ML25129A077
| ML25129A077 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 05/13/2025 |
| From: | Douglas Dodson NRC/RGN-IV/DORS/PBC |
| To: | Kapellas B Entergy Operations |
| Smallwood A | |
| References | |
| IR 2025001 | |
| Download: ML25129A077 (1) | |
Text
May 13, 2025 Brad Kapellas, Site Vice President Entergy Operations, Inc.
Grand Gulf Nuclear Station P.O. Box 756 Port Gibson, MS 39150
SUBJECT:
GRAND GULF NUCLEAR STATION - INTEGRATED INSPECTION REPORT 05000416/2025001
Dear Brad Kapellas:
On March 31, 2025, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Grand Gulf Nuclear Station. On April 15, 2025, the NRC inspectors discussed the results of this inspection with you and other members of your staff. The results of this inspection are documented in the enclosed report.
One finding of very low safety significance (Green) is documented in this report. This finding involved a violation of NRC requirements. One Severity Level IV violation without an associated finding is documented in this report. We are treating these violations as non-cited violations (NCVs) consistent with Section 2.3.2 of the Enforcement Policy.
If you contest the violations or the significance or severity of the violations documented in this inspection report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN:
Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region IV; the Director, Office of Enforcement; and the NRC Resident Inspector at Grand Gulf Nuclear Station.
If you disagree with a cross-cutting aspect assignment in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region IV; and the NRC Resident Inspector at Grand Gulf Nuclear Station.
B. Kapellas 2
This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Douglas E. Dodson II, Chief Reactor Projects Branch C Division of Operating Reactor Safety Docket No. 05000416 License No. NPF-29
Enclosure:
As stated cc w/ encl: Distribution via LISTSERV Signed by Dodson, Douglas on 05/13/25
SUNSI Review By: DED
Non-Sensitive
Sensitive
Publicly Available
Non-Publicly Available OFFICE RI:DORS/PBC SRI:DORS/PBC C:DRSS/DIOR C:DORS/PBC NAME BPannabecker ASmallwood JJosey DDodson SIGNATURE
/RA/
/RA/
/RA/
/RA/
DATE 05/12/25 05/12/25 05/12/25 05/13/25
Enclosure U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Number:
05000416 License Number:
NPF-29 Report Number:
05000416/2025001 Enterprise Identifier:
I-2025-001-0005 Licensee:
Entergy Operations, Inc.
Facility:
Grand Gulf Nuclear Station Location:
Port Gibson, MS Inspection Dates:
January 1, 2025, to March 31, 2025 Inspectors:
L. Carson, Senior Health Physicist R. Kopriva, Senior Project Engineer J. O'Donnell, Senior Health Physicist B. Pannabecker, Resident Inspector A. Smallwood, Senior Resident Inspector P. Elkmann, Senior Emergency Preparedness Inspector Approved By:
Douglas E. Dodson II, Chief Reactor Projects Branch C Division of Operating Reactor Safety
2
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Grand Gulf Nuclear Station, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations Failure to Transfer Licensed Radioactive Material to an Authorized Licensee Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 05000416/2025001-01 Open/Closed Not Applicable 71124.01 The NRC identified a Severity Level IV non-cited violation of 10 CFR 30.3(a) associated with Grand Gulf Nuclear Stations transfer of their licensed byproduct material to the Entergy Central Calibration Facility. Specifically, the Central Calibration Facility was not authorized or licensed to receive, possess, own, or use the licensed radioactive material.
Failure to Correct a Condition Adverse to Quality for the High-Pressure Core Spray Over Frequency Relay Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000416/2025001-02 Open/Closed
[H.14] -
Conservative Bias 71153 The inspectors reviewed a self-revealed, Green finding and associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, which requires, in part, that measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances are promptly identified and corrected. Specifically, from July 2023 to September 2024, the licensee failed to correct three conditions adverse to quality associated with high-pressure core spray system over frequency relay reliability, as evidenced by surveillance issues in July 2023 and September 2024, which caused the high-pressure core spray system to be inoperable.
Additional Tracking Items None.
3 PLANT STATUS At the beginning of the inspection period, Grand Gulf Nuclear Station, Unit 1, was operating at 88 percent rated thermal power (RTP) at the request of the electric grid operators as a result of transmission line damage from storms in Mississippi that occurred on December 29, 2024. After repairs to power distribution lines were completed, the station achieved 100 percent RTP on January 4, 2025. On February 15, 2025, a reactor SCRAM was manually inserted by the operators, due to a loss of main condenser vacuum. The unit restarted on February 23, 2025, and achieved 100 percent RTP on February 27, 2025. A rod pattern adjustment resulted in a power reduction to 78 percent RTP and a subsequent return to 100 percent RTP on February 28, 2025. Reactor power was reduced to 91 percent RTP on March 23, 2025, to support control rod drive hydraulic control unit maintenance with a subsequent return to 100 percent RTP that same day. On March 29, 2025, a reduction in power to 69 percent RTP was conducted to support a rod pattern sequence exchange. On March 29, 2025, the unit returned to 100 percent RTP where it remained at or near for the rest of the inspection period.
INSPECTION SCOPES Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors performed activities described in IMC 2515, Appendix D, Plant Status, observed risk significant activities, and completed on-site portions of IPs. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY 71111.01 - Adverse Weather Protection Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated the adequacy of the overall preparations to protect risk significant systems from impending severe weather during a high wind advisory from the National Weather Service on March 3, 2025.
71111.04 - Equipment Alignment Partial Walkdown Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:
(1) standby service water division II following maintenance on February 6, 2025 (2) diesel generator division II following maintenance on February 25, 2025
4 71111.05 - Fire Protection Fire Area Walkdown and Inspection Sample (IP Section 03.01) (5 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a walkdown and performing a review to verify program compliance, equipment functionality, material condition, and operational readiness of the following fire areas:
(1) standby service water pump building division II, fire zone 2M110, following maintenance on February 6, 2025 (2) lower cable spreading room, fire zone OC402, 148' elevation of the control building on February 10, 2025 (3) auxiliary building to primary containment seals on elevations 166' and 185', fire zones 1A420 and 1A519, on February 16, 2025 (4) diesel generator room division II, fire zone 1D303, following maintenance on February 25, 2025 (5) engineered safety feature switchgear room, fire zone 1A308, following maintenance on February 27, 2025 71111.06 - Flood Protection Measures Flooding Sample (IP Section 03.01) (2 Samples)
(1)
The inspectors evaluated flooding mitigation protections in the manhole, MH-21, for safety-related cables and sump pump operation located near standby service water basins, as documented in work order (WO) 54156336.
(2)
The inspectors evaluated external flooding mitigation protections related to condition report (CR) GGN-2025-00410, which documents a sinkhole located adjacent to a design-basis flood drainage channel.
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01)
(1 Sample)
(1)
The inspectors observed and evaluated licensed operator performance in the control room during reactor startup preparations and control rod drive mechanism venting and operation verification on February 20, 2025.
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
(1)
The inspectors observed and evaluated licensed operator simulator scenarios on March 27, 2025.
5 71111.12 - Maintenance Effectiveness Maintenance Effectiveness (IP Section 03.01) (1 Sample)
The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:
(1)
RISC-3 categorization of and 10 CFR 50.69 screening for division II standby diesel generator components on February 7, 2025 71111.13 - Maintenance Risk Assessments and Emergent Work Control Risk Assessment and Management Sample (IP Section 03.01) (3 Samples)
The inspectors evaluated the accuracy and completeness of risk assessments for the following planned and emergent work activities to ensure configuration changes and appropriate work controls were addressed:
(1) standby service water division II and standby diesel generator division II maintenance on February 3, 2025 (2) engineered safety feature 11 transformer maintenance on March 19, 2025 (3) residual heat removal division I on March 26, 2025 71111.15 - Operability Determinations and Functionality Assessments Operability Determination or Functionality Assessment (IP Section 03.01) (5 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the following operability determinations and functionality assessments:
(1) standby service water pump division II pump seal leakage, CR-GGN-2025-00222, on January 16, 2025 (2) residual heat removal division II jockey pump issues related to system venting after maintenance, CR-GGN-2025-00249, on January 23, 2025 (3) standby service water valve, P41-F201B, division II standby diesel generator cooler vent packing leakage, CR-GGN-2025-00637, on February 10, 2025 (4) standby diesel generator division II shroud bolt installation, CR-GGN-2025-0995, on February 24, 2025 (5) auxiliary building roof membrane leakage, CR-GGN-2025-00883, on March 5, 2025 71111.18 - Plant Modifications Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02)
(1 Sample)
The inspectors evaluated the following temporary or permanent modifications:
(1) standby service water pump shaft run out, engineering change (EC) 79246, on February 5, 2025
6 71111.20 - Refueling and Other Outage Activities Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated available outage activities following the loss of condenser vacuum and loss of 16BB2 and 16BB4 load centers SCRAM on February 15, 2025.
71111.24 - Testing and Maintenance of Equipment Important to Risk The inspectors evaluated the following testing and maintenance activities to verify system operability and/or functionality:
Post-Maintenance Testing (PMT) (IP Section 03.01) (5 Samples)
(1) residual heat removal valve E12-F004B post-maintenance testing, WO 53034421, on January 17, 2025 (2) standby diesel generator division II crankshaft deflection and thrust measurements, WO 53029853, on February 19, 2025 (3) standby diesel generator division II hot adjustment of lifters, WO 53027366, on February 20, 2025 (4) transformer 16BB2 replacement thermography, WO 54133324, on March 18, 2025 (5)
SCRAM time testing for control rods after maintenance, WO 54189810, on March 29, 2025 Surveillance Testing (IP Section 03.01) (2 Samples)
(1) reactor core isolation cooling/residual heat removal steam line flow functional test channel B, WO 54200399, on January 8, 2025 (2) drywell purge system division I isolation valve E61-F005A monthly test, WO 53028242, on January 21, 2025 Inservice Testing (IST) (IP Section 03.01) (1 Sample)
(1) residual heat removal valve E12-F003B stroke time testing, WO 53034425, on January 17, 2025 Diverse and Flexible Coping Strategies (FLEX) Testing (IP Section 03.02) (1 Sample)
(1)
FLEX building No.1, portable generator test, WO 53028121, on January 14, 2025 71114.06 - Drill Evaluation Required Emergency Preparedness Drill (1 Sample)
(1) blue team emergency preparedness drill on March 4, 2025 71114.08 - Exercise Evaluation - Scenario Review Inspection Review (IP Section 02.01 - 02.04) (1 Sample)
The inspectors evaluated the licensee's preliminary scenario for the March 18, 2025, biennial emergency preparedness exercise, which was submitted January 16, 2025, to
7 determine whether the proposed scenario would provide adequate opportunities for the licensee's emergency preparedness organization to demonstrate the key emergency preparedness functions. The inspectors consulted with evaluators from the Federal Emergency Management Agency to determine whether the proposed scenario provided adequate opportunities for participating offsite emergency response organizations to achieve their evaluation objectives.
(1)
The inspectors reviewed and evaluated the proposed scenario for the 2025 biennial emergency plan exercise and communicated comments to the licensee on February 19, 2025, as required by Inspection Procedure 71114.08.
RADIATION SAFETY 71124.01 - Radiological Hazard Assessment and Exposure Controls Radiological Hazard Assessment (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated how the licensee identifies the magnitude and extent of radiation levels and the concentrations and quantities of radioactive materials and how the licensee assesses radiological hazards.
Instructions to Workers (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated how the licensee instructs workers on plant-related radiological hazards and the radiation protection requirements intended to protect workers from those hazards.
Contamination and Radioactive Material Control (IP Section 03.03) (2 Samples)
The inspectors observed/evaluated the following licensee processes for monitoring and controlling contamination and radioactive material:
(1) surveys of potentially contaminated material leaving the radiologically controlled area (RCA)
(2) workers exiting the RCA during routine plant operations Radiological Hazards Control and Work Coverage (IP Section 03.04) (5 Samples)
The inspectors evaluated the licensee's control of radiological hazards for the following radiological work:
(1) condensate full-flow filter - B filter changes out and support work, radiological work permit (RWP) 2025-1099 Task-1, Revision 01, Radiation Area (RA)
(2) condensate full-flow filter - B filter changes out and support work, RWP 2025-1099 Task-6, Revision 01, High Radiation Area (HRA) and Locked High Radiation Area (LHRA)
(3) low-pressure feed water heater helium leak investigation, RWP 2025-1054 Task-6 (4)
Shepherd calibration source vendor repair, RWP 2024-1052 (5) general tours and inspection, RWP 2025-1005
8 High Radiation Area and Very High Radiation Area Controls (IP Section 03.05) (5 Samples)
The inspectors evaluated licensee controls of the following HRAs and very high radiation areas:
(1)
HRA - pre-coat filter room on the 133-foot elevation area-5 of the turbine building (2)
HRA - condenser area-6 of the turbine building 93-foot elevation (3)
HRA - offgas recombiner and reheater room on the 93-foot elevation area-1 of the auxiliary building (4)
HRA - pipe chase/tunnel room on the 87-foot elevation area-1 of the auxiliary building (5)
HRA - condenser retubing area on the 87-foot elevation area-1 of the turbine building Radiation Worker Performance and Radiation Protection Technician Proficiency (IP Section 03.06) (1 Sample)
(1)
The inspectors evaluated radiation worker and radiation protection technician performance as it pertains to radiation protection requirements.
71124.04 - Occupational Dose Assessment Source Term Characterization (IP Section 03.01) (1 Sample)
(1)
The inspectors evaluated licensee performance as it pertains to radioactive source term characterization.
External Dosimetry (IP Section 03.02) (1 Sample)
(1)
The inspectors evaluated how the licensee processes, stores, and uses external dosimetry.
Internal Dosimetry (IP Section 03.03) (2 Samples)
The inspectors evaluated the following internal dose assessments:
(1) containment worker intake (inhalation) on March 6, and 10, 2024 (2) condenser bay worker intake (ingestion) on March 24, 2024 Special Dosimetric Situations (IP Section 03.04) (1 Sample)
The inspectors evaluated the following special dosimetric situations:
(1) three declared pregnant worker evaluations
9 OTHER ACTIVITIES - BASELINE 71151 - Performance Indicator Verification The inspectors verified licensee performance indicator submittals listed below:
IE01: Unplanned Scrams per 7000 Critical Hours Sample (IP Section 02.01) (1 Sample)
(1)
January 1 through December 31, 2024 BI01: Reactor Coolant System (RCS) Specific Activity Sample (IP Section 02.10) (1 Sample)
(1)
January 1 through December 31, 2024 BI02: RCS Leak Rate Sample (IP Section 02.11) (1 Sample)
(1)
January 1 through December 31, 2024 OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
(1)
January 1 through December 31, 2024 PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual Radiological Effluent Occurrences (RETS/ODCM) Radiological Effluent Occurrences Sample (IP Section 02.16) (1 Sample)
(1)
January 1 through December 31, 2024 71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02) (1 Sample)
The inspectors evaluated the following licensee event reports (LERs):
(1)
LER 05000416/2024-004-00, High Pressure Core Spray Over Frequency Relay Trip (ML24326A363). The circumstances surrounding this LER and a Green, non-cited violation are documented in the Inspection Results section of this report. This LER is closed.
INSPECTION RESULTS Failure to Transfer Licensed Radioactive Material to an Authorized Licensee Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 05000416/2025001-01 Open/Closed Not Applicable 71124.01 The NRC identified a Severity Level IV non-cited violation of 10 CFR 30.3(a) associated with Grand Gulf Nuclear Stations transfer of their licensed byproduct material to the Entergy Central Calibration Facility. Specifically, the Central Calibration Facility was not authorized or licensed to receive, possess, own, or use the licensed radioactive material.
10
==
Description:==
From approximately calendar year 2000, Entergy Corporation, the parent company of the Grand Gulf Nuclear Station, assumed operation of the radiation instrument Central Calibration Facility adjacent to the Grand Gulf Nuclear Station. The Central Calibration Facility performs calibrations for the Entergy fleet sites: Arkansas Nuclear One, Grand Gulf Nuclear Station, River Bend Station, and Waterford-3. Based on an internal audit, between November 2021 and October 2023, the Central Calibration Facility performed 58 portable instrument calibrations for the four Entergy fleet sites.
In January 2025, inspectors reviewed the Central Calibration Facility's Radioactive Source Inventory List and noted that at least 15 radioactive sources, listed as "licensed," required a specific license to possess and were housed at the Central Calibration Facility for the purpose of instrument calibrations. Inspectors determined that all 15 of these inventoried radioactive sources were transferred from the Grand Gulf Nuclear Station to the Central Calibration Facility and were not being inventoried under the Grand Gulf Nuclear Station, Unit 1, license (NPF-29).
Inspectors determined that the Central Calibration Facility is operated in accordance with Entergy fleet Procedures EN-RP-317, Central Calibration Facility, Revision 2, and EN-FAP-RP-007, Operation of the [Radiation Protection] RP Central Calibration Facility, Revision 3. Both fleet procedures state that the Entergy Fleet Radiation Protection Manager is responsible for the overall implementation of this program. Both procedures also state that each Entergy sites RP Manager is responsible for returning instruments to the Central Calibration Facility for calibration. Based on this, inspectors determined that the Central Calibration Facility staff responsible for access and control of the transferred radioactive sources stationed at the Central Calibration Facility do not fall within the organizational structure of the Grand Gulf Nuclear Station license.
Inspectors questioned under what license the Central Calibration Facility was operating. Per the licensees response to NRC questions, the licensee assumed the Central Calibration Facility was part of their operating license since the facility is located within the owner control area of the site.
The inspectors concluded that the transfer of licensed radioactive material to the Central Calibration Facility from the GGNS was not done in accordance with NRC regulations.
Specifically, Grand Gulf Nuclear Station had inappropriately transferred byproduct material, which required a specific license to possess, to an unlicensed entity.
Corrective Actions: The licensee reviewed their Quality Assurance Program Manual to determine what changes in organizational structure have occurred, if any, and what changes are required to bring the licensed radioactive material back into the control of the NRC licensee, Grand Gulf Nuclear Station.
Corrective Action
References:
CR-GGN-2024-06745, CR-HQN-2024-01270, and CR-GGN-2025-01218 Performance Assessment: The NRC determined this violation was associated with a minor ROP performance deficiency and is best assessed using traditional enforcement.
Enforcement: The ROPs significance determination process does not specifically consider the regulatory process impact in its assessment of licensee performance. Therefore, it is necessary to address this violation which impedes the NRCs ability to regulate using traditional enforcement to adequately deter non-compliance.
11 Severity: This issue was determined to be a Severity Level IV, non-cited violation, consistent with NRCs Enforcement Policy, dated August 23, 2024, as informed by materials operations example 6.3.d.9, in which a licensee fails to seek NRC approval, when required, before changing the location where licensed activities are being conducted or where licensed material is being stored that has little or no radiological or programmatic significance, and all other safety and security requirements have been met. In this case, the inspectors determined that the Central Calibration Facility had appropriate security measures in place for the transferred licensed byproduct material stored in the facility.
Violation: Title 10 CFR 30.3(a) states, in part, no person shall manufacture, produce, transfer, receive, acquire, own, possess, or use byproduct material except as authorized in a specific or general license issued in accordance with the regulations in this chapter.
Contrary to the above, from calendar year 2000 through January 2025, the Grand Gulf Nuclear Station transferred byproduct material without authorization in a specific or general license. Specifically, NRC inspectors determined that the licensee, Grand Gulf Nuclear Station, had transferred byproduct material to the Entergy Fleet Central Calibration Facility in calendar year 2000. This calibration facility was not authorized to receive, possess, own or use byproduct material because they did not possess a specific or general license.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Failure to Correct a Condition Adverse to Quality for the High-Pressure Core Spray Over Frequency Relay Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000416/2025001-02 Open/Closed
[H.14] -
Conservative Bias 71153 The inspectors reviewed a self-revealed, Green finding and associated non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, which requires, in part, that measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances are promptly identified and corrected. Specifically, from July 2023 to September 2024, the licensee failed to correct three conditions adverse to quality associated with high-pressure core spray system over frequency relay reliability, as evidenced by surveillance issues in July 2023 and September 2024, which caused the high-pressure core spray system to be inoperable.
==
Description:==
On June 28, 2023, during a division III planned maintenance outage, the 17AC-181, high-pressure core spray (HPCS) pump over frequency trip relay (the relay), was found to be out of calibration and would not calibrate, as documented in CR-GGN-2023-14155. The relay was replaced with a new relay taken from on-site stores.
The new relay was calibrated with the previously installed capacitor from the failed relay.
On July 1, 2023, during surveillance testing of the system with the new relay, the HPCS pump tripped on over frequency. The licensee performed troubleshooting of the 17AC-181 relay, removed it from the bus, and calibrated the relay. The licensee determined the trip time was drifting and the relay was unable to be calibrated. This issue was repeatable, and the licensee determined it indicated a nonconforming part or a gap in the procedure instructions.
12 The licensee initially proposed the cause of the failure as infant mortality and sent the failed relay and its associated capacitor for analysis to determine if a degraded condition was present.
A new relay and capacitor set was received from another station and was calibrated in accordance with Grand Gulf Nuclear Station procedure. The calibration was successful; however, the licensee determined that the originally installed capacitor could not be removed from the system without risk of loss of power to the division III electrical bus due to current plant configuration. This led to the licensees decision to install the new calibrated relay with the already installed original capacitor. The licensee documented this in CR-GGN-2023-14202, which states, to prevent risk associated with losing the 17 bus and to exit the [limiting condition for operation (LCO)] in a timely manner, the original capacitor was used with the new relay. The HPCS pump tripped again on over frequency during subsequent testing.
The inspectors noted the vendor manual states that when external capacitors are furnished with their over frequency relays, they are identified by means of serial numbers to ensure that each relay that is to be installed is provided with the same auxiliaries with which it was calibrated in the factory. This means that, if the relays are calibrated on-site, they should be installed with the same capacitor with which they were calibrated.
On July 2, 2023, the licensee made the decision to re-install the original relay (the relay that would not calibrate) with the original capacitor (the capacitor that remained in the division III bus). The intent of the decision was to prevent the pump trip even though the relay would be out of tolerance on time delay (failed the trip time requirement of 1.25 +/- 0.09 seconds with a trip time of 20.12 seconds). The licensee performed an operability determination in CR-GGN-2023-14202 to justify this decision and assumed that the pump would start and run at a higher frequency.
On September 24, 2024, during division III loss of offsite power/loss of coolant accident (LOP/LOCA) testing, the HPCS pump tripped, as documented in CR-GGN-2024-05318. The trip occurred at 62.4 Hz, below the setpoint of 63 Hz +/- 0.5 Hz. CR-GGN-2024-05335 documents the physical condition of the 17AC-181 over frequency trip relay noting: 1) one of the coils had evidence of insulation distortion that indicated a potential for coil overheating with smells indicating that overheating occurred, 2) the timing cam spring had evidence of discoloration, 3) the timing cam backstop bar was not seating properly, 4) the cam initiation trip contact showed evidence the cam was out of time, and 5) when bench testing the relay, tapping on the bench caused the relay to trip. A new relay and matching capacitor were then installed for the 17AC-181 relay and the LOP/LOCA surveillance was again performed on September 27, 2024, with the HPCS pump running successfully powered from the division III electrical bus being supplied with power from the standby diesel generator division III.
Post-event, the capacitor was tested in accordance with recommendations from the Electric Power Research Institute (EPRI), and it failed three out of four test parameters. It failed capacitance, dielectric absorption, and leakage current. Failure analysis by the vendor determined the shelf life state of the relay was not in accordance with vendor specifications, specifically the relay may revert to a tripped state in a deenergized condition.
The licensee performed a root cause evaluation and determined the direct cause of failure was due to age related degradation of the relay, capacitor, or both. The relay had been in service for over 35 years. EPRI guidance recommends replacement of this type of relay at 8
13 years to prevent age related failures. Additionally, the licensee determined the root cause was due to having an unnecessary over frequency relay in the HPCS system, and the licensee identified multiple other contributing causes: not testing the capacitor supplied with the original relay, incorrect calibration and installation of the relay (not a matching pair), and not replacing a relay that was at least 35 years old.
The inspectors noted that during evaluation of this deficient condition in July 2023, the licensee did not recognize that degradation of the time delay mechanism springs and contacts could lead to an instantaneous trip of the relay causing a loss of safety function.
Specifically, the inspectors noted that the quarterly surveillance procedure for the HPCS pump, Procedure 06-OP-1E22-Q-0005, HPCS Quarterly Functional Test, Revision 136, is conducted using offsite power aligned to the division III bus. During the test, offsite power is at a stable 60 Hz and would not cause the over frequency relay to begin its timing or initiate its trip function. However, during LOP/LOCA surveillance testing using Procedure 06-OP-1P81-R-0001, HPCS Diesel Generator Function Test, Test No. 2 - LOP and LOCA Safety Related, Revision 139, as was the case in September 2024 when the 17AC-181 relay tripped instantaneously, the division III bus is deenergized and the division III standby diesel generator rapidly starts to supply power to the division III electrical bus and HPCS pump. A rapid start of the standby diesel generator during simulated LOP/LOCA conditions will cause an electrical bus transient that tests the functionality of the over frequency relay.
Considering all of the above, the inspectors assessed that the licensees operability evaluation and decision-making to re-install the original degraded relay that could not be calibrated was not justifiable and demonstrated inadequate decision-making. Additionally, the degraded and nonconforming relay had been installed for at least 35 years, and condition monitoring revealed degradation in July 2023, but the licensee reinstalled the original relay and failed to take appropriate action. Finally, the licensee failed to calibrate, install, and test the relay and external capacitor as a matched pair in July 2023.
The inspectors noted that Technical Specification 3.5.1 requires each emergency core cooling system injection/spray subsystem, which includes HPCS, to be operable in MODES 1, 2, and 3. If HPCS is inoperable in MODES 1, 2, or 3, Technical Specification 3.5.1, Condition B requires reactor core isolation cooling (RCIC) to be verified operable within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and HPCS restored to operable within 14 days or the allowable risk informed completion time. If these actions are not completed, the reactor must be in MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Considering the licensee inappropriately determined the HCPS pump was operable in July 2023 when it would have tripped instantly on LOP/LOCA, preventing it from meeting its intended safety function to inject water, this represents a condition prohibited by technical specifications.
Corrective Actions: The licensee corrected the equipment issue on September 29, 2024, by completing WO 53019672 and replacing the failed relay and installing a matching capacitor.
Post-maintenance testing conducted as part of WO 53019672 confirmed system operability was restored.
Corrective Action
References:
This issue was entered into the licensees corrective action program as Condition Report CR-GGN-2024-05318.
14 Performance Assessment:
Performance Deficiency: The licensee failed to adequately evaluate and correct conditions adverse to quality in accordance with 10 CFR 50, Appendix B, Criterion XVI, Corrective Action, associated with the HPCS motor over frequency relay, which led to the HPCS pump failing surveillances in July 2023 and September 2024. Specifically, in July 2023 the licensee failed to identify and correct conditions adverse to quality associated with the over frequency relay: (1) the degraded and nonconforming relay had been installed for at least 35 years, which was well past its expected service life of 8 years per EPRI guidance, and condition monitoring revealed degradation in July 2023, but the licensee reinstalled the original relay and failed to take appropriate action; (2) the relay needed to be calibrated and installed with a matched external capacitor, but the licensee failed to calibrate, install, and test the relay and external capacitor as a matched pair in July 2023; and (3) when the relay failed on time delay, the licensee evaluated the relay as operable and failed to recognize the relay degradation could cause the HPCS over frequency relay to trip instantaneously. As a result, the licensee placed the relay back in service in July 2023 and it tripped instantaneously during surveillance testing in September 2024.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Human Performance attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, failing to ensure the operability of the HPCS over frequency relay caused the system to be inoperable from July 2, 2023, through September 24, 2024.
Significance: The inspectors assessed the significance of the finding using IMC 0609, Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined that a detailed risk evaluation was required for this finding because the finding involved the loss of a single-train technical specification system longer than its technical specification allowed outage time. A senior reactor analyst performed a detailed risk evaluation using SPAR model version 8.82 with SAPHIRE version 8.2.11. The analyst determined that the performance deficiency resulted in a degraded condition that caused the HPCS system to be unavailable to perform its required safety function if powered from the division III diesel generator in the event of a LOP. Based on the performance and maintenance history associated with the 17AC-181 relay described above, the analyst determined that an exposure time of 1 year would be applicable. While the degraded condition of the relay precluded successful operation of the HPCS system in the event of a LOP, the analyst evaluated whether a subsequent manual start of the HPCS system powered from the division III diesel generator would have been possible. The analyst reviewed licensee operations procedures and determined that, given an initial trip of the system generated by the degraded 17AC-181 relay, subsequent manual operation of the system would be achievable during a design-basis event involving a LOP. Accordingly, the analyst determined that a recovery action to restore the HPCS function following a LOP condition using procedural operator actions would be applicable with a failure probability of 3E-2 in the conditional risk case. The analyst modified the fault tree HCS-ACT (HPCS Actuation and Control) to include a loss of power to the 17ac bus as being a failure mode for HPCS in the conditional case, with this recovery action available to preclude that failure mode. The analyst also set the basic event FLX-XHE-XE-ELAP (Operators Fail to Declare ELAP When Beneficial) to a failure probability of 1E-2 to reflect credit for the use of diverse and flexible
15 (FLEX) coping strategies. With these assumptions, the analyst quantified the SPAR model for all internal and external events except fire events to determine a total increase in average annual core damage frequency (delta-CDF) of 3.96E-7/yr. Dominant sequences included:
station blackout events with failure of HPCS and either RCIC or FLEX, as well as LOP events with failures of HPCS, reactor core isolation cooling, control rod drives, and failure of manual depressurization. The analyst determined that best available information to estimate the applicable increase in risk due to fire events would be based on the analysts review of results from the licensees fire probabilistic risk assessment model. Based on this review, the analyst determined that a delta-CDF of 5.08E-9/yr due to fire events would be applicable. The analyst determined that risk attributable to large early release frequency was not a dominant metric in the significance determination for this finding. Based on a total delta-CDF of 4.01E-7/yr, the analyst concluded that the finding was of very low safety significance (Green).
Cross-Cutting Aspect: H.14 - Conservative Bias: Individuals use decision-making practices that emphasize prudent choices over those that are simply allowable. The proposed action is determined to be safe to proceed, rather than unsafe to stop. Specifically, managers did not take timely action to address degraded HPCS conditions commensurate with their safety significance and ensure that conservative assumptions were used when determining how to proceed when degraded HPCS conditions were identified by the licensee.
Enforcement:
Violation: Title 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, requires, in part, that measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformance's are promptly identified and corrected.
Technical Specification 3.5.1, Emergency Core Cooling Systems (ECCS) and Reactor Core Isolation Cooling (RCIC) System, requires, in part, that each ECCS injection/spray subsystem is operable in MODES 1, 2, and 3. If HPCS is inoperable, Condition B requires RCIC to be verified operable by administrative means within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and HPCS restored to operable within 14 days or the allowable risk informed completion time. If required action and associated completion time of Condition B is not met, the reactor must be in MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
Contrary to the above, between July 2023 and September 2024, measures were not established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances were promptly identified and corrected. Specifically, between July 2023 and September 2024, the licensee failed to correct three conditions adverse to quality that caused HPCS and its over frequency relay to be inoperable and the over frequency relay tripped during surveillances in July 2023 and September 2024. This also represents a condition prohibited by Technical Specification 3.5.1.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS The inspectors verified no proprietary information was retained or documented in this report:
16 On March 11, 2025, the inspectors presented the occupational radiation safety inspection results to Brad Kapellas, Site Vice President, and other members of the licensee staff.
On March 24, 2025, the inspectors presented the emergency preparedness exercise scenario review inspection results to Jason Richardson, General Manager Plant Operations, and other members of the licensee staff.
On April 15, 2025, the inspectors presented the integrated inspection results to Brad Kapellas, Site Vice President, and other members of the licensee staff.
17 DOCUMENTS REVIEWED Inspection Procedure Type Designation Description or Title Revision or Date Corrective Action Documents CR-GGN-YYYY-NNNNN 2025-00624, 2025-00785, 2025-00883, 2025-00985, 2025-00995 04-1-01-R21-16 System Operation Instruction ESF Bus 16AB 36 07-S-22-P75-E001B-1 Standby Diesel Generator Slip Ring/Brush Inspection and Generator/Roto Megger Test 6
EN-OP-129 Operations Equipment Labeling 3
Procedures GGNA-GES-01 General Engineering Standard for A Total Plant Marking System 7
71111.04 Work Orders WO 53027323 71111.05 Corrective Action Documents CR-GGN-YYYY-NNNNN 2025-00659, 2025-00884, 2025-00930 Corrective Action Documents CR-GGN-YYYY-NNNNN 2025-00410 71111.06 Work Orders WO 54156336 71111.11Q Corrective Action Documents CR-GGN-YYYY-NNNNN 2025-00935, 2025-00936 Calculations ENTG-GGNS-00176-CALC-007 GGNS 10 CFR 50.59 Categorization for the DG System 0
71111.12 Procedures EN-OP-140 Risk Informed Completion Time 1
71111.13 Corrective Action Documents CR-GGN-YYYY-NNNNN 2025-00553, 2025-01320, 2025-01504, Corrective Action Documents CR-GGN-YYYY-NNNNN 2025-00222, 2025-00249, 2025-00637, 2025-00883, 2025-0995 71111.15 Engineering EC 79246
18 Inspection Procedure Type Designation Description or Title Revision or Date Changes 71111.18 Engineering Changes EC-79246 71111.20 Procedures EN-OP-115 Conduct of Operations 34 71111.24 Work Orders WO 53018121, 53022842, 53027366, 53029853, 53034421, 53034425, 54133324, 54189810, 54200399, 54221596, 54243516 Corrective Action Documents CR-GGN-2025-01364, GGN-2025-01382 Condition Reports generated during the Inspection February 22, 2023, Dress Rehearsal Exercise Evaluation Report GIN 2023-000059 EOF Mini Drill Critique GIN 2023-000115 26July2023 Blue Team Exercise Critique GIN 2023-00096 First Half Semi-Annual Health Physics Drill Report GIN 2023-00140 13Sep2023 Red Team Exercise Critique GIN 2023-00155 25Oct2023 Green Team Exercise Critique GIN 2024-00010 2023 GGNS Onsite Accountability Drill GIN 2024-00014 Second Half 2023 Semi-Annual Health Physics Drill GIN 2024-00128 28Aug2024 Yellow-Red Team Turnover Drill GIN 2025-00005 3Dec2024 Onsite Medical Drill with CC Medical Center and ASAP Ambulance GIN 2025-00009 20Dec2024 2024 Radiological Monitoring Drill GIN 2025-00010 18Dec2024 Second Half 2024 Semi-Annual Health Physics Drill GIN 2025-00010 6Jun2024 First Half Semi-Annual Health Physics Drills 71114.01 Miscellaneous GIN 2025-0004 12Dec2024 2024 Onsite Accountability Drill
19 Inspection Procedure Type Designation Description or Title Revision or Date 05-S-02-VI-3 Off Normal Event Procedure, Earthquake 10-S-01-1 Activation of the Emergency Plan, R133, 10/27/2020 10-S-01-12 Radiological Assessment and Protective Action Recommendations, R50, 11/28/2022 10-S-01-14 Emergency Radiation Monitoring, R26, 5/19/2019 EN-EP-306 Drills and Exercises, R11, 2/10/2022 EN-EP-313 Offsite Dose Assessment using the Unified RASCAL Interface, R4, 4/22/2020 EN-EP-603 Emergency Notifications, R1, 12/15/2021 EN-EP-609 Emergency Operations Facility Operations, R7, 05/01/2023 EN-EP-610 Technical Support Center Operations, R8, 05/01/2023 EN-EP-611 Operations Support Center Operations, R8, 05/01/2023 EPP 01-02 Grand Gulf Nuclear Station, Emergency Action Levels Wall Chart, Revision A Procedures GIN 2022-00195 Grand Gulf Nuclear Station, Emergency Action Level Technical Bases, R3 71114.04 Miscellaneous List of Changes to the Licensee Emergency Plan and Emergency Plan Implementing Procedures, June 1, 2024, to March 1, 2025 71114.06 Corrective Action Documents CR-GGN-YYYY-NNNNN 2025-01151, 2025-01152, 2025-01153, 2025-01154, 2025-01155, 2025-01156, 2025-01158, 2025-01159, 2025-01160 GGNS Scenario HH2_R1-12-21 Grand Gulf Nuclear Station, EAL Technical Bases 3
71114.08 Miscellaneous 2021-3-16_GGNS_IPX_Exercise Grand Gulf Nuclear Station #2021-3-16 Emergency Preparedness Ingestion
20 Inspection Procedure Type Designation Description or Title Revision or Date Pathway Exercise Scenario GGNS-NRC-01 Draft Scenario for the March 18, 2025, Biennial Exercise GGNS_2023_03_22_NRC_EXERCISE 2023 Emergency Preparedness Site Integrated Drill Scenario 05-S-01-EP-2M1-3 RPV Control Modes 1-3 0
05-S-01-SAP-1M1-4 RPV Control Modes 1-4 0
Procedures 10-S-01-12 Radiological Assessment and Protective Action Recommendations 50 RWP 2024-1301 ALARA Plan 01/21/2023 RWP 2024-1402 RWP Termination and Post-Job ALARA Review 04/10/2024 ALARA Plans RWP 2024-1403 RWP Termination and Post-Job ALARA Review 05/23/2024 Corrective Action Documents CR-GGN 2024-01870, 2024-01885, 2024-02048, 2024-02085, 2024-02641, 2024-02756, 2024-03181, 2024-03757, 2024-03764, 2024-04959, 2024-06107, 2024-06412, 2025-00514 Corrective Action Documents Resulting from Inspection CR-GGN 2025-00556, 2025-01218 Refueling Outage 23 Outage ALARA Report February 26, 2022, to May 2, 2022 08/09/2022 208' Aux Pool Inventory Status Board for 208' Auxiliary Building Pools 02/15/2024 EN-RP-143, Attachment 5 Central Facility Source Inventory 01/13/2025 EN-RP-143, Attachment 5 Central Facility Source Inventory 01/09/2024 EN-RP-143, Attachments 4 & 5 GGNS Leak Test & Source Inventory 11/14/2023 EN-RP-143, Attachments 4 & 5 GGNS Leak Test & Source Inventory 11/11/2024 71124.01 Miscellaneous GIN-2014-00024 2013 National Source Tracking System Reconciliation for NRC License NFP-29 01/29/2014
21 Inspection Procedure Type Designation Description or Title Revision or Date QAPM Entergy Quality Assurance Program Manual 46 RF24 Refueling Outage 24 Outage ALARA Report 04/18/2024 UCP-2501 Containment Pools Cycle 25 02/06/2025 08-S-01-28 Use and Control of Temporary Shielding 13 EN-RP-100 Radiation Worker Expectations 14 EN-RP-101 Access Control for Radiologically Controlled Areas 17 EN-RP-106 Radiological Survey Documentation 8
EN-RP-106-1 Radiological Survey Guidelines 8
EN-RP-108 Radiation Protection Posting 23 EN-RP-110 ALARA Program 14 EN-RP-110 ALARA Program 14 EN-RP-110-04 Radiation Protection Risk Assessment Process 8
EN-RP-110-06 Outage Dose Estimating and Tracking 1
EN-RP-121 Radioactive Material Control 19 EN-RP-121-01 Receipt of Radioactive Material 7
EN-RP-123 Radiological Controls for Highly Radioactive Objects 1
EN-RP-131 Air Sampling 18 Procedures EN-RP-152 Conduct of Radiation Protection 9
GGN-2411-00345 Hot Tool Room Area. Elevation 133 U2 RCA 11/19/2024 GGN-2502-00038 Turbine Building Elevation 166 North Section with CFFF-B Removal HRA and LHRA dose rates 02/04/2025 Radiation Surveys GGN-2502-00049 Turbine Building Elevation 166 North Section 02/05/2025 2024-1052 Shepherd Calibration Source Vendor Repair 0
Radiation Work Permits (RWPs) 2024-1301 Planned or Forced Outage-PM's, RT's, Surveillances, Tours, Inspection, and 0
22 Inspection Procedure Type Designation Description or Title Revision or Date General Maintenance in the Drywell 2024-1403 Reactor Vessel Disassembly and Reassembly 2
2025-1002 Ops Rounds, Surveillances, Tagouts, and Tours 0
2025-1004 General Maintenance Activities and Support Work 0
2025-1005 Tours and Inspections 0
2025-1006 Radwaste Shipping and Processing 0
2025-1099 Condensate Full-Flow Filter (CFFF) - B Filter change out and support work 1
Self-Assessments LO-GLO-2023-0100 Pre-NRC Inspection Self-Assessment 71124.01 11/13/2024 WO-53013938 Main Steam Line Monitor Calibration and Shephard Calibrator Failure 05/21/2024 WO-54144046 Main Steam Line Monitor - D Calibration 01/22/2025 Work Orders WO-54153614 Condensate Full-Flow Filter (CFFF) - B Filter change out and support work 02/06/2025 2024 WBC Long Calibration of the Mirion FASTSCAN Whole Body Counting System 07/09/2024 Calibration Records 2024 WBC New Calibration of the Mirion FASTSCAN Whole Body Counting System 07/12/2024 Corrective Action Documents CR-GGN-2023-16603, 2023-17118, 2024-01223, 2024-01743, 2024-02094, 2024-02386, 2024-02530, 2024-04184, 2024-04321, 2024-05883 Certificate No. L24-761 Certificate of Accreditation for Teledyne Brown Engineering for Chemical and Environmental Testing 10/05/2024 EN-RPT-19-003-R0 Standardization of a Bias Between DLRs and SRDs in the Entergy Fleet:
Update Based on 2018 Results 10/25/2019 71124.04 Miscellaneous FCBT-GET-RWT Generic Radiation Worker Training Lesson Plan, Section 3.23 07/23/2020
23 Inspection Procedure Type Designation Description or Title Revision or Date GGN-RPT-19-010-R0 Prospective Evaluation for Grand Gulf Nuclear Station 08/25/2020 GGN-RPT-21-002R0 Neutron Monitoring at Grand Gulf Nuclear Station 08/19/2021 GGN-RPT-23-002 R0 Grand Gulf Nuclear Station Alpha / Plant Characterization Data 11/08/2023 GIN-2024-00064 2024-2026 10CFR61 Waste Stream Analysis for Dry Active Waste 05/08/2024 NVLAP Lab Code: 100518-0 Scope of Accreditation to ISO/IEC 17025:2017 12/31/2024 NVLAP Lab Code: 100518-0 Certificate of Accreditation to ISO/IEC 17025:2017 12/31/2023 EN-RP-131 Air Sampling 18 EN-RP-201 Dosimetry Administration 5
EN-RP-202 Personnel Monitoring 17 EN-RP-203 Dose Assessment 10 EN-RP-205 Prenatal Monitoring 6
Procedures EN-RP-208 Whole Body Counting / In-Vitro Bioassay 7
Radiation Surveys GGN-2402-00097 Annual Dosimetry Office 02/08/2024 LO-GGN-2023-00101 Pre-NRC Inspection Occupational Dose Assessment IP 71124.04 11/17/2024 Self-Assessments QA-14/15-2023-GGNS-01 Quality Assurance Audit Report:
Combined Radiation Protection (RP) and Radwaste (RW) 12/11/2023 CR-GGN-YYYY-NNNNN 2024-05221, 2024-06703 Corrective Action Documents CR-GGN-2025-01375 Condition Report generated during the Inspection 2nd Qtr EOF 04/10/2024 - Scenario Documents 2nd Qtr EOF 05/01/2024 - Scenario Documents 71151 Miscellaneous 3rd Qtr EOF 11/30/2023 (Date for previous training, but ERO member
24 Inspection Procedure Type Designation Description or Title Revision or Date credited once qualified) - Scenario Documents 3rd Qtr EOF 05/22/2023 (Date for previous training, but ERO member credited once qualified) - Scenario Documents 1st Qtr 2025 SM/SIM (01/15/2025) -
Scenario Documents 1st Qtr 2025 SM/SIM (02/05/2025) -
Scenario Documents 4th Qtr. PI Data Sheet Occupational Radiation Safety Occupational Exposure Control Effectiveness 01/08/25 4th Qtr. PI Data Sheet Public Radiation Safety RETS/ODCM Radiological Effluent Occurrence 01/25/25 Grand Gulf Emergency Response Organization Pool and Minimum Staff Positions 10-S-01-12 Radiological Assessment and Protective Action Recommendations, R50 11/28/2022 EN-EP-306 Drills and Exercises, R11 02/10/2022 EN-EP-313 Offsite Dose Assessment using the Unified RASCAL Interface, R4 04/22/2020 EN-EP-603 Emergency Notifications, R1 12/15/2021 EN-LI-114 Regulatory Performance Indicator Process, R21 05/30/2023 EN-LI-114 Regulatory Performance Indicator Process 21 EP 01-02 Grand Gulf Nuclear Station, Emergency Action Levels Wallchart, Revision A Procedures GIN 2022-00196 Grand Gulf Nuclear Station, Emergency Action Level Technical Bases, R3