05000293/LER-2019-004, Manual Reactor Scram Due to Degrading Condenser Vacuum

Manual Reactor Scram Due to Degrading Condenser Vacuum

ML19162A032
Person / Time
Site:	Pilgrim
Issue date:	06/11/2019
From:	Miner P Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
2.19.042 LER 2019-004-00
Download: ML19162A032 (6)

LER-2019-004, Manual Reactor Scram Due to Degrading Condenser Vacuum

Event date:
Report date:
Reporting criterion:	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)(ix)(A) 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(iv)(B), System Actuation
2932019004R00 - NRC Website

text

~ Ente,gx 2.19.042 June 11, 2019 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Entergy Nuclear Operations, Inc.

Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 Peter J. Miner Manager, Regulatory Assurance 10 CFR 50.73 SUBJECT: Licensee Event Report 2019-004-00, Manual Reactor Scram Due to Degrading Condenser Vacuum Pilgrim Nuclear Power Station NRC Docket No. 50-293 Renewed Facility Operating License No. DPR-35 The enclosed Licensee Event Report 2019-004-00, Manual Reactor Scram Due to Degrading Condenser Vacuum, is submitted in accordance with Title 1 O Code of Federal Regulations 50. 73.

If you have any questions regarding this information, please contact me at 508-830-7127.

This letter contains no new regulatory commitments.

Sincerely, Peter J. Miner PJM/rjm

Enclosure:

Licensee Event Report 2019-004-00, Manual Reactor Scram Due to Degrading Condenser Vacuum

Letter No. 2.19.042 Page 2 of 2 cc:

NRC Region I, Regional Administrator NRC NRA Project Manager - Pilgrim NRC Senior Resident Inspector - Pilgrim

Enclosure 2.19.042 Licensee Event Report 2019-004-00, Manual Reactor Scram Due to Degrading Condenser Vacuum

BNRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04*2017) httQ://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r30 the NRG may not conduct or sponsor, and a person is not required to respond to, the information collection.

.PAGE Pilgrim Nuclear Power Station 05000-293 1 OF3

14. TITLE Manual Reactor Scram Due to Degrading Condenser Vacuum

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED SEQUENTIAL FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR REV MONTH DAY YEAR NIA NUMBER NO.

N/A 05 17 2019 2019

• 004

• 00 06 11 2019 FACILITY NAME DOCKET NUMBER N/A N/A

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

N D 20.2201 (b)

D 20.2203(a)(3)(i)

D 50.73(a)(2)(ii)(A)

D 50.73(a)(2)(viii)(A)

D 20.2201 (d)

D 20.2203(a)(3)(ii)

D 50.73(a)(2)(ii)(B)

D 50.73(a)(2)(viii)(B)

D 20.2203(a)(1)

D 20.2203(a)(4)

D so.73(a)(2)(iii)

D 50.73(a)(2)(ix)(A)

D 20.2203(a)(2)(i) 0 50.36(c)(1 )(i)(A) 181 50. 73(a)(2)(iv)(A)

D 50.73(a)(2)(x)

10. POWER LEVEL D 20.2203(a)(2)(ii) 0 50.36(c)(1 )(ii)(A)

D 50.73(a)(2)(v)(A)

D 73.11 (a)(4)

D 20.2203(a)(2)(iii)

D so.36(c)(2)

D 50.73(a)(2)(v)(B)

D 73.71(a)(s) 70 D 20.2203(a)(2)(iv)

D so.46(a)(3)(ii)

D 50.73(a)(2)(v)(C)

D 73.77(a)(1)

D 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A)

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

D 73.77(a)(2)(i)

D 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B)

D 50.73(a)(2)(vii)

D 73.77(a)(2)(ii)

D 50.73(a)(2)(i)(C) 0 OTHER Specify in Abstract below or in NRC Form 366A

12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT liLEPHONE NUMBER (Include Area Code)

!Mr. Peter J. Miner - Regulatory Assurance Manager

~08-830-7127 CAUSE SYSTEM COMPONENT MANU*

REPORTABLE

CAUSE

SYSTEM COMPONENT MANU-REPORTABLE FACTURER TOEPIX FACTURER TO EPIX X

KE MO H200 y

14. SUPPLEMENTAL REPORT EXPECTED

15. EXPECTED MONTH DAY YEAR D YES (If yes, complete 15. EXPECTED SUBMISSION DA TE) 1:8:i NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)

On Friday, May 17, 2019 at 2303 [EDT], with the reactor at approximately 70% core thermal power, Pilgrim Nuclear Power Station initiated a manual reactor scram due to degrading condenser vacuum as a result of the trip of Seawater Pump 8. Investigation into the cause identified the Seawater Pump B breaker ground sensing relay in the tripped state.

Following the Seawater Pump B trip and reactor scram, Main Condenser parameters responded as expected to a loss of seawater pump transient, no anomalies were noted. There were no radiological releases due to this event. All control rods inserted fully. All other plant systems responded as designed.

This event had no impact on the health and/or safety of the public.

This report is submitted in accordance with 1 O CFR 50.73(a)(2)(iv)(A).

BACKGROUND 05000- 293 YEAR 2019 SEQUENTIAL NUMBER

- 004 REV NO.

• 00 During planned operation, steam from the low pressure turbine is exhausted directly downward into the condenser shells through exhaust openings in the bottom of the turbine casings. The objective of the main condenser is to provide a heat sink for the turbine exhaust steam, turbine bypass steam, and other flows. The heat dumped to the main condenser is removed by the Circulating Water System, also called the Seawater System. The water is pumped from and returned to Cape Cod Bay. Two vertical, removable element seawater pumps located in the intake structure provide a continuous supply of condenser cooling water. The pumps have a rated flow of 155,500 gal/min each and are powered by 1250 hp, 4160 V, 3 phase induction motors.

The design seawater circulating water flow rate is 311,000 gal/min.

EVENT DESCRIPTION

On Friday, May 17, 2019 at 2303 [EDT], with the reactor at approximately 70% core thermal power, Pilgrim Nuclear Power Station initiated a manual reactor scram due to degrading condenser vacuum as a result of the trip of Seawater Pump B. Following the Seawater Pump B trip and reactor scram, Main Condenser parameters responded as expected to a loss of seawater pump condition.

During the manual reactor scram, the plant experienced a Group 2 Isolation, Miscellaneous Containment Isolation Valves, and a Group 6 Isolation, Reactor Water Clean-Up Reactor Building Isolation Actuation, as designed.

CAUSE OF THE EVENT

Investigation into the cause identified the Seawater Pump B breaker ground sensing relay in the tripped state. The cause of the Seawater Pump B motor trip was a failed power supply cable. High resistance on the degraded 4160 volt motor lead connection caused overheating of the insulation, which eventually faulted to ground causing the pump to trip.

CORRECTIVE ACTIONS

The Seawater Pump B motor power supply cable was repaired. Any further corrective actions will be documented in the corrective action program.

SAFETY CONSEQUENCES

rrhere were no actual consequences to safety of the general public, nuclear safety, industrial safety, or radiological safety for this event.

Page 2 of 3 (04-2017)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020 LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)

, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

3. LER NUMBER YEAR Pilgrim Nuclear Power Station 05000- 293 2019 REPORT ABILITY SEQUENTIAL NUMBER

- 004 REV NO.

- 00 This report is submitted in accordance with 1 O CFR 50.73(a)(2)(iv)(A), Any event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(B) of this section including 50.73(a)(2)(iv)(B)(1 ), Reactor Protection System.

PREVIOUS EVENTS There have been no events reported in the last three years related to the Seawater Pumps.

REFERENCES CR-PNP-2019-02882 Page 3 of 3