ML050490459
| ML050490459 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 01/12/2005 |
| From: | Public Service Enterprise Group |
| To: | Office of Nuclear Reactor Regulation |
| Cobey, Eugene W. RI/DRP/PB3 610-337-5171 | |
| Shared Package | |
| ML050120400 | List: |
| References | |
| Download: ML050490459 (35) | |
Text
P S E G N U C L E A R L L C 0
PSEG Nuclear Hope Creek NRC Public Meeting January 12, 2005 Hope Creek NRC Public Meeting January 12, 2005
P S E G N U C L E A R L L C 1
AGENDA Introduction Chris Bakken Hope Creek Root Cause Michael Gallagher
P S E G N U C L E A R L L C 2
INTRODUCTION Chris Bakken President and Chief Nuclear Officer Chris Bakken President and Chief Nuclear Officer
P S E G N U C L E A R L L C 3
INTRODUCTION
- We Agree With the NRCs Assessment and Findings
- We Have Taken Appropriate Corrective Actions for Each Finding
P S E G N U C L E A R L L C 4
HOPE CREEK PIPE FAILURE ROOT CAUSE Michael Gallagher Vice President -
Engineering & Technical Support Michael Gallagher Vice President -
Engineering & Technical Support
P S E G N U C L E A R L L C 5
PIPE FAILURE Condenser Feedwater Heater (3)
High Level Dump Valve Control Normal Level Control Pipe Failure Location High Pressure Turbine Main Steam From Reactor LV1039A Low Pressure Turbine (3)
Moisture Separator (2)
Drain Tank
P S E G N U C L E A R L L C 6
FAILED HANGER Hanger H25 LV1039A
P S E G N U C L E A R L L C 7
ROOT CAUSES/ACTIONS TAKEN A formal Operational & Technical Decision Making process to enable the execution of consistently good decisions The evaluation and decision to operate with the dump valve open did not consider all of the possible failure mechanisms.
Procedure changes to incorporate limitations Operating procedures did not limit operation with the dump valve open.
- Piping repaired
- Nozzle design improved
- Vibration monitoring on piping Extended operation with the dump valve open caused the pipe to fail due to fatigue.
Actions Taken Root Cause
P S E G N U C L E A R L L C 8
EXTENT OF CONDITION REVIEWS Hangers Condenser Nozzles Operating Procedures Operational & Technical Decision Making
P S E G N U C L E A R L L C 9
CONCLUSIONS We have identified the root causes of the pipe failure event.
We have completed all of the actions needed to safely startup and operate the plant.
We have completed extent of condition reviews and have verified no similar conditions exist.
P S E G N U C L E A R L L C 10 AGENDA Chris Bakken President and Chief Nuclear Officer Chris Bakken President and Chief Nuclear Officer
P S E G N U C L E A R L L C 11 AGENDA Introduction Chris Bakken HPCI Turbine Exhaust Line Joe Williams B Recirculation Pump Steve Robitzski and System Conclusion Chris Bakken
P S E G N U C L E A R L L C 12 INTRODUCTION Chris Bakken President and Chief Nuclear Officer Chris Bakken President and Chief Nuclear Officer
P S E G N U C L E A R L L C 13 INTRODUCTION We Will Replace the B Recirculation Pump Shaft During the Next Outage of Sufficient Duration
P S E G N U C L E A R L L C 14 HIGH PRESSURE COOLANT INJECTION (HPCI)
TURBINE EXHAUST PIPING Joe Williams Hope Creek System Engineering Manager Joe Williams Hope Creek System Engineering Manager
P S E G N U C L E A R L L C 15 HPCI EXHAUST PIPING Snubbers Condensate Storage Tank HPCI Pump HPCI Turbine HPCI System Suppression Chamber Reactor Turbine Exhaust
P S E G N U C L E A R L L C 16 HPCI EXHAUST PIPING Piping Snubber 2 ft.
P S E G N U C L E A R L L C 17 HPCI EXHAUST PIPING What Happened?
Two HPCI exhaust piping snubbers were damaged during dynamic bench testing.
One additional snubber had bent extension tube.
Performed extensive walkdowns and examinations of the system.
The HPCI exhaust piping was not damaged.
P S E G N U C L E A R L L C 18 HPCI EXHAUST PIPING Snubber Analysis The damaged snubbers were returned to the manufacturer.
The manufacturers analysis determined that internal components were damaged.
The bent snubber extension tube was visually examined.
Damaged components did not prevent the snubbers from performing their function.
P S E G N U C L E A R L L C 19 HPCI EXHAUST PIPING Possible Causes of Snubber Damage Exhaust line check valve cycling following October 10th event because of unusual system operational alignment.
Vibration due to presence of small amounts of water in system during system operation.
Isolated manufacturing problem with the two damaged snubbers.
P S E G N U C L E A R L L C 20 HPCI EXHAUST PIPING Actions to Address the Three Possible Causes Damaged snubbers were replaced.
System Piping Supports were inspected.
All Exhaust Line Snubbers were inspected and tested.
Repaired steam leakage through Turbine Inlet Valve.
Installed modifications to improve water removal and monitoring for water accumulation in the system.
Repaired the equipment problems to resolve the extended low flow operation of the system.
Exhaust line components will be monitored during system startup and operation.
P S E G N U C L E A R L L C 21 HPCI EXHAUST PIPING Conclusions HPCI system and piping supports operated safely during the October 10th event.
HPCI piping was not damaged.
We have implemented system improvements.
P S E G N U C L E A R L L C 22 RECIRCULATION PUMP AND SYSTEM Steve Robitzski Engineering Manager Steve Robitzski Engineering Manager
P S E G N U C L E A R L L C 23 REACTOR RECIRCULATION SYSTEM
P S E G N U C L E A R L L C 24 REACTOR RECIRCULATION SYSTEM Topics to Discuss B Recirculation Pump Shaft Vibration Recirculation System Vane Passing Frequency Vibration Containment Harmonic Vibration Noise
P S E G N U C L E A R L L C 25 B RECIRCULATION PUMP SHAFT VIBRATION Vibration levels are within industry experience.
There have been no failures of this design shaft in the industry.
Shaft vibration level is stable and has been over several years.
Pump shaft vibration is not significant contributor to other system vibration.
P S E G N U C L E A R L L C 26 ACTIONS Pump Shaft Vibration Pump mechanical seal has been replaced.
Coupling has been balanced and the pump/motor has been aligned.
Pump vibration monitoring plan has been developed including action and alert levels.
Procedures have been revised based on monitoring plan.
We have collected information necessary to design and plan the B pump replacement during next refueling outage.
P S E G N U C L E A R L L C 27 RECIRCULATION SYSTEM VANE PASSING FREQUENCY VIBRATION System flow and pumps are vibration sources in piping systems.
Vibration in piping systems is expected.
Source of energy for vibration in the system is the Recirculation Pump impeller vane pass and not the pump shaft vibration.
Start-up testing is performed on all new piping systems to assess vibration baselines.
P S E G N U C L E A R L L C 28 RECIRCULATION SYSTEM PIPING VIBRATION Typical Vibration Accelerations
P S E G N U C L E A R L L C 29 ACTIONS Piping System Vibration Damaged subcomponents have been repaired, and specific components have been reinforced.
Instrumentation has been installed on selected components.
Acceptance criteria has been developed.
We will monitor system vibration during start up and steady state operation.
P S E G N U C L E A R L L C 30 CONTAINMENT HARMONIC VIBRATION NOISE The noise is only present at Recirculation Pump speeds >1510 RPM.
Administrative limits have been in place since at least 1995 that limit pump operation less than 1510 RPM.
Principal source of noise is believed to be the Recirculation Pump impeller vane passing frequency, and not the pump shaft vibration.
P S E G N U C L E A R L L C 31 ACTIONS Containment Harmonic Vibration Noise Instrumentation has been installed on selected piping locations.
Pump speed will continue to be restricted to
<1510 RPM until testing plan developed and approved.
P S E G N U C L E A R L L C 32 CONCLUSIONS Hope Creek B pump shaft vibration and run hours are within industry experience.
The pump will continue to operate safely during the next operating cycle.
P S E G N U C L E A R L L C 33 CONCLUSION Chris Bakken President and Chief Nuclear Officer Chris Bakken President and Chief Nuclear Officer
P S E G N U C L E A R L L C 34 CONCLUSION Hope Creek Outage Nearly Complete Significant Improvements Made to Plant Confident in Safe Reliable Operation Through Next Cycle