L-2024-117, Safety Injection Tank Vent Through Wall Leakage

Safety Injection Tank Vent Through Wall Leakage

ML24194A149
Person / Time
Site:	Saint Lucie
Issue date:	07/11/2024
From:	Rasmus P Florida Power & Light Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-2024-117 LER 2024-002-01
Download: ML24194A149 (1)

Text

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July 11, 2024 L-2024-117 10 CFR 50.73

U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

Re: St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 2024-02-01 Date of Event: January 3, 2024

Safety Injection Tank Vent Through Wall Leakage

The attached Licensee Event Report, 2024-02-01, is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.

Should you have any questions regarding this submission, please contact Mr. Kenneth Mack, Fleet Licensing Manager, at 561-904-3635.

This letter contains no new or modified regulatory commitments.

Sincerely,

Paul Rasmus General Manager - Regulatory Affairs - Nuclear Fleet Florida Power & Light Company

Attachment

cc: St. Lucie NRC Senior Resident Inspector St. Lucie Station NRC Program Manager

Florida Pow er & Li ght Comp any

6501 S. Oc ean Driv e, Jen se n Beach, FL 3 4957 NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027 (04-02-2024) Estimated burden per response to comply wi1h this mandato,y 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 ineo<porated Into the licensing process and fed back to industry. Send comments regarding burden LICENSEE EVENT REPORT (LER) estimate to the FOIA, Library, and Information Collections Branch (T.e A10M), U. S. Nuclear Regulato,y email to lnfocollects.Resource@nrc.gov, and the 0MB reviewer

\\~)..... (See Page 2 for required number of digits/characters for each block) Commission, Washington, DC 20555-0001, or by at 0MB Office of Information and Regulato,y Affairs, (3150-0104), Attn: Desk Officer for the Nuclear Regulato,y (See NUREG-1022, R.3 for instruction and guidance for completing this form Commission, 725 17th Street NW, Washington, DC 20503. The NRC may not conduct or sponsor, and a person is blllr /lwww DH, gQl/./rn~diog-mJ/dQ~llectioa~IDY[]lgs/st.ittlHl 022/r3/) not required to respond to, a collection of Information unless the document requesting or requiing the collection displays a currently vaid OM! con trol number.

1. Facility Name ~ 050 2. Docket Number 3. Page

St. Lucie Unit 2 D 052 00389 1 OF 2

4. Title

Safety Injection Tank Vent Line Through Wall Leakage

5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Month Day Year Year Sequential Revision Month Day Year Faclllty Name D Docket Number Number No. 050

Docket Number 01 02 2024 2024 - 02 - 01 7 11 2024 Facility Name D 052

9. Operating Mode 110. Power Level 3 0

11. This Report Is Submitted Pursuant to the Requirements of 1 O CFR §: (Check all that apply) 10 CFR Part 20 D 20.2203(a)(2)(vl) 10 CFR Part 50 [ZJ 50. 73(a)(2)(11)(A) D 50. 73(a)(2)(vlll)(A) D 73.1200(a)

D 20.2201(b) D 20.2203(a)(3)(i) D 50.36(c)(1)(1)(A) D 50. 73(a)(2)(ll1(B) D 50. 73(a)(2)(vlil)(B) D 73.1200(b)

D 20.2201(d) D 20.2203(a)(3)(il) D 50.36(c)(1 )(ll)(A) D 50. 73(a)(2)(111) D 50. 73(a)(2)(1x)(A) D 73.1200(c)

D 20.2203(a)(1) D 20.2203(a)(4) D 50.36(c)(2) D 50. 73(a)(2)(1v)(A) D 50.73(a)(2)(x) D 73.1200(d)

D 20.2203(a)(2)(1) 10 CFR Part 21 D 50.46(a)(3)(il) D 50. 73(a)(2)(v)(A) 10 CFR Part 73 D 73.1200(8)

D 20.2203(a)(2)(11) D 21.2(c) D 50.69(g) D 50.73(a)(2)(v)(B) D 73. 77(a)(1) D 73.1200(f)

D 20.2203(a)(2)(111) D 50. 73(a)(2)(i)(A) D 50. 73(a)(2)(v)(C) D 73. 77(a)(2)(1) D 73.1200(g)

D 20.2203(a)(2)(1v) D 50. 73(a)(2)(i)(B) D 50. 73(a)(2)(v)(D) D 73. 77(a)(2)(11) D 73.1200(h)

D 20.2203(a)(2)(v) D 50. 73(a)(2)(i)(C) D 50. 73(a)(2)(vll)

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

12. Licensee Contact for this LER

Licensee Contact Phone Number (Include area code)

Bob Murrell 319-651-9496

13. Complete One Line for each Component Failure Described In this Report Cause System Component Manufacturer Reportable to IRIS Cause System Component Manufacturer Reportable to IRIS

B BQ PSF N/A y

14. Supplemental Report Expected Month Day Year 16. Expected Submission Date

[ZJ No Yes (If yes, complete 15. Expected Submission Date) D

16. Abstract (Limit to 1326 spaces, i.e., approximately 13 single-spaced typewritten lines)

This LER revision supersedes LER 2024-02-00 in its entirety.

On January 3, 2024, while in Mode 3, it was determined that the Reactor Coolant Pressure Boundary (RCPB) had a through wall flaw with Safety Injection Tank (SIT) leakage. The leakage was coming from the welded connection of a vent valve for SIT 2A2 outlet valve piping segment Sl-227. The cause of the leak was microcracks in weld material from a December 16, 2023, repair.

This leak resulted in the Unit being in a Degraded Condition. There were no Systems, Structures, or Components that were inoperable at the start of the event that contributed to the event. This event is being reported pursuant of 10 CFR 50.73(a)(2)

(ii)(A), Degraded Condition.

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027 (04.02-2024) Estimated burd en per re sponse to co mply with this mandato ry co ll ec tion req ues t: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons le arned are incorporated into the lice nsing process and fed ba ck to industry. Send co mm ents LICENSEE EVENT REPORT (LER) regard ing burden estima te to th e FOIA, Library, and Inform ation Collections Branch (T-6 A10M), U. S.

Nuclear Regula tory Co mm ission, Was hinglon, DC 20 555-0001, or by email to CONTINUATION SHEET lnfocollects.Resource@ nrc.gov, and th e 0MB rev iewer at: 0MB Office of lnfonn ation and Regulatory Affairs, (3150-0104), Attn: Desk Office r for th e Nuclear Reg ul atory Commi ssion, 72 5 17th Stree t NW,

(See NUREG-1022, R.3 for instruct ion and guidance for completing this form Wa shington, DC 20503. Th e NRC may not co nd uc t or spon so r, and a perso n is not requ ired to http://www nrc gov/reading-rm/doc-coHections/nuregs/staff/sr1022/r3/) respond to, a collec ti on of information unless th e doc um ent requesting or requiring th e co llection di spl ays a currently valid 0MB co ntrol number.

1. FACILITY NAME 050 2. DOCKET NUMBER 3. LER NUMBER YEAR SEQUENTIAL REV 1st. Lucie Unit 2 I 00389 D NUMBER NO.

I~ 052 I ~-I 02 1-0

NARRATIVE

Description of Event:

On January 3, 2024, while in Mode 3, it was determined that the Reactor Coolant Pressure Boundary (RCPB) had a through wall flaw with Safety Injection Tank (SIT) leakage. The leakage was coming from the welded connection of a vent valve for SIT 2A2 outlet valve piping segment Sl-227. This leak resulted in the Unit being in a Degraded Condition. There were no Systems, Structures, or Components that were inoperable at the start of the event that contributed to the event.

Cause of Event:

The leak was caused by microcracks in weld material from a December 16, 2023, repair. These microcracks occurred during solidificat ion of the weld material.

Safety Significance :

This event did not prevent any safety systems from performing their safety related functions based on the minimal amount of leakage identified.

This Licensee Event Report is being reported pursuant of 10 CFR 50.73(a)(2)(ii)(A), Degraded Condition.

This event did not result in a Safety System Functional Failure.

Corrective Act ions:

Repairs to Sl-227 were completed on January 5, 2024.

Sim ilar Events:

A review of events over the past 5 years identified one previous event that involved a similar underlying cause of the event reported under this Licensee Event Report. This event is documented in LER 2024-01, Sa fety Injection Tank Vent Line Through Wall Leakage, dated February 13, 2024. The cause of that event was stresses resulting fatigue crack initiation and propagation.

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