ML23335A112
| ML23335A112 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 12/15/2023 |
| From: | James Kim Plant Licensing Branch 1 |
| To: | Mcfeaters C Public Service Enterprise Group |
| Kim J | |
| References | |
| EPID L-2023-LRO-0055 | |
| Download: ML23335A112 (1) | |
Text
December 15, 2023 Charles V. McFeaters President and Chief Nuclear Officer PSEG Nuclear LLC - N09 P.O. Box 236 Hancocks Bridge, NJ 08038
SUBJECT:
HOPE CREEK GENERATING STATION - REVIEW OF RETEST SCHEDULE FOR DRYWELL TO SUPPRESSION CHAMBER VACUUM BREAKERS (EPID L-2023-LRO-0055)
Dear Charles McFeaters:
By letters dated July 31, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23212A170), PSEG Nuclear LLC (PSEG, the licensee) requested approval for continuation of the 18-month test schedule for the Hope Creek Generating Station drywell to suppression chamber bypass vacuum breakers per Technical Specifications Surveillance Requirement (SR) 4.6.2.1.f.
The U.S. Nuclear Regulatory Commission staff has completed its review of PSEGs submittal, as documented in the enclosed evaluation.
If you have any questions, please contact me at 301-415-4125 or James.Kim@nrc.gov.
Sincerely,
/RA/
James S. Kim, Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-354
Enclosure:
Review Evaluation cc: Listserv
Enclosure OFFICE OF NUCLEAR REACTOR REGULATION REVIEW OF RETEST SCHEDULE FOR DRYWELL TO SUPPRESSION CHAMBER VACUUM BREAKERS PSEG NUCLEAR LLC HOPE CREEK GENERATING STATION DOCKET NO. 50-354
1.0 INTRODUCTION
By letter dated July 31, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23212A170), PSEG Nuclear LLC (PSEG, the licensee) requested approval for continuation of the 18-month test schedule for the Hope Creek Generating Station (Hope Creek) drywell to suppression chamber bypass vacuum breakers per Technical Specifications (TS) Surveillance Requirement (SR) 4.6.2.1.f. The suppression chamber is a steel pressure vessel in the shape of a torus. Commission review and approval of subsequent vacuum breaker bypass leak test schedule is required per SR 4.6.2.1.f, if the bypass leakage test fails to meet the specified limit. The failure of the bypass leakage test to meet the specified leakage acceptance criteria on April 30, 2023, is reported in Licensee Event Report (LER) 2023-001-00, submitted by letter dated June 20, 2023 (ML23173A087). PSEG identified bypass leakage through one torus-to-drywell vacuum breaker, completed repairs, satisfactorily performed SR 4.6.2.1.f, and returned to power operation on May 6, 2023. On September 11, 2023, PSEG submitted additional information regarding the bypass leakage test (ML23254A226).
2.0 DISCUSSION Section 6.2.1.1.4.1 of the Hope Creek Updated Final Safety Analysis Report describes the drywell-to-torus vacuum breakers. These vacuum breakers are provided to protect the drywell from the effects of external to internal differential pressure (drywell vacuum), a design value of 3 pounds per square inch (psi), that could result from drywell spray. There are eight 24-inch vacuum relief valves (vacuum breakers), each located on the vent header of the drywell to suppression chamber vent system. These vacuum breakers are of the self-actuating, check type, that can also be remote manually operated from the main control room.
LER 2023-001-00 states that on April 30, 2023, PSEG attempted to perform SR 4.6.2.1.f but could not establish the initial test conditions (drywell-to-torus differential pressure). PSEG declared SUPPRESSION CHAMBER and PRIMARY CONTAINMENT INTEGRITY inoperable and completed a plant shutdown in accordance with TS. PSEG identified bypass leakage through one torus-to-drywell vacuum breaker, completed repairs, satisfactorily performed SR 4.6.2.1.f, and returned to power operation on May 6, 2023.
By letter dated September 11, 2023, PSEG states that it determined the direct cause was torus-to-drywell vacuum breaker A was not set appropriately to prevent mechanical interference from its associated limit switches or closing magnet assemblies. This caused mechanical interference of about 0.030 inches, preventing the vacuum breaker from fully seating. PSEG determined the root cause was failure to assess a first-call preventive maintenance on torus-to-drywell vacuum breakers as high risk. Consequently, the outage work management processes did not establish readiness milestones, appropriate readiness challenges, and effective risk management actions.
PSEG states that it found no similar LER or corrective action occurrences following a review of station LERs and the corrective action program for the past three years.
PSEG states that it established corrective actions to improve procedures to better define and identify high risk and non-recoverable work; PSEG will define non-recoverable and infrequently performed work associated with TS structures, systems, or components as high risk.
PSEG states that it established additional corrective actions to resolve the contributing causes:
procedure enhancements, reinforcing station expectations, and fleet wide communications of the learnings provided by this event.
3.0 EVALUATION On April 30, 2023, PSEG attempted to perform SR 4.6.2.1.f but could not establish the initial drywell-to-torus differential pressure of 0.80 psi required per TS. PSEG declared SUPPRESSION CHAMBER and PRIMARY CONTAINMENT INTEGRITY inoperable and completed a plant shutdown in accordance with TS. PSEG determined the direct cause was torus-to-drywell vacuum breaker A was not set appropriately to prevent mechanical interference from its associated limit switches or closing magnet assemblies. PSEG completed repairs, satisfactorily performed SR 4.6.2.1.f, and returned to power operation on May 6, 2023.
PSEG review of station LERs and the corrective action program for the past three years found no similar LER or corrective action occurrences.
PSEG determined the root cause as the failure to assess a first-call preventive maintenance on torus-to-drywell vacuum breakers as high risk causing the outage work management processes to not establish readiness milestones, appropriate readiness challenges, and effective risk management actions. Subsequently, PSEG established corrective actions to improve procedures to better define and identify high risk and non-recoverable work.
4.0 CONCLUSION
PSEG has presented enough information to provide confidence that they have identified failure mechanisms and the root cause associated with subject drywell-to-torus vacuum breakers and have established effective corrective measures. Accordingly, the U.S. Nuclear Regulatory Commission staff concludes that continuation of the 18-month test schedule for the drywell-to-torus vacuum breakers is acceptable.
Principal Contributor: Hanry Wagage Date: December 15, 2023
ML23335A112 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DSS/SCPB/BC NAME JKim KEntz BWittick DATE 12/1/2023 12/6/2023 11/27/2023 OFFICE NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME HGonzález JKim DATE 12/15/2023 12/15/2023