05000458/LER-2023-004, Drywall Post Accident Radiation Monitor Inoperable Due to Unrecognized Surveillance Failure
| ML23362A034 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 12/28/2023 |
| From: | Crawford R Entergy Operations |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RBG-48268 LER 2023-004-00 | |
| Download: ML23362A034 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| 4582023004R00 - NRC Website | |
text
- ) entergy RBG-48268 Randy Crawford Manager Regulatory Assurance 225-381-4177 10 CFR 50.73 December 28, 2023 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Licensee Event Report 50-458 / 2023-004-00, Drywell Post Accident Radiation Monitor Inoperable due to Unrecognized Surveillance Failure River Bend Station - Unit 1 NRC Docket Nos. 50-458 Renewed Facility Operating License No. NPF-47 In accordance with 10 CFR 50.73, enclosed is the subject Licensee Event Report.
This document contains no commitments.
Should you have any questions, please contact Mr. Randy Crawford, Regulatory Assurance Manager, at 225-381-4177.
Respectfully,
C-c-A---
Randy Crawford RC/tf
Enclosure:
cc:
Licensee Event Report 50-458 / 2023-004-00, Drywell Post Accident Radiation Monitor Inoperable due to Unrecognized Surveillance Failure NRC Region IV Regional Administrator - Region IV NRC Senior Resident Inspector - River Bend Station Entergy Operations, Inc., 5485 U.S. Highway 61 N. St. Francisville, LA 70775
Enclosure RBG-48268 Licensee Event Report 50-458 / 2023-004-00, Drywell Post Accident Radiation Monitor Inoperable due to Unrecognized Surveillance Failure
Abstract
On November 2, 2023, with River Bend Station in Mode 4 and 0% power, personnel discovered an unrecognized surveillance failure for the Division I Drywall Post Accident Radiation Monitor (RMS-RE20A). The monitor was declared Inoperable and the appropriate Technical Specification Condition was entered.
The surveillance was reperformed on RMS-RE20A and the monitor was declared Operable on November 12, 2023.
The surveillance failure was due to human performance error.
This condition is being reported as an Operation or Condition Prohibited by Technical Specifications per 10 CFR
- 50. 73(a)(2)(i)(B).
EVENT DESCRIPTION
- 2. DOCKET NUMBER
- 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.
458 2023 004 00 River Bend Station (RBS) Technical Specification (TS) Limiting Condition of Operation (LCO) 3.3.3.1, Post Accident Monitoring (PAM) Instrumentation requires both Division I and Division II Drywall Post Accident Radiation Monitors to be Operable in Modes 1 and 2. If one Drywall Post Accident Radiation Monitor is declared Inoperable, LCO 3.3.3.1 Condition A is entered, and the monitor must be restored to Operable in 30 days.
On November 2, 2023, with RBS in Mode 4 and 0% power, personnel discovered an unrecognized surveillance failure (STP-511-4289 RMS-Primary Drywall Area Radiation Monitor, Channel Calibration RMS-RE20A) for the Division I Drywall Post Accident Radiation Monitor (RMS-RE20A) [IL] [MON] during a review of a previously performed work package. The monitor was declared Inoperable and LCO 3.3.3.1 Condition A was entered. The surveillance was performed with satisfactory results on November 2, 2023, and the monitor was declared Operable on November 12, 2023.
The unrecognized surveillance failure was identified during a review of the last performance of STP-511-4289 which was performed on February 28, 2023. It was determined that RMS-RE20A was left in an out of tolerance state and did not meet the requirements of the surveillance. Therefore, RMS-RE20A is considered Inoperable from February 28, 2023, until November 12, 2023.
LCO 3.3.3.1 is applicable in Modes 1 and 2. RBS was in Mode 4 on February 28, 2023, and did not exit Mode 4 until entering Mode 2 on June 15, 2023. RBS then went from Mode 2 to Mode 1 on June 16, 2023, and remained in Mode 1 until entering Mode 3 on October 29, 2023, for a planned outage. RBS did not enter an applicable Mode again until November 13, 2023, when Mode 2 was entered for start up to exit the planned outage. Therefore, RBS was Operating in a manner prohibited by TS from June 15, 2023, until October 29, 2023.
Prior to February 28, 2023, STP-511-4289 was last performed on March 11, 2021, with satisfactory results. Therefore, RMS-RE20A was Operable until the failed surveillance performed on February 28, 2023.
EVENT CAUSE
The casual evaluation investigation has determined that the event was caused by a human performance error while performing the surveillance on February 28, 2023. The RBS technician performing the surveillance did not identify and correct a parameter that was found out of tolerance.
SAFETY ASSESSMENT
The primary purpose of the PAM instrumentation is to display plant variables that provide information required by the control room operators during accident situations. This information provides the necessary support for the operator to take the manual actions for which no automatic control is provided and that are required for safety systems to accomplish their safety functions for Design Basis Events. RMS-RE20B provides redundant function capability to RMS RE20A and was Operable from February 28, 2023, to November 12, 2023. Therefore, safety function was maintained throughout the time RMS-RE20A was Inoperable and this event was of minimal significance to the health and safety of the public.
CORRECTIVE ACTIONS
Complete:
- 2. DOCKET NUMBER
- 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.
458 2023 004 00 There are 82 active radiation monitors at RBS. A random sample of 20 completed radiation monitor work orders were selected based on the monitor classification and the work order having data tables like the data tables found in STP-511-4289. Seven of these work orders were completed by the technician that made the error on STP-511-4289 in February.
No additional errors were identified during this review.
Planned:
Culpability review in accordance with station procedures.
Individual performance management and practices in accordance with station procedures Distribute lessons learned to station personnel.
PREVIOUS SIMILAR OCCURRENCES No previous similar occurrences identified.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX]. River Bend equipment codes are identified as (XX). Page _3_ of _3_