IR 05000237/2021010

Design Basis Assurance Inspection (Teams) Inspection Report 05000237/2021010 and 05000249/2021010

ML21054A248
Person / Time
Site:	Dresden
Issue date:	02/23/2021
From:	Karla Stoedter Division of Reactor Safety III
To:	Rhoades D Exelon Generation Co, Exelon Nuclear
References
IR 2021010
Download: ML21054A248 (24)

Text

February 23, 2021

SUBJECT:

DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - DESIGN BASIS ASSURANCE INSPECTION (TEAMS) INSPECTION REPORT 05000237/2021010 AND 05000249/2021010

Dear Mr. Rhoades:

On January 29, 2021, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Dresden Nuclear Power Station, Units 2 and 3 and discussed the results of this inspection with Mr. P. Karaba, 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 involved a violation of NRC requirements. We are treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy.

If you contest the violation or the significance or severity of the violation 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 III; the Director, Office of Enforcement; and the NRC Resident Inspector at Dresden Nuclear Power Station, Units 2 and 3.

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 III; and the NRC Resident Inspector at Dresden Nuclear Power Station, Units 2 and 3. 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,

/RA/

Karla K. Stoedter, Chief Engineering Branch 2 Division of Reactor Safety

Docket Nos. 05000237 and 05000249 License Nos. DPR-19 and DPR-25

Enclosure:

As stated

Inspection Report

Docket Numbers:

05000237 and 05000249

License Numbers:

DPR-19 and DPR-25

Report Numbers:

05000237/2021010 and 05000249/2021010

Licensee:

Exelon Generation Company, LLC

Facility:

Dresden Nuclear Power Station, Units 2 and 3

Location:

Morris, IL

Inspection Dates:

January 11, 2021 to January 29, 2021

Inspectors:

K. Barclay, Reactor Inspector

J. Benjamin, Senior Reactor Inspector

J. Corujo-Sandin, Senior Reactor Inspector

B. Daley, Senior Reactor Inspector

M. Holmberg, Senior Reactor Inspector

J. Park, Reactor Inspector

Approved By:

Karla K. Stoedter, Chief

Engineering Branch 2

Division of Reactor Safety

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a design basis assurance inspection (teams) inspection at Dresden Nuclear Power Station, Units 2 and 3, 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

Missing or Inadequate Battery Surveillance Acceptance Criteria Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000237,05000249/2021010-01 Open/Closed

[P.2] -

Evaluation 71111.21M The inspectors identified a Green finding and associated Non-Cited Violation (NCV) of 10 CFR 50, Appendix B, Criterion XI, Test Control, when the licensee failed to establish acceptance criteria or account for instrument uncertainty in surveillance procedures for battery electrolyte temperature.

Additional Tracking Items

Type Issue Number Title Report Section Status URI 05000237,05000249/

2021010-02 Potential Non-Conservative DC Short-Circuit Current Values 71111.21M Open

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 Disease (COVID-19), regional inspectors were directed to begin telework. During this time regional baseline inspections were evaluated to determine if all or portions of the objectives and requirements stated in the IP could be performed remotely. In some cases, portions of an IP were completed remotely and on-site. The inspection documented below was determined that the objectives and requirements stated in the IP could be completed remotely.

REACTOR SAFETY

===71111.21M - Design Bases Assurance Inspection (Teams)

The inspectors evaluated the following components and listed applicable attributes, permanent modifications, and operating experience:

Design Review - Risk-Significant/Low Design Margin Components (IP Section 02.02)

=

For each component sample, the inspectors reviewed the licensing bases including:

(1) the Updated Final Safety Analysis Report (UFSAR);

(2) the Technical Specification (TS);and

(3) the Technical Requirements Manual (TRM). The inspectors reviewed a sample of operating procedures (including normal, abnormal and accident procedures) as well as the overall system/component health (including condition reports and operability evaluations, if any). The inspectors performed visual inspections of the accessible components to identify potential hazards and/or signs of degradation. Additional component specific attributes inspected are listed below.

(1) Unit 3: 125VDC Battery (3-83125-3AH4-F1 & 3-83125-3AH4-F2)

5. Mechanical design:

a. Flood protection b. Seismic c. High energy line break d. Room heat up e. Room ventilation

6. Test/inspection procedures, acceptance criteria, and recent results:

a. Performance testing b. TS surveillance c. Discharge testing d. Terminal corrosion resistance

7. Electrical design:

a. Battery sizing b. Duty cycle c. Float and equalizing voltages d. Battery loading e. Short circuit calculation f. Breakers g. Maximum allowed room temperature during normal and accident operations h. Voltage drop calculation i.

Minimum voltage j.

Hydrogen concentration calculation k. Battery life l.

Battery charger sizing m. Cable ampacity n. Ground protection o. Protective relays/breakers

(2) Unit 3: 125VDC Distribution Panel (3A-1)

1. Mechanical design:

a. Flood protection b. Seismic c. Room heat up d. Room ventilation

2. Electrical design:

a. Short circuit calculation b. Breaker ratings c. Minimum voltage at downstream panels d. Voltage drop calculation e. Coordination calculations

4. Surveillance procedures

(3) Unit 2: Isolation Condenser Outboard Condensate Return Valve (MOV 2-1301-3)

3. Mechanical design:

a. Weak link analysis b. Required thrust and torque c. Pressure locking and/or thermal binding d. Maximum allowed leakage e. Maximum differential pressure

4. Test/ inspection procedures, acceptance criteria, and recent results:

a. Leakage b. In service testing c. TS required surveillance d. Leak rate testing e. Actuation test

5. Motor:

a. Voltage drop b. Control logic c. Thermal overload

(4) Unit 2: Turbine Building Closed Cooling Water Heat Exchanger (2A)

2. Design calculations and considerations:

a. Tube plugging limit b. Heat transfer capacity

3. Test/inspection procedures, acceptance criteria, and recent results:

a. Flowrates b. Inspection or thermal performance test

Design Review - Large Early Release Frequency (LERFs) (IP Section 02.02) (1 Sample)

(1) Unit 2: Isolation Condenser (2-1302)

1. As built heat exchanger for conformance with design specifications and

construction code requirements

4. Design calculations and considerations:

a. Shell make-up capability b. Heat transfer capacity

5. Test/inspection procedures, acceptance criteria, and recent results:

a. Inspection and thermal performance tests b. Eddy current examination of internal tube bundles

6. Impacts of thermal transients (peak stress and fatigue) during shell refill on

heat exchanger tube bundles

Modification Review - Permanent Mods (IP Section 02.03) (5 Samples)

(1) Engineering Change (EC) 20170124: Replace Speed Board and Install Magnetic Pickup Sensor for Emergency Diesel Generator (EDG) Unit 2

(2) EC 405079: EPN 2/3-5203, EDG Fuel Oil Transfer Pump Motor - Determine Impact of Replacement Motor on Protective Devices/Calculations/UFSAR

(3) EC 405449: Reconfigure the 2/3 EDG Heating, Ventilation and Air Conditioning Dampers and Related Items to Fail Open on a Loss of Instrument Air

(4) EC 628890: Installation of Reactor Feed Pump Suction Strainers

(5) EC 399980: Replace/Modify Angled Main Steam Isolation Valve Disc with Spherical Edges to Reduce Seat Leakage

Review of Operating Experience Issues (IP Section 02.06) (2 Samples)

(1) Bulletin 1976-01: Boiling Water Reactor Isolation Condenser Tube Failure

(2) Information Notice 2017-06: Battery and Battery Charger Short-Circuit Current Contributions to a Fault on the Direct Current Distribution System

INSPECTION RESULTS

Missing or Inadequate Battery Surveillance Acceptance Criteria Cornerstone Significance Cross-Cutting Aspect Report Section Mitigating Systems Green NCV 05000237,05000249/2021010-01 Open/Closed

[P.2] -

Evaluation 71111.21M The inspectors identified a Green finding and associated Non-Cited Violation (NCV) of 10 CFR 50, Appendix B, Criterion XI, Test Control, when the licensee failed to establish acceptance criteria or account for instrument uncertainty in surveillance procedures for battery electrolyte temperature.

Description:

The inspectors identified deficiencies with the testing procedures for the safety-related 125 VDC and 250 VDC station batteries. Specifically, the inspectors found examples were the licensee failed to:

(1) establish acceptance criteria;

(2) account for instrument uncertainties; and/or

(3) account for errors when using indirect measurement methodologies in the procedures used to measure battery electrolyte temperature.

In accordance with Title 10 CFR Part 50, Appendix B, Criterion XI, Test Control, tests performed on safety-related components must incorporate the requirements and acceptance limits contained in applicable design documents. For the 125 VDC batteries, the applicable design document was calculation DRE18-0009, "Dresden Units 2 and 3, 125 VDC System

Analysis.

" This calculation establishes that 65 degrees Fahrenheit (degrees F) was used as the minimum electrolyte temperature when developing the battery sizing calculation.

Additionally, UFSAR Section 8.3.2.1.1 for the 250 VDC system and Section 8.3.2.2.1 for the 125 VDC system describe the minimum electrolyte temperature used for battery sizing as 65 degrees F.

To ensure continued compliance with design documents and regulatory requirements, the licensee periodically measured the battery electrolyte temperature using direct or indirect methods. When using an instrument to directly or indirectly measure a value, the measured value will always have an amount of uncertainty. These uncertainties need to be accounted for in an analysis or within the acceptance criteria to ensure the associated structure, system or component (SSC) remains within licensing and design bases values (i.e. greater than or equal to 65 degrees F). The licensee measured distinct battery parameters, including electrolyte temperatures, for the 125 VDC and 250 VDC station batteries on a monthly, quarterly and annual periodicity. For each of these frequencies the licensee developed and implemented specific surveillance procedures.

Monthly (every 31 days): Technical Specifications Surveillance Requirement (TSSR) 3.8.6.4 required the licensee to verify each battery pilot cell temperature is greater than or equal to minimum established design limits. The TS bases for TSSR 3.8.6.4 prescribes the minimum established design limit as 65 degrees F.

The licensee implemented procedure DOS 8300-16, "U2

(3) Monthly Station Battery Inspection," to satisfy the monthly surveillance requirement. The inspectors found that instead of measuring battery electrolyte temperature directly to meet TSSR 3.8.6.4, the licensee measured battery room ambient temperature and verified the room temperature was greater than or equal to 65 degrees F. The licensee had not accounted for any potential instrument uncertainty or indirect measurement effects when establishing the acceptance criteria. The inspectors reviewed a sampling of quarterly and annual battery inspection procedures which required both battery electrolyte and room temperatures to be measured and found instances where the average temperature of the battery was below the measured room temperature. In one instance, the average battery temperature was 1.3 degrees F below the room temperature with one of the individual battery cells being 2.9 degrees F below the room temperature. Additionally, the inspectors reviewed the measuring and test equipment (M&TE) calibration certificate for the instrument used to measured room temperature and found the acceptance tolerance was +/- 0.54 degrees F.

Quarterly (every 92 days): Technical Requirements Manual, Section 3.8.b, "Battery Monitoring and Maintenance," specifically Surveillance Requirement TSR 3.8.b.3, directs the licensee to verify the average electrolyte temperature of representative cells is greater than 65 degrees F.

The licensee used procedure DOS 8300-17, "U2

(3) Quarterly Station Battery Inspection," to meet this requirement. When successfully completed, this procedure was also credited as satisfying the monthly test required by TSSR 3.8.6.4. The inspectors found the licensee measured the electrolyte temperature directly for the pilot cell and six other representative battery cells during the performance of DOS 8300-17. However, this procedure failed to have explicit acceptance criteria to confirm the battery temperature remained within design limits.

Annually: IEEE Standard 450-1995, Section 4.3.3, "Yearly," directs the licensee check the specific gravity of each cell.

The licensee utilized procedure DES 8300-49, "Yearly Unit 2

(3) Safety Related 125V and 250V Station Battery Inspection," to meet the IEEE Standard. When successfully completed, the results from this procedure were also used to satisfy the quarterly (TSR 3.8.b.3) and monthly (TSSR 3.8.6.4) surveillance requirements. The inspectors reviewed procedure DES 8300-49 and found the licensee had failed to establish acceptance criteria to confirm acceptable results for the specific pilot cell electrolyte temperature (TSSR 3.8.6.4) and account for instrument uncertainty in the acceptance criteria for verifying the average electrolyte temperature of representative cells (TSR 3.8.b.3). The inspectors reviewed the M&TE calibration certificate for the instrument that measured battery electrolyte temperature found that the acceptance tolerance was +/- 0.9 degrees F.

Since the available acceptance criteria in procedure DOS 8300-16 was equal to the design acceptance limits, the inspectors concluded the instrument uncertainties were not accounted in the surveillance procedures. No evidence was provided to the inspectors to demonstrate these uncertainties had been accounted for elsewhere. The licensee was also unable to provide information explaining why procedures DOS 8300-17 and DES 8300-49 failed to contain acceptance criteria. As a result, the inspectors were concerned the lack of acceptance criteria and the failure to account for uncertainties could result in a situation where a surveillance test was declared satisfactory when in reality the battery electrolyte temperature was below the minimum established design limit of 65 degree F assumed in the UFSAR, design calculations, TS Bases and the TRM. Battery temperatures below the minimum design limit would result in a failed TS surveillance, require the licensee to enter the associated LCO action statement, and the need to restore battery pilot cell temperature to greater than or equal to the minimum established design limit within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. If battery temperature is not able to be restored within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, the licensee must declare the battery inoperable. The inspectors reviewed past surveillance test results and did not identify any instances where the battery should have been declared inoperable.

Corrective Actions: The licensee verified that previous surveillance test results were acceptable and the batteries remained operable. The licensee also created an assignment to evaluate the implementing procedures for TSSR 3.8.6.4 and TSR 3.8.b to ensure uncertainty from instruments and indirect measurements are considered when establishing acceptance criteria.

Corrective Action References:

AR 4398651: 2021 NRC DBAI Questions for DOS 8300-16

AR 4398689: NRC DBAI 2021 - Inadequate 50.59 for DOS 8300-16 Rev 16

Performance Assessment:

Performance Deficiency: The licensees monthly, quarterly, and annual battery surveillance procedures had missing or inadequate acceptance criteria for the performance of TSSR 3.8.6.4 and TSR 3.8.b.3. Specifically, the acceptance criteria were either missing or failed to account for instrument uncertainty and/or indirect measurement effects. This was contrary to Title 10 CFR Part 50, Appendix B, Criterion XI, Test Control, and was a performance deficiency.

Screening: The inspectors determined the performance deficiency was more than minor because if left uncorrected, it would have the potential to lead to a more significant safety concern. Specifically, failing to have acceptance criteria or implementing acceptance criteria without accounting for instrument uncertainty and indirect measurement effects would have the potential to result in a satisfactory test result, when in actuality the SSCs had failed the surveillance test. Since the acceptance criteria values used in one of the procedures were the same as those used in Technical Specifications, the Technical Requirements Manual, and the associated analysis used to establish the minimum design limit, this could have resulted in:

(1) the licensee failing to enter the required TS Limiting Condition of Operation (LCO) action;

(2) failing to declare the associated equipment inoperable;

(3) failing to enter the TRM action; and/or

(3) potentially place the plant in an unanalyzed configuration. This issue is similar to the guidance provided in IMC 0612, Appendix E, Example 3.g.

Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors screened the issue against the Mitigating Systems Cornerstone questions and determined that the finding was of very low safety significance (Green) because it was not a design or qualification issue, did not represent a loss of probabilistic risk assessment function, and was not associated with an SSC specifically designed to mitigate an external event. The inspectors did not identify an example where the deficient procedures resulted in an actual failed surveillance test.

Cross-Cutting Aspect: P.2 - Evaluation: The organization thoroughly evaluates issues to ensure that resolutions address causes and extent of conditions commensurate with their safety significance. Specifically, the NRC identified a similar NCV in the first quarter of 2020, and the licensees extent of condition failed to identify these additional battery surveillance examples. The previous NCV also involved instrument uncertainty and was documented in NRC Inspection Report 05000237/2020001 (ADAMS Accession Number ML20133J811).

Enforcement:

Violation: Title 10 CFR Part 50, Appendix B, Criterion XI, Test Control, requires, in part, that a test program shall be established to assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service is identified and performed in accordance with written test procedures which incorporate the requirements and acceptance limits contained in applicable design documents.

Calculation DR18-0009, revision 0, "Dresden Units 2 and 3, 125 VDC System Analysis,"

serves as the applicable design document and establishes that 65 degrees F was the minimum temperature assumed in the battery sizing calculation.

For the safety-related 125 VDC and 250 VDC station batteries: Procedure DOS 8300-16, "U2

(3) Monthly Station Battery Inspection," revision 22, is the implementing procedure to comply with applicable design documents and TSSR 3.8.6.4. Data Sheet 1, "Monthly Battery Surveillance Data Sheet," contains acceptance criteria that ambient room temperature must be greater than or equal to 65 degrees F when battery charging current is less than or equal to 2 amperes when on a float charge. The licensee credits complying with the ambient room temperature acceptance criteria for verifying that each battery pilot cell electrolyte temperature is greater than or equal to minimum established design limits (i.e. 65 degrees F).

Procedure DOS 8300-17, "U2

(3) Quarterly Station Battery Inspection," revision 22, is the implementing procedure to comply with applicable design documents, TSSR 3.8.6.4. and TSR 3.8.b.3. Section A, "Purpose", states in part, "this procedure contains actions to satisfy weekly AND monthly surveillance criteria." Data Sheet 2, "U2(3) 125 VDC Battery Cell Voltage, Level, and Specific Gravity Datasheet," measures the electrolyte temperature for the pilot cell and six other representative battery cells. Data Sheet 3, "U2(3) 125 VDC Battery Average Determination Datasheet," calculates the average electrolyte temperature of the pilot and representative cells.

Procedure DES 8300-49, "Yearly Unit 2

(3) Safety Related 125V and 250V Station Battery Inspection," revision 12, is the implementing procedure to comply with applicable design documents, TSSR 3.8.6.4. and TSR 3.8.b.3. Section A, "Purpose," states in part, "this procedure contains actions to satisfy weekly, monthly and quarterly surveillance criteria."

Data Sheet 1, "U2(3) 125 VDC Battery Yearly Surveillance," records all battery cell temperatures and calculates the average electrolyte temperature. Additionally, Step I.25 (e)states, "(AC) Verify Average Cell Temp is greater than 65 degrees F (TSR 3.8.b.3)."

Contrary to the above, as of January 29, 2021, the licensee failed to assure that the testing required to demonstrate that the 125 VDC and 250 VDC batteries would perform satisfactorily in service was identified and performed in accordance with written test procedures which incorporated the requirements and acceptance limits contained in applicable design documents, as evidenced by the following examples:

1) Specifically, for procedure DOS 8300-16, revision 22, the licensee failed to account for instrument uncertainties and the effects of indirect measurements (i.e. room temperature instead of the pilot cell temperature) when establishing the acceptance criteria to ensure successful completion of these tests would ensure the associated batteries would remain operable and within the acceptance limits as determined by applicable design documents and TSSR 3.8.6.4.

2) Specifically, for procedure DOS 8300-17, revision 22, the licensee failed to establish testing acceptance criteria to ensure the batteries would remain operable and within the acceptable limits contained in applicable design documents, TSSR 3.8.6.4. and TSR 3.8.b.3.

3) Specifically, for procedure DES 8300-49, revision 12, the licensee failed to establish acceptance criteria to confirm acceptable results for the specific pilot cell electrolyte temperature, as required by TSSR 3.8.6.4; and failed to account for instrument uncertainties when verifying the average electrolyte temperature of representative cells was greater than 65 degrees F, as directed by TSR 3.8.b.3.

Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.

Unresolved Item (Open)

Potential Non-Conservative DC Short-Circuit Current Values URI 05000237,05000249/2021010-02 71111.21M

Description:

During the inspectors review of calculation DRE18-0009, "Dresden Units 2 and 3, 125 VDC System Analysis," the inspectors noticed the licensee used 125 percent of the full load rating for the battery charger current contribution to the short circuit calculations. The inspectors were concerned that using 125 percent of the battery charger full load rating may be non-conservative based on NRC Information Notice (IN) 2017-06, "Battery and Battery Charger Short-Circuit Current Contributions to a Fault on the Direct Current Distribution System." Specifically, the Dresden 125 VDC battery chargers were silicon-controlled rectifier (SCR) type battery chargers and the testing described in the IN demonstrated SCR-type battery chargers produced significantly higher currents than expected. NRC IN 2017-06, stated, The testing validated that the initial fault current contribution to a downstream fault from a battery charger (specifically the SCR-type chargers vs. the CF-type) is much higher in the range of 7 to 10 times the battery charger full load ampere ratingduring the first 100 milliseconds than what is currently stated as 150 percent of battery charger full load rating in IEEE Standard 946-2004. The test results indicated that the initial short circuit contribution from the charger is not limited when connected in parallel with the battery.

The inspectors reviewed the licensees evaluation of NRC IN 2017-06 (OPXR ATI Assignment #: 4067133-02) and found the licensee did not discuss the vulnerability of SCR-type battery chargers producing higher currents or justify why the Dresden battery chargers were not susceptible to the higher current condition. The inspectors determined, based on a battery charger full load rating of 200 amperes, that the additional current contribution from a single battery charger could potentially range from 1150 to 1750 amperes.

Additionally, because the licensee parallels two battery chargers together when switching between battery chargers, the licensee models two battery chargers contributing to the total short circuit current, which could double the additional current contribution. The inspectors found that in one portion of the licensees 125 VDC distribution system the margin to exceeding the 10,000-ampere limiting fault rating of a circuit breaker may be as low as 298 amperes before any additional currents are considered. The inspectors also recognized that increasing the short-circuit current can affect the circuit breaker coordination studies and potentially change the conclusions of the licensees fire safe shutdown analyses.

Planned Closure Actions: The inspectors plan to review the licensees updated evaluation of NRC IN 2017-06, which is being tracked by AR 4398306, and determine if any performance deficiencies exist, whether the performance deficiencies are more than minor, and if a violation of NRC requirements occurred.

Licensee Actions: Based on inspectors' concerns the licensee entered the issue into their corrective action program to reopen the evaluation of NRC IN 2017-06. An action was assigned to the Engineering department to account for the potentially high fault current contribution to a downstream fault from a battery charger that is much higher-in the range of 7 to 10 times the charger full load ampere rating-during the first 100 milliseconds than what is currently stated as 150 percent in IEEE Std 946-2004. The Operations department evaluated the available information and determined the potentially affected batteries remain operable.

Corrective Action References:

AR 4398306: 2021 DBAI: OPEX IN 17-06 Evaluation Incomplete

AR 4056647: OPEX Review: IN 2017-06: Battery / Charger Short Circuits (Corporate AR)

AR 4399797: AR Generated to Determine Course of Action for 2021 DBAI: OPEX IN 17-06 Evaluation (Corporate AR)

EXIT MEETINGS AND DEBRIEFS

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

• On January 29, 2021, the inspectors presented the design basis assurance inspection (teams) inspection results to Mr. P. Karaba, Site Vice President and other members of the licensee staff.

DOCUMENTS REVIEWED

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

71111.21M Calculations

004-E-032

Dresden Units 2 and 3 Thermal Overload Review

0101-0072-01

Dresden Isolation Condenser Heat Transfer Calculation

0591-156-SED-

2

ISCO Shell Side Pressure

2-016-DRN

Evaluation of Stroke Time and Actuator Capacity for DC

Motor-Operated Valves at Dresden Nuclear Station

1303-M-205/206,

Hanger

No. M-1163D-254

Pipe Support Qualification

5569-39-19-1

25 VDC Fault Currents

294-TB-05

25 VDC Battery Replacement, Trolley Beam & Rack

Design

29-TB-05

25 VDC Battery Rack Details, U-3

8188-109B-D2

Flued Head Anchor X-109B

8900-15-EO-S

Re-evaluate Anchorage Assemblies for the Isolation

Condenser

9389-68-19-1

Calculation for Voltage Adequacy of Swing Diesel Circuit

Breaker Closing Coils

9389-68-19-2

Calculation for Voltage Adequacy of Swing Diesel Circuit

Breaker Closing Coils

9389-68-19-3

Calculation for Control Voltage Adequacy of Unit 3 Diesel

Generator Circuit Breaker Closing Coils

9389-68-19-6

Calculation for Control Voltage of Unit 2 Diesel Generator

Circuit Breaker Closing Coils

9630-13-19-1

Voltage Adequacy at the Closing Coils of Ten Selected

Circuit Breakers

BSA-D-99-04

Reconstitution of Isolation Condenser Design Basis with

Respect to Decay Heat Loads and Long Term Make-up

Requirements

1b

CE-DR-003

Calculation for Allowable Limits for Stems and Discs for

Valves with Tag Nos. 2(3)-1301-3

D2-ISCO-01C

Reanalysis Per NRC Bulletin 79-14

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

D3-lSP-07

Isolation Condenser Steam Side Setpoint Flow Rates

DRE-2-1301-3

MIDACALC Results, DC Motor Operated GL96-05 Gate

Valve

DRE01-0045

Isolation Condenser Vent Piping Flow Capability

DRE02-0020

Isolation Condenser Heat Removal Capacity Test Validation

DRE03-0011

Isolation Condenser System Combined DBD and DP

Calculation

and 0A

DRE03-0025

Baseline Calculation for 125 VDC ELMS-DC Conversion to

DCSDM

2B, 3D and

4D

DRE05-0011

Hydraulic Model of Condensate, Condensate Booster, and

Feedwater Systems to Evaluate Impact of Increased

Condensate Filtration Flow

DRE18-0009

Dresden Units 2 and 3, 125 VDC System Analysis

DRE97-0005

Isolation Condenser Return Valve 2/3-1301-3 Cool Down

Rate

DRE99-0011

Isolation Condenser Make-up Pumps Hydraulic Performance 1

EMD-067683

Calculation for Isolation Condenser Vent Piping

KPA-SWC-67-

131

Stress Report Dresden Unit 2 and 3 Isolation Condenser

NED-M-MSD-72

The Seismic Thrust Limits of the Dresden Non-Mark I MOVs

SL-4500-3

Overcurrent Protective Device Overcurrent Study, 125 VDC

Systems

03/24/1989

VE-4

Dresden Unit 3 Battery Room Ventilation

07/08/1985

XCE091.0208

MOV Structural Integrity Calculation, Non-Mark I MOVs,

Dresden Units 2 & 3

Calibration

Records

0011216087

Anton Paar DMA 35 Density Meter

2/01/2020

0011267136

Anton Paar DMA 35 Density Meter

09/17/2020

0011284855

Fluke 54 II B Digital Thermometer

2/18/2020

Corrective Action

Documents

00693719

U2 IC West End Pass Plate is Bowed, with Sheared Bolts

11/02/2007

00798153

MOV 2-1301-3 Thermal Binding Review

07/18/2008

01337933

NRC Concern: 3B Standby Liquid Control Squib Valve

Temperature

03/07/2012

01685226-02

Evaluation to Determine the Tube Plugging Limit for TBCCW

Heat Exchangers

04/07/2017

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

2498753

U3 125 VDC Level III Ground

05/11/2015

04056647

OPEX Review: IN 2017-06: Battery / Charger Short Circuits

09/28/2017

04069471

MOV 2-1301-3 Stroke Length Found Shorter than

Acceptable

11/01/2017

04107306

Discrepancy Found in HPCI AOP Critical Parameters

2/23/2018

04141412

MOV 2-1301-3 As-Found Stroke Length High

05/25/2018

04144225

Isolation Condenser 2-1301-3 Valve Troubleshooting

06/04/2018

292887

D2R26 - Results of ISCO Shell Internals Inspection Results

10/30/2019

297715

U2 Isolation Condenser Tritium is Above Goal

11/15/2019

04310460

2B TBCCW HX Has Reached Tube Plugging Limit

01/15/2020

04354304

U2 ISO Condenser West End Bell Leak

07/02/2020

04357922

U2 ISO Cond Press Reading High on PI 2-1340-3

07/20/2020

Corrective Action

Documents

Resulting from

Inspection

04396236

21 DBAI - NRC Identified Discrepancy in Calc on ISCO

01/15/2021

04396770

21 DBAI - Incorrect Code Reference in Piping Analysis

01/19/2021

04397127

21 DBAI - Inapplicable Information in EQ Binder EQ-74D

01/21/2021

04397286

21 DBAI Non Conservative Calculation Fault 125 VDC

system

01/21/2021

04398108

IST 10-Year Plan Valve Test Table Not Updated

01/26/2021

04398306

21 DBAI: OPEX IN 17-06 Evaluation Incomplete

01/27/2021

04398651

21 NRC DBAI Questions for DOS 8300-16

01/28/2021

04398660

21 DBAI: UFSAR Section 8.3.2.2.1 Update

01/28/2021

04398682

21 DBAI: Calculation 004-E-032 Justification Needed

01/28/2021

04398689

NRC DBAI 2021 - Inadequate 50.59 for DOS 8300-16

Rev 16

01/28/2021

04399797

OPEX IN 17-06 Evaluation Review

2/02/2021

Drawings

2E-2507

Schematic Diagram Primary CNMT Isolation System

Isolation Condenser VLV - Outboard MOV 1301-3 Control

AP

2E-3303

Key Diagram 4169 Switchgears 31, 32, 33, 34

S

2E-3322A

Key Diagram Turbine Building 125 VDC Main Bus

Distribution Panels

Z

2E-3685C

Schematic Diagram Turbine Building 125 VDC Main Bus 3 &

3A

S

2E-3685D

Wiring Diagram Turbine Building 125V VDC Main Bus

M

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

Distribution Panel

66-2-5636C1

Isolation Condenser

66-2-5636D1

Isolation Condenser - Shell Details

66-2-5637D1

Isolation Condenser - Tube Bundle Assembly

D-14297

Tee Strainer Assembly

ISI-201

Inservice Inspection Class II Isolation Condenser Piping

H

ISI-307

Inservice Inspection Class III Isolation Condenser and Vent

Piping

C

M-16

Diagram of Condensate Booster Piping

AQ

M-609C

Piping Plan Reactor Feed Pump Suction Line Condensate

Booster Piping

A

Engineering

Changes

0000358092

Unit 2 Isolation Condenser East End Tube Bundle Heat

Shield Installation - Gap Dimension

0000368127

U2 Isolation Condenser Water Box Repairs

0000399980

Replace/Modify Angled MSIV Disc with Spherical Edges to

Reduce Seat Leakage

0000405079

EPN 2/3 5203, EDG Fuel Oil Transfer Pump Motor.

Determine Impact of Replacement Motor on Protective

Devices/Calculations/UFSAR

0000405887

Replace Speed Board and Install Magnetic Pickup Sensor

for Emergency Diesel Generator (EDG) Unit 2

0, 1 and 2

0000620232

Load Profile for the Unit 3 125 VDC Main Battery Modified

Performance Test (DES 8300-19) Supersedes EC 401226

0000628890

Installation of a Reactor Feed Pump (RFP) Suction Strainer

2-3404-A, 2-3404-B, 2-3404-C

Engineering

Evaluations

0000363440

Isolation Condenser Tube Plugging Criteria

0000372073

Unit 2 Isolation Condenser Valve 2-1301-3 Opening Setting

Adjustment

0000372144

Preliminary Results of U2 ISCO Heat Capacity Test

09/13/2008

0000382128

Isolation Condenser Eddy Current Testing Tube Plugging

Criteria

0000399268

Preliminary Results of U2 ISCO Heat Capacity Test

09/13/2014

0000405702

Isolation Condenser Make-up Pump DOS 1300-05

Evaluation

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

0000617372

LLRT Scope Reduction

0000624559

MOV Program Risk Ranking and Scoping Document

(2018 PRA)

0000628678

Isolation Condenser Make-up Pump DOS 1300-05

Evaluation Dresden

0001493789

00001376-01, COM D2 3RFL, COM MOV Electrical Insp &

Diagnostic Test 2-1301-3, E: 2-1301-3, MOVA, L05

11/27/2017

EE-017002-15

GNB Battery Short Circuit Ratings: Justification for Short

Circuit Ratings

Generic Letter 95-07

Pressure Locking and Thermal Binding Susceptibility

Evaluation for Dresden Station

Miscellaneous

50.59 Applicability Review and Coversheet for DTP 47,

Rev. 20

10/27/2017

Inservice Testing (IST) Program Plan

Isolation Condenser System Health Report

U2 Daily Operator Surveillance Log

01/25/2021

Report - Master Lee, Eddy Current Examination Final

Report - ISO Condenser EPN: 2-1302-West

11/2017

Report - Master Lee, Eddy Current Examination Final

Report - ISO Condenser EPN: 2-1302-East

11/2015

Form N-1 Manufacturers Data Report for Nuclear Vessels,

Heat Exchanger 66-2-5637

2/31/1967

Letter from Commonwealth Edison to USNRC, Dresden

Station Units 1, 2, and 3 Response to IE Bulleting No. 76-01

03/17/1976

Letter from Commonwealth Edison to USNRC, Dresden

Station Units 1, 2, and 3 Emergency/Isolation Condenser

Information (Record of Phone Call)

03/03/1976

Letter from Exelon to USNRC, Dresden Nuclear Power

Station Unit 2 Completion of Isolation Condenser Tube

Bundle Integrity Testing; Response to NRC IE Bulleting

76-01

03/05/1998

TBCCW System Health Report

AC/DC Distribution - Engage Health System Health Report

11/2020

Engage Health System Health Reports (DIS - AC/DC

NA

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

Distribution)

04067133-02

Level 3 OPEX Evaluation: IN 2017-06

01/31/2018

2019-009-002

CFR 50.59 Evaluation - Installation of a Reactor Feed

Pump Suction Strainer 2-3404-A, 2-3404-B, 2-3404-C

2019-129

CFR 50.59 Screening-Installation of a Reactor Feed

Pump Suction Strainer 2-3404-A, 2-3404-B, 2-3404-C

205-92017

GE Specification - Instruction Book for Isolation Condenser

for Dresden

2/26/1968

2A TBCCW/EPN

2-3802-A

Eddy Current Examination Final Report

05/07/2017

2B TBCCW/EPN

2-3802-B

Eddy Current Examination Final Report

01/15/2020

CHRON# 188292

Test Report: GNB NCX-21 Series Cell Short Circuit Tests

05/06/1992

D03-8303A1-2-

P06

Screening Evaluation Work Sheet (SEWS) for 125 VDC / TB

Main Bus #3A-1

and 1

DR-MISC-14

Motor-Operated Valve Program Risk Ranking Input - PRA

Model Revision DR217B

DR-PSA-005.05

Electric Power (EP) System Notebook

DR-PSA-005.09

Instrument/Service and Pumpback Air (IA/SA/PBA) System

Notebook

DR-PSA-005.10

Isolation Condenser (IC) System Notebook

DR-PSA-005.20

Probabilistic Risk Assessment - Turbine Building Closed

Cooling Water (TBCCW) System Notebook

DRE-19-002

Surveillance Test Interval (STI) Evaluation Form - DOS

1300-01 Isolation Condenser Five Year Heat Removal

Capability Test

10/31/2019

DRE-2-1301-3

(DRE-2)

MIDACALC Results for 2-1301-3 DC Motor Operated

GL96-05 Gate Valve

EQ Binder

No. EQ-74D

Limitorque SMB Valve Actuators Located Outside Drywell

PNL-10719

Report - Pre-Phase 1 Aging Assessment of the BWR

Isolation Condenser System

08/1995

RRP 3-14-023

ASME Section XI Repair/Replacement Plan for WO 1617486-23

03/06/2014

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

RRP 3-16-024

ASME Section XI Repair/Replacement Plan for WO 1617486-28

05/02/2016

Section 35.40

Specifications Nuclear Class 1E Flooded Batteries NCN* -

Lead Calcium

03/2010

Section 93.10

GNB Flooded Classic Installation and Operation Manual

Section 4

08/2014

NDE Reports

Hydrostatic Test Certificate, ISLIP Flow Controls Inc,

Drawing D-14297

10/22/2019

Procedures

04932057

D3 QTR TSNC 125 VDC Sta Batt Surv

09/12/2019

CY-DR-120-160

Isolation Condenser

DAN 902(3) B-4

Isolation Condenser Valves Off Normal

DAN 902(3) H-2

Isolation Condenser Line Break (Group 5 Isolation)

DAN 902(3)-3 B-3 Isolation Condenser Vent Radiation High

DAN 902(3)-3

C-4

Isolation Condenser Temperature High

DAN 902(3)-3

D-4

Isolation Condenser Level Hi-Lo

DAN 902(3)-4

Isolation Condenser Channel A-B Initiation

DAN 902(3)-8

C-9

U2 125 VDC Battery Ground U3 125 VDC Battery Ground

DAN 902(3)-8

D-10

25 VDC Power Failure

DAN 923-1

U2 or U3 TBCCW Temp High

DAN 923-1 D-2

U2 or U3 TBCCW Press Low

DGA-12

Loss of Offsite Power

DGA-13

Loss of 125 VDC Battery Chargers with Simultaneous Loss

of Auxiliary Electrical Power

DOA 0010-01

Dresden Lock and Dam Failure

DOA 1300-01

Isolation Condenser Tube Leak

DOA 3800-01

Loss of Turbine Building Closed Cooling Water

DOA 6900-03

Failure of Unit 3 125 VDC Power Supply

DOA 6900-03

Failure of Unit 3 125 VDC Power Supply

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

DOA 6900-T1

Unit 2 and Unit 3 125 VDC Battery System Detailed Load

List

DOA 6900-T2

Unit 2 and Unit 3 125 VDC Battery System

DOP 1300-01

Standby Operation of the Isolation Condenser System

DOP 1300-02

Automatic Operation of the Isolation Condenser

DOP 1300-03

Manual Operation of the Isolation Condenser

DOP 6900-02

25 VDC Electrical System

DOP 6900-07

25 VDC Ground Detection - Unit 3

DOP 8300-06

Unit 2 (3) Supplemental Battery Information

DOS 1300-01

Isolation Condenser Heat Removal Capacity Test

DOS 1300-05

Isolation Condenser Make-Up Pump Capacity Test

DOS 8300-16

Unit 2 (3) Monthly Station Battery Inspection

DOS 8300-17

Unit 2 (3) Quarterly Station Battery Inspection

DTP 09

Leak Detection and Reduction Program

ML-NDE-017

Eddy Current Examination of Non-Ferromagnetic Heat

Exchanger Tubing

OP-AA-102-106

Operator Response Time Program

OP-DR-102-106

Operator Response Time Program at Dresden

PI-AA-115

Operating Experience Program

PI-AA-115-1003

Processing of Level 3 OPEX Evaluations

Self-Assessments 4385641

FASA: NRC DBAI Preparation

2/17/2020

SRPT 04323578-

Self-Assessment Report

Work Orders

00884517

D2 5RFL COM Isolation CDSR Insp/Eddy Current East

11/12/2015

01096660-24

D2 5RFL Com Isolation CDSR Insp/Eddy Current West

10/19/2017

01650222

D3 5Y TSNC 125 VDC STA Batt Modified Performance Test

04/28/2018

01703750-01

Isolation Condenser Heat Removal Test

09/13/2014

01705165-01

B Iso Condenser Make-Up Pump Capacity Test

04/07/2016

01712364-01

A Iso Condenser Make-up Pump Capacity Test

05/31/2016

01939575

Replace EDG Speed Board & Install Magnetic Pickup

Sensor U2

2/13/2016

04700713-01

D2 PRE/RFL Reg Iso Cond Leak Det & Reduction Program

10/28/2019

04716683-01

D2 QTR/CSD TS (IST) Cold Shutdown Valve Testing

11/12/2019

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

Surveillance

04718571-01

D2 24M TS Isolation Condenser Auto-Actuation

11/13/2019

04753909-01

D2 QTR TS Valve Timing (IST)

05/25/2018

04787291

D3 AN TSNC 125 VDC Main Station Batt Surv

03/14/2019

04899165

D3 QTR TSNC 125 VDC Sta Batt Surv

06/13/2019

04900547

D3 AN TSNC 125 VDC Main Station Batt Surv

03/05/2020

04945098-07

Installation of 2A Reactor Feed Pump (RFP) Suction Strainer 11/06/2019

04945098-08

Installation of 2A Reactor Feed Pump (RFP) Suction Strainer 11/03/2019

04945098-11

Installation of 2A Reactor Feed Pump (RFP) Suction Strainer 11/16/2019

04945098-15

Installation of 2A Reactor Feed Pump (RFP) Suction Strainer 11/07/2019

04945098-23

Installation of 2A Reactor Feed Pump (RFP) Suction Strainer 11/05/2019

05023261-01

Fatigue and Transient Monitoring Program

08/13/2020

05108899

D3 1M TSNC 125 VDC Station Battery Insp

01/20/2021

05113940

D3 WK TSNC 125 VDC Battery Surv

01/13/2021