Text

Integrated Inspection Report 05000237/2019002; 05000249/2019002; and 07200037/2019001
	ML19220B101
Person / Time
Site:	Dresden
Issue date:	08/08/2019
From:	Kenneth Riemer; NRC/RGN-III/DRP/B1
To:	Bryan Hanson; Exelon Generation Co, Exelon Nuclear
References
	IR 2019001, IR 2019002
	Download: ML19220B101 (35)
	v • d • e

August 8, 2019

SUBJECT:

DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3INTEGRATED INSPECTION REPORT 05000237/2019002; 05000249/2019002; AND 07200037/2019001

Dear Mr. Hanson:

On June 30, 2019, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Dresden Nuclear Power Station, Units 2 and 3. On July 8, 2019, the NRC inspectors 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.

The NRC inspectors did not identify any finding or violation of more than minor significance.

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 10 CFR 2.390, Public Inspections, Exemptions, Requests for Withholding.

Sincerely,

/RA/

Kenneth R. Riemer, Chief Branch 1 Division of Reactor Projects

Docket Nos. 05000237; 05000249; and 07200037 License Nos. DPR-19 and DPR-25

Enclosure:

As stated

Inspection Report

Docket Numbers:

05000237; 05000249; and 07200037

License Numbers:

DPR-19 and DPR-25

Report Numbers:

05000237/2019002; 05000249/2019002; and 07200037/2019001

Enterprise Identifiers: I-2019-002-0065 and I-2019-0001-0110

Licensee:

Exelon Generation Company LLC

Facility:

Dresden Nuclear Power Station, Units 2 and 3

Location:

Morris, IL

Inspection Dates:

April 01, 2019 to June 30, 2019

Inspectors:

J. Cassidy, Senior Health Physicist

J. Dalzell, Health Physicist

G. Edwards, Health Physicist

R. Elliott, Resident Inspector

N. Fields, Health Physicist

J. Havertape, Resident Inspector

A. Nguyen, Senior Resident Inspector

C. Phillips, Project Engineer

M. Porfirio, Illinois Emergency Management

C. St. Peters, Reactor Engineer

Approved By:

Kenneth R. Riemer, Chief

Branch 1

Division of Reactor Projects

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an integrated 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

No findings or violations of more than minor significance were identified.

Additional Tracking Items

Type Issue Number Title Report Section Status LER 05000249,05000237/2 019-001-00 LER 2019-001-00 for Dresden, Unit 2 and 3,

Secondary Containment Differential Pressure Exceeded Technical Specification due to Excess Ventilation Supply Flow.

71153 Closed

PLANT STATUS

Unit 2 began the inspection period at full power. On May 9, 2019, the reactor automatically scrammed due to a main turbine trip caused by a failure in the main turbine lubricating oil system. Unit 2 remained shut down in forced outage D2F57 for repair activities until May 13, 2019, when it synchronized back to the grid. The unit reached full power on May 17, 2019. On June 6, 2019, the unit was down powered to approximately 62 percent to conduct repairs on two Main Turbine Control Valve linear variable differential transducers (LVDTs) and perform a control rod sequence exchange. The unit returned to full power later that day and remained there for the rest of the inspection period.

Unit 3 began the inspection period at full power. On May 3, 2019, the unit was down powered to approximately 85 percent for repairs to the Main Turbine Control Valve #4 LVDT. The unit returned to full power the same day. On June 1, 2019, the unit was down powered to approximately 73 percent for quarterly turbine and main steam isolation valve testing, feedwater regulating valve maintenance, and control rod exercising and sequence exchange. The unit returned to full power on June 2, 2019, and remained there 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 plant status activities described in IMC 2515 Appendix D, Plant Status and conducted routine reviews using IP 71152, Problem Identification and Resolution. 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

External Flooding Sample (IP Section 03.04) (1 Sample)

(1) On April 29, 2019, through May 3, 2019, during periods of heavy rain and river flooding, the inspectors evaluated readiness to cope with external flooding for the following areas: Cribhouse, Unit 2 and Unit 3 emergency core cooling system (ECCS) corner rooms and torus basements, and the 2/3 emergency diesel generator room.

Summer Readiness Sample (IP Section 03.01) (1 Sample)

The inspectors verified that the licensees procedures and associated plant features for operation of both offsite alternating current (AC) power systems and the onsite alternate AC power systems appropriately addressed measures to monitor and maintain continued availability and reliability.

(1) On June 25, 2019, through June 28, 2019, the inspectors evaluated summer readiness of offsite and alternate AC power systems by performing walkdowns of the 345kV Switchyard, the Unit 2 and Unit 3 transformer yard, the Auxiliary Electrical Equipment Room, and the station battery rooms.

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 Division II low pressure coolant injection (LPCI) and containment cooling service water (CCSW) systems on April 1 and 2, 2019

(2) Unit 3 core spray system on April 29 and 30, 2019

(3) Unit 2 control rod drive system on May 10, 2019

71111.05Q - Fire Protection

Quarterly Inspection (IP Section 03.01) (5 Samples)

The inspectors evaluated fire protection program implementation in the following selected areas:

(1) Fire Zone (FZ) 6.2, Unit 2/3 Computer Room and Auxiliary Electrical Equipment Room, Elevation 517 feet on April 9, 2019

(2) FZ 8.2.4, Unit 2 and Unit 3 Cable Tunnel, Elevation 502 feet on April 10, 2019

(3) FZ 8.2.5.E, Unit 3 Switchgear Area, Elevation 517 feet on May 1, 2019

(4) FZ 11.2.3, Unit 2 High Pressure Coolant Injection (HPCI) Pump Room, Elevation 476 feet on May 1, 2019

(5) FZ 11.1.2, Unit 3 Southeast Corner Room, Elevation 476 feet on May 1, 2019

71111.06 - Flood Protection Measures

Inspection Activities - Internal Flooding (IP Section 02.02a.) (1 Sample)

The inspectors evaluated internal flooding mitigation protections in the:

(1) Unit 2 and Unit 3 CCSW Vaults

71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance

Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01) (2 Samples)

(1) The inspectors observed and evaluated licensed operator performance in the Control Room during an emergent downpower on Unit 3 to repair the turbine control valve #4 LVDT cable on May 3, 2019

(2) The inspectors observed and evaluated licensed operator performance in the Control Room during the Unit 2 SCRAM on May 9, 2019, and subsequent startup activities on May 11, 2019, through May 13, 2019

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

(1) The inspectors observed and evaluated annual exam senarios on May 15, 2019

71111.12 - Maintenance Effectiveness

Routine Maintenance Effectiveness Inspection (IP Section 02.01) (1 Sample)

The inspectors evaluated the effectiveness of routine maintenance activities associated with the following equipment and/or safety significant functions:

(1) Unit 2 and Unit 3 Reactor Building sumps and floor drain system

71111.13 - Maintenance Risk Assessments and Emergent Work Control

Risk Assessment and Management Sample (IP Section 03.01) (5 Samples)

The inspectors evaluated the risk assessments for the following planned and emergent work activities:

(1) Planned elevated risk on Unit 2 for the Division I LPCI and CCSW system maintenance windows on April 1 and 2, 2019

(2) Emergent elevated risk work to troubleshoot and repair the Unit 3 digital electrohydraulic control system controller failure on April 10, 2019

(3) Planned elevated risk for the Unit 3 HPCI room cooler maintenance window and the emergent risk impacts due to human performance issues on April 29, 2019, through May 2, 2019

(4) Emergent work to repair the Unit 3 turbine control valve #4 LVDT cable on May 2 and 3, 2019

(5) Emergent work to identify and repair the Unit 2 main condenser in-leakage, to address the Unit 2 B steam jet air ejector system perturbation, and elevated plant risk for adverse weather on May 16 and 17, 2019

71111.15 - Operability Determinations and Functionality Assessments

Operability Determination or Functionality Assessment (IP Section 02.02) (5 Samples)

The inspectors evaluated the following operability determinations and functionality assessments:

(1)3A Reactor Building Closed Cooling Water System Heat Exchanger Flaw Assessment

(2) Unit 3 Emergency Diesel Generator Pre-Lube Oil Line Support Clamp is Not Fully Engaged

(3) Potential vulnerability identified within the Core Spray system initiation logic

(4) Historical operability review of the Unit 2 Low Pressure ECCS Permissive Pressure Switch that did not pass its Technical Specification surveillance

(5) Unit 1 Diesel Fire Pump did not meet its surveillance acceptance criteria

71111.19 - Post-Maintenance Testing

Post Maintenance Test Sample (IP Section 03.01) (6 Samples)

The inspectors evaluated the following post maintenance tests:

(1)3A service water pump leak checks and maintenance run on April 13, 2019

(2) DOS 6600-01, Unit 3 Diesel Generator Surveillance Test on April 24, 2019

(3) Diagnostic testing of AOV 2-2001-5, Unit 2 Drywell Equipment Drain Sump Valve, after emergent repairs on May 5 and 6, 2019

(4) Unit 2 Average Power Range Monitor 6 calibrations and testing following power supply replacement on May 12, 2019

(5) Unit 2 Source Range Monitor 23 calibration and testing following repair on May 9 and 10, 2019

(6) DOS 2300-01, HPCI Valve Operability and Timing, after HPCI 2-2301-29 regulator replacement on June 18, 2019

71111.20 - Refueling and Other Outage Activities

Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)

(1) D2F57, Unit 2 Forced Outage after a SCRAM from May 9, 2019, through May 17, 2019

71111.22 - Surveillance Testing

The inspectors evaluated the following surveillance tests:

FLEX Testing (IP Section 03.02)

Main article: IP 71111.22

(1) Work Order (WO) 4882157 and WO 4882158, Annual A and B FLEX Barge Pump and Motor Operation Tests, on June 26, 2019

Inservice Testing (IP Section 03.01) (1 Sample)

(1) DOS 1100-04, 2A Standby Liquid Control System Quarterly/Comprehensive Pump Test, on April 4, 2019

Surveillance Tests (other) (IP Section 03.01) (2 Samples)

(1) DIS 1500-32, Unit 2 Division I & II LPCI ECCS Loss-of-Offsite-Power Selection Circuitry Logic System Functional Test, on April 17, 2019

(2) DOS 7000-03, Local Leak Rate Testing of the Primary Containment Airlock, on May 12, 2019

71114.06 - Drill Evaluation

Select Emergency Preparedness Drills and/or Training for Observation (IP Section 03.01) (2 Samples)

(1)2nd Quarter 2019 Focus Area Drill on June 6, 2019 (2)2019 Pre-Exercise Drill on June 25,

RADIATION SAFETY

71124.05 - Radiation Monitoring Instrumentation

Calibration and Testing Program (IP Section 02.02) (1 Sample)

The inspectors evaluated the calibration and testing program implementation.

(1) The inspectors reviewed the following:

Alarm Setpoint and Calibration Method Check of Personnel Contamination Monitors, Portal Monitors and Small Article Monitors

Bicron-NE IPM9D; Serial Number (SN) IPM9-143

Bicron-NE IPM9D; SN IPM9-154

Canberra ARGOS 5AB; SN 1011-286

Canberra ARGOS 5AB; SN 1011-277

Thermo Small Article Monitoring 12; SN SAM12-151

Thermo Small Article Monitoring 12; SN SAM12-152

Failure to Meet Calibration or Source Check Acceptance Criteria

Mirion MGP AMP-100; SN 0020787

Ludlum 177; SN 22697

Thermo RM25; SN 79403

Walk Downs and Observations (IP Section 02.01) (1 Sample)

The inspectors evaluated radiation monitoring instrumentation during plant walkdowns.

(1) The inspectors reviewed the following:

Portable Survey Instruments

Ludlum 177; SN 32173

Ludlum 177; SN 19267

Ludlum 177; SN 36092

Bicron RSO-5; SN 0022758

Thermo Fischer RO 20; SN 078610

Source Check Demonstration

Eberline RO20; SN 078046

Rotem Ram Gam-1; SN 079477

Ludlum 3; SN 0011111 Area Radiation Monitors and Continuous Air Monitors

Unit 2 Reactor Building 517 Drywell Continuous Air Monitor

Unit 3 Reactor Building 517 Drywell Continuous Air Monitor

Unit 3 Area Radiation Monitor (ARM) Reactor 613 Spent Fuel Pool

Unit 3 ARM Reactor 613 Spent Fuel Pool West Wall

Max Recycle ARM Chemical Addition Room

Personnel Contamination Monitors, Portal Monitors and Small Article Monitors

Canberra ARGOS 5AB; SN 1011-286

Canberra ARGOS 5AB; SN 1011-277

Canberra ARGOS 5AB; SN 1206-083

Thermo Small Article Monitoring 12; SN SAM12-151

71124.06 - Radioactive Gaseous and Liquid Effluent Treatment

Calibration and Testing Program (Process & Effluent Monitors) (IP Section 02.02) (1 Sample)

The inspectors reviewed the following gaseous and liquid effluent monitor instrument calibrations and tests:

(1)

WO 04618727-01 Unit 2/3 Quarterly Chimney Particulate, Iodine and Noble Gas Monitor

WO 04669719-01 Unit 2/3 Quarterly Reactor Building Ventilation Particulate, Iodine, and Noble Gas Monitor Functional Test

Dose Calculations (IP Section 02.05) (1 Sample)

The inspectors reviewed the following to asses public dose:

(1) The inspectors reviewed the following liquid and gaseous discharge permits to evaluate public dose calculations:

G-20170801-586-C

G-20170801-587-C

G-20170801-582-C

L-20170801-221-C

The inspectors also reviewed the following annual radiological effluent release reports:

Corrected Dresden Nuclear Power Station 2017 Radioactive Effluent Release Report

Dresden Nuclear Power Station 2018 Radioactive Effluent Release Report

Abnormal gaseous or liquid tank discharges

None were available for review during this inspection

Instrumentation and Equipment (IP Section 02.04) (1 Sample)

The inspectors reviewed the following radioactive effluent discharge system surveillance test results:

(1)

Stand-By Gas Treatment High Efficiency Particulate Filter Leak Test

High Radiation Sample Sink High Efficiency Particulate Filter and Charcoal Testing

Sampling and Analysis (IP Section 02.03) (1 Sample)

The inspectors reviewed the following:

(1) The inspectors reviewed the following radioactive effluent sampling and analysis activities:

Unit 2 Reactor Building particulate, iodine, and noble gas sample collection

Unit 3 Reactor Building particulate, iodine, and noble gas sample collection

Station Chimney particulate and iodine sample collection

Effluent discharges

None were available for review during this inspection

Walk Downs and Observations (IP Section 02.01) (1 Sample)

The inspectors walked down the following gaseous and liquid radioactive effluent monitoring and filtered ventilation systems to assess the material condition and verify proper alignment according to plant design:

(1)

Unit 2 Reactor Building Gaseous Discharge System

Unit 3 Reactor Building Gaseous Discharge System

Storm Water Collection System

71124.07 - Radiological Environmental Monitoring Program

Groundwater Protection Initiative (GPI) Implementation (IP Section 02.02) (1 Sample)

(1) The inspectors examined the remediation efforts associated with the 2014 Condensate Storage Tank Leak and other historical leaks at the facility.

Site Inspection (IP Section 02.01) (1 Sample)

The inspectors evaluated the radiological environmental monitoring program implementation.

(1) The inspectors evaluated the radiological environmental monitoring program implementation.

Walkdowns and calibration and maintenance record review

Air Sampling Station D-03

Air Sampling Station D-04

Air Sampling Station D-07

Thermoluminescent dosimeter (TLD) Monitoring Station D-03

TLD Monitoring Station D-04

TLD Monitoring Station D-07

The inspectors observed the following environmental sample collections and preparation:

Water Sample DSP 34A

Water Sample DSP 34B

Licensee actions in response to missed sample, inoperable sampler, lost TLD or anomalous measurement

D-25 (MI) (Milk); 06/27/2018; Farmer Resting Cow, Grass Substituted

D-04 (AP/AI) (Air Sampler); 10/19/2018; Low Reading of 67.5 Hours Due to Power Outage

D-23 (WW) (Well Water); 06/08/2018; Home Vacant, Water Turned Off

Sampling program for the potential of licensed material entering groundwater

Storm Water Collection System

Monitoring Well MD-11

Monitoring Well MW-DN-119I

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)===

Main article: IP 71151

(1) Unit 2, April 1, 2018 - March 31, 2019

(2) Unit 3, April 1, 2018 - March 31, 2019

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

(1) Unit 2, April 1, 2018 - March 31, 2019

(2) Unit 3, April 1, 2018 - March 31, 2019

OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)

(1) May 1, 2018 - May 1, 2019

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) October 1, 2018 - March 31, 2019

71152 - Problem Identification and Resolution

Annual Follow-up of Selected Issues (IP Section 02.03) (1 Sample)

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

(1) Preventive maintenance and monitoring of the Reactor Protection Scheme (RPS)logic relays on Units 2 and 3

Semiannual Trend Review (IP Section 02.02) (1 Sample)

(1) The inspectors reviewed the licensees corrective actions associated with an identified adverse trend in the area of Human Performance to ensure that it is not indicative of a more significant safety issue.

71153 - Follow-up of Events and Notices of Enforcement Discretion Event Follow-up (IP Section 03.01)

Main article: IP 71153

(1) The inspectors completed a Post-SCRAM review following the Unit 2 Turbine/Reactor Trip on May 9, 2019.

Event Report (IP Section 03.02) (1 Sample)

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

(1) LER 05000237/2019-001-00, Secondary Containment Differential Pressure Exceeded Technical Specification Due To Excess Ventilation Supply Flow (ADAMS Accession: ML19091A046) The circumstances surrounding this LER are documented in the results section and this LER is closed.

OTHER ACTIVITIES

- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL

60855.1 - Operation of an Independent Spent Fuel Storage Installation at Operating Plants Operation of an Independent Spent Fuel Storage Installation at Operating Plants

Main article: IP 60855

(1) The inspectors evaluated the licensees independent spent fuel storage installation cask loading activities on April 29th through May 3rd. Specifically, the inspectors observed the following activities:

Fuel loading of MPC-68M-614

Removal of the loaded transfer cask (HI-TRAC) from the spent fuel pool

Lid-to-shell root pass welding

Hydrostatic testing and non-destructive weld evaluations

Canister processing including bulk water removal (blowdown) and forced helium dehydration

Vent and drain port cover welding and non-destructive weld evaluations

Helium leak testing

Stack-up and download of the Multi-Purpose Canister from the HI-TRAC into the storage cask (HI-STORM)

Radiological field surveys

The inspectors performed walkdowns of the East and West Independent Spent Fuel Storage Installation (ISFSI) pads, including independent radiation surveys, and walkdowns of the ISFSI haul path and vertical cask transporter.

The inspectors evaluated the following:

Spent fuel selection for the four casks for this loading campaign

Changes to the Emergency Plan related to the ISFSI Emergency Action Levels

Selected corrective action program action requests

Selected 72.48 screenings

Change in canister drying method from vacuum drying to forced helium dehydration

INSPECTION RESULTS

Observation: Preventive Maintenance and Monitoring of the RPS Logic Relays 71152 On May 21, 2019, Unit 3 received a spurious Channel B Reactor Scram signal (half scram). During troubleshooting efforts, it was identified that the 3-0590-108F relay (Unit 3 Channel B RPS Scram Contactor) was chattering and tripped multiple times. Jumpers were installed around the B RPS Channel test switch, which was a source of high resistance in the past, and troubleshooting was conducted to take voltage readings along the B2 RPS logic string. High resistance and dirty contacts were found on the 3-0590-105D, Low Reactor Water Level, HFA relay. The contacts were burnished on the 3-0590-105D relay, as well as the other relays in the logic string, to ensure any resistance buildup was cleared before returning the system to service. Extent of condition voltage checks were completed on all RPS logic strings on both Unit 2 and Unit 3 and no other issues were identified.

The inspectors observed the licensees troubleshooting and extent of condition efforts. They also reviewed the licensees work group evaluation which included an evaluation of the stations maintenance practices for the components within the RPS logic strings since this was not the first instance of dirty contacts and high resistance causing spurious half scrams.

The inspectors reviewed industry operating experience and preventive maintenance templates to ensure the proper maintenance practices were being implemented. The inspectors determined that the licensee conducted a timely evaluation of the issue with sufficient detail to identify appropriate corrective actions. The extent of condition checks and evaluation were timely and of sufficient depth to ensure the risk to other components was appropriately addressed.

The corrective actions for the dirty contacts include enhanced monitoring and voltage checks during the quarterly surveillance activities that cycle these contacts. However, the inspectors did note that the frequencies of these surveillances are currently under revision per the Surveillance Frequency Control Program to move from quarterly to semi-annually and then eventually to yearly, which will decrease the potential effectiveness of them in timely detection of increased resistance across the contacts. The inspectors also noted that these relays used to have a replacement frequency of every 8 years, which was recently changed to an as-needed basis. This change was implemented based on changes to industry templates for HFA relay maintenance. Most relays for both units have been replaced within the last 5 to 8 years. Other components within the RPS logic strings, such as the test switches and RPS scram contactors, still have replacement frequencies corresponding to unit outages and industry templates. The inspectors determined that while the enhanced monitoring corrective actions seem reasonable, the changes in the surveillance frequencies and preventive maintenance practices will need to be monitored closely to ensure that equipment degradation can still be detected in a timely manner to prevent potential failures which could cause instability of the unit.

Observation: Semi-Annual Trend Review of Decline in Human Performance and Equipment Reliability 71152 The inspectors and licensee have identified declines in the areas of Human Performance and Equipment Reliability throughout the 6-month period from January 2019 through June 2019.

The licensee has completed or is in the processing of completing multiple causal products related to the declines in these areas. There have also been several external assessments throughout the first half of 2019 that have highlighted areas for improvement in the licensee's current plans to address these deficiencies. Following are some examples and overall summaries of the issues.

The licensee has experienced multiple equipment failures since the fall of 2018 that have included safety-related and nonsafety-related, but risk-significant, components. Some of the equipment failures have led to emergent unit down powers or unscheduled high-risk work windows to effect repairs. As an example, in May 2019, Unit 2 experienced a turbine trip and a subsequent reactor scram due to improper maintenance on a portion of the main turbine lube oil system, which starved couplings on one of the main turbine shaft components from being properly lubricated. The turbine tripped on low lube oil system pressure and the couplings and shaft in question were found to be severely degraded and overheated due to the lack of oil flow. The maintenance error was believed to have occurred in 2013 when a gasket that allowed lube oil to enter the coupling area of the shaft was not properly fabricated (missing a hole) and caused a lower than designed oil flow to the couplings. The root cause report for this event is still in progress and the residents will review this information as it gets finalized to determine if there is a performance deficiency.

The licensee has also experienced multiple events where underlying causes of the issues were determined to be lack of risk recognition or appropriate mitigation strategies for work.

An example of this was in January 2019, when the Unit 2 Reserve Auxiliary Transformer tripped during maintenance. Workers were installing a modification on the transformer and while performing that work came into contact with a relay on the door of the transformer. This contact resulted in the transformer tripping and the loads from the transformer automatically transferring to their backup source. The work was not screened as risk-significant and the impact of contact with this particular relay (or even its location in the cabinet) were not realized prior to work commencing in the field. This issue did have an associated violation that was documented in the first quarter 2019 report (2019001).

Another example was in April 2019, when maintenance personnel were performing work on the Unit 3 HPCI room cooler. They were attempting to drain the cooler when valves in the system were found to be leaking significantly onto components in the area. Directly underneath the cooler were junction boxes for some of the motor-operated valves in the HPCI system. One of these valves was the minimum flow valve and it opened when water intruded into the box. This caused the torus level on Unit 3 to rise. The operators in the control room did not identify this rise in torus level until the high-level alarms were received in the control room approximately 90 minutes later. This event illustrated both the lack of risk recognition and mitigation on behalf of the maintenance workers for the potential water impact on components in the area and also showed the human performance error of the operators in the control room for not properly monitoring their control boards to identify an abnormal condition. This issue was determined to not have an associated performance deficiency.

Minor Violation 71153 Minor Violation: On January 30, 2019, the licensee lost secondary containment when actions were taken, in accordance with Dresden Abnormal Operating procedure (DOA) 5700-01, Loss of Heating Boilers, Revision 25, to open the doors to the reactor building ventilation plenum after a trip of the heating boiler which was a performance deficiency. The licensee stated in LER 2019001-00 that the cause of the loss of secondary containment was inadequate procedural guidance in DOA 5700-01, Loss of Heating Boilers, Revision 25.

Technical Specification 5.4.1.a required that written procedures shall be established, implemented, and maintained covering the following activities: The applicable procedures recommended in Regulatory Guide 1.33, Revision 2; Appendix A, February 1978; Regulatory Guide 1.33, Revision 2; Appendix A, February 1978, Paragraph 6, Procedures for Combating Emergencies and Other Significant Events, Subparagraph r; and Other Expected Transients that may be Applicable, applied to DOA 5700-01.

The inspectors reviewed the licensees causal documentation and the corrective actions proposed and taken which were documented in Action Request 4215383, North RB DP

[reactor building differential pressure] Local Indication On 613 feet Not Accurate, dated January 30, 2019, and had no further concerns.

Screening: The inspectors determined the performance deficiency was minor. The inspectors answered no to all four questions from IMC 0612, Appendix B, Issue Screening, dated January 1, 2018, because the event only lasted a few moments.

Enforcement:

This failure to comply with Technical Specification 5.4.1.a 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 July 8, 2019, the inspectors presented the integrated inspection results to Mr. P. Karaba, Site Vice President, and other members of the licensee staff.

On May 2, 2019, the inspectors presented the independent spent fuel storage installation inspection results to Mr. J. Stovall, Plant Manager, and other members of the licensee staff.

On May 3, 2019, the inspectors presented the radiation protection inspection results to Mr. J. Stovall, Plant Manager, and other members of the licensee staff.

On June 27, 2019, the inspectors presented the Radiation Protection 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

60855.1

ALARA Plans

DR-0-19-00204/5

2019 Dry Cask Activities (4 Casks)

03/13/2019

Calculations

DRE00-0022

Expanded Analysis to Address Change to HI-STORM

Overpack

DRE06-0037

Dose Versus Distance from a Single Cask at the Dresden

ISFSI

DRE06-0038

HI-STORM CoC Radiation Protection Program Dose Rate

Limits for Dresden

DRE15-0011

Thermal Evaluation of HI-STORM Under Flood Condition at

Dresden

03/11/2015

DRE18-0012

Independent Spent Fuel Storage Installation (ISFSI)

Expansion - Construction Pad Design

DRE19-0001

Cask Loading Design Analysis

01/15/2019

DRE19-0002

Dresden Unit 2 Fuel Selection Packages for 2019 Campaign

- ISFSI

01/28/2019

DRE19-0003

Dresden Unit 2 Fuel Selection Package Alternate

Assemblies for 2019 Campaign - ISFSI

01/28/2019

Corrective Action

Documents

Selected ISFSI-Related Action Requests Generated Since

May 30, 2016

AR 2727372;

NOSA-DRE-16-

Independent Spent Fuel Storage Installation Audit Report

11/02/2016

AR 4177227;

NOSA-DRE-18-

Independent Spent Fuel Storage Installation Audit Report

2/04/2018

AR 4207754

Dresden Spent Fuel Loading Campaign (SFLC) Readiness

Assessment

03/08/2019

Corrective Action

Documents

Resulting from

Inspection

AR 4245705

2/3-7900 HMPL2 High Mast Pole Light One Fixture is Out

05/01/2019

AR 4245958

NRC ID'ed Record of PM WO Missing Procedure

05/03/2019

IR 4250890

Recommended Clarification of Source Term Limits in FSPS

05/20/2019

Engineering

Changes

26654

Dresden 2019 Dry Cask Storage Fuel Selection Packages -

ISFSI

2/21/2019

Inspection

Procedure

Type

Designation

Description or Title

Revision or

Date

26911

Spent Fuel Casks for the 2019 Loading Campaign

EC 397528

Dry Cask Storage - East ISFSI Screen Replacements

2

EC 620257

FHD Skid Evaluation for Dry Cask Processing

2/04/2019

EC 623798

Issue Major Revision 001 to DRE06-0036 West ISFSI Fire

Hazard Analysis

07/03/2018

ECR 440769

Railroad Track Inspection

04/08/2019

Miscellaneous

SOC Daily MRC Report

05/18/2017