IR 05000454/2012009

IR 05000455-12-008; 01/30/2012 - 02/13/2012; Byron Station, Unit 2; Special Inspection

ML12087A213
Person / Time
Site:	Byron
Issue date:	03/27/2012
From:	West S K Division Reactor Projects III
To:	Pacilio M J Exelon Generation Co, Exelon Nuclear
References
IR-12-008
Download: ML12087A213 (38)

Text

March 27, 2012

Mr. Michael Senior Vice President, Exelon Generation Company, LLC President and Chief Nuclear Office (CNO), Exelon Nuclear 4300 Warrenville Road Warrenville, IL 60555

SUBJECT: BYRON UNIT 2 - NRC SPECIAL INSPECTION TEAM (SIT) REPORT 05000455/2012008

Dear Mr. Pacilio:

On February 13, 2012, the U.S. Nuclear Regulatory Commission (NRC) completed a reactive inspection pursuant to Inspection Procedure 93812, "Special Inspection" at your Byron Station, Unit 2. The enclosed inspection report documents the inspection results, which were discussed on February 13, 2012, with Mr. Tim Tulon and other members of your staff. The special inspection was commenced on January 30, 2012, in accordance with NRC Management Directive 8.3, "NRC Incident Investigation Program," and Inspection Manual Chapter 0309, "Reactive Inspection Decision Basis for Reactors," based on the initial risk and deterministic criteria evaluation made by the NRC on January 30, 2012. The special inspection reviewed the circumstances surrounding the January 30, 2012, electrical insulator failure in the Byron switchyard that resulted in a Unit 2 automatic reactor trip and Notice of Unusual Event emergency declaration. The inspectors examined activities conducted under your license as they relate to safety and compliance with the Commission's rules and regulations and with the conditions of your license. No findings were identified during this inspection. In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its enclosure, and your response (if any) will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records System (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,/RA/ Steven West, Director Division of Reactor Projects Docket No. 05000455 License No. NPF-66

Enclosure:

Inspection Report 05000455/2012008

w/Attachments:

1. Supplemental Information 2. Special Inspection Team Charter 3. Timeline of Events cc w/encl: Distribution via ListServ Enclosure U.S. NUCLEAR REGULATORY COMMISSION REGION III Docket No.: 50-455 License No.: NPF-66 Report No.: 05000455/2012008

Licensee: Exelon Generation Company, LLC Facility: Byron Station, Unit 2 Location: Byron, IL Dates: January 30, 2012 - February 13, 2012 Inspectors: J. Benjamin, Senior Resident Inspector, Team Lead, DRP C. Moore, Operator Licensing Examiner, DRS M. Munir, Reactor Inspector, DRS

Observer: J. Draper, Reactor Engineer, DRP Approved by: S. West, Director Division of Reactor Projects Enclosure

SUMMARY OF FINDINGS

........................................................................................................... 1

REPORT DETAILS

....................................................................................................................... 2 Event Description ...................................................................................................................... 2

4OA5 Other Activities - Special Inspection (IP 93812) ...................................................... 4 4OA6

Management Meetings .......................................................................................... 18

SUPPLEMENTAL INFORMATION

KEY POINTS OF CONTACT

Licensee

T. Tulon, Site Vice President

B. Youman, Plant Manager

D. Coltman, Operations Manager

J. Feimster, Design Engineering Manager

D. Damptz, Acting Maintenance Director

S. Swanson, Nuclear Oversight Manager

R. Gayheart, Training Director

D. Gudger, Regulatory Assurance Manager

R. Cameron, Licensed Operator Requalification Lead

Nuclear Regulatory Commission

S. West, Director, Division of Reactor Projects, Region III

E. Duncan, Chief, Reactor Projects Branch 3, Region III

LIST OF ITEMS

OPENED, CLOSED AND DISCUSSED

Opened

05000454/2012008-01;

05000455/2012008-01 URI Inadequate Undervoltage Protection

05000454/2012008-02;

05000455/2012008-02 URI Operability Determination Procedure Implementation Concerns

05000454/2012008-03;

05000455/2012008-03 URI Missed Opportunities to Identify a Latent Undervoltage Protection Design Issue

Attachment 1

LIST OF DOCUMENTS REVIEWED

The following is a partial list of documents reviewed during the inspection.

Inclusion on this list does not imply that the NRC inspector reviewed the documents in their entirety, but rather that selected sections or portions of the documents were evaluated as part of the overall inspection effort.

Inclusion of a document on this list does not imply NRC acceptance of the document or any part of it, unless this is stated in the body of the inspection report. -

IR 1319612; B2F26 Frequency Oscillation Observed on 2B DG; January 29, 2012 -

IR 1319652; B2F26 2B DG Output Power Swings 500 KW; January 30, 2012 -

IR 1319655; B2F26 Investigate Oil Drainage from 3L Cylinder Inspection Cover; January 30, 2012 -

IR 1319894; B2F26 2TO07P High Pressure Seal Oil B/U PP Wouldn't Start; January 30, 2012

-

IR 1319908; B2F26 U2 Reactor Trip Due to Electrical Fault and Unusual Event; January 30, 2012 -

IR 1319916; Minor Leak on Compression Fitting 2MS237D; January 30, 2012

-

IR 1319932; Minor Leak on 2MS95AB Sample Cooler Canister; January 30, 2012

-

IR 1319937; B2F26 2VP03CV Did Not Start; January 30, 2012

-

IR 1319968; B2F26 2PR-011 Containment Atmosphere PRM Tripped - Needs Restart; January 30, 2012 -

IR 1319989; B2F26 2PR21J; January 30, 2012 -

IR 1310006; B2F26 U2 Trip SAT C-Phase Found Open; January 30, 2012

-

IR 1320073; B2F26 2A GS Cond Fan Leakage; January 30, 2012

-

IR 1320079; B2F26 Leakage at 2B GS Fan Casing; January 30, 2012

-

IR 1320095; Emergent Security Support Request; January 30, 2012 -

IR 1320102; Slight Packing Leak at 2HD046B; January 30, 2012 -

IR 1320111; B2F26 2B FW PP Emergent Oil PP Appears to Have Failed; January 30, 2012

-

IR 1320119; 2MS004F Has Minor Packing Leak; January 30, 2012

-

IR 1320123; Contingency WO for Condenser in-Leakage Testing; January 30, 2012

-

IR 1320140; B2F26 CC Low Flow to 2A and 2D RCP Thermal Barrier HXs; January 30, 2012 -

IR 1320144; B2F26 2MS004LL Does Not Appear to be Responding Properly; January 30, 2012 -

IR 1320145; B2F26 2PR 01J Cannot be Started Following the Loss of Units SATs; January 30, 20112 -

IR 1320154; B2F26 Div 22 HVAC Tripped and Will Not Restart; January 30, 2012

-

IR 1320157; B2F26 Div 21 HVAC Tripped and Will Not Restart; January 30, 2012 -

IR 1320158; B2F26 2LC-ES094 Controller Cover is Open and Press Gage Lens Off; January 30, 2012 -

IR 1320160; B2F26 U2 Main Turbine Turning Gear Motor Won't Start; January 30, 2012

-

IR 1320161; B2F26 2PR030J Cannot be Started After Loss of Unit 2 SATs; January 30, 2012

-

IR 1320179; B2F26 U2 RX Trip Caused RCS Contaminated Water Leaks; January 30, 2012 -

IR 1230192; B2F26 Water Intrusion Leaking Through Area 7 on to 2RH01PA; January 30, 2012 -

IR 1320198; B2F26 2VT05CB Tripped; January 30, 2012

-

IR 1320203; B2F26 Unit 2 Turbine Turning Gear Motor Will Not Start; January 30, 2012

-

IR 1320204; Oil Filter on 2B TDFW PP Needs Replacing; January 30, 2012

-

IR 1320205; B2F26 U2 kV Output Breaker

GCB 10-11 Failed to Close; January 30, 2012 -

IR 1320206; B2F26 2A Air Side Seal Oil Filter 2TO04S-FA High DP; January 30, 2012 -

IR 1320221; B2F26 2CB025 Air Leak; January 30, 2012

-

IR 1320225; B2F26 U2 Hotwell Loss of Integrity; January 30, 2012

-

IR 1320227; B2F256 Emergent Dose Request for U2 Walk Down; January 30, 2012

Attachment 1 -

IR 1320241; B2F26 U2 MG Output Disconnect Linkage Requires Adjustment; January 30, 2012 -

IR 1320244; Emergent Dose - B2F26; January 30, 2012 -

IR 1320252; B2F26 U1 NDCT Overflow; January 30, 2012 -

IR 1320266; B2F26 2WF04PB Failed to Start on Sump Level; January 30, 2012

-

IR 1320267; B2F26 Suspect Severe Bearing Damage to PP & Turbine Bearings; January 30, 2012 -

IR 1320324; B2F26 2CV225 Dry Packing Leak - B2F26; January 30, 2012

-

IR 1320326; B2F26 2CV225 Dry Pipe Cap Leak - B2F26; January 30, 2012 -

IR 1320327; B2F26 Water Drips Now, Air In-leakage at Power; January 30, 2012 -

IR 1320328; B2F26 2RC8042C Dry Packing Leak - B2F26; January 30, 2012

-

IR 1320330; B2F26 2RC8042D Dry Packing Leak - B2F26; January 30, 2012

-

IR 1320352; B2F26

SAT 242-1 Oil Sample Results - Increased Combustible Gases; January 31, 2012 -

IR 1320353; B2F26

SAT 242-2 Oil Sample Results - Increased Combustible Gases; January 31, 2012 -

IR 1320354; B2F26 Need Oil Samples from 2C and 2B FW PPs; January 31, 2012

-

IR 1320355; B2F26 Emergent Dose Approval Required for 2WF04PB; January 31, 2012

-

IR 1320359; B2F26 2B Fuel Oil Pump Inlet Pressure is High Out of Spec; January 31, 2012 -

IR 1320361; B2F26 2B AF PP Gearbox Oil PP Trips Thermal Overloads; January 31, 2012 -

IR 1320373; B2F26 LL - MPA Overfeed Following B2F26 Shutdown; January 30, 2012

-

IR 1320382; B2F26 Thermal Overloads for 2A AF PP Aux Lube Oil PP Tripped; January 31, 2012 -

IR 1320392; B2F26 2A Seal Injection Filter - 2CV01FA; January 30, 2012

-

IR 1320394; B2F26 2CV01FB-2B Seal Injection Filter; January 30, 2012 -

IR 1320395; B2F26 U-2 RC Filter 2CV03F; January 30, 2012 -

IR 1320406; B2F26 3/4"Service Air Drain Valve Leaking By Post U2 Trip; January 30, 2012

-

IR 1320419; B2F26 RF Leak Causing Water Intrusion to Area 7 & 2A RH Pump Room; January 30, 2012 -

IR 1320511; B2F26 Review of U2 RCP Seal Operating Conditions Needed; January 30, 2012 -

IR 1320516; 2EIR-DC035 Bus 212 Ground Recorder has Flashing Message Box; January 31, 2012 -

IR 1320525; B2F26 Ops and MM Support of BOP

FW-15; January 31, 2012

-

IR 1320526; B2F26

SAT 242-1 Mod Open Light Socket Broke in MCR; January 31, 2012

-

IR 1320536; U1 Condensate Tritium; January 30, 2012

-

IIR 1320571; B2F26 Byron Fire Department Response to UE; January 30, 2012 -

IR 1320581; 2A MSIV Low Pressure Alarm in Prior to Reaching Setpoint; January 31, 2012 -

IR 1320605; B2F26 DG Lube Oil Purifier Trouble Alarm; Event Date March 16, 1987 - Discovery Date January 26, 2012 -

IR 1320610; B2F26 2A Seal Injection Filter Has HI DP; January 31, 2012

-

IR 1320625; B2F26 Additional Unit 2 Trip Issues Requiring Investigation; January 30, 2012 -

IR 1320662; B2F26 Contingency Needs Created for U2 RD Current Balancing; January 31, 2012 -

IR 1320683; B2F26 U1 OLR Eval Not Performed Prior to Making Equipment Unavailable; January 31, 2012 -

IR 1320687; B2F26 U1/U2 OLR Eval Not Performed Following Failure of

BT 10-11; January 30, 2012 -

IR 1320769; B2F26 Diaphragm Leak on 2CV8421; January 30, 2012 -

IR 1320899; B2F26 EOC Walkdown - 2RE9157 Solenoid Valve Wet; January 31, 2012

-

IR 1320901; B2F26 EOC Walkdown - 2RE9157 Open Limit Switch is Wet; January 31, 2012

-

IR 1320903; B2F26 EOC Walkdown - 2RE9157 Closed Limit Switch is Wet; January 31, 2012

Attachment 1 -

IR 1320906; B2F26 EOC Walkdown - 2RE9159B Solenoid Valve is Wet; January 31, 2012 -

IR 1320907; B2F26 EOC Walkdown - 2RE9159B Open Limit Switch is Wet; January 31, 2012

-

IR 1320908; B2F26 EOC Walkdown - 2RE9159B Closed Limit Switch is Wet; January 31, 2012 -

IR 1320910; B2F26 EOC Walkdown - 2RE9159B 2nd Solenoid Valve is Wet; January 31, 2012 -

IR 1320911; B2F26 EOC Walkdown - 2RE9160B Solenoid Valve is Wet; January 31, 2012

-

IR 1320913; B2F26 EOC Walkdown - 2RE9160B Open Limit Switch is Wet; January 31, 2012

-

IR 1320915; B2F26 EOC Walkdown - 2RE9160B Closed Limit Switch is Wet; January 31, 2012 -

IR 1320916; B2F26 EOC Walkdown - 2RY8028 Solenoid Valve is Wet; January 31, 2012 -

IR 1320920; B2F26 EOC Walkdown - 2RY8029 Open Limit Switch is Wet; January 31, 2012

-

IR 1320921; B2F26 EOC Walkdown - 2RY8028 Closed Limit Switch is Wet; January 31, 2012

-

IR 1320925; B2F26 EOC Walkdown - 2SI8963 Closed Limit Switch (NSR) is Wet; January 31, 2012 -

IR 1320927; B2F26 EOC Walkdown - 2SI8964 Solenoid Valve is Wet; January 31, 2012 -

IR 1320929; B2F26 EOC Walkdown - 2SI8964 Open Limit Switch is Wet; January 31, 2012

-

IR 1320929; B2F26 EOC Walkdown - 2SI8964 Closed Limit Switch is Wet; January 31, 2012

-

IR 1320930; BwF26 EOC Walkdown - 2SI8964 Closed Limit Switch (NSR) is Wet; January 31, 2012 -

IR 1320932; B2F26 EOC Walkdown - Junction Box 2JB509A is Wet; January 31, 2012 -

IR 1320933; B2F26 EOC Walkdown - Junction Box 2JB307A is Wet; January 31, 2012

-

IR 1320934; B2F26 EOC Walkdown - Junction Box (Pull Box) 2JB1784A is Wet; January 31, 2012 -

IR 1320938; B2F26

MCC 234V Rattling Noise; January 31, 2012

-

IR 1320939; B2F26 LL - IST Cold Shutdown Testing; January 31, 2012 -

IR 1320941; B2F26 U2 Loss of Offsite Power Annunciator Lit After Power Restart; January 31, 2012 -

IR 1321014; B2F26 Replace Ceramic Insulators on U1 345KV Line from MPTS; January 31, 20121 -

IR 1321015; B2F26 Replace Ceramic Insulators on 345KV Line from U1 MPTS; January 31, 2012 -

IR 1321016; B2F26 Replace Ceramic Insulators on 345KV Line to U2 SATs; January 31, 2012

-

IR 1321018; B2F26 Replace Ceramic Insulators on 345KV Line to U1 SATs; January 31, 2012

-

IR 1321033; B2F26 Inspect Transmission Lines From

SAT 142 to Switch Yard Disconnect; January 31, 2012 -

IR 1321035; B2F26 Inspect U1 MPT Transmission Line Up to Switch Year Disconnect; January 31, 2012 -

IR 1321037; B2F26 Inspect

SAT 242 Transmission Line Up to Switchyard Disconnect; January 31, 2012 -

IR 1321039; B2F26 Inspect U2 MPT Transmission Line Up to Switchyard Disconnect; January 31, 2012 -

IR 1321055; Blowdown Valve Failed Closed; February 1, 2012 -

IR 1321113; 2PR06J Valve Leaking Actively; February 2, 2012

-

IR 1321114; TR Pond Sump Pumps 1 & 2 Will Not Run; February 1, 2012

-

IR 1321129;

LL-B2F26 Verification of Ground Removal Good Practice; January 31, 2012

-

IR 1321228; MMD Resources Unable to Support 0A Chiller Window; January 31, 2012

-

IR 1321246; Missing Blades on Cooling Motor; February 1, 2012 -

IR 1321264; RP Training Deferred Due to B2F26; January 30, 2012 -

IR 1321268; Water Leaking from Bottom of Condenser; February 1, 2012

-

IR 1321301; U2 RX Trip IR to Include in Operator Training; January 30, 2012

-

IR 1321360; 2CV8117 Letdown Orific Outlet HDR RLF VLV Lifted," February 1, 2012

Attachment 1 -

IR 1322212; Potential Design Vulnerability in SY Single Open Phase; February 3, 2012 -

IR 1325902; Gaps in Guidance of OP Determination Procedure

- B2F26 Loss of C Phase Inspection 2012 Status Report; February 3, 2012 - B2F26 OCC Turnover 1730; January 30, 2012 - B2F26 Execution Scope Log

- MD 8.3; Unit 2 Deterministic Criteria Evaluation; January 30, 2012

- PWR B Spar Model for Byron Units 1 & 2;

IE-LOOPSC

- Byron U2 Abnormal Gaseous Release; January 30, 2012 - January 31, 2012

- Shift Manager Daily Events; January 12, 2012 - Gaseous Release Permit Report; Permit #2012047; 15 Abnormal Batch Release Unit 2; Permit Start January 2013 and Permit End January 2, 2013; January 31, 2012 - Byron MRC Agenda; Updated on November 29, 2011

- 2BCA-0.1; Loss of All AC Power Recovery Without SI Required - Unit 2; Revision 200 WOG 2

- PORC Checklist; Post Transient Review; February 7, 2012 -

LS-AA-108-108; Unit Restart, Start Up PORC for B2F26, Attachments 109, Department Checklists; Revision 12; February 2, 2012 -

LS-AA-1150; NRC Form 351 Event Notification Worksheet; February 6, 2012

-

OP-AA-102-104; Evaluation of the Effect of a Single Open-Phase Condition on 480V ESF Equipment - Log #12-007; February 6, 2012 -

OP-AA-108-108; Unit Restart Review; Revision 12 -

OP-AA-108-114; Post Transient Review; 2C Steam Generator Experienced a P-14

HI-2 SG Level; February 6, 2012 -

MA-AA-716-004; Unit 2 MCCs Troubleshooting Log; Revision 10

- NOS Byron Site Status Report; January 10, 2012

- PNO; Byron U2 Restarts After Loss of Offsite Power and Declaring a Notice of Unusual Event; February 7, 2012 -

LER 05000454/1996-007-00; Loss of Offsite Power Due to a Failure of an Insulator on Phase B of the Unit 1 Station Auxiliary Transformer from Water Intrusion; May 23, 1996 -

LER 05000333/2005-006-00 and 05000220/2005-006-00; Inoperable 115 kV Line in Excess of TS Allowed OOS Time; December 19, 2005 -

LER 05000220/2005-004-00; Operation Prohibited by TS Due to Unrevealed Inoperability of One Offsite Power Source; December 19, 2005 -

LER 05000334/2007-002-00; Undetected Loss of 138 kV 'A' Phase to System Station Service Transformer Leads to Condition Prohibited by Plant TS; November 27, 2007 -

LER 05000455/2008-001-00; Unit 2 EDG and Auxiliary Feedwater Pump Automatic Start Resulting from a Loss of Offsite Power Due to a Failed Insulator Causing a Differential Phase Overcurrent; March 25, 2008 - Dwg 6E-1-4017C; Relaying & Metering 6900V Swgr Bus 258

- Dwg 6E-1-4030AP21; 6.9kV Swgr Bus 158 Undervoltage and Underfrequency Relays

- Dwg 6E-2-4008A; 480V Auxiliary Building ESF

MCC 231X1 (2AP21E) Part 1

- Dwg 6E-2-4008B; 480V Auxiliary Building ESF

MCC 231X1 (2AP21E-A) Part 2 - Dwg 6E-2-4008E; 480V Auxiliary Building ESF

MCC 231X2 (2AP25E & 231X2A (2AP25E-A) - Dwg 6E-2-4008G; 480V Auxiliary Building ESF

MCC 231X2B (2AP25E-B)

- Dwg 6E-2-4008Q; 480V Auxiliary Building ESF

MCC 231X3 (2AP22E)

- Dwg 6E-2-4008U; 480V Auxiliary Building ESF

MCC 231X5 (2AP30E)

- Dwg 6E-2-4008AG; ESW Cooling Water ESF

MCC 231Z1 (2AP93E)

- Dwg 6E-2-4008BC; 480V Auxiliary Building ESF

MCC 233X4 (2AP44E) - Dwg 6E-2-4008BE; 480V Auxiliary Building ESF

MCC 233V2 (2AP46E) - Dwg 6E-2-4008BY; 480V Turbine Building

ESF

MCC 231Y1 (2AP51E)

- Dwg 6E-2-4008CA; 480V Turbine Building

ESF

MCC 231V3 (2AP53E)

- Dwg 6E-2-4008CC; 480V Turbine Building

ESF

MCC 233V4 (2AP55E)

Attachment 1 - Dwg 6E-2-4008CU; 480V Turbine Building ESF

MCC 231V5 (2AP57E) - Dwg 6E-2-4008CW; 480V Turbine Building ESF

MCC 231Z2 (2AP59F)

- Dwg 6E-2-4008DQ; 480V Auxiliary Building ESF

MCC 233X3(2AP42E) - Dwg 6E-2-4008AU; 480V Auxiliary Building ESF

MCC 233X1 (2AP38E) - Dwg 6E-2-4008BA; 480V Auxiliary Building ESF

MCC 233X3 (2AP42E)

- Dwg 6E-2-4008BJ; 480V Auxiliary Building ESF

MCC 234V1 (2AP39E)

- Dwg 6E-2-4008BL; 480V Auxiliary Building ESF

MCC 234V2 (2AP41E)

- Dwg 6E-2-4008BN; 480V Auxiliary Building ESF

MCC 233V3 (2AP43E)

- Dwg 6E-2-4008BQ; 480V Auxiliary Building ESF

MCC 234V4 (2AP45E) - Dwg 6E-2-4008BS; 480V Auxiliary Building ESF

MCC 234X5 (2AP47E) - Dwg 6E-2-4008CL; 480V Turbine Building ESF

MCC 234Y2 (2AP54E)

- Dwg 6E-2-4008CN; 480V Turbine Building ESF

MCC 234Y3 (2AP56E)

- Dwg 6E-2-4008DG; 480V Turbine Building ESF

MCC 234V6 (2AP58E)

- Dwg 6E-2-4008DJ; 480V Turbine Building ESF

MCC 234Z2 (2AP60E) - Dwg 6E-2-4008J; 480V Auxiliary Building ESF

MCC 232X1 (2AP23E) - Dwg 6E-2-4008L; 480V Auxiliary Building ESF

MCC 232X2 (2AP27E & A)

- Dwg 6E-2-4008Y; 480V Auxiliary Building ESF

MCC 232X3 (2AP24E)

- Dwg 6E-2-4008AA; 480V Auxiliary Building ESF

MCC 232X4 (2AP28E) &

MCC 232X4A (2AP28EA) - Dwg 6E-2-4008AC; 480V Auxiliary Building ESF

MCC 232X5 (2AP32E) - Dwg 6E-2-4008AN; 480V ESW Cooling Tower ESF

MCC 232Z1 (2AP92E)

- Dwg 6E-2-4008AQ; 480V ESW Cooling Tower ESF

MCC 232Z1A (2AP88E)

- Dwg 6E-2-4008CY; 480V CW Pump House

MCC 233U1 (2AP97E)

- Dwg 6E-2-4008DL; 480V CW Pump House

MCC 234U1 (2AP96E)

- Dwg 6E-2-4030SX02; Essential Service Water Pump 2B 2SX01PB - Dwg 6E-2-4030AP35; Bus Tie Breaker ACB #2421 (4.16kV ESF Swgr, Bus 242 to 4.16kV Bus 244) - Dwg 6E-2-4030AP21; 6.9kV Swgr Bus 258 Undervoltage and Underfrequency Relays

- Dwg 6E-2-4030AP17; 6.9kV Swgr Bus 256 Undervoltage and Underfrequency Relays

- Dwg 6E-2-4030AP13; 6.9kV Swgr Bus 256 Undervoltage and Underfrequency Relays - Dwg 6E-2-4019A; Relaying & Metering Diagram 480V ESF Swgr Bus 231X & 231Z; Revision K - Dwg 6E-2-4019B; Relaying & Metering Diagram 480V ESF Swgr Bus 232X & 232Z; Revision K - Dwg 6E-2-4019C; Relaying & Metering Diagram 480V ESF Swgr Bus 233X & 233Y; Revision K - Dwg 6E-2-4019D; Relaying & Metering Diagram 480V ESF Swgr Bus 234X & 234Y; Revision K - Op Eval 12-001, Potential Design Vulnerability in Switchyard Single Open Phase Detection

-

BYRSER-08, 8.2.4 Adequacy of Station Electric Distribution System Voltages

-

OP-AA-108-115, Operability Determinations (CM-1), Revision 11 - NUREG 0800, Branch Technical Positions (PSB-1, 2, 4, 8,11,15, 17, 18, 21) - NUREG 0800, Section 8.1 Electric Power

- NUREG 0800, Section 8.2 Offsite Power System

- NUREG 0800, Section 8.3.1 A-C Power Systems (Onsite)

- NUREG 0800, Section 8.3.2 D-C Power Systems (Onsite)

- RCP Seal Package Training Document,

RCP-1, Revision 25 - NRC Information Notice 2005-04: Single Failure and Fire Vulnerability of Redundant Electrical Safety Buses -

OP-AA-108-108, Unit Restart Review, Revision 12

-

AR 01322414, Fleet Review of Potential Design Vulnerability in Switchyard Attachment 1 - BOP

AP-55, Isolating/Restoring the Unit 2 System Auxiliary Transformers 242-1 and 242-2 with the Unit 2 Auxiliary Transformers De-Energized, Revision 11 - Shift Logs from 1/30/2012 - 1/31/2012 - Byron Station Read and Sign for Byron U-2 Trip response -

CC-AA-5001, Attachment 1, SSCS Inspected and Degraded Conditions Identified During Post Transient Walkdown - Unit 2 SAT Fluid Analysis Report from January 30, 2012

-

OP-AA-102-104, Unit 1/2 Standing Order,12-006, February 3, 2012

- BAR 2-21-C7, Bus 241 Overload or Volt Low, Revision 8 - 2BEP-0, Reactor Trip or Safety Injection, Revision 202 WOG 2 - 2BEP

ES-0.1, Reactor Trip Response Unit 2, Revision 203 WOG 2

- 2BEP

ES-0.2, Natural Circulation Cooldown Unit 2, Revision 200 WOG 2

- EC Eval #0000387571, B2F26 Review of U2 RCP Seal Loss of Seal Cooling Event, Revision 0 - TS 3.3.5, Loss of Power Diesel Generator Start Instrumentation - Exelon Energy Delivery Technical Bulletin

TB 05-018, dated April 25, 2005

Attachment 1

LIST OF ACRONYMS

USED [[]]

AC Alternating Current

ADAMS Agencywide Document Access Management System

AF Auxiliary Feedwater

AOP Abnormal Operating Procedure

CC Component Cooling Water

CD /

CB Condensate/Condensate Booster

CLB Current Licensing Basis

CV Centrifugal Charging

CFR Code of Federal Regulations

DC Direct Current DG Emergency Diesel Generator

DRP Division of Reactor Projects

DRS Division of Reactor Safety

EDG Emergency Diesel Generator

EN Event Notification

EOP Emergency Operating Procedure ESF Engineered Safety Features

°F Degrees Fahrenheit

gpm Gallons per Minute

HVAC Heating, Ventilation, and Air Conditioning hz Hertz

IEMA Illinois Emergency Management Agency

IMC Inspection Manual Chapter

IP Inspection Procedure

IR Inspection Report

IR Issue Report kV Kilovolt

LER Licensee Event Report

LOP Loss of Power

MCC Motor Control Center

mrem miilirem

MSIV Main Steam Isolation Valve

NARS Nuclear Accident Reporting System

NO [[]]

UE Notice of Unusual Event

NRC U.S. Nuclear Regulatory Commission

NSR Nonsafety-Related

OpEval Operability Evaluation

PA Protected Area

PARS Publicly Available Records System

PO [[]]

RV Power-Operated Relief Valve

pCi/L Picocuries Per Liter

RCP Reactor Coolant Pump

RHR Residual Heat Removal RPS Reactor Protection System

SAT Station Auxiliary Transformer

S/G Steam Generator

SR Safety-Related

SSC Structure, System and Component SX Essential Service Water

Attachment

1 TS Technical Specification

TSSR Technical Specification Surveillance Requirement

UAT Unit Auxiliary Transformer

UFSAR Updated Final Safety Analysis Report URI Unresolved Item

Vac Volts Alternating Current

WO Work Order

WOG Westinghouse Owners Group

Attachment

2 BYRON [[]]

SPECIA L

INSPEC [[]]

TION [[]]

CHART [[]]

ER This Special Inspection Team is chartered to assess the facts and circumstances surrounding the Byron Unit 2 reactor trip and subsequent equipment issues on January 30, 2012. The Special Inspection will be conducted in accordance with Inspection Procedure 93812,

"Special Inspection," and will include, but not be limited to, the items listed below.

1. Establish a historical sequence of events related to the January 30, 2012, Byron Unit 2 reactor trip. Include relevant plant conditions, system line-ups, and operator actions. 2. Review the licensee's post-trip data to determine the root cause of the Unit 2 reactor trip. Independently review plant data and records to confirm the adequacy of the licensee's

assessment and planned corrective actions. 3. Assess operator response to the January 30, 2012, event. 4. Review the licensee's root cause evaluation plan and schedule. Evaluate whether the root cause evaluation plan is of sufficient breadth and depth. Confirm that the time

allowed to perform the root cause evaluation is commensurate with the safety significance of the issue. Communicate with the licensee that the NRC will inspect the completed root cause evaluation and the associated corrective actions as part of routine

inspection activities.

5. Review the circumstances surrounding equipment problems associated with the January 30, 2012, event. Include in this review an assessment of the licensee's performance in addressing these issues. Consider cause determinations; planned corrective actions; prior similar events; the adequacy of past corrective actions, if

applicable; the adequacy of the licensee's extent of condition review; and the adequacy

of past operability reviews, if applicable. The review should include, but not be limited to

the following issues: * Unit

2 RCP undervoltage relay actuation; * Switchyard C-Phase Disconnect Switch (Bus 13) failure; * Unit 2 System Auxiliary Transformers (

SAT s) damage assessment and operability determination; * Unit 2 secondary side water hammer impact to equipment functionality and availability; * Starting of safety-related equipment when the

SAT s were de-energized from an undervoltage condition; * 2B Essential Service Water (

SX) pump failure to start prior to de-energizing the SATs; * Reactor coolant filter leakage and the impact on safety-related equipment, including the 2A Residual Heat Removal pump motor; and * The amount and impact of tritium released to the environment as a result of the event. Additional Inspection Requirements Determine if there are any lessons learned from this Special Inspection.

Attachment 2 Charter Approval

/RA/ /RA by Gary L. Shear for/ Eric Duncan, Chief Steven West, Director Branch 3 Division of Reactor Projects

Division of Reactor Projects

Attachment 3 Event Timeline January 30, 2012, Byron Unit 2 Reactor Trip The timeline developed was created independently by the special inspection team, with estimates based on the best information available at the time of the inspection.

Approximated times are preceded with "~" prior to the listed time. During the development of this timeline, all times were referenced to the main control room control room clock, which was considered the official time. The times listed below are based on

a 24-hour central standard time (CST) clock (i.e., 1001:33 is 10:01 and 33 seconds a.m.,

CST ). January 30, 2012 Initial Conditions: Unit 1 and Unit 2 operating at 100 percent power. ~1001:54 An insulator stack supporting the "C" phase conductor for 345kV Bus 13 that supplies power to the Unit 2

SAT s breaks, resulting in an open "C" phase conductor. 1001:55 6.9kV

NSR [[]]

RCP Bus 258 and Bus 259 supplied by the Unit

2 SAT s are affected by the open "C" phase. Unit 2

RPS senses the

RCP bus undervoltage and initiates an automatic reactor trip. 1001:55 Unit 2

ESF Bus 241 and Bus 242 supplied by the Unit 2 SATs are affected by the open "C" phase. However, due to the design of the undervoltage protection logic, a bus undervoltage protection signal is not processed and Bus 241 and Bus 242 remain energized with the A-B

phase at nominal 4000 Vac, the A-C phase at about 2400 Vac, and the B-C phase at about 2400 Vac. 1001:56 2A

SX pump low discharge pressure annunciator alarm is received due to an overcurrent trip of the running 2A

SX pump. 1001:56 2A (motor-driven)

AF pump and 2B (diesel-driven)

AF pump receive auto-start signals as designed due to the RCP bus undervoltage

condition. The 2B

AF pump starts and operates as designed. The 2A

AF pump is unable to start and run due to the undervoltage condition. 1001:59 Overcurrent trip of the running 2A

CC pump. The 2B

CC pump is unable to start and run due to the undervoltage condition. A loss of cooling to all four

RCP thermal barrier heat exchangers occurs. ~ 1002 Unit 2 operators enter procedure 2

BEP-0, "Reactor Trip or Safety Injection." 1002:00 Overcurrent trip of the running 2B CV pump.

1002:01-02

RCP seal injection flow annunciator alarms received for the 2A, 2B, 2C, and 2D

RCP s indicating a loss of

RCP seal injection to all four

RCP s. 1002:02-03 Overcurrent trip of the running 2A, 2B, and 2D

CD /

CB pumps. 1002:05 Overcurrent trip of the running auxiliary building supply fan.

Attachment 3 1002:13 Overcurrent trip of the running auxiliary building exhaust fan. 1002:32 Main generator reverse power trip occurs and generator output breakers 10-11 and 11-12 trip open. 1002:33 Nonsafety-related Bus 243 and Bus 244 supplied by the Unit 2 UATs trip upon the main generator reverse power trip. Nonsafety-related loads

including circulating water pumps, feedwater pumps, a reactor cavity fan,

station air compressors, control rod drive mechanism booster and exhaust fans, and heater drain pumps de-energize. 6.9kV Bus 256 and Bus 257 automatically transfer from the Unit

2 UAT s to the (degraded)

SAT s as designed. With phase "C" open, the current flow on the "A" and "B" phases increases. 1002:35 Overcurrent trip of

RCP 2C and

RCP 2D. 1002:43

ESF Bus 241 low voltage alarm is received in the main control room for about 2 seconds then clears. 1003:13 Overcurrent trip of

RCP 2A and

RCP

2B. ~1004 Operators attempt to start the 2B

SX pump, but the pump fails to start. 1004:54 Operators start the 1A

SX pump and open the Unit 1 to Unit 2 cross-connect valves to supply

SX from Unit 1 to Unit 2. ~1009-1010 Based upon a field report of smoke from the Unit 2 242-1 and 242-2

SATs, and a suspected electrical issue, operators open the SAT 242-1

and

SAT 242-2 feeder breakers to

ESF Bus 241 and Bus 242, and

NSR Bus 243 and Bus 244. 1009:48

ESF Bus 241 is electrically isolated following the manual operator action. Undervoltage logic is satisfied and an undervoltage signal is processed.

The 2A

DG starts and restores power to

ESF Bus 241 in about 6-8 seconds. Safe shutdown loads begin to automatically sequence onto

ESF Bus 241 being powered from the 2A

DG. 1010:07 ESF Bus 242 is electrically isolated following the manual operator action. Undervoltage logic is satisfied and an undervoltage signal is processed.

The 2B

DG starts and restores power to

ESF Bus 242 in about 6-8

seconds. Safe shutdowns loads begin to automatically sequence onto

ESF Bus 242 being powered from the 2B

DG. 1009:56 2A CV pump automatically starts and runs.

1010:15 2B

CV pump automatically starts and runs. 1010:16 2A

CC pump automatically starts and runs. Seal cooling is restored to the

RCP seals. 1018 Byron Station declares a Unit 2

NOUE due to the loss of offsite power to ESF Bus 241 and Bus 242 for greater than 15 minutes.

Attachment 3 1023 The licensee requests offsite assistance from the Byron Fire Department based upon the report of smoke from the Unit

2 SAT s. 1048 The Byron Fire Department arrives and is available as a resource. No actual fire occurred. The smoke from the Unit 2

SATs was caused by a

sudden heat up of the SAT windings due to an electrical current inrush

following the insulator failure. 1026 Nonsafety-related Bus 243 is energized from

ESF Bus 241, and

NSR Bus 244 is energized from

ESF Bus 242. Operators begin restoring

NSR loads in accordance with licensee procedures. 1039 The licensee notifies the

NRC Headquarters Operations Center of the Unit 2 reactor trip, loss of offsite power, and

NOUE emergency declaration. 1041 The Unit

2 SAT high side windings are de-energized by the opening of switchyard breakers 7-13 and 12-13 and associated motor-operated disconnects. 1048 The Unit 2 main steam isolation valves (

MSIV s) are closed in accordance with licensee procedure due to the loss of main condenser circulating water flow and the Unit 2 shutdown condition. 1100 Operators enter procedure

2BEP [[]]

ES 0.2, "Natural Circulation Cooldown." 1320 The Operations Field Supervisor completes an investigation of water reportedly spraying onto the 2A

RHR pump. The assessment concludes that the water spray does not impact the ability of the pump to start and operate. 2201 Unit 2 enters Mode 4. January 31, 2012 1233 Operators place Unit 2 in shutdown cooling using the 2B

RHR pump.

28 Unit 2 enters Mode 5 2000 The Byron

NOUE is terminated following the completion of a Unit 2

SAT functionality assessment and physical restoration of the Unit

2 SAT s supplying

ESF Bus 241 and Bus 242.

M. Pacilio -2-

In accordance with

10 CFR 2.390 of the

NRC's "Rules of Practice," a copy of this letter, its enclosure, and your response (if any) will be available electronically for public inspection in

the

NRC Public Document Room or from the Publicly Available Records System (

PARS ) component of

NRC 's document system (

ADAMS ).

ADAMS is accessible from the

NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room). Sincerely, /RA/ Steven West, Director Division of Reactor Projects

Docket No. 05000455 License No. NPF-66 Enclosure: Inspection Report 05000455/2012008 w/Attachments: 1. Supplemental Information 2. Special Inspection Team Charter

3. Timeline of Events

cc w/encl: Distribution via ListServ

DOCUME [[]]

NT [[]]

NAME Byron 2012 008

SIT. docx Publicly Available Non-Publicly Available Sensitive Non-Sensitive To receive a copy of this document, indicate in the concurrence box "C" = Copy without attach/encl "E" = Copy with attach/encl "N" = No copy

OFFICE [[]]

RIII [[]]

RIII [[]]

NAME [[]]

ED uncan:dtp

SW est

DATE 03/26/12 03/27/12

OFFICI AL

RECORD [[]]

COPY Letter to M. Pacilio from S. West dated March 27, 2012

SUBJEC T:

BYRON [[]]

UNIT 2 -

NRC [[]]

SPECIA L

INSPEC TION

TEAM (

SIT )

REPO [[]]

RT 05000455/2012008