IR 05000317/2021003

Integrated Inspection Report 05000317/2021003 and 05000318/2021003

ML21312A398
Person / Time
Site:	Calvert Cliffs
Issue date:	11/09/2021
From:	Matt Young Division of Operating Reactors
To:	Rhoades D Exelon Generation Co LLC, Exelon Nuclear
Young M
References
IR 2021003
Download: ML21312A398 (20)

Text

November 9, 2021

SUBJECT:

CALVERT CLIFFS NUCLEAR POWER PLANT, UNITS 1 AND 2 -

INTEGRATED INSPECTION REPORT 05000317/2021003 AND 05000318/2021003

Dear Mr. Rhoades:

On September 30, 2021, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Calvert Cliffs Nuclear Power Plant, Units 1 and 2. On October 20, 2021, the NRC inspectors discussed the results of this inspection with Mr. Thomas Haaf, Site Vice President 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 did not involve a violation of NRC requirements.

If you disagree with a finding not associated with a regulatory requirement 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 I; and the NRC Resident Inspector at Calvert Cliffs Nuclear Power Plant, Units 1 and 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, Matt R. Young, Chief Projects Branch 5 Division of Operating Reactor Safety

Docket Nos. 05000317 and 05000318 License Nos. DPR-53 and DPR-69

Enclosure:

As stated

Inspection Report

Docket Numbers:

05000317 and 05000318

License Numbers:

DPR-53 and DPR-69

Report Numbers:

05000317/2021003 and 05000318/2021003

Licensee:

Exelon Generation Company, LLC

Facility:

Calvert Cliffs Nuclear Power Plant, Units 1 and 2

Location:

Lusby, MD

Inspection Dates:

July 1, 2021 to September 30, 2021

Inspectors:

H. Anagnostopoulos, Senior Health Physicist

K. Chambliss, Resident Inspector

R. Clagg, Senior Resident Inspector

J. DeBoer, Sr Emergency Preparedness Inspector

D. Kern, Senior Reactor Inspector

S. Obadina, Resident Inspector

R. Rolph, Senior Resident Inspector

S. Veunephachan, Health Physicist

Approved By:

Matt R. Young, Chief

Projects Branch 5

Division of Operating Reactor Safety

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated inspection at Calvert Cliffs Nuclear Power Plant,

Units 1 and 2, 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

Inadequate Design Modification Results in Reactor Trip Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events Green FIN 05000318/2021003-01 Open/Closed None (NPP)71111.18 A self-revealed Green finding was identified when the licensee failed to perform an adequate design modification in accordance with Engineering Standard (ES)-021, Design Inputs Requirements (DIR) Preparation, Revision 3. Specifically, on April 15, 2003, the licensee failed to include failure of redundant equipment for the dual positioner system as a failure effect in the modification package.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000317/2020-001-00 LER 2020-001-00 for Calvert Cliffs Nuclear Power Plant,

Unit 1 Regarding Undervoltage Condition on 4.16kV Electrical Bus 11 Resulted in Actuation of Emergency Diesel Generator 1A 71153 Closed LER 05000318/2021-002-00 LER 2021-002-00 Calvert Cliffs Nuclear Power Plant,

Unit 2, Manual Reactor Trip due to Lowering Steam Generator Level following Main Feedwater Regulating Valve Going Shut 71153 Closed

PLANT STATUS

Unit 1 began the inspection period at rated thermal power. On September 10, 2021, the unit was down powered to 80 percent to support waterbox cleaning and main turbine valve testing.

The unit was returned to rated thermal power on September 11, 2021 and remained at or near rated thermal power for the remainder of the inspection period.

Unit 2 operated at or near rated thermal power for the entire 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 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.

Starting on March 20, 2020, in response to the National Emergency declared by the President of the United States on the public health risks of the coronavirus (COVID-19), resident and regional inspectors were directed to begin telework and to remotely access licensee information using available technology. During this time, the resident inspectors performed periodic site visits each week, increasing the amount of time on site as local COVID-19 conditions permitted.

As part of their onsite activities, resident inspectors conducted plant status activities as described in IMC 2515, Appendix D; observed risk significant activities; and completed on site portions of IPs. In addition, resident and regional baseline inspections were evaluated to determine if all or a portion of the objectives and requirements stated in the IP could be performed remotely. If the inspections could be performed remotely, they were conducted per the applicable IP. In some cases, portions of an IP were completed remotely and on site. The inspections documented below met the objectives and requirements for completion of the IP.

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 for Units 1 and 2, forecasted tropical storm Elsa on July 8, 2021.

External Flooding Sample (IP Section 03.03) (1 Sample)

(1) The inspectors evaluated that flood protection barriers, mitigation plans, procedures, and equipment are consistent with the licensees design requirements and risk analysis assumptions for coping with external flooding on Units 1 and 2, turbine building roofs on September 29, 2021.

71111.04 - Equipment Alignment

Partial Walkdown Sample (IP Section 03.01) (3 Samples)

The inspectors evaluated system configurations during partial walkdowns of the following systems/trains:

(1) Unit 2, 23 high pressure safety injection pump during 2MOV656, auxiliary high pressure safety injection header isolation valve, out of service for maintenance, August 6, 2021

(2) Unit 1, 12 auxiliary feedwater pump during 13 auxiliary feedwater pump out of service for preventative maintenance, September 1, 2021

(3) Unit 1, 12 train of low head safety injection, high head safety injection, and containment spray while the 11 train was out of service for maintenance on the emergency core cooling system room air cooler, September 20, 2021

Complete Walkdown Sample (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated system configurations during a complete walkdown of the Units 1 and 2 fire protection systems on August 25, 2021.

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) Unit 1, auxiliary feedwater pump room, fire area 42, July 16, 2021

(2) Units 1 and 2, 11-13 and 21-23 charging pump rooms, fire areas 5-7 and 8-10, July 29, 2021

(3) Unit 1, 1A emergency diesel generator building, fire area EDG1A, August 6, 2021

(4) Unit 1, service water pump room, fire area 39, August 27, 2021

(5) Unit 2, 21 emergency core cooling system pump room, fire area 1, September 27, 2021

71111.06 - Flood Protection Measures

Inspection Activities - Internal Flooding (IP Section 03.01) (2 Samples)

The inspectors evaluated internal flooding mitigation protections in the:

(1) Unit 2, 21 and 22 emergency core cooling pump rooms ground water leakage, August 26, 2021

(2) Units 1 and 2, 0C station blackout diesel basement, September 22, 2021

Cable Degradation (IP Section 03.02) (1 Sample)

The inspectors evaluated cable submergence protection in:

(1) Units 1 and 2, manhole inspections of 2MH16, 2MH19, and 1MH19, for U-4000-23, 4 kilovolt service transformer, September 27, 2021

71111.07A - Heat Sink Performance

Annual Review (IP Section 03.01) (1 Sample)

The inspectors evaluated readiness and performance of:

(1) Unit 1, 11A and 11B service water heat exchangers, September 15, 2021

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 the Unit 1 downpower to 80 percent for waterbox cleaning and main turbine valve testing on September 10, 2021.

Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)

(1) The inspectors observed and evaluated licensed operator simulator training involving a loss of condenser vacuum, reactor trip, loss of all feedwater, and initiation of once through core cooling resulting in a declaration of a Site Area Emergency on August 31, 2021.

71111.12 - Maintenance Effectiveness

Maintenance Effectiveness (IP Section 03.01) (3 Samples)

The inspectors evaluated the effectiveness of maintenance to ensure the following structures, systems, and components (SSCs) remain capable of performing their intended function:

(1) Unit 2, WO C93784714, 21 feedwater regulating valve, A and B positioner replacement, July 13, 2021

(2) Units 1 and 2, service water system, September 29, 2021

(3) Unit 2, emergency diesel generators, September 30, 2021

Quality Control (IP Section 03.02) (1 Sample)

The inspectors evaluated the effectiveness of maintenance and quality control activities to ensure the following SSC remains capable of performing its intended function:

(1) Units 1 and 2, WO C93764655 and C3764889, relief valve on the 11 emergency core cooling system room air cooler and drive belts and a relief valve on the 21 saltwater air compressor, September 21, 2021

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) Unit 1, elevated risk condition due to 11A and 11B service water heat exchanger debris intrusion, July 26, 2021

(2) Unit 2, elevated risk condition due to high pressure safety injection header isolation valve preventative maintenance, August 4, 2021

(3) Unit 1, elevated risk condition due to preventative maintenance on 1CV4523, auxiliary feedwater block valve, September 3, 2021

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) Unit 2, AR04434624, 22 proportional heater has erratic amperage indication, July 14, 2021

(2) Units 1 and 2, AR04426261, seismic monitoring system display is frozen, July 20, 2021

(3) Unit 1, AR04435701, 11A and 11B service water heat exchanger debris intrusion reduces flow below required limits, July 21, 2021

(4) Unit 1, AR04435173, auxiliary feedwater actuation system response time testing not performed after logic module replacement, August 9, 2021

(5) Unit 2, AR04438310, 21 auxiliary feedwater pump packing leak-off increased following pump run, September 15, 2021

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 permanent modification:

(1) Unit 2, ES199602497, modification to install additional positioner for feedwater regulating valves to eliminate single point vulnerability, September 21, 2021

71111.19 - Post-Maintenance Testing

Post-Maintenance Test Sample (IP Section 03.01) (4 Samples)

The inspectors evaluated the post-maintenance test activities performed to verify system operability and functionality after the following maintenance items:

(1) Unit 1, WO C93759515, 11 high pressure safety injection motor operated valve maintenance, August 4, 2021

(2) Unit 2, WO C93751204, 22 high pressure safety injection motor operated valve maintenance, August 6, 2021

(3) Unit 1, WO C93669849, auxiliary feedwater actuation system response time testing, August 9, 2021

(4) Unit 1, WO C93764659, testing of the 11 emergency core cooling system room air cooler post maintenance of the cooler, September 21, 2021

71111.22 - Surveillance Testing

The inspectors evaluated the following surveillance tests:

Surveillance Tests (other) (IP Section 03.01)

(1) Unit 2, STP-O-5A21-2, "21 Auxiliary Feedwater Pump Quarterly Surveillance Test,"

Revision 009, July 26, 2021

(2) Unit 1, STP-O-8A-1, "Test of 1A DG and 11 4K BUS UV," Revision 34, September 24, 2021

FLEX Testing (IP Section 03.02) (1 Sample)

(1) Units 1 and 2, WO C93761493 and C93761646, three year maintenance of FLEX generators and pumps, September 14, 2021

71114.06 - Drill Evaluation

Drill/Training Evolution Observation (IP Section 03.02) (1 Sample)

The inspectors evaluated:

(1) The conduct of a simulator training evolution involving a lightning strike in the switchyard, a loss of offsite power, a reactor trip, and initiation of once through core cooling resulting in a Site Area Emergency declaration on August 5,

71124.07 - Radiological Environmental Monitoring Program

Environmental Monitoring Equipment and Sampling (IP Section 03.01) (1 Sample)

(1) The inspectors evaluated environmental monitoring equipment and observed collection of environmental samples.

Radiological Environmental Monitoring Program (IP Section 03.02) (1 Sample)

(1) The inspectors evaluated the implementation of the licensees Radiological Environmental Monitoring Program.

GPI Implementation (IP Section 03.03) (1 Sample)

(1) The inspectors evaluated the licensees implementation of the Groundwater Protection Initiative Program to identify incomplete or discontinued program elements.

71124.08 - Radioactive Solid Waste Processing & Radioactive Material Handling, Storage, &

Transportation

Radioactive Material Storage (IP Section 03.01)

Inspectors evaluated the licensees performance in controlling, labelling and securing radioactive materials, including:

(1) Material stored in the radioactive waste facility truck bay

(2) Material staged for the dry fuel storage campaign near the spent fuel pool

Waste Characterization and Classification (IP Section 03.03) (2 Samples)

The inspectors evaluated the licensees characterization and classification of radioactive waste, including:

(1) Characterization analysis results for dry active waste

(2) Characterization and classification of waste type for shipping package 19-102

Shipment Preparation (IP Section 03.04) (1 Sample)

The inspectors observed that a shipment containing radioactive material is prepared according to requirements.

(1) Specifically, the inspectors observed Resin Liner Shipment W21-011.

Shipping Records (IP Section 03.05) (4 Samples)

The inspectors evaluated the following non-excepted radioactive material shipments through a record review:

(1) Shipping package 19-102

(2) Shipping package 19-106

(3) Shipping package 20-065

(4) Shipping package 20-114

OTHER ACTIVITIES - BASELINE

===71151 - Performance Indicator Verification

The inspectors verified licensee performance indicators submittals listed below:

MS06: Emergency AC Power Systems (IP Section 02.05)===

(1) Unit 1, July 1, 2020 - June 30, 2021

(2) Unit 2, July 1, 2020 - June 30, 2021

MS07: High Pressure Injection Systems (IP Section 02.06) (2 Samples)

(1) Unit 1, July 1, 2020 - June 30, 2021

(2) Unit 2, July 1, 2020 - June 30, 2021

MS08: Heat Removal Systems (IP Section 02.07) (2 Samples)

(1) Unit 1, July 1, 2020 - June 30, 2021

(2) Unit 2, July 1, 2020 - June 30, 2021

MS09: Residual Heat Removal Systems (IP Section 02.08) (2 Samples)

(1) Unit 1, July 1, 2020 - June 30, 2021

(2) Unit 2, July 1, 2020 - June 30, 2021

MS10: Cooling Water Support Systems (IP Section 02.09) (2 Samples)

(1) Unit 1, July 1, 2020 - June 30, 2021

(2) Unit 2, July 1, 2020 - June 30, 2021

71152 - Problem Identification and Resolution

Annual Follow-up of Selected Issues (IP Section 02.03) (3 Samples)

The inspectors reviewed the licensees implementation of its corrective action program related to the following issues:

(1) Units 1 and 2, review the evaluations and corrective actions for multiple identified sinkholes inside the protected area and identified degradation of the site subsurface drain system (AR 04395128, 04380234, 04362394), September 29, 2021

(2) Failure to verify supplemental plant indications (SPI) when performing valve position verifications as required by ISTC-3700 of the 2012 American Society of Mechanical Engineers OM Code

(3) Review of the Licensees follow-up corrective actions and extent of condition for Failure to Include Emergency Diesel Generator Starting Air System Check Valves in the Inservice Testing Program NCV 2020-01

71153 - Follow Up of Events and Notices of Enforcement Discretion Event Report (IP Section 03.02)

The inspectors evaluated the following licensee event reports (LERs):

(1) LER 05000317/2020-001-00, Undervoltage Condition on 4.16 Kilovolt Electrical Bus 11 Resulted in Actuation of Emergency Diesel Generator 1A (ADAMS Accession No.

ML21027A171). The inspectors determined that it was not reasonable to foresee or correct the cause discussed in the LER therefore no performance deficiency was identified. The inspectors did not identify a violation of NRC requirements.

(2) LER 05000318/2021-002-00, Manual Reactor Trip Due to Lowering Steam Generator Level Following Main Feedwater Regulating Valve Going Shut (ADAMS Accession No. ML21139A096). The inspection conclusions associated with this LER are documented in this report under Inspection Results for Report Section

INSPECTION RESULTS

Inadequate Design Modification Results in Reactor Trip Cornerstone Significance Cross-Cutting Aspect Report Section Initiating Events

Green FIN 05000318/2021003-01 Open/Closed

None (NPP)71111.18 A self-revealed Green finding was identified when the licensee failed to perform an adequate design modification in accordance with Engineering Standard (ES)-021, Design Inputs Requirements (DIR) Preparation, Revision 3. Specifically, on April 15, 2003, the licensee failed to include failure of redundant equipment for the dual positioner system as a failure effect in the modification package.

Description:

On March 21, 2021, at 1059, during Unit 2 startup activities following the refueling outage, the 21 main feedwater regulating valve positioner A failed. Since the completion of design modification ES199602497, Unit 2 - Add dual positioners to feed reg valve, Dual Positioners To Feed Reg Valve - Hardware Only, each main feedwater regulating valve is equipped with a dual positioner system. When the A positioner failed, the steam generator water level control system automatically switched from the A positioner to the B positioner. The licensee performed a functionality assessment, AR04410557, and determined that the failure of the A positioner caused a loss of redundancy on the 21 main feedwater regulating valve. In addition, the B positioner was controlling the main feedwater regulating valve and maintaining steam generator levels. At 2219, the B positioner failed, the feedwater regulating valve failed shut, and Unit 2 was manually tripped from 38 percent power due to lowering level in the 21 steam generator. The inspectors reviewed the licensee root cause investigation, AR04410594, and noted that foreign material in the B positioner caused the main feedwater regulating valve to fail shut. The foreign material was traced back to the positioner manufacturing process. In addition, the root cause investigation cited a contributing cause that design engineering documentation used to build main feedwater regulating valve lesson plans and operating procedures did not include all possible failure modes (i.e., failure of redundant equipment). The design documentation included the fail-as-is failure mechanism for the valve.

The inspectors reviewed procedures associated with the modification process in effect when ES199602497 was implemented. Specifically, the inspectors reviewed ES-021, Design Input Requirements (DIR) Preparation, Revision 3, and noted that it requires the modification paperwork to include an evaluation of the proposed activity and failure effect requirements of structure, system and component(s), including a definition of those events and accidents which they must be designed to withstand. ES-021 also states, that the failure effects of the new item should be discussed, and the evaluation should address if, and how, the failure effects impact plant trip potential. The inspectors reviewed ES199602497, implemented in 2003, and noted the purpose of the modification was to eliminate single failure points for plant trips. ES199602497 provided a detailed discussion of the failure modes and effects for the single positioner system and why those failure modes were no longer applicable with the dual positioner system and why a discussion of plant trip potential was not required in accordance with ES-021.

Based on their review of the modification, the inspectors concluded that redundant failures of the positioner system would impact plant trip potential and noted that these failures were not included in the design modification as required by ES-021. The inspectors also reviewed the licensees procedure for parts quality and receipt inspection. Specifically, SM-AA-3019, Parts Quality Initiative, Revision 10, provides guidance on how to identify, procure, receive, and test parts to be used in critical applications. The inspectors noted that the classification for the positioner system changed from critical to non-critical due to the implementation of ES199602497 in 2003. Per SM-AA-3019, non-critical equipment is screened out of the parts quality initiative process. In addition, the inspectors reviewed SM-AA-102, Warehouse Operations, Revision 28, which establishes the process for receipt, storage, and handling of material, parts, and components. The inspectors noted that receipt inspection for non-safety-related items only requires visual inspection of the item and the positioners were classified as non-safety-related. The inspectors concluded that due to the change in positioner classification implemented by ES199602497, a failure of one positioner would now create a single point vulnerability, where the second positioner would be more prone to failure because testing intended to preclude infant mortality during the initial receipt inspection process was no longer performed.

The inspectors reviewed plant computer system data and noted that at the time of the failure of the A positioner, Unit 2 was operating at approximately 10 percent power and 21 steam generator water level was being controlled through the main feed regulating valve bypass valve. The inspectors reviewed WC-AA-106, Work Screening and Processing, Revision 19, which discusses the licensees process for prioritizing deficient plant equipment conditions.

The procedure states that the shift manager performs a review of all applicable issues generated during the shift and performs screening as required. The screening process entails using the priority screening matrix for issues. The matrix has a category for generation risk, which includes failure of conditionally critical equipment. OP-AA-107, Integrated Risk Management, Revision 4, defines conditionally critical equipment as redundant equipment, that if unavailable, introduces the risk of the loss of planned generation. The inspectors determined that the loss of the A positioner resulted in the licensee entering a conditionally critical configuration. However, the condition was not recognized due to the changes implemented by ES199602497 and the issue was not assigned the correct priority.

Specifically, as discussed above, the design document did not include redundant failures, which could cause the valve to fail shut like the B positioner did on March 21. Therefore, a risk mitigation plan was not developed, in accordance with OP-AA-107, to evaluate the risk of proceeding with the startup with only the B positioner. This resulted in the licensee proceeding with power ascension even though conditionally critical equipment had failed. As a result, with 21 steam generator water level being controlled by the remaining 21 main feedwater regulating valve B positioner, when the B positioner failed the plant tripped.

Stopping the power ascension when the 'A' positioner failed and continuing to control steam generator water level using the bypass feedwater regulating valves, could have afforded the licensee additional time to repair or replace the 'A' positioner while keeping the plant stable.

The inspectors concluded that the inadequate design modification in 2003 prevented the station from identifying, evaluating, reducing, and mitigating the risk of proceeding with startup with only the 'B' positioner in service, which contributed to the reactor trip that occurred on March 21, 2021.

Corrective Actions: The licensees immediate corrective actions included replacement of both positioners. The licensee also installed screened o-rings in the positioners to prevent foreign material from entering the positioner internals. The licensee plans to install screened o-rings on the Unit 1 main feedwater regulating valve positioners during the 2022 refueling outage.

The licensee plans to review training on conditionally critical systems that have had redundant equipment installed to ensure that the failure modes are covered as part of the lesson plan.

Corrective Action References: AR04410594, AR04410871, AR04410557

Performance Assessment:

Performance Deficiency: The inspectors determined the licensees failure to perform an adequate design modification, in accordance with ES-021, Design Input Requirements (DIR)

Preparation, Revision 3, was a performance deficiency. Specifically, the licensee failed to include failure of redundant equipment for the dual positioner system as a failure effect in modification package. This resulted in the licensee failing to assign the correct priority for failure of conditionally critical equipment on March 21, 2021.

Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Design Control attribute of the Initiating Events cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, on April 15, 2003, the licensee failed to include failure of redundant equipment for the dual positioner system as a failure effect in the modification package. As a result, on March 21, 2021, the licensee failed to assign the correct priority for failure of conditionally critical equipment, which contributed to the reactor trip.

Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined that the finding contributed to a reactor trip but did not cause the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition.

Therefore, the inspectors determined the finding to be of very low safety significance (Green).

Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to this finding because the inspectors determined the finding did not reflect present licensee performance.

Enforcement:

Inspectors did not identify a violation of regulatory requirements associated with this finding.

Minor Performance Deficiency 71124.07 Minor Performance Deficiency: The inspectors identified a minor performance deficiency in the placement and maintenance of the areas surrounding the environmental monitoring program air sample stations located at SAF-3 and SAF-4. Specifically, procedure CY-AA-170-1000, "Radiological Environmental Monitoring Program and Meteorological Program Implementation," Revision 12, step 4.2.2, requires (in part) "Where practical, the samplers should be located in an area that is free from obstructions due to large mass objects or trees that may significantly alter the air flow in front of the sampler." Contrary to this requirement, SAF-3 and SAF-4 were located in areas that were obstructed by a concrete storage vault, electrical service panels, a portable booth, trees, and overgrown vegetation.

The inspectors also noted that procedure CY-AA-170-1000 contained subjective evaluation criteria and did not reflect the guidance for air sampler placement that is available in applicable industry documents. The inspectors first identified and communicated this issue to the licensee in 2015, and again in 2017 and 2019.

Exelon documented the deficiency in its corrective action program as AR04446366.

Screening: The inspectors determined the performance deficiency was minor. The performance deficiency is minor in that it was not willful, does not warrant traditional enforcement, was not a precursor to a significant event, would not lead to a more significant safety concern, and did not adversely affect the Public Radiation Safety cornerstone objective.

Minor Performance Deficiency 71124.07 Minor Performance Deficiency: Procedure EN-AA-408, "Radiological Groundwater Protection Program", Revision 1 implements the voluntary Groundwater Protection Initiative that was set forth by the Nuclear Energy Institute (NEI). Using the guidance provided in Nuclear Energy Institute 07-07, "Industry Groundwater Protection Initiative - Final Guidance Document,"

Revision 1, the inspectors determined that Objective 1.3, Criteria f, "Establish a long-term program for preventative maintenance of groundwater wells" was not being met. Following a procedure review and interviews with licensee staff, no evidence for such a program could be identified.

The licensee documented the deficiency in their corrective action program as AR04447038.

Screening: The inspectors determined the performance deficiency was minor. The performance deficiency is minor in that it was not willful, does not warrant traditional enforcement, was not a precursor to a significant event, would not lead to a more significant safety concern, and did not adversely affect the Public Radiation Safety cornerstone objective.

Significance: The inspectors assessed the significance of the finding using Appendix D, Public Radiation Safety SDP.

Observation: Review of the Licensees Follow-up Corrective Actions and Extent of Condition for Failure to Include Emergency Diesel Generator Starting Air System Check Valves in the In-service Testing Program NCV 2020-01 71152 The inspectors reviewed a self-assessment and associated corrective actions that were completed by the licensee staff. The self-assessment evaluated a population of 4215 valves that had previously been marked exempt from in-service testing. The licensee concluded that 12 out of the 4215 valves reviewed should have been included in the in-service testing program. All 12 of the valves identified are on the 1B, 2A, and 2B emergency diesel generator starting air skids and serve as check valves and their safety-related function is to open in order to start the engine.

The licensees evaluation also included an action for a plan to replace emergency diesel generator starting air receiver inlet check valves 2A-DSA-106, 2A-DSA-110, 2B-DSA-106, 2B-DSA-110, 1B-DSA-106, and 1B-DSA-110 with a model valve that has a soft seating design which will aid in successful in-service testing and minimize the potential for back leakage. Currently, only the 2A-DSA-110 has been upgraded with the new soft seat design with the remaining 5 valves still in the planning stages to be replaced based upon their quarterly in-service testing test results. The licensee has also formally adopted these 6 check valves into their in-service testing program.

The inspectors reviewed the self-assessment, extent of condition review, in-service testing procedures, relevant issue reports, planned and completed corrective action records, interviewed the responsible system engineer and licensee subject matter expert on the topic, and physically inspected the 1B, 2A, and 2B emergency diesel generators starting air systems to review valve locations and overall material condition. Based on the documents reviewed, discussions with personnel and system walkdowns, the inspectors determined the licensee's evaluation of the issue was adequate and provided for corrective actions appropriately focused to correct the problem and commensurate with the safety significance of the problem. No performance deficiencies were identified.

Observation: Units 1 and 2, review the evaluations and corrective actions for multiple identified sinkholes inside the protected area and identified degradation of the site subsurface drain system (AR 04395128, 04380234, 04362394),

September 29, 2021 71152 The inspectors reviewed the licensee's evaluation and corrective actions associated with the multiple identified sinkholes inside the protected area and identified degradation of the site subsurface drain system. The identified sinkholes and degradation of the subsurface drain system are documented in AR04395128, AR04380234, AR04434378, AR04362394, and AR04442507. The licensees drainage system is comprised of the storm drain system, the outfall, and the subsurface drain system. The drain systems are below grade at 6 feet, 25 feet, and 50 feet, respectively. The inspectors reviewed vendor documentation of inspection for the drain system piping and noted that some of the piping had failed due to corrosion, and several sinkholes developed. In addition, during a severe weather event, the storm drain system was overwhelmed due to the failed piping, which increased the amount of water in the system and enlarged the sinkhole associated with the outfall portion of the drain system.

The inspectors reviewed documentation associated with previous sinkholes attributed to the subsurface drain system, in 2001, to determine corrective actions the station has taken in the past in response to sinkhole identification. At that time, an engineering evaluation was performed, and a portion of the piping was retired to prevent corrosion of the subsurface drain system as well as future sinkholes. In response to the recent sinkholes, the licensee initiated actions to stabilize and fill the sinkholes and will also be retiring a portion of the drain system and re-routing the piping to prevent sinkholes in the future. The inspectors also reviewed the preventative maintenance for the drain system and noted that it includes camera inspections for the subsurface drain system, inspection, cleaning, and sampling of the storm drain system, and monthly sampling and analysis of the water in the outfall portion of the drain system. The inspectors concluded that the licensee has taken timely and appropriate actions in accordance with the licensee's corrective action program procedure, PI-AA-125, "Corrective Action Program Procedure," Revision 007. Based on the documents reviewed and discussions with licensee personnel, the inspectors noted that licensee personnel identified problems and entered them into the corrective action program at an appropriately low threshold. No performance deficiencies were identified.

Observation: Untimely Corrective Action to Verify Supplemental Plant Indications when Performing Valve Position Verifications as Required by ISTC-3700 of the 2012 American Society of Mechanical Engineers OM Code 71152 In August 2020, NRC inspectors identified that valve position verification testing (American Society of Mechanical Engineers OM 2012 Code - ISTC 3700) for atmospheric dump valve 2-MS-3939 did not include the SPI requirements of Title 10 of the Code of Federal Regulations, 50.55a(b)(3)(xi). Specifically, when implementing paragraph ISTC-3700, "Position Verification Testing," licensees shall verify that valve operation is accurately indicated by supplementing valve position indicating lights with other indications, such as flow meters or other suitable instrumentation to provide assurance of proper obturator position for valves with remote position indication. This requirement became effective on July 1, 2018, when Calvert Cliffs implemented their fifth 10-year interval inservice test program plan. The licensee promptly evaluated plant records of SPIs to verify 2-MS-3939 obturator position was properly indicated. The issue was entered into the corrective action program to evaluate the extent-of-condition and ensure SPI requirements were properly implemented through the inservice test program (AR04365737).

The inspectors selected this issue as an annual sample for focused review related to the licensees problem identification, evaluation, and resolution performance. Inspection scope included review of issue documentation and prioritization, causal evaluation, corrective actions for the Unit 1 and 2 steam generator atmospheric dump valves (1/2-MS-3938-CV, 1/2-MS-3939-CV) and the extent-of-condition which included 404 valves subject to American Society of Mechanical Engineers OM Code inservice test requirements.

The inspectors interviewed plant staff and reviewed plant drawings, procedures, and test records for 124 of the 404 inservice test program valves to determine whether SPI requirements were properly implemented. Prior to this inspection, Calvert Cliff engineers had identified eight valves that did not have adequate test procedures/instructions to verify SPI requirements were met. Corrective actions (AR04365737-03) were in progress to address those eight valves. The inspectors identified 14 additional valves (seven on each unit) that did not have adequate procedure instruction or test records to assure SPI had been implemented to verify proper obturator position. These valves involved auxiliary feedwater, component cooling, and pressurizer pressure relief functions. The inspectors also identified various documentation errors in the inservice test program plan fifth 10-Year Interval, inservice test program basis document, and Calvert Cliffs SPI test record. Calvert Cliff Engineers promptly corrected the documentation errors, reviewed operation and maintenance history for the 14 subject valves for indication of valve performance anomalies and determined that the 14 subject valves were operating properly. With the exception of SPI, testing required by the inservice test plan for the 14 subject valves was current and successfully completed. The inspectors determined the licensee evaluation of current valve performance was technically sound.

The inspectors determined licensee staff appropriately entered the problem into their corrective action program, assigned appropriate priority commensurate with the potential safety significance, and initiated corrective actions to restore compliance with Title 10 of the Code of Federal Regulations, 50.55a(b)(3)(xi). Actions included an extent-of-condition review to verify SPI performance for all American Society of Mechanical Engineer OM Code valves, establishment of a detailed SPI test record to track SPI completion, revision of numerous existing test procedures, and creation of new test SPI test procedures. However, corrective action to establish SPI test procedures for the Unit 1 and 2 steam generator atmospheric dump valves had been deferred until November 30, 2021, and the inspectors identified inadequate SPI testing for 14 additional valves, which the licensee had missed in their extent-of-condition review. The inspectors concluded corrective action was incomplete and untimely. Failure, since July 1, 2018, to use SPI to verify valve operation was accurately indicated during biennial valve position verification tests for these 14 valves was a violation of Title 10 of the Code of Federal Regulations, 50.55a(b)(3)(xi). The inspectors determined the significance was minor because the inspectors did not identify an associated adverse impact on the reliability and availability of the subject 14 valves. The licensee entered the issue into the corrective action program for prompt evaluation and resolution (ARs 04451534, 04451540, 04451542, 04451544, and 04454318). This failure to comply with Title 10 of the Code of Federal Regulations, 50.55a(b)(3)(xi), constitutes a minor violation that is not subject to enforcement action in accordance with the NRCs enforcement policy.

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

• On October 20, 2021, the inspectors presented the integrated inspection results to Mr. Thomas Haaf, Site Vice President and other members of the licensee staff.

• On September 17, 2021, the inspectors presented the radiological environmental monitoring program inspection results to Mr. Thomas Haaf, Site Vice President and other members of the licensee staff.

• On August 25, 2021, the inspectors presented the emergency diesel generator starting air check valves problem identification and resolution inspection results to Mr. Ken Greene, Regulatory Affairs and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71152

Corrective Action

Documents

280912

282033

04365737

Corrective Action

Documents

Resulting from

Inspection

04451534

04451540

04451542

04451544

04454318

Miscellaneous

Calvert Cliffs Unit 1 SPI Test Record

Revision 0

Calvert Cliffs Unit 2 SPI Test Record

Revision 0

IST-CCNP-

BDOC-V-015

Calvert Cliffs IST Program Basis Document

08/19/21

IST-CCNP-PLAN

IST Program Plan 5th 10-Year Interval

Revision 7

Procedures

STP M-673A-1

PORV Response Time Test

Revision 1

STP O-5A11-1

AFW Pump Quarterly Surveillance Test

Revision 9

STP O-66D SPI-2

Component Cooling Containment Isolation SPI Test (Modes

5-6),

Revision 0

STP-O-65G-2

Component Cooling Valve Quarterly Operability Test

Revision 14