05000424/LER-2021-001, Train a Safety Injection Pump Inoperability Causes the Unit to Operate in a Condition Prohibited by Technical Specifications

Train a Safety Injection Pump Inoperability Causes the Unit to Operate in a Condition Prohibited by Technical Specifications

ML21319A348
Person / Time
Site:	Vogtle
Issue date:	11/15/2021
From:	Pitts D Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-21-0910 LER 2021-001-00
Download: ML21319A348 (5)

LER-2021-001, Train a Safety Injection Pump Inoperability Causes the Unit to Operate in a Condition Prohibited by Technical Specifications

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
4242021001R00 - NRC Website

text

~ Southern Nuclear It Or"§yton Pitt§ 7821 Rlvir RD Site Vice Pre ldent WaynelibOfO GA, 30830 V09!1e Unlll> 1-2 106-S4B>oo1n ~J

'iOO*S48*3321 fax Novembe r 15, 2021

U. S. Nuclar Regulatory Commission A TIN : Document Control Desk Washington, D, C, 2055Se0001

Vogt! Electric Gener~ting Pl~nt Unit 1 License~ Event Report 2021 -001e00 1A S~fety Jniection Pump Om~r~tion in ;;J Conditlan Prohibited by Technical Speeiflc~tions

In g!Ceordance with the requirements of 10 CFR 50.73(a)(2)(i){B), Southern Nuclear Opert!lting Company is submitting the ~nclosed License Event Report, 2021 -001 ~00 for Vo9tle gleetrie Generating Plant Unit 1. This letter eontaimi no NRC commitmnm, lf you have g1ny questions, plea~~ contact Jeff 0al ~t (706) 848-3 792.

Respectfully submitted,

Drayton Pitts Site Vice President Vogtle 1&2

RDP/KCW

ec : Regloni!\\!l Administr~tor NRR Project Manager - Vogtle 1 & 2 Senior Resident Inspector= Vogt! 1 & 2 RType : CVC7000 VogtJe EJectri,c Generating Plant Unit 1 Licensee Event Report 2021-001-00.

1A Safety Injection Pump Op.eration in a Condition Prohibited by_ Technical Specifications

Enclosure

Unit 1 Licensee Event Report 2021-001-00

Abstract

On 9/16/2021 at 04 :54, the Unit 1 A Safety Injection (SI) pump was started for a surveillance. Bearing temperatures rose unexpectedly, the pump was stopped, and it was declared inoperable. An investigation found a piece of plastic tubing between the gears of the lube o il pump, resulting in oil starvation of two bearings and their subsequent failure. The bearings were replaced, the system was flushed, and the pump was restored to operable status on September 29, 2021. Improper oil sampling on the Unit 1 Alpha train SI pump introduced foreign material (FM) into the pump's oil system.

The 1A SI pump would not have been able to perform its required safety function from September 6, 202 1 at 1436, until Mode 4 was entered on September 12, 2021 at 0759. Technical Specification (TS) 3.5.2 Condition A should have been entered due to one train of Emergency Core Cooling Systems (ECCS) inoperable. Required Action A.1 has a completion time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or in accordance with the Risk Informed Completion Time Program, combined with 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> for the unit to be in Mode 4, would give 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> of total allowed out of service time. The 137.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> that the 1A SI pump would not have been able to perform its required safety function exceeded this, and therefore the plant was operated in a condition prohibited by TS.

A--.---Event Description On 9/16/2021 at 04:54, with plant operating conditions before the event consisting of Unit 1 in Mode 6, at O percent power, and approximately 103 degrees Fahrenh e it, the Unit 1 A Safety Injection (SI) [BQ] pump was started to complete a surveillance. After the pump start, bearing temperatures rose rapidly, the pump was stopped, and was declared inoperable.

Subsequent investigation determined that improper oil sampling on the Unit 1 Alpha train SI pump introduced foreign material (FM) into the pump's oil system. The foreign material introduction was not recognized at the time of the samples. The safety injection pump subsequently failed to operate due to low oil flow conditions resulting in bearing failure. The lube oil pump was found with a piece of plastic tubing between the gears of the pump resulting in the pump seizing.

Timeline of Unit 1 events :

• 9/6/2021 1436-SI pump A was last run during an in-service test (1ST) with no signs of degradation. Additionally, an oil sample was taken during this run.

• 9/12/2021 0500- Unit enters Mode 3 for the start of planned outage.

• 9/12/2021 0759-Unit enters Mode 4, and TS 3.5.2 no longer applied.

• 9/16/2021 0454-SI pump A failed while the unit was in Mode 6.

• 9/29/2021-SI pump A returned to operable status. Unit was in Mode 6, and TS 3.5.2 was not applicable.

The Safety Injection pump would not have been able to perform its required safety function from September 6, 2021 at 1436 when the pump was last run with no signs of degradation, until the mode of applicability for this pump was exited on September 12, 2021 at 0759 due to a planned refueling outage. Technical Specification (TS) 3.5.2 Condition A should have been entered because one train of Emergency Core Cooling Systems (ECCS) was inoperable in Modes 1-

3. TS 3.5.2 Required Action A.1 has a completion time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or in accordance with the Risk Informed Completion Time Program. The required act ion time, combined with the 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> for the unit to be in Mode 4, would give 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> of total allowed out of service time. The 137.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> that the 1A SI pump would not have been able to perform its required safety function exceeded this allowed out of service time, and therefore the plant was operated in a condition prohibited by TS for 47.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Therefore, this condition is being reported under 10 CFR 50.73(a)(2)(i)(B).

There were no structures, components, or systems that were inoperable at the start of the event that contributed to the event.

B. Cause of Event

The cause of the event was foreign material intrusion into the SI pump oil system. This led the pump outboard bearing to be starved of lubrication which resulted in failure of the bearing when the pump was started.

The foreign material intrusion was caused by improperly obtaining the oil samples for this pump. A plastic tube was inserted into the gearbox next to the oil pump shaft. This caused pieces of the plastic tubing to be removed from the end of the tube and left in the lube oil system.

C. Safety Assessment

During the time the A-train SI pump was inoperable, the 8-train SI pump was available to perform its specified safety function. The operating crew responded correctly to the event. The applicable procedures were properly entered, and documentation met expectations.

The event was within the analysis of the Updated Final Safety Analysis Report Chapter 15. There was no release of radioactivity. This event did not pose a threat to the health and safety of the public. Therefore, the safety significanc e of thi~ i~~110 i~ VP.rv ln\\A/

~D. Corrective Action The failure was corrected by replacement of the bearings, flushing the lube oil system, and restoring the pump to an operable status on September 29, 2021.

The oil sampling method has been changed.

E. Previous Similar Events

None