IR 05000335/1994006
| ML17228A530 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 03/24/1994 |
| From: | George Macdonald, Moore R, Shymlock M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML17228A529 | List: |
| References | |
| 50-335-94-06, 50-335-94-6, 50-389-94-06, 50-389-94-6, NUDOCS 9404110122 | |
| Download: ML17228A530 (14) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTASTREET, N.W., SUITE 2900 ATLANTA,GEORGIA 303234199 Report Nos.:
50-335/94-06 and 50-389/94-06 Licensee:
Florida Power and Light Company 9250 West Flagler Street Miami, FL 33102 Docket Nos.:
50-335 and 50-389 License Nos.:
DPR-67 and NPF-16 Facility Name:
St.
Lucie 1 and
Inspection Conducted:
February 28 - March 4, 1994 Inspectors:
. MacDonald, Reactor Inspector orW R. Moore, actor Insp tor 3/4/>2 Date Signed Date Signed Approved by:
M. Shymlock, ief Plant Systems Section Engineering Branch Division of Reactor Safety SUMMARY Date Signed Scope:
This routine, announced inspection was conducted in the areas of Electrical Maintenance and Station Blackout Implementation.
Additionally,Emergency Diesel Generator sequencer relay inspections, modifications, and the Unit 2 protective relay refurbishment activities were reviewed.
Results:
Electrical corrective maintenance items reviewed adequately implemented regulatory requirements for safety related electrical equipment with the exception of the items described in non-cited violations (NCV) 50-335/94-06-01 and NCV 50-389/94-06-02.
Non-cited violation 50-335/94-06-01 was identified for a failure to make a
required report in accordance with the plant technical specifications.
The 1B Emergency Diesel Generator (EDG) failure of April 24, 1992 was not reported to the NRC. (paragraph 2.2)
9404110122 940325 PDR, ADOCK 05000335
Non-cited violation 50-389/94-06-02 was identified for the licensee's failure to implement adequate design controls in Plant Change Modification (PC/M)87-292.
PC/M 87-292 changed the charging pumps and boric acid make-up pumps EDG sequencer load block assignment.
(paragraph 2.3)
The licensee implemented the staff recommendations identified in the Station Blackout (SBO) Supplemental Safety Evaluation (SSE).
SBO procedures and training were implemented.
The unit crosstie modification testing demonstrated that Unit.2 EDGs could provide power to Unit 1.
The licensee's periodic inspections of the safety related General Electric HFA relays have improved the HFA relay reliability as evidenced by the reduced number of HFA relay failures in the latest Unit 2 integrated safeguards test.
Further, the licensee was in the process of replacing these problem relays.
PC/M 183-293 replaced six Unit 2 HFA relays with pull-to-lock switches which will enhance the operators ability to accomplish the unit crosstie evolution within the required 10 minute period.
The Unit 2 protective relay refurbishment activities were adequately controlled.
The relay refurbishments implemented corrective action for a previously identified hardware deficienc Persons Contacted Licensee Employees REPORT DETAILS 2.0
- W. Bladow, guality Manager
- C. Burton, Plant Manager
- L. Clark, Electrical Maintenance Technical Support Supervisor
- J. Dyer, guality Control Supervisor
- J. Hosmer, Plant St. Lucie Engineering Manager
- L. Leon, Engineer, Protection and Controls
- L. McLaughlin, Licensing Manager
- A. Menocal, Mechanical Maintenance Department Head
- J. Riley, Information Services
- L. Rogers, Instrument and Controls Department Supervisor
- M. Smith, Protection and Controls
- D. Stewart, Technical Staff
~J. Walls, guality Assurance
- T. Ware, Technical Training Supervisor
- C. Wasik, Site Engineering
- D. Wolf, Site Engineering Supervisor
- R. Young, Technical Staff Other licensee employees contacted during this inspection included engineers, technicians and administrative personnel.
Other NRC employees
- S. Elrod, Senior Resident Inspector - St. Lucie
- T. Johnson, Senior Resident Inspector - Turkey Point
- L. Trocine, Resident Inspector
- Turkey Point
- Denotes those individuals that attended the exit meeting.
Acronyms and Abbreviations used throughout this report are listed in the last paragraph.
Electrical Maintenance (IP 62705}
The inspectors reviewed'the licensee's maintenance activity on safety related electrical systems.
A sample of maintenance documentation between 1991 and 1994 was selected from the 480 VAC, 120 VAC, and EDG systems.
Aspects of maintenance activity reviewed included procurement of parts and equipment, equipment failure cause analysis, and post maintenance testing.
Additionally, the inspectors reviewed EDG failure reporting over this time period and implementation of Plant Change Modification (PC/M} 87-292.
This PC/M transferred'he Unit 2 charging pumps and boric acid make-up (BAMU} pumps from the 5 minute EDG sequencer load block to the zero load bloc.1 The following maintenance work 93013218 92055432 93003545 93012872 92008235 92055226 93029526 92007774 92008563 92007258 92008665 92045270 93006036 92005019 92055676 93014648 93026514
,
93000635 92056292 93021309 92007093 92011247 92008169 92007351 93009516 93003678 92007586 92007574 93025072 92043386 92000480 92046105 92006312 93004145 92052962 93006620 93022006 92045897 92002817 92049487 92007166 93029493 93014386 92042450 93001137 92001826 93014280 93002236 93020491
.
92002733 93022889 92008287 orders (WOs) were reviewed:
2.2 Task descriptions provided adequate guidance for work activity with references for specific procedures and specified required post maintenance testing.
Measuring and test equipment was appropriately documented for traceability and verification of calibration.
The work orders included documentation which verified that replacement parts and equipment were procured at the appropriate material quality levels.
The inspectors concluded that the above work orders adequately documented electrical maintenance activities.
As discussed in the following paragraph equipment failure analysis was adequately accomplished.
The inspectors noted several occurrences of 480 VAC molded case circuit breaker (MCCB} failures. which were attributed to a broken handle mechanism, e.g.
WO 92045270 and WO 93006036.
The licensee initiated a root cause investigation of this General Electric (GE} MCCB failure mechanism in 1991 through a failure analysis contractor and corresponded with the vendor, GE.
Report No. FPI-91-169, Root Cause Investigation of GE MCCB Failure, concluded the cause was a manufacturing defect.
The vendor disagreed with this conclusion and indicated the failure was attributable to breaker aging and a high number of manual operations.
Although the licensee had not resolved the issue, the investigation activity demonstrated appropriate involvement in equipment failure cause analysis.
EDG Failure Reporting The inspectors reviewed the station EDG operating logs for the 1991 - 1994 period to determine if EDG failures had been identified in accordance with Regulatory Guide (RG) 1.108, Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power Plants, revision 1, and reported to the NRC as required by the licensee's Technical Specifications (TS).
During the inspection entrance meeting on February 28, 1994, the licensee informed the inspectors that they had reviewed EDG documentation the previous week and identified an EDG failure which had not been reported. to the NRC as required by TS 4.8. 1.1.3, Reports.
The failure occurred April 24, 1992,
and was identified as a valid failure on the 1B EDG.
The licensee issued a special report dated March 1, 1994, to comply with the TS reporting requirement.
The inspectors review of the EDG logs did not identify another unreported EDG failure.
The failures which had occurred were categorized in accordance with RG 1. 108.
All EDG failures, including the non-reported failure of April 24, 1992, were accounted for in the EDG reliability determinations for SBO and surveillance intervals.
The licensee's failure to report the April 24, 1992, failure was a violation of regulatory requirements as implemented by TS 4.8.1. 1.3, Reports.
The inspectors reviewed the licensee's identification and correction of this violation to determine if the NRC Enforcement Policy criteria of 10 CFR Part 2, Appendix C, Section VII B for non-cited violations had been met.
The violation was identified by the licensee.
It was not a violation which could have been prevented by corrective actions for a previous finding in the past two years.
The corrective action was accomplished within a reasonable length of time, and the violation was not willful.
This item is identified as non-cited violation NCV 50-335 94-06-01 Failure to Re ort EDG Failure as Re uired b
Technical S ecifications.
2.3 Plant Change/Modification (PC/M)87-292 The inspectors reviewed the licensee's Unit 2 modification which transferred the charging pumps and BANU from the 5 minute sequencer load block to the zero load block.
PC/H 87-'292, Place the CVCS Charging Pumps and BAHU on the EDG Zero Load block, revision 0, was installed during the Unit 2 outage of April, 1992.
During operator simulator training on July 23, 1992, the licensee discovered that this modification introduced an unanalyzed charging pump common mode failure.
Unit 2 was in mode 1 at 100 percent power.
The failure occurred during a loss of offsite power (LOOP) in conjunction with a safety injection actuation signal (SIAS).
Both charging pumps tripped due to a pump stop signal from the charging pump recirculation valve which occurred 180 seconds after the SIAS pump start, as the valve cycled to the full open position.
This recirculation valve trip signal was a feature unique to Unit 2.
The licensee initiated In-House Event Report (IER)92-044 on July 23, 1992, and Problem Report (PR) JB-92-008 on August 3, 1992 to address this issue.
A Substantial Safety Hazard Determination (SSHD)
analysis was also initiated on July 31, 1992 via REA SLN-92-135, to evaluate the impact of the delayed charging flow on the Unit 2 accident analysis.
The IER and PR determined that the problem was not reportable nor safety significant because the charging pump flow could be restored. manually from the control room in eight minutes which was within the ten minute period allowed in the small break loss-of-coolant-accident (SBLOCA) analysis.
The SBLOCA was the only accident analysis which included charging pump input.
The SSHD concluded that the peak cladding temperature would remain substantially below the limits specified in 10 CFR 50.4 The PR concluded that the cause of the problem was design error in that the control wiring diagrams were not adequately reviewed for this modification.
The PR specified the following corrective actions:
l.
Issue a supplement to PC/N 87-292 to restore the time delay for the charging pumps and BAMU to the 5 minute load block.
2.
Analyze the control circuits and provide proposed circuit changes which will allow Unit 2 charging pumps and BAMU to be placed on the zero load block.
3.
Provide the schedule for the PC/M to add the charging pumps to the zero load block, correcting the (recirculation valve cycle) timing problem.
Install the proposed circuits at the simulator prior to PC/M implementation and verify they function as expected.
5.
Issue a policy statement to Engineering defining the extent of engineering analysis required when changing complex circuits, extent of post modification testing required, and to provide simulator testing as a check on proposed changes to complex control circuits prior to implementation.
6.
Include PR JB-92-008 in the Technical Alert Program (TAP) and provide training to the site and PEG engineering groups.
The inspectors verified that the above corrective actions had been implemented.
The charging pump and BANU were returned to the 5 minute load block via PC/N 87-292, supplement I, on August 4 and 5, 1992.
Supplement 2 to PC/M 87-292 dated December 17, 1992, was developed but not installed.
This PC/N supplement will transfer the charging pumps and BANU to the zero load block and resolve the recirculation valve timing problem.
Post maintenance testing for this change included the requirement for simulator testing of the circuit.
guality Instruction, gI 3.1-3, Engineering Packages, revision 8, implemented the program requirement for simulator testing of complex logic circuit changes before plant installation of the change.
The TAP report included PR JB-92-008.
With the exception of the implementation of the PC/M supplement 2 load block change, the above corrective actions were completed.
This design error was a violation of 10 CFR 50 Appendix B, Criterion III, Design Control.
The licensee's measures for design verification and post modification testing failed to identify the design error and an inappropriate design change was implemented on Unit 2.
The inspectors concluded that the licensee's efforts in identifying and correcting the violation meet the criteria specified in section VII.B of the Enforcement Policy for a non-cited violation.
This item is identified as NCV 50-389 94-06-02 Inade uate Desi n Controls on Unit 2 Se uencer Char in Pum Loadin Bloc.1 Station Blackout Implementation (92701)
The inspectors reviewed. the status of the licensee's implementation of station blackout requirements.
The areas reviewed included the licensee's activities on the NRC staff recommendations in the SBO SSE, and the SBO unit cr osstie modification.
SBO SSE Recommendations By letter dated Hay 18, 1992, the NRC issued Supplemental Safety Evaluation (SSE) St. Lucie, Units 1 And 2, Response To Station Blackout Rule.
NRC recommendations as follows:
l.
2.
3.
5.
6.
7.
Complete Unit 1 Ventilation Studies Confirm Unit
RCS Inventory For SBO Complete SBO Procedures For Unit Cr osstie Confirm Unit
EDG Target Reliability Program Meets RG 1.155 Maintain Unit 2 EDG Target Reliability at a.975 Complete SBO EDG Load Analysis Update FSAR To Include SBO Description 3.1.1 Ventilation Studies The licensee prepared calculations to complete the Unit 1 ventilation studies.
The inspectors reviewed the following calculations:
1.
PSL-IFJH-92-049, SBO CEA HG Area Temperature Analysis, revision 0, October 12, 1992.
2.
PSL-IFORM-92-011, Charging Pump Room Temperature Calculation, revision 0, April 17, 1992.
3.
PSL-IFJH-92-030, SBO CR And RAB Area Temperature Calculation, revision 0, October 9, 1992.
007-AS92-C-001, SBO Containment Temperature Analysis, revision 0, August 13, 1992.
The calculated temperatures were w 120'
for all areas analyzed and thus met the recommendations for those rooms identified as condition
rooms per section 2.7 of NUHARC 87-00, revision 1.
The worst case area was the inverter rooms with a maximum ambient temperature of 115.1'.
The licensee modified the controls of HVS-5A/B, RAB Electrical Equipment Room Supply Fans Train A/B, in PC/H 147-193 to automatically load as SBO loads.
This will result in reducing the temperatures in the RAB electrical equipment and inverter rooms since the original analysis assumed no ventilation for 30 minutes.
The containment analysis results indicated a maximum ambient temperature of 165'
which was bounded by the licensee's LOCA analysis.
The licensee had addressed SSE recommendation number 1 above regarding Unit 1 ventilation studie.1.2 RCS Inventory The licensee completed calculation PSL-IFJF-92-042, revision 0, regarding SBO RCS Inventory Analysis.
The results indicated that the RCS inventory would maintain the core covered during the four hour coping duration.
The licensee had addressed SSE recommendation Number
above regarding Unit
RCS Inventory.
SBO Procedures The licensee prepared procedures for response to SBO.
The following procedures were reviewed:
1.
1-EOP-10, Station Blackout Emergency Operating Procedures, revision
2.
1-EOP-99, Emergency Operating Procedure Appendices/Figures/Tables, revision
3.
4.
2-EOP-10, Station Blackout Emergency Operating Procedures, revision
2-EOP-99, Emergency Operating Procedure Appendices/Figures/Tables, revision 8 The procedures contained guidance for diagnosing SBO and instructions for SBO mitigation and restoration.
Specific instructions were included for accomplishing the unit crosstie evolution to utilize the Unit 2 EDGs as AAC sources for a Unit
SBO.
Guidance for use of Unit
EDGs as AAC sources for a Unit 2 SBO was also provided.
The procedures contained detailed EDG loading instructions including a listing of allowable EDG KW load values to support starting of LOOP and SBO.loads.
The licensee had completed training for operations personnel on the SBO procedures.
The inspectors reviewed. the licensed operator requalification program lesson plan 0802229, Station Blackout Modification Study Guide.
The guide included training on SBO diagnosis, SBO mitigation, SBO unit crosstie, and SBO restoration.
The inspectors reviewed training records and verified that simulator training had been conducted for operations personnel on accomplishing SBO unit crosstie evolutions.
The training provided was 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of classroom instruction and 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of simulator exercises.
The licensee had addressed SSE recommendation number
regarding SBO procedures.
EDG Reliability Program The inspectors reviewed the licensee's EDG reliability program to determine if the requirements of RG 1. 155, position C. 1.2 were implemented.
Administrative Procedure (AP) No. 0010022, Emergency Diesel Generator Reliability Program, revision 0, established the program at St. Lucie.
The purpose of the procedure was to track EDG reliability and provide plant management with information to ensure EDG reliability was maintained at or above SBO target reliability level.1.5 3.1.6 The procedure designated a target reliability of 0.975 with trigger values of 3, 4, and 5 failures for 20, 50, and 100 starts respectively.
This was consistent with the St. Lucie plant category and coping duration values.
The licensee's TS surveillance test program for EDG testing meets the RG 1. 155 criteria for an EDG surveillance test program.
Procedure AP-0010022 designated the responsibility for monitoring EDG reliability to the EDG system engineer.
The procedure additionally required periodic reporting to management of EDG reliability levels.
EDG Target Reliability The inspectors reviewed the licensee's reliability monitoring information and verified that existing reliability levels were measured against the target values and management was appropriately informed.
Interoffice memoranda dated June '10, 1993, and December 31, 1993 communicated EDG reliability to management.
The June 10, 1993 memorandum identified to the site vice president that Unit 2 EDGs met the 0.975 criteria however, Unit
EDGs exceeded a single trigger condition because of five failures in the last 100 starts.
The memorandum also included a description and results of all actions taken, as required for exceeding a single trigger value.
The December 31, 1993, memorandum to the Technical Support Supervisor reported that the EDG reliability was 0.975 and 0.99 for Units 1 and 2 respectively.
The inspectors concluded that the licensee had developed and implemented an EDG reliability program consistent with the requirements of RG 1. 155.
The licensee had addressed SSE recommendations numbers 4 and 5 regarding Unit
EDG reliability program and Unit 2 EDG target rel iabil ity.
EDG Load Analysis The licensee completed steady state and transient EDG loading analyses for the EDGs.
The inspectors reviewed the following calculations:
1.
PSL-OFJE-93-004, St.
Lucie Station Blackout Emergency Diesel Generator Transient Analysis, revision
2.
PSL-I-FJE-90-013, St.
Lucie Unit
EDG 1A and 1B Electrical Loads, revision
3.
PSL-2-FJE-90-020,.St. Lucie Unit 2 EDG 2A and 28 Electrical Loads, revision
The Unit 1 SBO, Unit 2 NBO EDG calculation indicated an EDG loading of 3451 kw peak and 3121 kw steady state which was w the EDG continuous rating of 3685 kw.
Unit 1 SBO, Unit 2 NBO EDG transient response calculation results indicated that SBO transients would not exceed the vendor load profil The Unit 2 SBO, Unit
NBO calculation indicated an EDG loading of 3302 kw steady state which was w the EDG continuous rating of 3500 kw.
The licensee had addressed SSE recommendation number 6 regarding EDG loading analysis.
3.1.7 FSAR Update The licensee had performed the Unit
The Unit 2 FSAR update for SBO will be included in the next periodic FSAR update.
The licensee addressed SSE recommendation number 7 regarding FSAR update.
3.2 SBO Unit Crosstie Modifications Licensee PC/M 028-190 for Unit 1 and PC/M 290-289 for Unit 2 implemented the crosstie between units 1 and 2.
The modification utilized existing safety related 4 kV breakers in buses 1AB and 2AB to crosstie the units.
The modification allowed either EDG from either unit to power either safety related bus in the opposite unit.
The modifications were performed as safety r elated modifications.
The crosstie modification met the requirements of RG 1. 155.
New material utilized for the modification was procured as safety related equipment.
A spare breaker in bus 2AB and the 1C HPCI breaker in bus 1AB wer e utilized for the crosstie breakers.
The modification installed new cable between buses lAB and 2AB and modified the breaker cubicles to serve as feeder breakers with changes to the protection and controls.
The inspectors reviewed the modification and verified that the new equipment had been installed.
New meters, key-lock switches, and annunciators had been installed in each control room for breaker operation and control.
The inspectors reviewed breaker controls and verified that the breakers could only be operated from the control room.
Local operation was only possible with the breakers racked to the test position.
Review of the modification indicated that cable pull deficiencies occurred.
The inspector verified that the deficiencies were resolved prior to post modification testing.
The modification initially used an existing unsuitable relay within the breaker control circuit.
This deficiency and another wiring deficiency were discovered during post modification testing.
Change request notices CRN 028-190-3712 and 290-289-3713 for units 1 and 2 respectively were written to replace the relays.
The post modification testing was satisfactorily completed.
The testing demonstrated that the Unit 2 EDGs could energize the lAB bus via the crosstie modification.
EDG Sequencing HFA Relays and PCM 183-293 (IP 62705)
Failures of safety related GE HFA latching relays have occurred at St.
Lucie.
The inspectors reviewed this issue to determine the adequacy of licensee corrective actions.
The failures were discussed in NRC Inspection Report 50-335,389/93-14.
The licensee has implemented
periodic visual latch engagement inspections of the safety related GE HFA relays.
Twenty-three relays have been inspected and 3 relays required adjustment.
Test results after implementation of the latch engagement inspections have shown fewer HFA relay failures.
Due to the poor reliability of the HFA relays, the licensee prepared PC/M 183-293 to replace the GE HFA latching relays with pull-to-lock switches with slip contacts.
The PC/M replaced the GE HFA relays for the ICW and CCW pumps in Unit 2.
The inspectors reviewed the modification package and determined that the new control scheme was adequate.
The modification was in progress and the inspectors observed the installation of switches in the control room.
The switches were installed, in accordance with modification requirements.
Installation was adequate, however loose washers were not cleaned up after installation.
The post modification testing specified in the PCM was reviewed.
The testing checked all control circuit interlocks and functions.
The outage schedule did not allow the inspectors to witness the testing during this inspection.
The resident inspectors will observe the post modification testing.
The inspectors concluded that the licensee corrective action regarding safety related GE HFA relays in Unit 2 was adequate.
Unit 2 Protective Relay Refurbishment (IP 62705)
The licensee identified a hardware deficiency regarding protective relay internal wiring.
The Unit I relays were refurbished during the Unit I 1993 refueling outage.
This issue was discussed in NRC Inspection Report 50-335,389/93-14.
The inspectors reviewed-the Unit 2 protective relay refurbishment activities to determine the adequacy of licensee corrective action.
All Unit 2 safety related protective relays were scheduled to be rewired or replaced during this Unit 2 refueling outage.
The licensee was responsible for managing the work under their gA program with relay vendor technicians performing the relay refurbishment activities onsite.
The licensee prepared procedures to control relay refurbishment, dedication of material, and gC inspection and acceptance activities.
The inspectors reviewed the procedures and determined that the refurbishment activities were adequately controlled by the procedures.
The inspectors witnessed refurbishment of several relays and verified that the refurbishment was conducted in accordance with the procedures and the vendor relay drawings.
Adequate gC hold points were utilized and the inspectors concluded that the refurbishment activities were well controlle s.
7.
Exit Meeting
The inspection scope and results were summarized on March 4, l994 with those individuals indicated in paragraph 1.
The inspectors described the areas inspected and discussed in detail the inspection findings listed below.
There were no dissenting comments received from the licensee.
Proprietary information is not contained in this report.
Non-Cited Violation NCV 50-335/94-06-01, Failure to Report EDG Failure as Required by Technical Specifications Non-Cited Violation NCV 50-389/94-06-02, Inadequate Design Controls on Unit 2 Sequencer Charging Pump Loading Block Abbreviations'and Acronyms AAC AP BAHU CCW CEA CR CRN CVCS EDG EOP FSAR GE HPCI ICW IER
.IP kv LOCA LOOP MCCB NBO NCV NRC NUHARC PC/H PEG PSL gA gC gI RAB RCS REA RG Alternate Alternating Current Administrative Procedure Boric Acid Hake-Up Component Cooling Water Control Element Assembly Control Room Change Request Notice Chemical and Volume Control System Emergency Diesel Generator Emergency Operating Procedure Final Safety Analysis Report General Electric High Pressure Coolant Injection Intake Cooling Water In-House Event Report Inspection Procedure Kilo-volts Alternating Current Loss of Coolant Accident Loss of Offsite Power Molded Case Circuit Breaker Non-Blackout Non-Cited Violation Nuclear Regulatory Commission Nuclear Management and Resources Council Plant Change Modification Production Engineering Group Plant St. Lucie guality Assurance guality Control
.guality Instruction Reactor Auxiliary Building Reactor Coolant System Request for.Engineering Assistance Regulatory Guide
SBLOCA SBO SIAS SSE SSHD TAP VAC WO
Small Break Loss of Coolant Accident Station Blackout Safety Injection Actuation System Supplemental Safety Evalution Substantial Safety Hazard Determination Technical Alert Program Volts Alternating Current Work Order