05000321/LER-2021-003, High Pressure Coolant Injection System Discharge Valve Failure to Open

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High Pressure Coolant Injection System Discharge Valve Failure to Open
ML21305A874
Person / Time
Site: Hatch Southern Nuclear icon.png
Issue date: 11/01/2021
From: Dean E
Southern Nuclear Operating Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-21-0966 LER 2021-003-00
Download: ML21305A874 (4)
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LER-2021-003, High Pressure Coolant Injection System Discharge Valve Failure to Open
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(v), Loss of Safety Function
10 CFR 50.73(a)(2)
3212021003R00 - NRC Website
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text

A Southern Nuclear November 1, 2021 Docket Nos.: 50-321 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Edwin 0. Dean Ill Vice President - Plant Hatch Edwin I. Hatch Nuclear Plant - Unit 1 Licensee Event Report 2021-003-00 Hatch Nuclear Plant 11028 Hatch Parkway North Baxley. GA 31513 912 537 5859 tel 912 366 2077 fax NL-21-0966 High Pressure Coolant lniection Discharge Valve Failure to Open Ladies and Gentlemen:

In accordance with the requirements of 10 CFR 50.73(a)(2)(v)(D), Southern Nuclear Operating Company hereby submits the enclosed Licensee Event Report.

This letter contains no NRC commitments. If you have any questions, please contact the Plant Hatch Licensing Manager, Jimmy Collins, at 912.453.2342.

Respectfully submitted, Edwin D. Dean Ill Vice President - Plant Hatch ED/CJC Enclosure: LER-2021-003-00 Cc:

Regional Administrator - Region II NRR Project Manager - Plant Hatch Senior Resident Inspector - Plant Hatch RTYPE: CHA02.004

Edwin I. Hatch Nuclear Plant - Unit 1 Licensee Event Report 2021-003-00 High Pressure Coolant Injection Discharge Valve Failure to Open Enclosure LER 2021-003-00

NRC F.ORM 366 U.S. NUCLEAR REGULA TORY COMMISSION APPROVED BY 0MB: NO. 31&0-0104 EXPIRES: 0813112023 LICENSEE EVENT REPORT (LER)

(See Page 3 for raqulnKI number of dlgltslcharactens for each block)

(See NUREG-1022, R.3 for instruction and guidance for completing this form

~111:o..11ovtroJfli!lG*rrotd-col!ect10nGtnur4QJ!.1lAffltr.10wra/l

3. Page Edwin t. Hatch Nuclear Plant Unit 1 05000 321 1 OF 2
4. Title Unit 1 High Pressure Coolant Injection System discharge valve failure to open
5. Event Data
8. LER Number
7. Report Date
8. Other Facllltlff Involved Monlh Day Yur Year Sequential Revlalon Month Day Yor Facility Name Docket Number Number No.

05000 09 08 2021 2021 -

003 -

00 11 01 2021 Fac!Hty Name Docllet Number 05000

9. Operating Mode rO. Power Level 1

100

11. This Report Is Submitted Pursuantto the Requirements of 10 CFR §: (Check all that apply) 10 CFR Part 20 20.2203(a)(2)(vl) 50.36(c)(2)
50. 73(a)(2)(1v)(A)
50. 73(a)(2)(x) 20.2201(b) 20.2203(a)(3)(1) 50.48(a)(3)(11)
50. 73(a)(2)(v)(A) 10 OfR Part73 20.2201(d) 20.2203(a)(3)(11) 50.89(g)
50. 73(a)(2)(v)(B)
73. 71.(a)(4) 20.2203(a)(1) 20.2203(a)(4) 50,73(a)(2)(1)(A)

SO. 73(a)(2)(v){C) 73.71(a)(5)

D 20.2203(a)(2)(1) 10 OF-R Part 21 50.73(a)(2)(I)(B)

~

50. 73(a)(2)(v)(D) 73.77(8)(1)(1) 20.2203{a){2){H)

D 21.2(c)

50. 73(a)(2)(1)(C) so. 73(a)(2)(vll)
73. 77(a)(2)(I) 20.2203(a){2)(iil) 10 CFR Part 50 50.73(a)(2)(11)(A)

D 50.73(a)(2)Mlll(A) 73.77(a)(2)(11) 20.2203(a)(2}(1v) 50.36(c)(1)(1)(A) 50.73(8)(2)(11)(8)

50. 73(a)(2)(vlll)(B) 20.2203(a)(2)(v) 50.36(c)(1 )(ll)(A)
50. 73(a)(2}(111)
50. 73(a)(2)(Ix)(A)

OTHER (Specify here, in abstract,.or NRC 366A).

12. Licensee Contact for this LER LicenaNContact Phone Number (!nol!lclt IIWI IIOC!1)

Edwin I. Hatch / Jimmy Collins - Licensing Manger 912-453e2342 Cauae System ComJ)Oflent Manufacturer Reportable to IRIS

Cause

System Component Msnufai;turvr Rtportl>>lt to IRl!I A

BJ ISV L200 y

14. Supplemental Report Expected YHr Ill No ID Yes (If yes, ~mplete 15. Expected Submission Date)
15. Expected Submlaalon Date

Abstract

On September 8, 2021, while Unit 1 was at 100% rated thermal power, the High Pressure Coolant Injection (HPCI) pump discharge isolation valve was stroked closed as a part of a valve surveillance activity. Up to this point, HPCI was operable, When the valve was given an open signal, the valve did not return to the open position. Without the ability to open this valve, HPCI is inoperable.

Systematic troubleshooting determined that the pinion gear key in the valve actuator had not been properly staked during previous maintenance activities in 2006, leading to the key moving and the pinion gear disengaging from the actuator motor shaft. This caused the valve to become inoperable, not allowing it to stroke to the open position.

As a corrective action, the pinion gear key was properly staked per procedure to the actuator motor shaft and the pinion gear reinstalled.

NQC =

EVENT DESCRIPTION

On September 8, 2021 at 0159, while Unit 1 was in MODE 1 at 100% rated thermal power, the High Pressure Coolant Injection (HPCI) pump [EIIS BJ} discharge isolation valve [EIIS ISV] was stroked closed as a part of a valve surveillance activity. Up to this point, HPCI was operable. When the valve was given an open signal, the valve did not return to the open position. Without the ability to open this valve, HPCI is inoperable. There was no other safety related equipment inoperable that contributed to this event. HPCI was returned to operable status on September 9, 2021 at 1444.

EVENT CAUSE ANALYSIS

Systematic troubleshooting determined that the pinion gear key in the valve actuator had not been properly staked during previous maintenance activities in 2006, leading to the key moving and the pinion gear disengaging from the actuator motor shaft. This caused the valve to become inoperable, not allowing it to stroke to the open position. The cause of the incorrect staking was the SNC maintenance electrician performing the activity in 2006 did not peen enough metal to retain the key as was required in the guidance/procedure.

REPORTABILITY ANO SAFETY ASSESSMENT:

HPCI does not have a redundant system; therefore, this condition is being reported as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function per 10 CFR 50.73{a)(2)(v)(D). While the HPCI system was inoperable, the Reactor Core Isolation Cooling (RCIC) system and low pressure emergency core cooling systems were operable. Therefore, there were no safety consequences due to this event. The operating crew responded correctly to the event. The event was within the analysis of the UFSAR Chapter 15. There was not a release of radioactivity during this event.

CORRECTIVE ACTIONS

As a correc.tive action, the pinion gear key was properly staked per procedure to the actuator motor shaft and the pinion gear reinstalled.

PREVIOUS SIMILAR EVENTS

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