IR 05000528/1998007
| ML17313A668 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/04/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML17313A667 | List: |
| References | |
| 50-528-98-07, 50-528-98-7, 50-529-98-07, 50-529-98-7, 50-530-98-07, 50-530-98-7, NUDOCS 9811100235 | |
| Download: ML17313A668 (45) | |
Text
ENCLOSURE LI.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Docket Nos.:
License Nos.:
Report No.:
Licensee:
Facility:
Location:
Dates:
inspectors:
Approved By:
50-528 50-529 50-530 NPF-41 NPF-51 NPF-74 50-528/98-07 50-529/98-07 50-530/98-07 Arizona Public Service Company Palo Verde Nuclear Generating Station, Units 1, 2, and 3 5951 S. Wintersburg Road Tonopah, Arizona August 23 through October 3, 1998 J. Moorman, III,Senior Resident Inspector D. Carter, Resident Inspector D. Corporandy, Resident Inspector N. Salgado, Resident Inspector G. Pick, Senior Project Engineer W. Walker, Senior Resident Inspector P. Harrell, Chief, Project Branch D ATTACHMENT:
Supplemental information 98iii00235 98ii04 PDR ADQCK 05000528
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EXECUTIVE SUMMARY Palo Verde Nuclear Generating Station, Units 1, 2, and 3 NRC Inspection Report 50-528/98-07; 50-529/98-07; 50-530/98-07
~Oerations The Unit 3 reactor shutdown for the seventh refueling outage was well planned and conducted in accordance with procedures.
Supervisory oversight and direction of the operating crew and operator performance during the shutdown were excellent (Section 01.1).
Operator oversight and direction of the evolution to drain Unit 3 to the midloop condition, and decisions to take conservative actions during the evolution, were excellent (Section 01.2).
Observation of core offload activities associated with the Unit 3 refueling outage indicated that refueling personnel consistently used good communications and demonstrated a safety-conscious approach to performing refueling operations (Section 01.3).
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Corrosion induced failure of a nonsafety-related pressure switch in the secondary plant caused Unit 1 to experience a power transient.
Operator response to the transient was good (Section 02.1).
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An unclear work plan for preparing the Unit 1sulfuric acid system for maintenance, and failure of auxiliary operators to followthe work plan for establishing a vent path for the acid day tank, contributed to the rupture of the tank. The recovery plan following the incident was prompt and appropriate (Section 02.2).
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The control room staff responded in a prompt manner to the loss of a nonsafety-related load center in Unit 3. The operations crew exhi~"ed good oversight of activities during the response by appropriately prioritizing the critical plant parameters in order of safety significance.
However, recognition that the safety-related battery chargers had been lost at the onset of the event was not accomplished in a timely manner.
Once discovered, corrective actions were accomplished to restore the battery chargers (Section 04.1).
h1aintenance Qualified engineers and technicians used approved procedures to effectively conduct main steam safety valve testing.
The licensee promptly and appropriately considered the affect of Unit 3 main steam safety valves, with out-of-tolerance setpoints, on the other two units. When a similar problem was identified in Units 1 and 2, the licensee conducted testing in a timely manner and returned out-of-tolerance main steam safety valves to Technical Specification acceptable values (Section M1.3).
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proactive approach for the prevention of material condition deficiencies caused by boric acid corrosion was implemented by the licensee.
Pre-outage containment
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-2-walkdowns and zone inspections of auxiliary building components resulted in the early identification of potential problems that would result from boric acid corrosion (Section M2.1).
A prejob sensitive issues brief for transferring new fuel assemblies from dry storage to the spent fuel pool was characterized by poor communications and poor questioning attitude displayed by all participants.
This was evidenced by the lack of a thorough discussion of contingencies for possible problems and unfamiliarity with the requirement for the fuel building roll up door to be fullyfunctional prior to new fuel movement.
Once begun, the fuel transfer was conducted in accordance with approved procedures (Section M4.1).
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The initial documented evaluation of an information notice did not fullyaddress the issue of the refueling water tank level instrumentation being affected by the fuel building ventilation system.
However, instrument uncertainty appropriately accounted for the maximum level error that the refueling water tank, would experience due to ventilation system operation (Section E4.1).
Plant Su o
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An untimely initial declaration (44 minutes) of a Notification of Unusual Event was made in response to rupture of the Unit 1 sulfuric acid day tank because the shift manager left the control room to personally assess the scene instead of implementing his emergency response responsibilities (Section 02.2).
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Re ort Details Summa of Plant Status Unit 1 operated at 100 percent power throughout this inspection period until August 31, 1998, when a power transient caused by a failed nonsafety-related moisture separator reheater (MSR) pressure switch resulted in a power decrease to approximately 93 percent power. Operators reduced power to 90 percent to stabilize the unit. See Section 02.1 for details.
On September 1, the unit was returned to 100 percent power after the failed pressure switch was replaced and remained there for the duration of this inspection period.
Unit 2 operated at essentially 100 percent power for the duration of this inspection period, Unit 3 operated at 100 percent power until August 29, at which time the unit began a coastdown.
On September 19, the unit was shut down for the planned seventh refueling outage.
Midloop conditions were established on September 22 to support steam generator nozzle dam installation during the outage.
See Section 01.2 for details.
I. 0 rations
Conduct of Operations 01.1 P a wn Un't a.
In cti n S e 71707 On September 18 and 19, 1998, the inspectors observed the control room (CR) staff commence a planned reactor shutdown in preparation for the seventh refueling outage.
b.
Observ ion and Findin s Approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> prior to shutdown, operators commenced a pov,~: reduction from 80 to approximately 20 percent power in accordance with Procedure 40OP-9ZZ05,
"Power Operations," Revision 22, and the Shutdown Plan. Reactor engineering had prepared a detailed power reduction plan to maintain the axial shape index (ASI) within a predetermined band as power was reduced.
The predicted ASI values were continuously monitored to ensure that they remained within the acceptable band, which provided for significant margins to keep the ASI values well below the upper and lower limits as power was reduced.
Actual measured ASI values were verified to be very close to predicted values.
The reactor was tripped from approximately 20 percent power at 12 a.m. on September 19. Following the trip, the operators performed Procedures 40EP-9EO01, "Standard Post Trip Actions," Revision 2, and 40EP-9EO02,
"Reactor Trip," Revision 1.
The CR supervisor (CRS) displayed excellent oversight and direction during the reduction in power prior to the trip and during performance of post-trip activities. The shift manager provided excellent supervisory oversight of the CR staff. The shutdown was monitored by key managers, as well as a representative from the Nuclear Assurance Department.
The reactor engineer played a key role in monitoring and
-2-advising on reactor parameters during the downpower preceding the reactor trip. The CR operators exhibited excellent attentiveness and responsiveness to plant conditions.
Proper three-way communications were implemented by the CR staff.
Conclusions The Unit 3 reactor shutdown for the seventh refueling outage was well planned and conducted in accordance with procedures.
Supervisory oversight and direction of the operating crew and operator performance during the shutdown were excellent.
Midloo /Reduced Invento Activities Unit 3 Ins ection Sco e 71707 On September 21 and 22, 1998, the licensee drained the reactor coolant system (RCS)
to the midloop condition using Procedure 40OP-9ZZ16, "RCS Drain Operations,"
Revision 10. This was done to allow installation of steam generator nozzle dams in preparation for eddy current testing of the steam generator tubes.
The inspectors reviewed the licensee's preparations for midloop operations, including specific training on this evolution. Inspectors, observed CR operators as they performed the various evolutions.
Observations and Findin s The licensee augmented the onshift operating crew with a team dedicated to perform midloop operations.
The midloop'team was comprised of a CRS, reactor operator (RO),
and shift technical advisor (STA), who acted as the midloop coordinator.
There was a clearly defined division of the CR activity oversight between the midloop team and the normal shift crew. The inspectors observed that the midloop team maintained positive control of the evolution at all times.
The inspectors noted that the dedicated midloop crews had undergone midloop training approximately 1 week prior to the scheduled draindown to midloop. The inspectors reviewed Procedure 40OP-9ZZ16 prior to the reduction of RCS inventory and verified that all the prerequisites were met.
From discussions with the midloop crew members, the inspectors determined that the crew was knowledgeable of the draindown procedure, contingency plans, and the shutdown risk assessment.
The inspectors verified that the licensee had calculated and was sensitive to the short amount of time that existed between loss of shutdown cooling and boiling in the core.
The licensee minimized unnecessary work while the unit was in a reduced inventory condition. To prevent loss of shutdown cooling or RCS level perturbations, the licensee
'tationed a senior RO at the entry of the auxiliary building to screen work activities.
In addition, the licensee maintained sources of offsite and onsite power available and limited access to critical equipment areas.
The licensee also limited open containment penetrations during reduced inventory and midloop operations and had a plan in place to close the open containment penetrations in the event of a threat to fuel integrit l I
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-3-On September 22 at 12:25 a.m., the midloop RO secured the RCS drain down at 111 feet, 6 inches, in accordance with Procedure 40OP-9ZZ16, to allow level indicators to stabilize. At 12:26 a.m., the CR received a report of a flash and loud bang in the area of Load Center 3ENGN-L02. Loss of this load center resulted in numerous alarms being received in the CR. The licensee's response to this event is discussed in Section 04.1 of this report. The draindown was halted while operators addressed the loss of'Load Center 3ENGN-L02.
The draindown was recommenced at 8:16 a.m. and the inspectors observed the completion of the draindown.
Reactor vessel level indication was provided by narrow-and wide-range level instruments and by a gage glass system.
The inspectors noted that the narrow-and wide-range instruments provided accurate level indication as determined by agreement and overlap between the different trains of indication during the draindown.
However, one train of indication of the gage glass system was sluggish and did not agree with the other instruments at the time that it should have begun indicating. Since Procedure 40OP-9ZZ16 required agreement between the instruments, the draindown was stopped to address the discrepancy.
After troubleshooting the gage glass anomaly, the crew determined that the gage glass was unreliable.
Procedure 40OP-9ZZ16 allowed the draindown to continue, with management concurrence, if one of the instruments was determined to be unreliable. The Director of Operations was in the CR observing the draindown and gave the approval to continue.
To compensate for the unreliable gage glass, the draindown was stopped when the narrow-range instruments indicated level was 8 inches above the centerline of the hot legs to allow a visual verification of level by removal of a steam generator hot leg manway. After removal of the manway, level was visually verified to be consistent with the instrumentation and the draindown was completed.
The midloop team, onshift operating crew, and operations management demonstrated a safety conscious approach to reduced inventory operations.
Conclusions Operator oversight and direction of the evolution to drain Unit 3 to the midloop condition, and decisions to take conservative actions during the evolution, were excellent.
Full-Core Offload Unit 3 Ins ection Sco e 71707)
The inspectors observed portions of the licensee's performance of a full-core offload as controlled by Procedure 72IC-9RX03, "Core Reloading," Revision 11.
Observations and Findin s The core offload activities were controlled by the guidance provided by Procedure 72IC-9RX03. The refueling senior reactor operator (SRO) was in charge of the overall fuel movement process and was stationed in containment to directly
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-4-supervise core alterations.
Good communications were observed between the refueling SRO, fuel pool bridge operator, and CR. The inspector independently verified that both startup channels were operable during the fuel movement.
Conclusions Observation of core offload activities associated with the Unit 3 refueling outage indicated that refueling personnel consistently used good communications and demonstrated a safety-conscious approach to performing refueling operations.
Operational Status of Facilities and Equipment Failure of MSR S stem Pressure Switch Unit 1 Ins ection Sco e 71707 On August 31', 1998, at 3:11 a.m., Pressure Switch 1 JMTNPSL512 (PSL-512), which measures main steam reheat pressure, failed low. Following the failure of the pressure switch, reactor power was initiallydecreased to 93 percent by the operations staff and was subsequently decreased to 90 percent to stabilize the unit. The inspectors discussed this event with operations personnel and reviewed the event documentation.
Observati nsandFin in s When Pressure Switch PSL-512 failed low, as designed, the indicated low pressure (<10 percent of full load pressure) caused the MSR first stage reheater drain tank high level dump valves to open, the second stage steam supply valves to close, and the MSR shell drain high level dump valves to open, which caused a loss of flow to the heater drain tanks. The levels in both heater drain tanks dropped below 4 feet (the low-low level heater drain pump trip setpoint); however, only Heater Drain Pump B tripped.
Heater Drain Pump A did not trip as expected.
Allother plant equipment responded as required, The loss of flowfrom Heater Drain Pump B resulted in a decrease of feedwater flow.
With Heater Drain Pump B tripped, the excess condensate from the feedwater heater shells was diverted directly to the condenser at a location that caused flow induced vibration to the condenser tubes.
The operators returned I'eater Drain Pump B to service to avoid this vibration. Since failure of Pressure Switch PSL-512 caused a number of valves in the heater drain system to change position, the Operations department developed an action plan to minimize the impact on the heater drain system when Pressure Switch PSL-512 was replaced and the <10 percent of full-load pressure signal was cleared.
Part of the plan required the first stage reheat to be valved out of service.
With both stages of reheat out of service, it was necessary to limit reactor power to 90 percent.
Pressure Switch PSL-512 was replaced, and the operators implemented the action plan without incident. Unit 1 was returned to 100 percent power on September Jt
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-5-Pressure Switches PSL-512 and -513 on all three units had been scheduled for replacement as a result of a Unit 3 switch failure in 1997.
Replacements had been prioritized according to time in service.
The licensee's root cause analysis for the failed Unit 3 pressure switch concluded that the bellows would leak before it would break.
The licensee had implemented an inspection schedule for the pressure switch bellows leakage based on an identified period of time, which would provide sufficient time to observe bellows degradation before it became ino'perable.
Consequently, initial investigation of the failure of Pressure Switch PSL-512 focused on its brass bellows.
Some degradation of the brass bellows was observed, though not to the extent of the brass bellows in the similar Unit 3 switch. However, a corroded microswitch in Pressure Switch PSL-512 appeared to have caused its failure and the corrosion appeared to have resulted from minor water intrusion through the degraded brass bellows.
Following the discovery of the corroded microswitch, the licensee initiated actions to confirm the adequacy of the microswitches for the other five pressure switches.
Unit 1 Pressure Switch PSL-513 was determined not to be an immediate concern since it had been'replaced only a few months earlier.
Unit 3 was coasting down toward a refueling outage, at which time its two pressure switches were scheduled to be replaced.
Prior to the end of this inspection period, the inspectors confirmed that both Unit 3 pressure switches were replaced.
The licensee inspected the Unit 2 pressure switches.
No corrosion was observed.
The licensee plans to replace the Unit 2 pr~ssure switches
" prior to the end of this year.
The licensee also investigated the reason for Heater Drain Pump A not tripping. The investigation identified that a switch in the Heater Pump A trip circuitry acted erratically, so the switch was'replaced.
Conclusions Corrosion induced failure of a nonsafety-related pressure switch in the secondary plant caused Unit 1 to experience a power transient.
Operator response to the transient was.
good.
02,2 Ru ture of Sulfuric Acid Da Tank Unit 1 a.
Ins ection Sco e 93702 On September 10, 1998, at approximately 2:56 a.m., the Unit 1 sulfuric acid day tank ruptured. The licensee declared a Notice of Unusual Event (NOUE). The resident inspectors were notified and responded to the site. The'inspectors observed the condition of the ruptured acid day tank and surrounding area, reviewed the Unit 1 CR logs, Condition Report/Disposition Request (CRDR) 1-8-0466, documentation of the associated equipment root cause failure analysis, written statements of personnel involved with the incident, and the licensee's recovery action I I
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-6-Observations and FIndin s The sulfuric acid storage tank has two pipes installed, one to the chemical waste neutralizing tank (CWNT) and the other to the acid day tank.
In preparation for modification work to a check valve in the acid transfer system, a technician was performing an air purge of the piping to the acid day tank. Successful purges of the piping and the valve modification had already been completed on Units 2 and 3. The technician that was performing the purge of the Train 8 acid transfer piping had successfully performed the purge on the Train A acid transfer piping 2 days earlier.
In accordance with the licensee's standard practice, the technician purged the air hose for approximately 30 minutes to ensure the air source was dry prior to connecting the hose to the suction side of the Transfer Pump B for the system purge.
The source of the purge air was unregulated instrument air with a nominal header pressure of 110 psig.
The licensee did not have any special procedures or instructions for purging the acid transfer system; however, a written plan had been prepared for guidance.
When the purge was performed in Unit 2, the demineralizer operator who performed the purge suggested that, for subsequent purges, the valves to the CWNT be opened.
This suggestion was not incorporated prior to the Unit 3 acid transfer system purges; however, it was incorporated into the written plan for purge of the Unit 1 acid transfer system The demineralizer operator performing the Unit 1 acid transfer system purge did not open the valves to the CWNT as instructedby the plan. The licensee's evaluation of the incident also noted that the step in the plan to open the CWNT valves did not warn operators of the need to have the valves open to prevent overpressurization and did not clearly specify the sequence for opening the valves.
Although a final determination of the causes of the acid tank rupture has not been completed, opening of the valves to the CWNT would have provided a pressure relief path. Approximately 20 seconds after the technician connected the air purge line to the suction side of the Acid Transfer Pump Train B and began the purge, the technician heard what he described as a loud explosion.
Upon hearing the explosion, the technician immediately closed the air purge valve and proceeded to the acid day tank. The technician entered the turbine building and observed fumes and vapor coming from the area of the acid day tank. He left the area and called the Unit 1 CR to inform the shift manager of an explosion and damage in the turbine building.
Shortly after receiving the call, the site and shift managers left the CR to survey the damage and to make sure that no personnel were injured. The site shift manager returned to the CR at 3:11 a.m., determined that a NOUE should be declared, and notified the CRS of his evaluation.
The CRS stated that he would get the shift manager back to the CR to make the call. The shift manager returned to the CR at 3:30 a.m. and at 3:40 a.m. declared a NOUE. The shift manager then exited the NOUE based on the acid leak havirig been contained and isolated.
Procedure 16DP-OEP13, "Emergency Classification," Revision 1, stated that emergencies should be classified within a goal of 15 minutes from the time conditions are specified.
This procedure also stated that it is the responsibility of the affected unit
-7-shift manager to determine the initial classification of the event per the procedure and to organize the onshift staff to place the plant into a safe condition. Section 4.0 of the procedure, which provided guidance on event classification, indicated that a NOUE should'be declared for an explosion affecting the protected area resulting in visible damage.
Approximately 44 minutes elapsed from the time the technician reported the acid day tank "explosion" to the CR until the NOUE was declared.
The inspectors reviewed Palo Verde docketed information to ascertain if, with regard to event notification, any prior weaknesses had been identified. NRC Inspection Report 50-528/97-10: 50-529/97-10:50-530/97-10 documented inspection of the implementation of the licensee's emergency plan during their biennial emergency preparedness exercise.
An exercise weakness was identified for the licensee's failure to promptly recognize and declare a NOUE. The licensee's response letter, dated July 18, 1997, stated that the causes of the failure to promptly recognize and declare a NOUE were the artificialityof the exercise scenario and personnel error by the shift supervisor for failing to remove himself from the immediate operation of the plant and followprocedural and training guidance.
In this acid day tank rupture event, the licensee took 44 minutes to declare a NOUE, from the time sufficient information was available to satisfy the procedural requirements for the event declaration until the shift manager returned to the CR. By deciding to leave the CR to survey the scene the shift manager was not available to conduct his emergency response responsibilities, which included timely initial classification of this event.
During review of this issue, no violation of NRC regulatory requirements were identified; however, the untimely declaration of the NOUE was considered a weakness in the implementation of the emergency response plan.
Following the rupture of the Unit 1 acid day tank, the licensee suspended all further purge activities to the Units 2 and 3 acid day tanks. The Unit 1 acid tank and adjacent area were immediately quarantined to prese.":~ the as-found conditions.
Radiation protection technicians surveyed the adjacent area and floor drains to confirm that no release of radioactivity had occurred.
Once measurements of pH were taken to assess the magnitude of the acid spill, the area was neutralized and cleaned.
A temporary modification was implemented to replace the damaged acid day tank with a tanker as the source of sulfuric acid for the condensate demineralizer regeneration system.
A 10 CFR 50.59 screening was performed to validate the adequacy of the temporary modification. The tanker was positioned in the yard korea near the entrance of the turbine building closest to the ruptured acid day tank. Connections to the demineralizer regeneration system were made via a transfer hose, and hose connections outside of bermed areas were provided with a drip catch.
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Conclusions An untimely initial declaration (44 minutes) of a Notification of Unusual Event was made in response to rupture of the Unit 1 sulfuric acid day tank because the shift manager left the control room to personally assess the scene instead of implementing his emergency response responsibilities.
An unclear work plan for preparing the Unit 1 sulfuric acid system for maintenance, and failure of auxiliary operators to followthis work plan for
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The recovery plan following the incident was prompt and appropriate.
Operator Knowledge and Performance 04.1 Res onse to the Loss of Load Center 3ENGN-L02 Unit 3 a.
Ins ection Sco e 71707 On September 22, 1998, nonsafety-related Load Center 3ENGN-L02 experienced a phase-to-phase fault, which affected a number of electrical loads in the plant. At the time of this event, the plant was in a cold shutdown condition. The inspectors were present in the CR at the time of the event and observed the performance of the operations crew in responding to the event. The inspectors also reviewed logs of the event and procedures used by the operators.
b.
Observations and Findin s On September 22, '1998, at 12:26 a.m., multiple alarms were received in the CR.
Concurrent with the alarms, the CR received a call from an auxiliary operator (AO) who reported a loud bang and a flash coming from the vicinityof Load Center L02. Smoke was reported in the vicinityof the load center, but no visible damage or flames were observed.
A fire emergency event was declared and the onsite fire department was contacted and responded to the scene.
Procedure 16DP-OEP13, "Emergency Classification," Revision 1, was referenced, but the shift manager determined that the plant conditions did not warrant any emergency classification. The inspectors independently confirmed that no emergency classification'was appropriate.
When Load Center 3ENGN-L02 tripped, Load Centers 3ENGN-L06 and -L16, also deenergi
".". since they were supplied by load. Upon receipt of the alarms, the inspector observed a prompt and orderly response by the CR staff. Shutdown cooling and RCS parameters were verified to be unaffected by the dedicated midloop team, which then maintained continuous monitoring of shutdown cooling and RCS parameters.
The applicable sections of Procedure 40NO¹AO-9ZZ12, "Degraded Electrical Power,"
Revision 5, were performed.
The Train B Essential Chiller tripped at the onset of the event. An AO was sent to access the condition of the chiller. The chiller was restarted once the AO was able to confirm that there was no apparent damage or deficiencies at the chiller.
Various other equipment affected by the loss of Load Centers 3ENGN-L02, -L06, and-L16 were checked and restarted where appropriate.
Applicable Technical Specification (TS) Limiting Conditions for Operation (LCO) were entered and exited as appropriate.
In accordance with the applicable procedures, notifications were made on the plant loudspeaker system to affected plant personnel.
For example, when Load
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-9-Center 3ENGN-L06 deenergized, the breathing air compressor tripped, and plant personnel were informed over the plant loudspeaker system to discontinue associated activities.
In parallel with these activities, the STA performed Safety System Functional Status Checks from Procedure 40EP-9E011, "Lower Mode Functional Recovery," Revision 2, to confirm that required plant equipment and components were adequately functioning.
By 1:08 a.m., the licensee had determined that Load Center 3ENGN-L02 had likely experienced a phase-to-phase ground in the 13.8-kV to 480-Vac transformer as a result of water intrusion into the load center cabinet.
I The CRS provided oversight and direction for the numerous activities resulting from the loss of Load Centers 3ENGN-L02, -L06, and -L16. The CR staff were prompt and orderly in their response to the event and activities were appropriately prioritized to address critical plant parameters in order of safety significance. After significant safety parameters were stable and controlled, the computer alarm data was checked and alarm responses were addressed in accordance with applicable procedures.
At 1:40 a.m., during review of the computer alarm data, the midloop RO identified that Battery Chargers B and D had not been supplying the respective batteries and buses since the onset of the event at 12:26 a.m. Upon discovery, the licensee immediately entered Condition B of TS LCO 3.8.5. Action B.1 of the LCO stated that, with the required dc electrical power subsystem inoperable, the affected battery cell parameters were to be verified to meet Table 3.8.6-1 limits within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter.
Once identified, the crew took prompt and appropriate actions to restore the battery chargers.
During review of the root cause for not identifying the loss of the battery chargers in a more timely manner, the inspectors noted that the method used by the STA to perform the safety system status check was narrowly focused.
The guidelines provide the specific indications to '. erify; however, a compl>>~ understanding of the plant status may not, in all cases, be obtained by using these indications.
In this specific instance, the STA checked the voltage on the dc bus, as specified by the procedure, to verify it was satisfactory, but did not observe indications adjacent to the voltage meter which would have provided the information for determining the battery chargers were not in service.
The inspectors discussed this observation with the licensee.
The licensee stated that training of the use of the safety system status check
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would be enhanced to ensure that personnel monitored al: available indications when performing the checks.
The inspectors considered the identification of the battery charger problem to be untimely since the TS allowed outage time was 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and control board indications existed to inform the crew that the chargers were not supplying the respective buses.
Conclusions The CR staff responded in a prompt manner to the loss of a nonsafety-related load center in Unit 3. The operations crew exhibited good oversight of activities during the response by appropriately prioritizing the critical plant parameters in order of safety
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significance.
However, recognition that the safety-related battery chargers had been lost at the onset of the event was not accomplished in a timely manner.
Once discovered, corrective actions were accomplished to restore the battery chargers.
Miscellaneous Operations Issues 08.1 Closed Licensee Event Re ort LER 50-528/98-005-00:
Missed Response Time Test For Reactor Protection Instrumentation.
This event was discussed and dispositioned as a noncited violation in NRC Inspection Report 50-528,-529,-530/98-04.
No new issues were revealed during review of this LER.
II. Maintenance M1 Conduct of Maintenance M1.1 General Comments on Maintenance Activities a.
Ins ection Sco e 62707 The inspectors observed all or portions of the following work activities:
848674
"Repair Drain Valve 3PSIAV032 on HPSI Discharge" (Unit 3)
762508
"Installation of LPSI Pump Shaft Modification"(Unit 3)
768223
"install a Bonnet Bypass Spring Check to Relieve Overpressurization on Shutdown Cooling Isolation Valve 655" (Un~t 3)
R b.
Observations and Findin s The inspectors found the work performed under these activities to be properly performed.
Allwork observed was performed with the work package present and in active use.
Work and foreign material exclusion practices observed were good.
Technicians were experienced and knowledgeable of their assigned tasks.
C.
Conclusions Knowledgeable technicians used approved procedures to perform routine maintenance activities in a safety conscious manner.
Good work and foreign material control practices were observe 't
-11-M1.2 General Comments on Surveillance Activities a.
Ins ection Sco e 61726 The inspectors observed all or portions of the following surveillance activities:
73ST-1XI12 40OP-9SG03
"Safety Injection Train B Emergency Core Cooling System Throttle Valves Inservice Test," Revision 13 (Unit 2)
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"Steam Generator High Rate Blowdown to the Main Condenser,"
Revision 7 (Unit 1)
"Class 1E Diesel Generator and Integrated Safeguards Surveillance Test-Train A," Revision 8 (Unit 3)
b.
Observations and Findin s The inspectors found that knowledgeable personnel performed these surveillances satisfactorily, as specified by applicable procedures.
c.
Conclusions Knowledgeable technicians used approved procedures to conduct surveillance activities in a safety conscious manner.
M1.3 Tes in of Main Steam Safe Valves MSSV Units 1 2 and 3 a.
Ins ection Sco e 61726 The inspectors observed portions of Surveillance Test 73ST-9ZZ18, "Main Steam and Pressurizer Safety Valve Set Pressure Verification," Revision 12, for testing of the Unit 3 MSSVs prior to the refueling outage.
The inspectors also reviewed the licensee's subsequent actions and testing of selected MSSVs for Units'1 and 2, based on Unit 3 MSSV test results.
b.
Observations and Findin s The inspectors verified that necessary precautions were implemented prior to and during the Unit 3 MSSY testing. Appropriate equipment and properly calibrated instruments were used in the testing. The testing was performed using the Furmanite Trevitest assist device.
As required by the licensee's procedure, contract personnel performing the test were qualified in accordance with ANSI/ANS 3.1-1978, "Selection Qualification and Training of Personnel for Nuclear Power Plants."
During the tests of the Unit 3 MSSVs, the as-found setpoints on 7 of the 20 MSSVs were outside of the TS requirements of +3 percent.
The as-left setpoints for all but 1 of the 20 MSSVs were verified to be within +1 percent of the required value.
One of the MSSVs (MSSV-557), which lifted outside of the TS requirements, was returned to
-12-service with its setpoint at 1.1 percent lower than its required value. All7 of the MSSVs, which lifted outside of the TS requirements, willbe replaced during the current Unit 3 refueling outage.
Four of the 20 MSSVs required adjustments to achieve as-left setpoints within+1 percent.
Upon completion of the Unit 3 MSSV testing, the licensee reviewed the seven MSSVs with out-of-tolerance, as-found setpoints to determine if any common traits could be
~ identified. The licensee identified that four of the MSSVs had been replaced from the warehouse during the previous refueling outage and three of the valves had been refurbished by the vendor and replaced during the previous refueling outage.
The licensee identified and immediately tested six Unit 1 and two Unit 2 MSSVs with similar traits. Three of the Unit 1 valves were found to be outside of the+3 percent TS tolerances and were reset and returned to service within+1 percent of the setpoints.
One of the Unit 2 valves was found to be outside of the+3 percent tolerance and was reset to within+1 percent of its setpoint.
The licensee performed a preliminary analyses by modeling the as-found Unit 3 MSSV setpoints for worst case pressure transient scenarios.
The modeling assumed the worst case, with the highest within toleran'ce pressurizer safety valve setting. The preliminary analyses demonstrated that the peak steam generator pressures would not have exceeded 110 percent of the design value {I.e., would have remained within acceptable values).
The pressurizer safety valves cannot be tested while the unit is at power and willbe tested during the refueling outage.
If the as-found setpoints exceed the values assumed in the model, the model willbe revised to include the as-found values.
c.
Conclusions Qualified engineers and technicians used approved procedures to effectively conduct main steam safety valve testing. The licensee promptly and appropriately considered the affect of Unit 3 main steam safety valves with out-of-tolerance setpoints on the other two units. When a similar problem was identified in Units 1 and 2, the licensee conducted testing in a timely manner and returned out-of-tolerance main steam safety valves to Technical Specification acceptable values.
M2 Maintenance and Material Condition of Facilities and Equipment M2, Review of Materiat Condition Durin Plant Tours Units l ~2and 3 a.
Ins ection Sco e 71707 The inspectors performed routine plant tours and assessed the material condition of components and systems.
The inspectors also reviewed the results of the licensee's boric acid walkdown of the Unit 3 containmen I I
-13-b.
Observations and findin s The inspectors identified several safety-related valves with indications of minor packing leakage.
Where appropriate, valves had contamination control devices attached that would contain any boric acid deposits.
The licensee had identified these valves during routine zone inspections.
The inspectors verified that work requests were generated to address the repair of the valves with active leaks.
The inspectors did not identify any corrosion concerns associated with boric acid deposits on safety-related components.
The licensee performed boric acid walkdowns of the Unit 3 containment prior to the outage commencing in accordance with Procedure 70TI-9ZC01, "Boric Acid Corrosion Prevention Program," Revision 2.
The walkdown was a physical walkdown and formal inspection of the'containment for the purpose of Identifying small coolant leaks from the RCS. The licensee identified several instances of minor packing and body-to-bonnet leakage as evidenced by boric acid deposits..identified items were-included in the work scope for the outage.
c.
Conclusions A proactive approach for the prevention of material condition deficiencies caused by boric acid corrosion was implemented by the licensee.
Pre-outage mntainment walkdowns and zone inspections of auxiliary building components resulted in the early identification of potential problems that would result from boric acid corrosion.
M4 Maintenance Staff Knowledge and Performance M4.1 N wF elTransferred oS en FueIPool SFP Unit3 a.
Ins ection Sco e 62707 The inspectors observed the licensee's activities associated with transferring new fuel assemblies from dry storage to the SFP. The inspectors reviewed applicable procedures and work orders and held discussions with Operations and Refueling and Mechanical Services (RAMS) personnel.
The inspectors also observed portions of the fuel transfer.
b.
Observations and Findin s In preparation for the Unit 3 refueling outage, the licensee was in the process of transferring new fuel assemblies from dry storage to the SFP. The inspectors observed the portion of the transfer after approximately 60 new fuel assemblies had been transferred and 30 assemblies remained.
The licensee was required to conduct a sensitive issues briefing prior to commencing the activity. The inspectors attended two sensitive issue briefings, which discussed the transferring of new fuel from dry storage to the SFP.
Both briefings were held in the Unit 3 CR. The attendees for the briefing included the shift manager, site manager, Work Control SRO, STA, and RAMS personnel.
During the briefing on August 25,
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-14-1998, the participants discussed an emergent problem concerning the fuel building (FB)
roll-up door. The door had been damaged during the night shift and was in the process of being repaired.
Both trains of FB essential ventilation were rendered inoperable because the FB roll-up door could not be secured.
The briefing participants concluded that, with the current condition of the FB door, an additional step would be incorporated into the work order to restrict the movement of new fuel to regions where no irradiated fuel was stored..
The inspectors questioned licensee personnel on whether there were any contingencies that required the FB roll-up door to be secured should a new fuel assembly be damaged.
The licensee personnel responded that only helium would be released and that they were unaware of any affect on contingencies associated with recovery activities from an event involving new fuel assembly damage.
After the briefing had concluded, the inspectors informed the site manager that the guidance of Procedure 72AC-ORX01, "Response Plan to Severe Damage to New Fuel Assemblies,"
Revision 1, should have been reviewed prior to concluding the briefing. Shortly thereafter, the inspectors were informed by the site manager that the fuel movement was suspended because of the inability to meet the procedure's requirements of securing the FB should a new fuel assembly be damaged during the transfer.
The inspectors were also informed later on the same day by the licensee that Procedure 78OP-OFX03, "Spent Fuel Handling Machine," Revision 9, Precaution Step 3.2.8, also required the FB roll-up door to be closed while moving fuel to ensure that essential ventilation capabilities were not compromised.
A second briefing was held on September 1, after the FB door had been repaired.
This briefing was conducted by the team leader and was more comprehensive than the previous briefing.
Again, Operations failed to review the contingencies of Procedure 72AC-ORX01. Once prompted by the inspectors, the procedure was reviewed by Operations and it was determined that all contingencies could be met if new fuel became damaged during the transfer.
The inspectors reviewed the approved work instructions in progress.
The RAMS personnel performing the fuel handling adhered to their procedures.
The licensee initiated CRDR 3-8-0213 to evaluate revising Procedure 40OP-9ZZ22,
"Irradiated Fuel Damage," Revision 0, to include new fuel damage to prevent overlooking the existing guidance of Procedure 72AC-ORX01 when performing operations or maintenance activities involving handling of iew fuel.
Conclusion A prejob sensitive issues brief for transferring new fuel assemblies from dry storage to the spent fuel pool was characterized by poor communications and poor questioning attitude displayed by all participants.
This was evidenced by the lack of a thorough discussion of contingencies for possible problems and unfamiliarity with the requirement for the fuel building roll-up door to be fullyfunctional prior to new fuel movement.
Once begun, the fuel transfer was conducted in accordance with approved procedure I l<
f l
-15-III. En ineerin Engineering Staff Knowledge and Performance Licensee Res onse to Indust 0 eratin Ex erience IOE Information Ins ection Sco e 37551 The inspectors reviewed the licensee's evaluation of Information Notice 97-33,
"Unanticipated Effect of Ventilation System on Tank Level Indications and Engineering Safety Features Actuation System Setpoint," dated June 11, 1997.
Observations and Findin s Information Notice 97-33 informed addressees of the potential for affecting instrumentation output for certain transmitters by ambient pressure variations with the operation of plant ventilation equipment.
It stated, in part, that it is important that instrument reference legs accurately reflect the pressure that exists in the space above the fluid level in a tank, so false levels are not indicated.
Procedure 65DP-OQQ01, "Industry Operating Experience Review," Revision 1, provided guidance for screening and initiating actions to incorporate lessons learned from industry operating experience information into the plant design, programs, or operating practices.
Specifically, Procedure 65DP-OQQ01 required the licensee to generate a CRDR to evaluate industry operating experience information for applicability.
On July 1, 1997, the licensee initiated CRDR 9-7-Q398 to evaluate this information notice. The licensee responded to the CRDR in Memorandum 478-00089-PP, "Closure of Review CRDR 9-7-Q398," dated July 31, 1997.,The memorandum stated that, where the instrumentation is vented to rooms where o~eration of plant ventilation could create a pressure change, the licensee's setpoint program accounts for barometric pressure effects in the setpoint calculations.
The licensee concluded that the information provided in the information notice did not affect any programs, engineering practices, or procedures.
The inspectors reviewed licensee drawings of the refueling water tank (RWT) and confirmed that the reference leg of the RWT level instrumentation is located outside.
However, the RWT is vented into the FB normal exhaust ventilation system and would also be affected by the FB essential ventilation system.
The inspectors identified that the licensee's evaluation did not specifically address the affects of FB ventilation on RWT level instrumentation.
The licensee provided Calculation 13-JC-CH-209, "Refueling Water Tank Level Instrument (Chx-L-203x, x=A,B,C,D) Setpoint and Uncertainty Calculation," dated June 29, 1998. The inspectors reviewed the calculation to determine if the RWT level transmitter uncertainty included the effects of the FB normal and essential ventilation systems.
The inspectors determined that the calculation adequately addressed the
Ir
{
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-16-uncertainty associated with the change in barometric pressure that could be produced by the FB ventilation systems.
However, the calculation did not adequately detail the
'ifferent modes of FB ventilation operation, nor the effects that the different modes of FB ventilation would have on RWT level.
The inspectors obtained actual data of the change in RWT level associated with running the Unit 2 FB ventilation system on September 22, 1998. The data indicated that, when the ventilation system was shifted to its emergency mode of operation, RWT level increased by approximately 0.125 percent, which was within the calculated uncertainty considered in Calculation 13-JC-CH-209.
C.
On September 28, 1998, the licensee issued Memorandum 478-00153-PP, "Supplement to Closure Review of CROR 97-Q398 (IN 97-33)." This memorandum described in greater detail the possible effects that fuel building ventilation would have on RWT level, including the effects of a fuel building essential ventilation actuation signal and safety injection actuation signal, which are design basis operating conditions.
In addition, it stated that Calculation 13-JC-CH-209 would also be revised to include additional detail concerning the FB ventilation effects on the RWT sensing line.
~Con Iusions The initial documented evaluation of an information notice did not fullyaddress the issue of the refueling water tank level instrumentation being affected by the fuel building ventilation system.
However, instrument uncertainty appropriately accounted for the maximum level error that the refueling water tank would experience due to ventilation system operation.
IV. Plant Su rt R1 Radlolog'.;al Protection and Chemistry Controls R1.1 General Comments on Radiolo ical Protection Controls 71750 The inspectors observed radiation protection personnel, including supervisors, routinely touring the radiologically controlled areas.
Licensee personnel working in radiologically controlled areas exhibited good radiation, work practices.
Contaminated areas and high radiation areas were properly posted.
Area surveys posted outside rooms were current. The inspectors checked a sample of doors, required to be locked for the purpose of radiation protection, and all were in accordance with requirement l t
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-17-V. Mana ement Meetin s X1 Exit Meeting Summary The inspectors presented the inspection results to members of licensee's staff at the conclusion of the inspection on October 8, 1998. The licensee acknowledged the findings presented.
The inspectors asked the licensee whether any material examined during the inspection should be considered proprietary.
No proprietary information was identifie,I
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ATTACHMENT PARTIALLIST OF PERSONS CONTACTED Licensee M. Banks, Communication Representative, Owner Services S. Burns, Department Leader, Maintenance Engineering D. Garnes, Unit 1 Department Leader, Operations R. Fullmer, Director, Nuclear Assurance F. Gowers, Site Representative, El Paso Electric Co.
R. Henry, Site Representative, Salt River Project J. Hesser, Director, Engineering W. Ide, Vice President, Nuclear Engineering D. Kanitz, Engineer, Nuclear Regulatory Affairs A. Krainik, Department Leader, Nuclear Regulatory Affairs J. Levine, Senior Vice President, Nuclear D. Mauldin, Director, Maintenance
'. Overbeck, Vice President, Nuclear Production T. Radke, Director, Outages D. Smith, Director, Operations R. Sorenson, Department Leader, Chemistry G. Sowers, PRA Section Leader, PVNGS J. Velotta, Director, Training P. Wiley, Unit 2 Department Leader, Operations M. Winsor, Department Leader, System Engineering INSPECTION PROCEDURES USED 37551 60710 61726 62707 71707 71750 92901 92902 92903 93702 Onsite Engineering Refueling Activities Surveillance Observations Maintenance Observations Plant Operations Plant Support Activities Followup-Operations Followup - Maintenance Followup - Engineering Prompt Onsite Response to Events at Operating Power Reactors
-2-ITEMS OPENED CLOSED AND DISCUSSED Closed 50-528/98-005-00 50-528/9806-04 LER Missed response time test for reactor protection instrumentation (Section 08.1).
NCV Failure to adhere to radiological exposure permit requirements caused spread of contamination (Note: This item is closed in this report because it was not officially closed in the original Report 50-528, -529, -530/98-06).
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-3-LIST OF ACRONYMS USED AO ASI CFR CR CRDR CRS CWNT FB LCO LER MSR MSSV NCV NRC NOUE PDR RAMS RCS RO RWT SFP SRO STA TS auxiliary operator axial shape index Code of Federal Regulations control room condition report/disposition request control room supervisor condensate water neutralizing tank fuel building limiting condition for operation licensee event reports moisture separator reheater main steam safety valve Noncited Violation Nuclear Regulatory Commission Notification of Unusual Event public document room refueling and mechanical services reactor coolant system reactor operator refueling water tank spent fuel pool senior reactor operator shift technical advisor Technical Specifications
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