05000353/LER-1917-006, Regarding HPCI Lnoperability During Post Maintenance Testing

Regarding HPCI Lnoperability During Post Maintenance Testing

ML17268A272
Person / Time
Site:	Limerick
Issue date:	09/25/2017
From:	Libra R Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LG-17-128 LER 17-006-00
Download: ML17268A272 (4)

LER-1917-006, Regarding HPCI Lnoperability During Post Maintenance Testing

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v), Loss of Safety Function 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)(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)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)
3531917006R00 - NRC Website

text

Exelon Generation LG-17-128 September 25, 2017 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 2 Renewed Facility Operating License No. NPF-85 NRC Docket No. 50-353 10 CFR 50.73

Subject:

LER 2017-006-00, HPCI lnoperability during Post Maintenance Testing Enclosed is a Licensee Event Report (LER) which addresses HPCI lnoperability during Post Maintenance Testing at Limerick Generating Station (LGS), Unit 2.

This LER is being submitted pursuant to the requirements of 1 O CFR 50.73(a)(2)(v)(D), any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.

There are no commitments contained in this letter.

If you have any questions, please contact Robert B. Dickinson at (610) 718-3400.

Respectfully,

~

Ub-L-Richard W. Libra Vice President - Limerick Generating Station Exelon Generation Company, LLC cc: Administrator Region I, USNRC USNRC Senior Resident Inspector, LGS

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150*01 04 EXPIRES: 03/31/2020 (04*2017)

, the http://www.nrc.qov/readinq-rm/doc-collections/nureqs/staff/sr1022/r3/)

NRG may not conduct or sponsor, and a person is not required to respond to, the inlormat1on collection.

3. PAGE Limerick Generating Station, Unit 2 05000353 1 OF 3

4. TITLE HPCI lnoperability during Post Maintenance Testing

5. EVENT DATE

6. LEA NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED I

SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH OAY YEAR YEAR NUMBER NO MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 07 27 17 2017 - 006

- 00 09 25 17

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

D 20.2201 (bl D 20.2203(a)(3)(il D 50.73(a)(2)(ii)(A)

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

D 20.2201 (dl D 20.2203(a)(3)(iil D 50.73(a)(2)(ii)(B)

D 50.73(a)(2)(viii)(B) 1 D 20.2203(a)(1 l D 20.2203(a)(4l D so.13(a)(2)(iiil D 50.73(a)(2)(ix)(A)

D 20.2203(a)(2)(il D 50.36(c)(1 )(i)(A)

D 50.73(a)(2)(iv)(A)

D 50.73(a)(2)(x)

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

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

D 13.11 (a)(4l D 20.2203(a)(2)(iiil D so.3s(c)(2)

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

D 73.71 (a)(S)

D 20.2203(a)(2)(iv)

D so.4s(a)(3)(iil D 50.73(a)(2)(v)(C)

D 13.77(a)(1 l 100 D 20.2203(a)(2)(v)

D 50.73(a)(2)(i)(A)

[gJ 50. 73(a)(2)(v)(D)

D 13_11(a)(2)(il D 20.2203(a)(2)(vi)

D 50.73(a)(2)(i)(B)

D 50.73(a)(2)(vii)

D 13.11(a)(2)(iil D 50.73(a)(2)(i)(C)

D OTHER Spec1ty 1n Abslracl below or m YEAR 2017 -

SEQUENTIAL NUMBER 006 On July 27, 2017, following the relay replacement per the PMT, Operations personnel closed the Suppression Pool suction valve with the Condensate Storage Tank suction valve already closed resulting in Unit 2 HPCI being inoperable. Operations personnel realized the inoperability and reestablished the HPCI suction source from the Suppression Pool. HPCI was made operable approximately 20 minutes after being initially isolated.

IV.

Cause of the Event

REV NO.

00 A Root Cause Investigation was performed to determine the cause of Unit 2 HPCI being placed in a condition that prevented the fulfillment of the safety function. The investigation concluded that Maintenance Planning personnel developed incorrect written instructions for performing post maintenance testing of the relay.

The following contributing causes were identified:

The PMT written instructions were not reviewed by Operations There was inadequate technical review of a first-time preventative maintenance activity.

There was inadequate Operations shift review of the work activity during work execution.

V.

Corrective Actions Completed/Planned The following actions are in place or are planned:

Conduct a Technical Human Performance (THU) workshop with the Maintenance Planning Department to increase awareness of THU tools.

Include THU behavior discussion topics during weekly Maintenance Planning Department all hands meetings.

The Operations Department will assist the Maintenance Planning Department in developing post maintenance tests.

VI.

Previous Similar Occurrences There have been no previous similar occurrences of inoperability of a system due to errors in PMT written instructions at LGS. Page _3 _ of _3_