ML17010A035

LER 16-008-00 for Pilgrim Nuclear Power Station Regarding Emergency Diesel Generator 'A' Past Inoperability

ML17010A035
Person / Time
Site:	Pilgrim
Issue date:	12/09/2016
From:	Perkins E P Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
2.16.075 LER 16-008-00
Download: ML17010A035 (7)

Text

/ December 9, 2016 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Entergy Nuclear Operations, Inc. Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth. MA 02360

SUBJECT:

Licensee Event Report 2016-008-00, Emergency Diesel Generator 'A' Past lnoperability I Pilgrim Nuclear Power Station Docket No. 50-293 Renewed License No. DPR-35 LETTER NUMBER: 2.16.075

Dear Sir or Madam:

The enclosed Licensee Event Report 2016-008-00, Emergency Diesel Generator 'A' Past lnoperability, is submitted in accordance with 10 Code of Federal Regulations 50. 73. The date the condition was discovered was September 28, 2016. As such, this 60-day 10 CFR 50.73 Licensee Event Report was due to the NRC Staff on November 27, 2016. This LER is being submitted late and Pilgrim Nuclear Power Station is addressing this through the Corrective Action Program. If you have any questions or require additional information please contact me at (508) 830-8323. There are no regulatory commitments contained in this letter. Sincerely, Everett P. _ __> Manager, Regulatory Assurance EPP/sc

Attachment:

Licensee Event Report 2016-008-00, Emergency Diesel Generator 'A' Past lnoperability (4 pages)

Entergy Nuclear Operations, Inc. Pilgrim Nuclear Power Station cc: Mr. Daniel H. Dorman Regional Administrator, Region I U.S. Nuclear Regulatory Commission 2100 Renaissance Blvd., Suite 100 King of Prussia, PA 19406-2713 Ms. Booma Venkataraman, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-8C2A Washington, DC 20555 NRG Senior Resident Inspector Pilgrim Nuclear Power Station Letter No. 2.16.075 Page 2 of 2 Attachment Letter Number 2.16.075 Licensee Event Report 2016-008-00 Emergency Diesel Generator 'A' Past lnoperability (4 Pages)

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 (02-2014) Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> . .. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the FOIA, Privacy and Information Collections \ LICENSEE EVENT REPORT (LER) Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by "****** (See Page 2 for required number of internet e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC digits/characters for each block) 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 12. DOCKET NUMBER 1* PAGE Pilgrim Nuclear Power Station 05000293 1 OF4 4. TITLE Emergency Diesel Generator 'A' Past lnoperability 5. EVENT DATE 6. LER NUMBER 7. REPORT DATE 8. OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR MONTH DAY YEAR N/A N/A NUMBER NO. FACILITY NAME DOCKET NUMBER 09 28 2016 2016 -008 -00 12 09 2016 N/A N/A 9. OPERA TING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO lHE REQUIREMENTS OF 10 CFR §: (Check all that apply) D 20.2201(b) D 20.2203(a)(3)(i) D 50.73(a)(2)(i)(C) D 50.73(a)(2)(vii) N D 20.2201(d) D 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(A) D 50.73(a)(2)(viii)(A) D 20.2203(a)(1) D 20.2203(a)(4) 0 50.73(a)(2)(ii)(B) D 50.73(a)(2)(viii)(B) D 20.2203(a)(2)(i) 0 50.36(c)(1 )(i)(A) D 50.73(a)(2)(iii) D 50.73(a)(2)(ix)(A) 10. POWER LEVEL D 20.2203(a)(2)(ii) 0 50.36(c)(1)(ii)(A) D 50.73(a)(2)(iv)(A) D 50.73(a)(2)(x) D 20.2203(a)(2)(iii) D 50.36(c)(2) [8J 50.73(a)(2)(v)(A) D 73.71(a)(4) 100 D 20.2203(a)(2)(iv) D 50.46(a)(3)(ii) [8J 50.73(a)(2)(v)(B) D 73.71(a)(5) D 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A) D 50.73(a)(2)(v)(C) 0 OTHER D 20.2203(a)(2)(vi) [8J 50. 73(a)(2)(i)(B) [8J 50.73(a)(2)(v)(D) Specify in Abstract below or in NRC Form 366A 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT I TELEPHONE NUMER (Include Area Code) Mr. Everett P. Perkins, Jr. -Regulatory Assurance Manager 508-830-8323 13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN lHIS REPORT CAUSE SYSTEM COMPONENT MANU-REPORTABLE CAUSE SYSTEM COMPONENT MANU-REPORTABLE FACTURER TOEPIX FACTURER TOEPIX x EK RV C099 y 14. SUPPLEMENTAL REPORT EXPECTED 15. EXPECTED MONTH DAY YEAR D YES (If yes, complete 15. EXPECTED SUBMISSION DATE) [8J NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) On September 28, 2016, while performing the pre-start checks prior to running the Emergency Diesel Generator (EDG)-A *or the monthly Technical Specification (TS) surveillance, the oil level in the EDG radiator fan right angle gearbox was found be low and additional checks found the gearbox oil pressure relief valve in a loose state which provided a pathway for gear oil to be pumped out of the gear box while the EDG was operating. EDG-A was declared inoperable, the relief valve was repaired, pressure tested and the pressure adjusting threaded union was staked to eliminate any risk from vibration induced motion in the future, the gearbox oil was replaced and the EDG run for a post-maintenance test. A Functional Failure Determination completed on October 11, 2016 determined that the EOG would not have been able to run for its stated mission time of 30 days. This condition existed for a period of 28 days since the last surveillance test on August 31, 2016 which is greater than the TS Allowed Out of Service Time (AOT) of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. However, the Station Black Out Diesel Generator was available during this time frame. This issue is reportable under 10 CFR 50. 73(a)(2)(i)(B) as an Operation or Condition which was Prohibited by the plant's TSs. On September 15, 2016 EDG-B was made inoperable to perform its monthly operability run. This created a situation where *or a brief period of time both EDGs were inoperable which is a condition that could have prevented the fulfillment of the safety function of a system needed to shut down the reactor and maintain it in a safe condition, remove residual heat, and mitigate the consequences of an accident which is reportable in accordance with 50. 73(a)(2)(v)(A), 50. 73(a)(2)(v)(B), and 50.73(a)(2)(v)(D). EDG-B remained available and could quickly have been restored by manual action to an operable condition if needed during the operability run. rThere was no impact to public health and safety from this condition. NRC FORM 366 (02-2014)

NRC FORM 366A (02-2014) U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER) CbNTINUATION SHEET 1. FACILITY NAME 2. DOCKET Pilgrim Nuclear Power Station 05000293 BACKGROUND APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to lnfocollects.Resource@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 currenlly valid OMB control number, the NRG may not conduct or sponsor, and a person is not required to respond to, the information collection. 6. LERNUMBER 3. PAGE YEAR I SEQUENTIAL I REVISION NUMBER NUMBER 2 OF4 2016 -008 -00 rThe safety objective of the emergency diesel generators (EDGs) is to provide a source of on-site AC power adequate for the safe shutdown of the reactor following abnormal operational transients and postulated accidents assuming a complete loss of off-site power, as described in Pilgrim Nuclear Power Station (PNPS) Updated Final Safety Analysis Report (UFSAR). Two EDGs and their associated fuel supply systems provide a single failure proof source of standby AC power. Pilgrim EDGs are 2600 KW ALCO 251-F type diesel generators. These EDGs are designed to automatically start upon receiving a valid signal, and come to operating speed ready to assume load. Each generator is sufficient to power all loads on its emergency bus upon failure of all off-site power. Each generator has the ability to pick up loads in sequence within a specified time period. The two EDGs at PNPS are cooled by a self-contained system consisting of radiators and a fan that is driven through a right angle gearbox. rThe standby AC power source provides two independent diesel generators as the onsite sources of AC power to emergency service portions of the station Auxiliary Power Distribution System. Each onsite source provides power to safely shut down the reactor, maintain the safe shut down condition, and operate all auxiliaries necessary for station safety. Historical review revealed that this fan drive gearbox was replaced on the EOG-A in the May 2000 time frame. At time, the original gearbox, Cotta Transmission Model Number J1327-2 was replaced with an upgraded Model Number J1327-3. Correspondence with the OEM vendor indicated the inside of the cases were identical with the only major physical change on the outside which was the addition of a relief valve in the oil circuit. Changes to the gearbox inspections were not updated to include any inspections or preventive maintenance for the relief valve. EVENT DESCRIPTION On September 28, 2016, while performing the pre-start checks prior to running the Emergency Diesel Generator (EDG)-A monthly Technical Specification (TS) surveillance, the oil level in the EOG radiator fan right angle gearbox was found low and additional checks found the gearbox oil pressure relief valve was loose. rThe two EDGs at PNPS are each cooled by self-contained systems consisting of radiators and fans that rotate a right angle gearbox. At the time of discovery, even though the oil level was low, the EOG would have started on a valid start signal. However, it would have been losing gearbox oil and we conservatively assumed it would have overheated due to failure of the cooling fan from gearbox damage. Failure Determination completed on October 11, 2016 conservatively determined that the EOG would not have been able to run for its stated mission time of 30 days. This condition existed for a period of 28 days, which is greater than the TS Allowed Out of Service Time (AOT) of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. However, the Station Black Out Diesel Generator was available during this time frame. CAUSE OF THE EVENT rThe failure was determined to be low oil level found in the EOG-A radiator fan right angle gearbox due to the external relief valve pressure setting screw and the cap which goes over it being disconnected from the valve body. This allowed a pathway for oil to escape the gearbox when the EOG was running. NRC FORM 366A (02-2014)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (02-2014) 1. FACILITY NAME LICENSEE EVENT REPORT (LER) CONTINUATION SHEET 2. DOCKET 6. LER Nll\llBER Pilgrim Nuclear Power Station 05000293 YEAR I SEQUENTIAL I REVISION NUMBER NUMBER 2016 -008 -00 NARRATIVE 3. PAGE 3 OF4 The radiator fan right angle gearbox oil level is checked prior to every monthly EOG run and the last time it was performed was August 31, 2016 with no problem identified during the pre-start checks. The last maintenance performed on the EOG radiator fan right angle gearbox was part of the routine examination and checks during the 2 year Preventive Maintenance (PM), which was completed on March 7, 2015. The inspection includes draining and changing the oil, performing internal inspection of the drive gears and bearings and performing backlash measurements of the drive and driven gears. However, the two (2) year PM does not perform any maintenance on ihe gearbox oil pressure relief valve. The relief pressure of 15 psig was set at the time of installation in 2000. Changes to the gearbox inspections were not updated to include any inspections or preventive maintenance for the relief valve. The failure is attributed to minimal engagement of the pressure adjusting threaded union for the relief valve setting of 15 psig, and there is some contribution from either engine vibration or possibly human error which makes the cause indeterminate. CORRECTIVE ACTIONS EOG-A was declared inoperable, the relief valve was repaired, pressure tested and the pressure adjusting threaded union was staked to eliminate any risk from vibration induced motion in the future, the gearbox oil was replaced and *he EOG run for a post-maintenance test. PNPS conducted an extent of condition review for EDG-B by performing an inspection to ensure that a common mode failure did not exist. 1 -, The following are additional corrective actions to address this issue which are being processed through the PNPS Corrective Action Program: 1. Update station procedure 8.9.1, "Emergency Diesel Generator and Associated Emergency Bus Surveillance," to identify the plug that is used to check the oil level and visually inspect the valve to ensure the cap is appropriately aligned before and after each EOG run. 2. Incorporate a vendor manual change to capture the upgraded EDG's Cotta Transmission gear box. The gear box was updated in the 2000 time frame but the drawings/vendor manual was never updated. 3. Establish PM's for both EOG radiator fan right angle gearbox relief valves. SAFETY CONSEQUENCES There were no consequences to the safety of the general public, nuclear safety, industrial safety, and radiological safety due to this event. The safety objective of the EDGs is to provide a source of on-site AC power adequate for the safe shutdown of the reactor following abnormal operational transients and postulated accidents assuming a complete loss of off-site power, as described in PNPS UFSAR. At the time of the event, the preferred AC and the secondary AC power sources were Operable and available to perform their intended safety function. In addition, the Station Blackout AC Power Source was Functional and available as the onsite source of AC power to the emergency service portions of the Auxiliary Power Distribution System. NRC FORM 366A (02-2014)

NRC FORM 366A (02-2014) 1. FACILITY NAME LICENSEE EVENT REPORT (LER) CONTINUATION SHEET 2. DOCKET U.S. NUCLEAR REGULATORY COMMISSION 6. LER NUMBER 3. PAGE 05000293 YEAR I SEQUENTIAL I REVISION NUMBER NUMBER 4 OF4 Pilgrim Nuclear Power Station 2016 -008 -00 NARRATIVE REPORT ABILITY In a determination completed on October 11, 2016 it was conservatively determined that EOG-A would not have been able to run for its stated mission time of 30 days. This condition existed for a period of 28 days, which is greater than the TS Allowed Out of Service Time (AOT) of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. However, the Station Black Out Diesel Generator was available during this time frame. This issue is reportable under 10 CFR 50.73(a)(2)(i)(B) as an Operation or Condition which was Prohibited by the plant's Technical Specifications. In addition, on September 15, 2016 EDG-B was made inoperable to perform its monthly operability run. This created a condition that could have prevented the fulfillment of the safety function of a system needed to shut down the reactor and maintain it in a safe condition, remove residual heat, and mitigate the consequences of an accident which is reportable in accordance with 10 CFR 50.73(a)(2)(v)(A), 50.73(a)(2)(v)(B), and 50. 73(a)(2)(v)(D). The date the condition was discovered was September 28, 2016. As such, this 60-day 10 CFR 50.73 Licensee Event Report was due to the NRC Staff on November 27, 2016. This LER is being submitted late, and PNPS is addressing this through the Corrective Action Program. PREVIOUS EVENTS Events involving LERs where both EDGs were inoperable were reviewed. One related LER was identified and is summarized as follows: LER 2016-001, "Both Emergency Diesel Generators Inoperable," dated June 9, 2016 stated while EDG-B was out for maintenance, EOG-A was declared inoperable due to a 130 dpm leak from the jacket water pressure boundary. There were no other LERs involving EOG inoperability at PNPS identified in a search of the past five (5) years.

REFERENCES:

CR-PNP-2016-7443 CR-PNP-2016-9552 CR-PNP-2016-9653 CR-PNP-2016-9831 NRC FORM 366A (02-2014