removal [EIIS: BP] (RHR) (low head) pumps.

During normal plant operation the SIS is not in operation. However, active system components (i.e., pumps, and valves) are in standby readiness for safety injection (SI). The SI signal actuates SIS operation.

The SIS, in combination with the RHR System, mitigates the consequences of the defined range of loss-of-coolant and secondary accidents by providing the emergency core cooling or reactivity control that is needed to protect the reactor core. By preserving the integrity of the reactor core, the SIS limits the release of fission products from the reactor fuel and ensures the ability to provide long-term decay heat removal from the core.

The SIS includes two major subsystems (refueling water storage tank and accumulators). The refueling water storage tank (RWST) provides the major source of borated demineralized water during the first (injection) phase of the system's accident response. The accumulators, which are passive components, discharge into the cold legs of the reactor coolant piping when pressure decreases to approximately 660 psig, thus rapidly assuring core cooling for large breaks.

The SI signal opens the SIS isolation valves [EIIC: ISV] and starts the HHSI pumps and the RHR pumps.

The four HHSI pumps take suction from the RWST, are cross-connected and can deliver coolant to either Unit 3 or Unit 4.

"se O11I Z6ISIr-20011

KRC FORM366A U.S&UCKEAB REGULATORY COMMISSION 11-20011 LICENSEE EVENT REPORT ILERI TEXT CONTINUATION FACITY MMW IOCENUBE ER NUMBDERO6 I

FPAGEIZ Turkey Point Unit 4 TEXT XIfSIorgrspwlselieosrssfddmvonsCVwlesohfRCAonm35Wtm 11 The RHR pumps deliver coolant to all three cold legs through the piping between the accumulators and the cold legs. The HHSI pumps deliver into two separate headers, one going to the cold legs and one to the hot legs.

After the injection operation, coolant spilled from the break and water collected from the containment spray [EIIS: BE] is cooled and returned to the reactor coolant system [EIIS: AB] by the recirculation system.

For the recirculation phase of the accident the reactor coolant, which eventually drains to the containment sump, is recirculated through the sump line from the containment to the suction of the RHR pump through two independent and redundant recirculation lines. During recirculation, one recirculation train will be in service. Each train includes either of the two RHR pumps and either one or two RHR heat exchangers [EHIC: HX]. The flow will go from the discharge of the RHR pump through the heat exchanger and then into the reactor via either the low head injection path or the high head injection path via the HHSI pumps.

Any one of the four HHSI pumps, in conjunction with associated system components, can achieve the safety function of the SIS.

On August 3, 2004 during inspection of 4B HHSI pump, it was discovered that the outboard bearing oiler was empty. The 4B HHSI pump had an oil leak from the inboard side of the outboard bearing and the oil level in the glass was not visible. The 4B HHSI pump was declared inoperable and repaired. A past operability evaluation was conducted which conservatively concluded that the 4B HHSI pump would not have been able to perform its safety function of long term core cooling with the bearing oil leak condition.

CAUSE OF THE EVENT

The cause of the 4B HHSI pump oil leak is human performance error. During disassembly of the outboard bearing housing, several problems were found that contributed to the oil leak. The anti-rotation pin was jammed into the thrust ring and incorrect gasket/shim material was used during final bearing housing assembly in 1994. The anti-rotation pin was not properly aligned with the thrust ring, exerting pressure on the outer race of the bearings, which, in turn, exerted pressure on the bearing cover. This distorted the bearing cover face, and prevented the gasket/shim from sealing properly. In addition, the gasket/shim material found in the housing was not supplied by the original equipment manufacturer and was found to be susceptible to degradation by oil over time. A contributing cause was insufficient procedural guidance for bearing housing assembly.

The cause of the delay in identifying the need to correct the oil leak was a weakness in documentation consistency and retrievability under the oil addition program for safety-related components. In the case of the oil leak on the 4B HHSI pump, oil addition sheets were not retrievable and rendered oil leak rate trending calculations unreliable. Oil leak rate was being monitored by one organization, without the knowledge that oil additions were being made by another organization.

N"C lIeU a3165 -21911US. NUCLEAR REBUIATORT COMMISSION N RCFORII366A US.INUCtLM RI6UIRATORY COWllSSIO11 I0-20011 LICENSEE EVENT REPORT I[ERI TEXT CONTINUATION OACICff NAME m IOCKETNUMHEB 1ER NUMBER [61 i

FACE13 l

YEARSEQUENTIAL REVISION YEAR NUMER NUMBER Turkey Point Unit 4 05000251 YEAR

- U REVSIO Page 4 of 6 TEXT (IfmuousuaIsougurgeitus,,ddIIon~lco~lsullRcfionu,35W(1

ANALYSIS OF THE EVENT

Past Operability Assessment During a walkdown performed on April 21, 2004, the SI system engineer noted a pool of oil in the trough under the outboard seal area. He also noted the outboard oiler was approximately 1/3 full. The system engineer entered the condition into the corrective action program and proceeded to evaluate the oil leakage from the 4B HHSI pump outboard bearing. At that time, an oil leak rate was calculated based on a review of historical oil addition over the previous month. The oil leak rate was determined to be acceptable to support unassisted accident mission time. The investigation determined the leak rate did not increase with the pump running, i.e. no difference was noted between standby and running leak rates. The condition report investigation initiated the work order that repaired the leak on August 5, 2004.

It was expected that the leak rate would not increase significantly over the short term due to the observed nature of the gasket leak from the unpressurized oil reservoir. Based on this consideration, the repair was scheduled for a normal system workweek. The oiler was subsequently found empty prior to repairing the oil leak.

In order to determine the oil leak rate after the oiler was found empty on August 3, 2004, documentation of historical make-up oil added to the 4B HHSI pump was gathered. Review of the data indicated that on 4/23/04, 6/6/04, 6/23/04 and 7/26/04 oil was added to the 4B HHSI pump under generic oil addition work orders and was documented on oil addition sheets. The generic work orders are filed in the maintenance shop and planning library. Since this data was not transmitted to Document Control, it was not readily retrievable. During this period, the system engineer was unaware of the numerous times make-up oil was added to the 4B HHSI pump. This omission directly affected the system engineer's leak rate monitoring and calculations in a non-conservative manner.

In order to ensure long term core cooling (30-day mission time for HHSI pumps) without any oil addition, it was calculated that the leak rate must be less than 0.13 ounces (oz.) per day. (The capacity of a 4 oz. oiler divided by the 30-day mission time, 4/30 = 0.13). The oil addition records for the 4B HHSI pump outboard bearing oiler indicated that the leakage rate was less than 0.13 oz./day until about June 6, 2004. From June 6, 2004 until August 3, 2004, the oil addition records indicate that the leakage rate increased from approximately 0.23 oz./day to approximately 1 oz./day. During the period from June 6, 2004, when the leakage rate increased above 0.13 oz./day, until the pump was repaired on August 5, 2004, the 4B HHSI pump was considered inoperable since there was no assurance that it could provide its function of long term core cooling.

Reportability

A review of the reporting requirements of 10 CFR 50.72 and 10 CFR 50.73 and NRC guidance provided in "Event Reporting Guidelines," 10 CFR 50.72 and 10 CFR 50.73 (NUREG-1022, Rev. 2) was performed for the subject condition. As a result of this review, the condition is reportable as described below.

Nit FilM 366A S20011

NRC FORM 36 US. UCLH REGULATORY COMMISSION i-20011 LICENSEE EVENT REPORT [LERI T

CONTINUATION FACIUTY WM l 0OC NUMBER iI NUMBED 161 PACE 131 eYEAR QUENTIAL REVISION Turkey Point Unit 4 05000251 204 03 0

Page 5 of 6 TE XXT (llmorespae Is urett ususo'dIufafaIesoIIRCfolmhSn 1111I

1. Part 50.73(a)(2)(i)(B) of Title 10 CFR states that the licensee shall report "Any operation or condition which was prohibited by the plant's Technical Specifications except when:

(1)

The Technical Specification is administrative in nature; (2)

The event consisted solely of a case of a late surveillance test where the oversight was corrected, the test was performed, and the equipment was found to be capable of performing its specified safety functions: or (3)

The Technical Specification was revised prior to discovery of the event such that the operation or condition was no longer prohibited at the time of discovery of the event."

The applicable Technical Specification is 3.5.2. It states, in part, "The following Emergency Core Cooling System (ECCS) equipment and flow paths shall be OPERABLE:

a. Four OPERABLE Safety Injection (SI) pumps, each capable of being powered from its associated OPERABLE diesel generator, with discharge aligned to the RCS cold legs,...

APPLICABILITY: MODES 1, 2, and 3**....

ACTION:

c.

With one of the four required Safety Injection pumps inoperable and the opposite unit in MODE 1, 2, or 3, restore the pump to OPERABLE status within 30 days or be in at least HOT STANDBY within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />."

The 4B HHSI pump was considered inoperable from June 6, 2004 until it was repaired on August 5, 2004, a period of 60 days. Since the pump was inoperable greater than the allowed out-of-service time of 30 days, Action c of Technical Specification 3.5.2 was not met. Therefore, this condition is considered reportable under 10 CFR 50.73(a)(2)(i)(B).

ANALYSIS OF SAFETY SIGNIFICANCE Based on the analysis described below, it is concluded that the health and safety of the public were not affected by this event.

Any one of four HHSI pumps can achieve the safety function of the SIS. With one pump inoperable, any one of the three remaining pumps is capable of providing adequate core cooling.

A scoping evaluation of the risk impact of having one HHSI pump inoperable for 60 days was performed using the baseline PSA model with core damage frequency (CDF) of 7.454E-6/year. The CDF increase over 60 days due to 4B HHSI pump being unavailable is approximately 2.0E-7. This is below the risk significance threshold of 1.01E-6 for CDF increase. The increase of Large Early Release Frequency (LERE)

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XNC FORM 366A US NUCLEKR REGUATORY COMMISSION n-20011 LICENSEE EVENT REPORT IHERI TEXTCONTINUATION FACIIfNAMEM DOCKNUMU LE UNUMBDI 161 FACEMI YEAR SEQUENTIAL I REVISION Turkey Point Unit 4 05000251 NUMBER I NUMBER Page 6 of 6 TENT llw/mogrnassddImIoiror~aes,1IowatooIsormXWTh~ozJs over 60 days is estimated to be below 1.0E-8, which is below the risk significance threshold of 1.0E-7 for LERF increase.

CORRECTIVE ACTIONS

1. The 4B HHSI pump outboard bearing leak was repaired and the pump was returned to service on August 5, 2004.

2. All HHSI pumps have been walked down. No Unit 3 or 4 HHSI pumps were found with similar oil leaks.

3. Maintenance procedure 0-CMM-062.1, "High Head SIS Pump Rotating Element Replacement," was revised to incorporate human performance barriers to help prevent recurrence of bearing housing assembly errors.

4. Investigation of safety-related components was performed to determine if other oil leaks exist that require immediate corrective action. In addition, safety and non-safety related oil addition sheets were evaluated. This was done to determine if any other components have oil leaks or require frequent oil additions. No other component with a mission critical unattended run time was found to have an active oil leak.

5. A night order had been issued to Operations personnel instructing them to take specific action when identifying an oil leak by entering the condition into the corrective action program.

6. Plant corrective action program and maintenance procedures will be revised to establish additional barriers regarding the monitoring, documentation and corrective action required, upon discovery of equipment oil leaks and/or oil level anomalies.

ADDITIONAL INFORMATION

EIIS Codes are shown in the format [EIIS SYSTEM: IEEE system identifier, component function identifier, second component function identifier (if appropriate)].

FAILED COMPONENTS IDENTIFIED:

NONE

SIMILAR EVENTS

A search of Turkey Point and Institute Of Nuclear Power Operations (INPO) operating experiences did not identify any similar events. An industry operating experience (OE) report was submitted to the INPO Nuclear Network and assigned OE#19173.

e FORK 3A6U -20011