05000364/LER-2023-002, Main Steam Safety Valve Lift Pressure Outside of Technical Specifications Limits Due to Setpolnt Drift

Main Steam Safety Valve Lift Pressure Outside of Technical Specifications Limits Due to Setpolnt Drift

ML23334A228
Person / Time
Site:	Farley
Issue date:	11/30/2023
From:	Dean E Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-23-0828 LER 2023-002-00
Download: ML23334A228 (1)

LER-2023-002, Main Steam Safety Valve Lift Pressure Outside of Technical Specifications Limits Due to Setpolnt Drift

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)
3642023002R00 - NRC Website

text

~ Southern Nuclear November 30, 2023 Docket No.:

50-364 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin Dean Ill Vice President* Farley Joseph M. Farley Nuclear Plant-Unit 2 Licensee Event Report 2023-002-00 Main Steam Safety Valve Lift Pressure Outside of Technical Specifications Limits due to Setpoint Drift Ladies and Gentlemen:

Joseph M. Farley Nuclear Plant 7388 North State Hwy 95 Columbia, Alabama 36319 334.661.2100 tel 334.661.2512 fax EDDEANil@southemco.com NL-23-0828 In accordance with the requirements of 10 CFR 50.73(a)(2)(i)(B), Southern Nuclear Company is submitting the enclosed Licensee Event Report for Unit 2.

This letter contains no NRC commitments. If you have any questions regarding this submittal, please contact Gene Surber, Licensing Manager, at (334) 661-2265.

Respectfully submitted, 0/J4 Edwin Dean Ill Vice President - Farley SD/rgs/cbg Enclosure: Unit 2 Licensee Event Report 2023-002-00 Cc: Regional Administrator, Region II NRR Project Manager - Farley Nuclear Plant Senior Resident Inspector - Farley Nuclear Plant RTYPE: CFA04.054

Joseph M. Farley Nuclear Plant - Unit 2 Licensee Event Report 2023-002-00 Main Steam Safety Valve Lift Pressure Outside of Technical Specifications Limits due to Setpoint Drift Enclosure Unit 2 Licensee Event Report 2023-002-00

NRCFORM366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-4104 EXPIRES: 03/31/2024 (10-01-2023)

Esllmaled burden per l8SpOIIS8 to comply will lhls mandato,y CGllec8o!l request 80 hows. Reported lessons

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LICENSEE EVENT REPORT (LER) leamed are lncorpora1lcl ln111 Ille licensing ptllC8SS and r.d bade to lndus1ry. Send common1s l99IRinll burden

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estimate to Ille FOIA, linly, and lnlonnation CalJaclioo6 Blanch {T~ AIOM), U. S. Nudear Regulato,y

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ComnlSsion, Washington, DC 20555-0001, ot by emai lo lnfocolleds.Rosolrce@nrc.gov, and Ille 0MB,.,,.,_

at 0MB Office of Information and RegulalDry Affaita, (3150-0104), Attn: Oesll Officer for Ille Nuclear Ragutatocy (See NUREG-1022, R.3 for Instruction and guidance for completing this form Comnusion, 72517111 Sfleel NW, WashinGton, DC 20503; email: oira subrrissjon@omb IQD gov. The NRC may b1t11*/fwww,a[l;,gl2Y/11111dlag*1ID/doc-colllllllilla!ilau1119s/sl11ffllitillZZ{Q[)

not conduct o, sponso,, and a person Is not roqwed lo respond ID, a oolectlon of Information W1lass Iha docunenl n,quosllng o, l8IJlirlng Ille oolectlon displays a runanlly valid 0MB control number.

1. Faclllty Name

~ 050

2. Docket Number

3. Page Joseph M. Farley Nuclear Plant, Unit 2 052 364 1 OF 2

4. Tltle Main Steam Safety Valve Lift Pressure Outside of Technical Specifications Limits due to Setpolnt Drift

5. Event Date

6. LER Number

7. Report Date

8. Other Facllltlea Involved Month Day Year Year Sequenllal Revision Monlll Day Year Faclllty Name Docket Number Numbor No.

050 10 03 23 2023 -

002 -

00 11 30 2023 Faclllty Name Docket Number 052

9. Operating Mode 110. Power Level 1

92

11. This Report Is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply) 10 CFR Part 20 20.2203(a)(2)(vl) 10 CFR Part 50

50. 73(a)(2)(11)(A)

50. 73(a)(2)(vill)(A) 73.1200(8) 20.2201(b) 20.2203(8)(3)(1) 50.36(c)(1)(I)(A) 50.73(a)(2)(11)(B)

50. 73(a)(2)(vlll)(B) 73.1200(b) 20.2201(d) 20.2203(8)(3)(11) 50.36(c)(1)(11)(A) 50.73(a)(2)(111)

50. 73(a)(2)(Ix)(A) 73.1200(c) 20.2203(8)(1) 20.2203(8)(4) 50.36(c)(2) 50.73(a)(2)(Iv)(A)

50. 73(a)(2)(x) 73.1200(d) 20.2203(a)(2)(I) 1 0 CFR Part 21 50.46(a)(3)(11)

50. 73(a)(2)(v)(A) 10 CFR Part 73 73.1200(e) 20.2203(8)(2)(11) 21.2(c) 50.69(g)

50. 73(a)(2)(v)(B) 73.77(a)(1) 73.1200(f) 20.2203(a)(2)(111) 50.73(a)(2)(I)(A)

50. 73(a)(2)(v)(C)

73. 77(a)(2)(I) 73.1200(g) 20.2203(a)(2)(Iv)

~ 50.73(a)(2)(I)(B)

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

73. 77(a)(2)(11) 73.1200(h) 20.2203(a)(2)(v)

50. 73(a)(2)(I)(C) 50.73(a)(2)(vll)

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

12. Licensee Contact for this LER Licensee Contact Phone Number (Include area code)

Gene Surber. Licensina Manaaer (334) 661-2265 Cause System Component Manufacturer Reportable to IRIS Cause System Component Manufacturer Reportable to IRIS X

SB RV D245 y

14. Supplemental Report Expected Month Day Year 0

15. Expected Submlnlon Date No Yes (If yes, complete 15. Expected Submission Date)

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

On October 3, 2023, while in Mode 1 at 92% power level, it was discovered that a Unit 2 Main Steam Safety Valve (MSSV) failed its as-found lift pressure test. The MSSV lifted above the Technical Specification (TS) 3.7.1 allowable lift setting value.

Setpoint drift is the most likely cause of the MSSV setpoint failure.

It is likely that the MSSV was outside of the TS limits longer than the allowable completion times for the associated Required Action Statements during the operating cycle in all applicable modes of operation. Therefore, this condition is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by TS.

The MSSV setpoint was adjusted to within the TS limits and returned to service restoring compliance. The MSSV that failed the surveillance setpoint test was replaced with a refurbished valve during the 2R29 refueling outage and sent to vendor for analysis.

EVENT DESCRIPTION

I

2. DOCKET NUMBER

3. LER NUMBER 364 I

YEAR SEQUENTIAL REV NUMBER NO.

• I 002 1-0 On October 3, 2023, at 1650 CDT, while operating in Mode 1 and at 92% power level, a B Loop Main Steam Safety Valve (MSSV), Q2N11V0011 C [EIIS:SB:RV] as-found lift pressure did not meet the acceptance criteria of+/- 3% of setpoint (1102 psig) as required by Technical Specifications (TS) Surveillance Requirement (SR) 3.7.1.1. The MSSV lifted high at 1140 psig which is 5 psig outside of its acceptance range of 1069 to 1135 psig. The +/- 3% as-found lift pressure requirement is an ASME Section 111, 1971 edition, and Farley TS requirement to ensure that the MSSV provides adequate protection by preventing the steam pressure from exceeding 110% of the main steam system design pressure.

EVENT ANALYSIS

The MSSV (Manufacturer: Dresser, Model Number: 3707R, Serial Number: BP-09820) was sent to NWS Technologies for failure analysis due to the failed as-found test. Setpoint drift is the most likely cause of the MSSV setpoint failure.

REPORTABILITY AND SAFETY EVALUATION:

This failure constitutes a condition that is reportable pursuant to 10 CFR 50.73(a)(2)(i)(B), "Any operation or condition which was prohibited by the plant's Technical Specifications." The applicable accident/transient analyses requires five MSSVs per Steam Generator [EIIS:SB:SG] to provide overpressure protection for design basis transients occurring at 102% Rated Thermal Power. On October 3, 2023, MSSV Q2N11 V0011 C was found outside of its required setpoint range and was declared inoperable. As it is not possible to determine when the valve exceeded the allowable setpoint range, the MSSV was likely inoperable for greater than the TS allowed completion time. Based on the MSSV as-found lift setpoint being less than 110% of design Steam Generator pressure (1194 psig), and properly reseating, this one MSSV failure did not result in a loss of safety function.

CORRECTIVE ACTIONS

MSSV Q2N11V0011C was adjusted within TS tolerance and returned to operable status. Additonally, an expanded scope inspection of MSSVs Q2N11V0011 E and Q2N11V0011 D was completed satisfactory. The MSSV (SN BP-09820) was subsequently removed from its location during the 2R29 refueling outage for analysis and was replaced on October 17, 2023, with a refurbished valve that was heat soaked and placed in the Q2N11V0011C location at the required 1102 psig

+/-1%.

PREVIOUS SIMILAR EVENTS

A similar event was reported in 2017 (LER 2017-002-00) and in 2020 (LER 2020-001-01).

OTHER SYSTEMS IMPACTED:

No other systems were affected by this event. Page 2

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