05000445/LER-2007-001, Regarding Emergency Diesel Generator Inoperable for Longer than Allowed by TS Due to Paint on Metering Rod

Regarding Emergency Diesel Generator Inoperable for Longer than Allowed by TS Due to Paint on Metering Rod

ML080240252
Person / Time
Site:	Comanche Peak
Issue date:	01/17/2008
From:	Blevins M Luminant Generation Co, Luminant Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-200700221, TXX-08001 LER 07-001-00
Download: ML080240252 (9)

LER-2007-001, Regarding Emergency Diesel Generator Inoperable for Longer than Allowed by TS Due to Paint on Metering Rod

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function 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)(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
4452007001R00 - NRC Website

text

Mike Blevins Executive Vice President

& Chief Nuclear Officer Mike.Blevins @ LuminanLcom Luminant Power P 0 Box 1002 6322 North FM 56 Glen Rose, TX 76043 T 254 897 5209 C 817 559 9085 F 254 897 6652 CP-200700221 Log # TXX-08001 Ref. #

10CFR50.73(a)(2)(i)(B) 10CFR50.73(a)(2)(v)(D)

January 17, 2008 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NO. 50-445 CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS LICENSEE EVENT REPORT 445/07-001-00

REFERENCE:

Dear Sir or Madam:

Enclosed is Licensee Event Report (LER) 07-001-00 for Comanche Peak Steam Electric Station (herein referred to as Comanche Peak Nuclear Power Plant) Unit 1, "Emergency Diesel Generator Inoperable for Longer Than Allowed By Technical Specifications Due to Paint on Metering Rod."

This communication contains no new licensing basis commitments regarding Comanche Peak Nuclear Power Plant (CPNPP) Unit 1.

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde

• South Texas Project

• Wolf Creek

" Z/

U. S. Nuclear Regulatory Commission TXX-08001 Page 2 01/17/2008 Sincerely, Luminant Generation Company LLC Mike Blevins By:

'r1erd W. Madden Director, Oversight & Regulatory Affairs Enclosure c -

E. E. Collins, Region IV B. K. Singal, NRR Resident Inspectors, Comanche Peak

Enclortjre to TXX-OROO1 NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 08/3112010 (9-2007)

, the NRC may Digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the Digis/caracersfor achbloc)

Iinformation collection.

t. Facility Name

2. Docket Number

3. Page COMANCHE PEAK NUCLEAR POWER PLANT UNIT 1 05000445 1 OF 7

4. Title Emergency Diesel Generator Inoperable for Longer Than Allowed by TS Due to Paint on Metering Rod

5. Event Date

6.

6 ERNumber Reort Date

8. Other Facilities Involved Month Day YEAR Year Sequential Revision Month Day Ye Fac lity Name Docket Numbers N/A 05000 11 21 007 2007 00 01 17 08 Facility Name Docket Numbers 05000

9. Operating t I. This report is submitted pursuant to the requirements of 10 CFR : (Check all that apply)

Made 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii)

10. Paser 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A)

Level 100 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) 50.7 2(a)(2)(x) 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.7 1(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)

X 50.73(a)(2)(i)(B)

X 50.73(a)(2)(v)(D)

Specify in Abstract below or in NRC Forn 366A

12. Licensee Contact For This LER Facility Name lTelephone Number (Include Area Code)

Tim Hope - Nuclear Licensing Manager1 254-897-6370Cause System Component Manufacturer Reportable

Cause

System C mponent Manufacturer Reportable To EPIX To EPIX

14. Supplemental Report Expected Month Day Year YES NO SUBMISSION fYES cSX DATE 7

(If YES. complete EXPECTED SUBMISSION DATE)

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

On November 21, 2007, at 1020 hours0.0118 days <br />0.283 hours <br />0.00169 weeks <br />3.8811e-4 months <br /> Comanche Peak Nuclear Power Plant (CPNPP) Unit 1 was in Mode 1 operating at 100% power. During a monthly surveillance test on the Unit 1 Train B Emergency Diesel Generator (EDG), the EDG failed to start as required. During troubleshooting activities, a technician identified what appeared to be paint residue from a small drop of paint on one of the fuel pump control racks. The residue was removed and at 2132 the EDG was successfully started, declared operable, and returned to service. The most probable cause for this event was determined to be a paint drop that was not cleaned off of the 6L fuel pump control rack following painting activities on the EDG. This paint drop is believed to have prevented the operation of the control rack, which subsequently prevented the entire mechanical linkage from rotating. The lack of movement precluded sufficient fuel from being admitted to all of the cylinders which prevented the engine from starting. Corrective actions include procedure revisions to require a post maintenance "pull test" of the fuel pump control rack mechanisms and to require "as you go" inspection and cleanup when painting around sensitive components, and enhancement of pre-job briefings for painters to heighten their sensitivity to this type of event.

All times in this report are approximate and Central Time unless noted otherwise.

Enclosure to TXX-08001

1.

DESCRIPTION OF THE REPORTABLE EVENT

A.

REPORTABLE EVENT CLASSIFICATION

10CFR50.73(a)(2)(i)(B) "Any operation or condition which was prohibited by the plant's Technical Specifications" and 10 CFR 50.73(a)(2)(v)(D) "Any event or condition that could have prevented the fulfillment of a safety function."

B.

PLANT OPERATING CONDITIONS PRIOR TO THE EVENT On November 21, 2007, CPNPP Unit 1 was in Mode 1, operating at 100% power.

C.

STATUS OF STRUCTURES, SYSTEMS, OR COMPONENTS THAT WERE INOPERABLE AT THE START OF THE EVENT AND THAT CONTRIBUTED TO THE EVENT There were no structures, systems, or components that were inoperable at the start of the event that contributed to the event.

D.

NARRATIVE SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES CPNPP has two Emergency Diesel Generators (EDGs) [EIIS: (EK) (DG)] per unit (one per safety related train) and they provide a backup power supply for their respective safety related busses. Each EDG automatically starts in emergency mode whenever an undervoltage condition is experienced on its respective emergency bus or a Safety Injection signal is received. The EDGs are 16 cylinder Delaval Enterprise Type DSRV-16-4 engines and are tested monthly per Technical Specification (TS) 3.8.1. The governor is connected to the control rack [EIIS: (EK) (DG) (MTR) (P) (FC)] of the fuel injection pump for each cylinder by a common mechanical linkage system. The governor controls engine speed by rotating the linkage causing the control rack to slide in and out of the pump body to regulate fuel delivery to each cylinder.

From October 24 to November 21, 2007 CPNPP Unit 1 was in Mode 1 operating at 100%

power. During this time period, cosmetic painting activities involving the engine and other components were being conducted in the Unit 1 Train B EDG room. A thorough pre-job briefing was conducted each day prior to painting, which included review of a book with photos showing areas on the EDG that were not to be painted. This book was developed to address industry operating experience issues that involved painting activities that affected EDG operability at other plants. In addition, after each day's painting a visual inspection of l

NKC FORaM 36OA (9-2007)

Enclosure to TXX-08001

the EDG was performed to identify any paint that had inadvertently spattered or dripped onto areas of the EDG that were not to be painted.

On October 24, 2007, the Unit I Train B EDG was started and successfully passed its monthly TS SR 3.8.1.2 surveillance test. This test verifies that the EDG starts from standby conditions and achieves the TS acceptance criteria for steady state voltage and frequency.

On November 21, 2007, the next monthly TS SR 3.8.1.2 surveillance test was being performed on the Unit 1 Train B EDG. At 1020 hours0.0118 days <br />0.283 hours <br />0.00169 weeks <br />3.8811e-4 months <br />, the EDG was given a slow start signal from the Main Control Room, but it failed to start as required. The "Unit Failed to Start" alarm and the "Unit Tripped" light were received. The EDG was declared inoperable and the applicable alarm procedure was performed to investigate the alarm indications.

Per Shift Manager (Utility, Licensed) direction, the fuel pump control racks were not manually manipulated during performance of the "check fuel racks free and max position" alarm procedure step because the EDG did not appear to have rolled. Investigation was initially centered on air start system alignment, alignment and fill of the fuel day tank, and venting of the fuel system. No problems were found with the EDG as a result of performing the alarm procedure.

At 1318 hours0.0153 days <br />0.366 hours <br />0.00218 weeks <br />5.01499e-4 months <br />, troubleshooting activities began. These troubleshooting efforts focused on the EDG's failure to roll. At 1649 hours0.0191 days <br />0.458 hours <br />0.00273 weeks <br />6.274445e-4 months <br /> Operations attempted a second slow start of the EDG. The engine rolled up to 90-100 rpm but the EDG did not start and the "Unit Failed to Start" alarm, both of the "Starting Air Low Pressure" alarms, and the "Unit Tripped" light were received. At this point, focus shifted to potential problems with the EDG fuel supply.

At 1802 hours0.0209 days <br />0.501 hours <br />0.00298 weeks <br />6.85661e-4 months <br /> Operations attempted a fast start of the EDG, and personnel (Utility, Non-licensed) were assigned to watch the governor and fuel linkage to the fuel pump during the start. During this third start attempt the EDG did not start and both the "Unit Failed to Start" and "Voltage Regulator System Trouble" alarms were received. During this start attempt, the governor was observed to respond but there was no observed movement of the fuel pump control racks. At this point, focus shifted to potential problems with the fuel pump control racks.

At 1939 hours0.0224 days <br />0.539 hours <br />0.00321 weeks <br />7.377895e-4 months <br /> workers (Utility, Non-licensed) discovered that the 6L fuel pump control rack was bound solid and the 2L fuel pump control rack was restricted to approximately 50% of its movement. Based on these observations, the fuel pump control racks on the Unit 1 Train B EDG were manually stroked and the 2L and 6L fuel pump control racks became free. During this same time frame, the fuel pump control racks on the other three EDGs were also manually manipulated and found to be free and operated smoothly. After the fuel

pump control racks on the Unit 1 Train B EDG were freed up, another slow start of the EDG was planned. Just prior to the start, a visual inspection of the fuel pump control racks was performed. During this inspection, very small paint spots were observed on fuel pump control racks 4R and 4L, and what appeared to be the residue from an approximately 3/16 inch diameter drop of paint was observed on the 6L fuel pump control racks (where the shaft enters the fuel pump).

At 2132 hours0.0247 days <br />0.592 hours <br />0.00353 weeks <br />8.11226e-4 months <br />, after the paint residue was removed, a successful slow start of the Unit 1 Train B EDG was performed and the EDG was determined to be operable.

E.

THE METHOD OF DISCOVERY OF EACH COMPONENT OR SYSTEM FAILURE,'

OR PROCEDURAL OR PERSONNEL ERROR During troubleshooting activities, a Maintenance Technician (Utility, Non-licensed) identified paint residue on one of the EDG fuel pump control racks.

II.

COMPONENT OR SYSTEM FAILURES A.

FAILURE MODE, MECHANISM, AND EFFECT OF EACH FAILED COMPONENT Not applicable - there were no component failures associated with this event.

B.

CAUSE OF EACH COMPONENT OR SYSTEM FAILURE The most probable cause for this event was determined to be a paint drop that was not cleaned off of the 6L fuel pump control rack following painting activities on the EDG. This paint drop is believed to have prevented the operation of the control rack, which subsequently prevented the entire mechanical linkage from rotating. The lack of movement precluded sufficient fuel from being admitted to all of the cylinders which prevented the engine from starting.

C.

SYSTEMS OR SECONDARY FUNCTIONS THAT WERE AFFECTED BY FAILURE OF COMPONENTS WITH MULTIPLE FUNCTIONS Not applicable - there were no component failures associated with this event.

D.

FAILED COMPONENT INFORMATION

Not applicable - there were no component failures associated with this event.

III.

ANALYSIS OF THE EVENT

A.

SAFETY SYSTEM RESPONSES THAT OCCURRED Not applicable - no system responses occurred during this event.

B.

DURATION OF SAFETY SYSTEM TRAIN INOPERABILITY As discussed above, the most probable cause for the failure of the Unit 1 Train B EDG to start during the monthly surveillance test was an approximately 3/16 inch diameter drop of paint on the 6L fuel pump control rack. Painting activities were conducted in the Unit 1 Train B EDG room from October 15 to November 21, 2007, however, the only time that painting was conducted in the vicinity of the Unit 1 Train B EDG fuel pump control racks was from October 29 to November 1, 2007. Therefore, assuming that the drop of paint was inadvertently left on the 6L fuel pump control rack on October 29, Luminant Power believes the maximum time that the Unit 1 Train B EDG could have been inoperable was from October 29 to November 21, 2007 (24 days, approximately 576 hours0.00667 days <br />0.16 hours <br />9.523809e-4 weeks <br />2.19168e-4 months <br />). Similarly, assuming that the drop of paint was inadvertently left on the 6L fuel pump control rack on November 1, the minimum time that the Unit 1 Train B EDG could have been inoperable was 20 days (approximately 480 hours0.00556 days <br />0.133 hours <br />7.936508e-4 weeks <br />1.8264e-4 months <br />). During this time period the completion times of TS 3.8.1 Condition B were exceeded for the Unit 1 Train B EDG.

Consequently, this condition is reportable under 10 CFR 50.73(a)(2)(i)(B) as an operation or condition prohibited by Technical Specifications. Since the Unit 1 Train A EDGJ was inoperable for 65 minutes (while that EDG was being barred over in preparation for its monthly surveillance test) during the same time period that the Unit 1 Train B EDG was inoperable, this condition is also reportable under 10 CFR 50.73(a)(2)(v)(D) as an event or condition that could have prevented the fulfillment of a system safety function.

C.

SAFETY CONSEQUENCES AND IMPLICATIONS OF THE EVENT The safety function of the CPNPP EDGs is to automatically start and provide power in emergency mode whenever an undervoltage condition is experienced on their respective emergency bus or a Safety Injection signal is received. As noted above, the Unit 1 Train B EDG could have been inoperable from October 29 to November 21, 2007 (approximately 576 hours0.00667 days <br />0.16 hours <br />9.523809e-4 weeks <br />2.19168e-4 months <br />). During this period of time, the Unit 1 Train A EDG was also inoperable for 65 minutes on November 7, 2007 (while that EDG was being barred over in preparation for its monthly surveillance test). During this 65 minute period, two trains of emergency power may not have been available. Since at least one EDG per unit is required to perform the safety function, a loss of safety function for the system occurred during the 65 minutes that the Unit 1 Train A EDG was inoperable on November 7, 2007.

From October 29 to November 21, 2007, no events occurred requiring the EDGs to start and perform their safety function of providing power to the safety related busses. Since the period of time that both Unit 1 EDGs were inoperable was relatively short (65 minutes), and two offsite power sources were available, the potential safety significance is low.

Therefore, this event had minimal safety consequences and the health and safety of the public was not affected:

IV.

CAUSE OF THE EVENT

Although a specific root cause for this event could not be conclusively determined, Luminant Power believes that the probable cause of the event is an approximately 3/16 inch diameter paint drop that was not cleaned off of the 6L fuel pump control rack following painting activities on the EDG. This paint drop is believed to have prevented the operation of the control rack, which subsequently prevented the entire mechanical linkage from rotating. The lack of movement precluded sufficient fuel from being admitted to all of the cylinders which prevented the engine from starting.

V.

CORRECTIVE ACTIONS

The Unit 1 Train B EDG was immediately declared to be inoperable and troubleshooting was initiated to determine the cause for the failure to start. All painting activities in the EDG rooms were suspended until the cause could be determined and addressed. The fuel racks on the other three EDGs were manually manipulated to determine their condition. The paint residue was removed from the Unit 1 Train B EDG and it was successfully started, declared operable, and returned to service.

As a part of the CPNPP Corrective Action Program, the following corrective actions will be taken for this event:

The CPNPP General Plant Painting procedure will be revised to 1) require a post maintenance "pull test" of the fuel pump control rack mechanisms to ensure they are free to operate (in addition to the visual inspections), 2) require "as you go" inspection and cleanup when painting around sensitive components, and 3) add an attachment capturing the pictures and information presently contained in the pre-job briefing notebook used by painters.

This event will be included in the pre-job briefing for painters to heighten their sensitivity to the problems paint drops and spatter can cause for mechanical linkages. The information in the pre-job briefing notebook used by painters will be examined by System Engineering to ensure that it contains all sensitive areas on the EDG that should not be painted.

Enclosure to TXX-08001 (9-2007)

LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET VI.

PREVIOUS SIMILAR EVENTS

There have been no previous similar reportable events at CPNPP in the last three years.