ML24184B867

From kanterella
Jump to navigation Jump to search
Condition Prohibited by Technical Specifications Due to Safety Injection Check Valve Not Full Closed
ML24184B867
Person / Time
Site: Calvert Cliffs Constellation icon.png
Issue date: 07/02/2024
From:
Constellation Energy Generation
To:
Office of Nuclear Reactor Regulation
Shared Package
ML24184B865 List:
References
LER 2024-001-01
Download: ML24184B867 (1)
v • d • e


Text

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/202 (04 2024) Estimaled burden per response to tofl'j)iy wilh this mandatOIY co a ection request 80 hoUIS. Reported lesson:

/ -~--*:::**\\ LICENSEE EVENT REPORT (LER) learned are in cOfJ)Ofated inlD the licen sing process and fed back ID induslly Send co1M1ents regarding bu rder estimate to the FO IA, libr.ry, and lnfonna1ion Colections Branch (T-6 A10M), U. S. Nuclear Regula t011

\\.,. a t 0MB Office ~ -:.,_.,; (See Page 2 for required number of digits/characters for each block) Comm ission, Was hin gton, DC 20555-0001, or by emai to lnfoco ects.Resource@rvc.gov, and the 0MB reviewe

..... (See NUREG-1022, R.3 for instruction and guidance for completing this form Comm ission, 725 17th Street of lnfoonation and Regula!Drf AffairsNW, Wash ing ton, DC 20503, The NRC may not conduct or sponsor, and a person,, (3150-0104), Attn Desk Officer for the Nuclear Regu lat011 h1l12*//www.nrc.gov/read ing-rm/doc-collections/nur i:gs/staff/sr1022/r3D not requ ired to respo nd to, a collection of infonnation un less the document requesting or requiring the collectior displays a curren!y va rd 0M B control number.

1. Facility Name ~ 050 2. Docket Number 3.Page Calvert Cliffs Nuclear Power Plant, Unit 1 052 05000317 1 OF 5
4. Title Condition Prohibited by Technical Specifications due to Safety Injection Check Valve Not Full Closed
5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved

Month Day Year Year Number No. Month Day Year 050 Sequential Revision Facility Name Docket Number 01 13 2024 2024 001 01 07 02 2024 Facility - - 052 Name Docket Number

9. Operating Mode 110. Power Level
11. This Report Is Submitted Pursuant to the Requirements of 10 CFR § : (Check all that apply) 10 CFR Part 20 D 20.2203(a)(2)(vl) 10 CFR Part 50 0 50.73(a)(2)(ii)(A) D 50.73(a)(2)(viii)(A) 73. 1200(a) 20.2201(b) D 20.2203(a)(3)(1) 50.36(c)(1)(i)(A) 50. 73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 73.1200(b) 0 20.2201(d) D 20.2203(a)(3)(ii) 50.36(c)(1)(ii)(A) D 50.73(a)(2)(iii) 50. 73(a)(2)(ix)(A) 73.1200(c)

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

D 20.2203(a)(2)(1) 10 CFR Part 21 D 50.46(a)(3)(ii) D 50.73(a)(2)(v)(A) 10 CFR Part 73 73.1200(e)

D 20.2203(a)(2)(ii) D 21.2(c) 50.69(g) D 50.73(a)(2)(v)(B) 73.77(a)(1) 73.1200(f)

D 20.2203(a)(2)(iii) 50.73(a)(2)(i)(A) D 50. 73(a)(2)(v)(C) 73. 77(a)(2)(i) 73. 1200(g)

D 20.2203(a)(2)(iv) ~ 50.73(a)(2)(i)(B) D 50.73(a)(2)(v)(D) D 73.77(a)(2)(ii) 73.1200(h)

D 20. 2203(a)(2)(v) 50. 73(a)(2)(i)(C) D 50. 73(a)(2)(vii)

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

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

Michael J. Fick, Principal Regulatory Engineer 410-495-6714

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 CKV YOBS y

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

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

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

In January 2024, it was discovered that a check valve in the safety injection system was not full shut and was therefore leaking by its seat. This check valve is also a containment isolation valve. Operations personnel declared the valve inoperable and immediately entered the applicable technical specification limiting condition for operation as required. However, because the condition existed for a time longer than allowed by the plant's technical specifications, this event is considered a condition prohibited by the plant's technical specifications and a licensee event report is required. The cause of the issue was due to a valve packing leak that allowed boric acid to build up and increase friction preventing the valve from going shut. To correct the issue, the valve was cleaned, disassembled, inspected, and repaired during the scheduled Unit 1 refueling outage in February 2024.

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027 (04 202 4) Estimated burden per response to comp ly w ith this mandat o ry c ollec tio n 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 incorporated into the licens ing proc ess a n d fed back to industry. Send comments LICENSEE EVENT REPORT (LER) regarding burden estimate to the FOIA, Library, and Info rmat ion Co llections Branch (T-6 A10M), U.S.

Nuclear Regulatory Commiss ion, Wash ington, DC 20555-0001, or by email to CONTINUATION SHEET lnfocollects.Resource@nrc.gov, and the 0MB reviewer at: 0 MB Offic e of Information and Regulatory Affairs, (3150-0104), Attn: Desk Officer for the Nuc lear Regu lato ry Commission, 725 17th Street NW, (See NUREG-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503 The NRG may not condu c t o r sponsor, and a person is not required to http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3D respond to, a collection of informa tion unless the doc ument requesting or requiring the collection displays a currently valid 0MB control numbe r.

1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER 050 YEAR SEQUENTIAL REV NUMBER NO.

Calvert Cliffs Nuclear Power Plant, Unit 1 052 05000317 2024 -001 01

NARRATIVE PLANT AND SYSTEM IDENTIFICATION

Calvert Cliffs Nuclear Power Plant, Unit 1, is a Combustion Engineering Pressurized Water Reactor with a licensed maximum power level of 2737 megawatts thermal. The Energy Industry Identification System code used in the text is identified as [8Q].

A. CONDITION PRIOR TO EVENT

Unit: 1 Date: January 13, 2024 Power level: 100 Mode: Unit 1 was in Mode 1 when the condition was discovered.

B. DESCRIPTION OF EVENT

On January 13, 2024, Operations performed a partial technical specification surveillance test to determine if a check valve in the safety injection system, that is located in the Unit 1 containment building and is classified as a containment isolation valve, was leaking by. This was in response to a condition identified on January 11, 2024, when a review of the main control room logs identified that the 128 Safety Injection Tank (SIT) level had lowered one inch (approximately 40 gallons) and system pressure had lowered 1.5 psig in approximately six hours. It was unclear what caused the issue due to the number of components and flow paths in the system.

However, maintenance on the system performed during that time could explain the drop in SIT level and pressure assuming a safety injection check valve in the system was leaking by. Operations initiated an issue report (IR04730811) documenting the issue with the 128 SIT on January 11, 2024. Troubleshooting was performed to assist Operations in determining the cause for 128 SIT's drop in level and pressure. On January 13, 2024, an unsatisfactory result was obtained during the performance of the partial technical specifications surveillance test due to the inability to lower test pressure to at least 40 psig, as required to perform the test (Test pressure could not be lowered below 250 psig which was approximately the pressure of the associated 128 SIT). Therefore, Operations declared the check valve, 1CKVSl-148 inoperable and entered Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.3.A, for one or more penetration flow paths with one containment isolation valve inoperable. IR04730916 was initiated. On January 16, 2024, a Unit 1 containment entry was performed to verify the actual position of the check valve. After manually cycling the check valve, it was left in the shut position.

C. DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES

January 11, 2024: 12:00: Operations discovered 128 SIT level had lowered one inch (approximately 40 gallons) and pressure had lowered 1.5 psig in about six hours.

January 13, 2024: 16:35: Technical Specification 3.6.3.A was entered due to 1CKVSl-148 out of service due to leak-by observed during partial performance of STP O-065J-1.

NRC FORM 366A (04-02-2024 ) Page_2_ of _5_

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES : 04/30/2027 (04-02-2024)

Estimated burden per response to comply with this mandatory co llection 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 incorporated into the licensing process and fed back to industry. Send comments LICENSEE EVENT REPORT (LER) regarding burden estimate to the FOIA, Library, and Information Collections Branch (T-6 A 10M), U. S.

Nuclear Regulatory Commission, Washington, DC 20555-0001, or by email to CONTINUATION SHEET lnfocollects.Resource@nrc.gov, and the 0MB reviewer at: 0MB Office of Information and Regulatory Affairs, (3150-0104), Attn: Desk Officer for the Nuclear Regulatory Commission, 725 17th Street NW, (See NUREG-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. The NRG may not conduct or sponsor, and a person is not required to http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3Q respond to, a collection of information unless the document requesting or requiring the collection displays a currently valid 0MB control number.

1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER 050 YEAR SEQUENTIAL REV NUMBER NO.

Calvert Cliffs Nuclear Power Plant, Unit 1 052 05000317 2024 - 001 - 01

NARRATIVE January 16, 2024: During a Unit 1 containment entry, station personnel found the check valve in the open position. The check valve would not shut without assistance from operations personnel. Operations personnel utilized the weighted arm of the check valve and left the check valve in the shut position.

February 12,2024: 12 :25: Unit 1 entered Mode 5 (Cold Shutdown).

February-March 2024: During a scheduled Unit 1 refueling outage, the check valve was disassembled, inspected and repaired. Repairs involved the replacement of two (2) rings of packing and the replacement of the packing bushing. Upon reassembly and successful post maintenance operability testing, the check valve was returned to Operable status and the associated TS LCO was exited.

D. CAUSE OF EVENT

The method of discovery for this event was self-revealing and is documented in the site's Corrective Action Program (CAP) under IR 04730916. The valve was inspected during the Unit 1 refueling outage in February 2024. It was determined that the failure of 1CKVSl-148 was due to an increase in frictional forces between the valve's packing and the valve stem due to boric acid corrosion buildup within the packing. Over time, the frictional forces overcame the gravitational force of the weighted lever arm and valve disc and prevented the valve from closing. Contributors to the excessive amount of boric acid corrosion buildup within the packing included :

  • 1CKVSl-148 had not been overhauled and had its packing replaced since 2004.
  • OPEX review identified that the site's work procedures to install packing are not aligned with industry/EPRI standards to consolidate individual packing rings one at a time as opposed to consolidating the entire packing set at once as had been performed previously.

Additional factors that contributed to the degraded issue with 1CKVSl-148 involved challenges associated with the surveillance procedure that has been utilized to test the check valve's performance in the reverse-flow or closed direction. Imprecise acceptance criteria and the periodic use of manual assistance during some historical tests potentially contributed to the site failing to identify the degrading condition of 1 CKVSl-148 at an earlier opportunity.

E. SAFETY ANALYSIS

The subject event satisfies the criteria in NUREG-1022, Revision 3, for any event or condition that was prohibited by the plant's Technical Specifications. A Licensee Event Report (LER) is required if a condition existed for a time longer than permitted by the TS (i.e., greater than the total allowed restoration and shutdown outage time of completion time in the STS), even if the condition was not discovered until after the allowable time had elapsed and the condition was rectified immediately upon discovery. It is assumed that there was firm evidence that a condition prohibited by TS existed before discovery, for a time longer than permitted by the TS.

Specifically, for this event, the condition was discovered on January 13, 2024 at 16:35 when the partial surveillance test failed. There is firm evidence that the condition existed on January 11, 2024, when Operations personnel identified that the 128 SIT level and pressure had decreased. The cause of the lowered level and decreased pressure was confirmed when the partial surveillance test failed on January 13, 2024, and

NRC FORM 366A (04-02-2024 ) Page_3_ of _s_

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027 (0 4 *02 *2024)

Estimated burden per response to comp ly with this mandatory 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 incorporated into the licens ing process and fed back to industry, Send comments LICENSEE EVENT REPORT (LER) regarding burden estimate to the FOI A, Library, and Information Collections Branch (T*G A 10M), U, S.

Nuclear Regulatory Comm ission, Washington, DC 20555-0001, or by ema il to CONTINUATION SHEET lnfocollects.Resource@nrc.gov, and the 0 MB reviewer at: 0MB Office of Information and Regulatory Affairs, (3150.0104), Attn: Desk Officer for the Nuclear Regulatory Comm ission, 725 17th Street NW,

(See NUREG-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. The NRG may n o t conduct or sponsor, and a person is not required to http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3 D respond to, a co llection of infomnation un less the document requesting or requiring the collection displays a currently valid 0MB contro l number.

1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER 050 YEAR SEQUENTIAL REV NUMBER NO.

Calvert Cliffs Nuclear Power Plant, Unit 1 052 05000317 2024 - 001 - 01

NARRATIVE further verified via the Unit 1 containment entry on January 16, 2024 when the check valve was found in the open position. The degraded condition affected the close function of the valve, such that the containment isolation function could not be satisfied. Technical Specification 3.6.3 "Containment Isolation Valves" Limiting Condition for Operation states "Each Containment Isolation Valve Shall be Operable", and is applicable in Modes 1, 2, 3 and 4. With one or more penetration flow paths with one containment isolation valve inoperable (Condition A), the required action is to isolate the affected penetration flow path by use of at least one closed and de-activated automatic valve, closed manual valve, blind flange, or check valve with flow through the valve secured within four (4) hours or in accordance with the risk informed completion time (RICT) program.

Required action also requires verification that the affected penetration flow path is verified isolated once per 31 days following isolation for isolation devices outside Containment AND prior to entering MODE 4 from MODE 5 if not performed within the previous 92 days for isolation devices inside containment. With Required Action and associated Completion Time not met (Condition D), required action is to be in Mode 3 within six (6) hours and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. As noted above, there is firm evidence that the condition (check valve open) existed from January 11, 2024 at 12:00 until February 12, 2024 when Unit 1 entered Mode 5 at 12:35. Therefore, this event is reportable pursuant to 10CFR50.73.(a)(2)(i)(B). This event did not result in any actual nuclear safety consequences.

F. CORRECTIVE ACTIONS

During the 2024 Unit 1 refueling outage, the check valve was cleaned, disassembled, inspected and repaired.

Repairs involved the replacement of two (2) rings of packing and the replacement of the packing bushing. The valve body and internals were cleaned and inspected with no evidence of damage identified. The surveillance test of the check valve's forward and reverse flow safety functions were subsequently performed satisfactorily to meet post-maintenance operability testing. Additionally, the CAP investigation performed under IR 04730916 includes the following corrective actions to address the identified causes for this event:

  • Implementation of a Condition Monitoring Plan (CMP) in accordance with site procedures for the applicable family of Safety Injection check valves that will require disassembly and inspection activities to include requirements for freedom of movement in the lnservice Testing Program to replace the exercise close test that has been utilized in the reverse-flow or closed direction portion of the applicable surveillance procedure.
  • Change the site's packing installation strategy to align with industry/EPRI standards regarding the consolidation of packing rings.
  • Completion of requalification training for Operations staff regarding acceptable/unacceptable actions taken during surveillance testing.

G. PREVIOUS OCCURRENCES

A review of Calvert Cliffs' events was performed. There were no previous occurrences of a safety injection check valve failing to close due to increased friction from an accumulation of boric acid.

H. COMPONENT FAILURE DATA

NRC FORM 366A (04*02*2024) Page_4_ of _5_

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027 (04-02-2024)

Estimated burden per response to comply with this mandatory 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 incorporated into the licensing process and fed back to industry. Send comments LICENSEE EVENT REPORT (LER) regarding burden estimate to the FOIA, Library, and Information Collections Branch (T-6 A 10M), U. S.

Nuclear Regulatory Commission, Washington, DC 20555-0001, or by email to CONTINUATION SHEET lnfocollects.Resource@nrc.gov, and the 0MB reviewer at: 0MB Office of Information and Regulatory Affairs, (3150-0104), Attn: Desk Officer for the Nuclear Regulatory Commission, 725 17th Street NW,

(See NUREG-1022, R.3 for instruction and guidance for completing this form Washington, DC 20503. The NRC may not conduct or sponsor, and a person is not required to http://www.nrc.gov/reading-rm/doc-colleclions/nuregs/staff/sr1022/r3/} respond to, a collection of information unless the document requesting or requiring the collection displays a currently valid 0MB control number.

1. FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER 050 YEAR SEQUENTIAL REV NUMBER NO.

Calvert Cliffs Nuclear Power Plant, Unit 1 052 05000317 2024 -

001 01

NARRATIVE

Component IEEE 803 IEEE805 FUNCTION ID SYSTEM ID 1CKVSl-148 128 Safety Injection Header Check Valve CKV BQ

NRC FORM 366A (04-02-2024) Page _s_ of _s_

Retrieved from "https://kanterella.com/w/index.php?title=ML24184B867&oldid=3685074"