IR 05000275/1995012
| ML16342D039 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/24/1995 |
| From: | Wong H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML16342D038 | List: |
| References | |
| 50-275-95-12, 50-323-95-12, NUDOCS 9509050031 | |
| Download: ML16342D039 (40) | |
Text
ENCLOSURE U.S.
NUCLEAR REGULATORY COMMISSION
REGION IV
Inspection Report:
50-275/95-12 50-323/95-12 Licenses:
DPR-80 DPR-82 Licensee:
Pacific Gas and Electric Company 77 Beale Street, Room 1451 P.O.
Box 770000 San Francisco, California Facility Name:
Diablo Canyon Nuclear Power Plant (DCPP), Units 1 and
Inspection At:
Diablo Canyon Site, San Luis Obispo County, California Inspection Conducted:
June 25 through August 5, 1995 Inspectors:
M. Tschiltz, Senior Resident Inspector G. Johnston, Senior Project Inspector D. Corporandy, Project Inspector D. Acker, Senior Project Inspector Approved:
Ins ection Summar ong, ie
,
ea or ProJects rane ate Areas Ins ected Units
and
Routine, announced inspection of operational safety verification, onsite followup to events, plant maintenance, surveillance observations, onsite engineering, plant support activities, followup plant maintenance, and in-office review of licensee event reports (LERs).
Results Units
and
~0eratinns:
~
equality Control review identified that operators failed to recognize all of the Technical Specification (TS) required functions ef the Unit 2, Loop 1, wide range T,. instrument when removing the instrument from service.
As a result, the applicable TS action statement was not immediately entered.
This error was noted 26 days (of the 30-day action statement)
after removing the instrument from service.
(Section 2.3)
950905003i 950825 PDR ADQCK 05000275
/
An improvement in the conduct of tailboards by Operations personnel was noted.
The tailboards for surveillance testing were thorough and covered information that was relevant to observed testing.
During the tailboards, operators demonstrated a questioning attitude.
The importance of the use of self verification was stressed.
(Section 5.3)
Maintenance:
~
following corrective maintenance on the Emergency Diesel Generator (EDG) 1-2 governor, a resistance value recorded in the dedication procedure was identified by the inspector to be outside the specified acceptance criteria.
This discrepancy was not noted by the maintenance or the engineering personnel who had reviewed and approved the procedure.
(Section 4. I)
During control room ventilation damper motor operator maintenance a
torque switch limiter plate was replaced without specific authorization in the work package.
Subsequent investigation revealed that the technical review and approval for installation of the limiter plate in Limitorque Model SMB-00 operators had been performed; however, no authorizing work instructions had been included in the work order (WO).
(Section 4.3)
~E Corrective actions for EDG 1-2 submitted to the NRC in Special Report 95-03 were not comprehensive in that they did not include an inspection of the remaining EDGs for similar problems during scheduled maintenance-periods.
After the basis for the decision was questioned by the NRC inspector, the licensee revised the corrective actions to include the additional inspections.
(Section 6. I)
Plant The Security Department's initial responses and investigations following the discovery of a controlled substance in the radiologically controlled area (RCA) and a helicopter landing on the breakwater adjacent to the intake structure were both timely and thorough.
(Sections 3. 1 and 3.2)
An improvement in.the overall cleanliness and housekeeping in the RCA was noted during this inspection period.
(Section 7. 1)
Summar of Ins ection Findin s:
Inspection Followup Item 275/9512-01 was opened (Section 5.3).
Violation 275/9508-01 was closed (Section 8).
LER 275/94-013, Revision 0, was closed (Section 9).
Attachments:
~
Attachment
Persons Contacted and Exit Meeting
~
Attachment
DETAILS
PLANT STATUS (71707)
1.1 Unit
Unit 1 began the inspection period at 100 percent power.
Power was reduced by approximately 20 percent for approximately 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> on July 16, 1995, after a
main turbine intercept valve test failure.
The unit operated at 100 percent power for the remainder of the inspection period.
1.2 Unit
Unit 2 began the inspection period at 100 percent power and operated at that level for the entire inspection period.
OPERATIONAL SAFETY VERIFICATION (71707)
2. 1 Unit 2 Control Room Observations i
During a routine tour of the control room, just prior to morning shift turnover, the inspector noted that Unit 2 main control board steam generator wide range= level recorders, LR-517 and LR-537, were unreadable, due to excess ink on the trace.
The ink covered between 1/4 to 1/2 the width of the paper.
All the paper visible was covered with ink, indicating that the problem had existed for some time.
The inspector questioned the senior control operator who observed the recorders and directed an operator to attempt to fix the recorders.
The operator informed the inspector that they often had problems with recorders with new pens.
The licensee later initiated an action request (AR) to have the recorders repaired.
2. 1. 1 Conclusion Although these recorders are not required by TS, the inspector considered that the failure of the licensee to note, the problem with these recorders appeared due.to failure to maintain control board awareness.
2.2 0 erabilit Verification of EDG 2-1 The inspector performed a verification of the operability of EDG 2-1.
The verification included a physical walkdown of the EDG and the associated support systems.
The support systems included the diesel fuel oil system, air start system, including the receivers and compressor, the 4160 V switchgear, remote controls in the control room, and the radiator and cooling exhaust bays.
The inspector visually inspected the diesel engine, verifying that the associated engine systems were in good order.
This included confirming the overspeed trip mechanism was latched.
The air start receivers were at normal pressure.
The inspector did note that a compressor started during walkdown in the area; this confirmed that the compressor was operating properly.
Th inspector did not observe any obvious air leaks that may have caused the compressor to start and concluded that this was likely a start in response to normal leakage.
The engine local controls were observed set in the appropriate positions and control power appeared to be properly aligned.
The inspector noted that the housekeeping around the diesel engine appeared to be good, with no observed oil or fuel leaks and no loose debris.
2.2. 1 Conclusion The inspector did not observe any problems which affected EDG 2-1 operability requirements.
2.3 Ino erable Wide Ran e Resistance Tem erature Detector RTD Unit 2 Background
On June 4,
1995, operators, observed that the reactor coolant system (RCS) wide range T,. instrument (TE-413B) indication for Unit 2 Loop
was oscillating.
The channel was declared inoperable.
A TS information sheet was initiated which noted that TS 3.3.6, pertaining to postaccident monitoring, had a 30-day limiting condition for operation action statement when 2 of 4 channels are inoperable.
This action statement was not entered since only 1 of 4 channels was inoperable.
Operators failed to recognize the applicability of TS 3.3.3.5, which required entering a limiting condition for operation action statement when removing the T,. channel from service due to the loss of reliable remote shutdown monitoring temperature indication.
On June 30, 1995, the licensee entered TS 3.3.3.5 after guality Control and Technical Haintenance personnel identified that TS 3.3.3.5 was also applicable.
At that -point in time, Unit 2 was 26 days into the 30-day action statement.
i 2.3. 1 Actions Taken to Restore Remote Shutdown T,. Indication After considering several options, including a request for a Notice of Enforcement Discretion and a unit shutdown, the licensee restored remote shutdown indication by substituting the output of one of the two EAGLE 21 solid state protection Loop
RCS narrow range T,. RTDs for the inoperable Loop
The licensee arrived at this option after confirming the following:
EAGLE 21 needs only 1 narrow range RTD, as described in the Final Safety Analysis Report; the resistance device is the same as used for the failed wide range RTD and, therefore, calibration would not be a problem; both the failed RTD and the EAGLE 21 RTD use the same power source, and the electrical leads from both use the same easily accessible containment penetration, hence permitting rewiring to be performed outside the containment at the penetration.
2.3.2 Safety Significance The requirement for the wide range T,. indication of TS 3.3.3.5 ensures
.that RCS temperature information is available at the dedicated shutdown panel in the event of a main control room evacuation.
This information is necessary in
order to monitor decay heat removal from the core.
The temperature indication was restored within the allowed outage time.
2.3.3
,Conclusion This occurrence resulted from a weakness in the licensee's identification and tracking of TS actions; however, no violation of Technical Specifications occurred.
After identifying the issue, the licensee's response appeared thorough and all identified options were carefully considered before deciding on the course of action.
The implementation of the chosen alternative was performed and completed without any significant problems.
The licensee has initiated a nonconformance report on this problem.
ONSITE FOLLOWUP TO EVENTS (93702)
3. 1 Unauthorized Helico ter Landin Background At about 5:40 p.m.
on June 27, 1995, an unidentified military type transport helicopter briefly landed on the breakwater to the intake structure.
Two men got out of the helicopter and walked to the back of the aircraft.
The licensee's secur'ity forces responded to the l,anding, the two men reboarded the helicopter, and the helicopter was observed taking off and leaving the area.
The licensee informed the onsite NRC inspector shortly after the incident.
Following the event, the licensee confirmed with the local National Guard that the helicopter was one of theirs.
The following day, the Diablo Canyon Security Director contacted the National Guard Headquarters in Sacramento, California.
According to the National Guard, the aircraft was based in Stockton, California.
The area around Diablo Canyon was not within the approved flight plan for the helicopter.
The helicopter had made an emergency landing because a battery door had become unlatched.
The two men who exited the helicopter were following standard procedures for such an incident, and the door was relatched before the helicopter took off from the breakwater.
The National Guard committed to conduct a full investigation of this incident and to take action, as necessary, to deal with the National Guard personnel involved and to enact such measures as necessary to prevent any further such unauthorized occurren'ces.
3.1.1 Safety Significance The landing of the National Guard helicopter on the breakwater at the intake, although not authorized by the licensee, did not propose a significant security risk and did not have a negative impact on the safe operation of the facility.
3. 1.2 Conclusion The inspector noted that the helicopter landing at the intake breakwater received prompt response from the licensee's security forces.
The followup by
the licensee was effective in confirming that the helicopter and personnel onboard were from the National Guard.
Furthermore, the inspector noted that the licensee's Security Director appropriately emphasized the potential seriousness of the event to the National Guard and that the National Guard appeared responsive in assuring the licensee that a full investigation of the event would be conducted, and measures enacted, as necessary, to prevent such an occurrence in the future.
3.2 Controlled Substance Found Within the RCA Background At about 8:50 a.m.
on June 28, 1995, a health physics technician noticed a small ( 1 inch X
1 inch) clear plastic bag on the floor at the 85 foot level of the auxiliary building at the RCA access point within the RCA adjacent to a radiation portal monitor near a west wall.
The plastic bag contained what appeared to be about 1/2 gram of a controlled substance.
Security was informed and performed a field test on the substance.
The field test results indicated that the substance was a controlled substance.
The licensee sent a sample of the substance to an independent laboratory for investigation.
Security issued a 1-hour
CFR 50.73 report on this and also informed the inspector, of the incident within an hour of discovery.
Since the substance was found in a controlled access area in a location where it would likely have been noticed within a short time, the inspector asked Security if they were planning to check on who had accessed the area within the period shortly before discovery.
The licensee decided to retrieve security records to see who had entered the RCA between 4 a.m. that morning (the time when the floor was cleaned)
and 8:50 a.m.,
the time of discovery.
According to the Security Director, they also intended to perform a preliminary check to see if anyone in the RCA had been identified earlier as having a drug problem.
The controlled substance was later identified by the independent laboratory as methamphetamine.
Although the licensee was unable to identify the person with the substance, the licensee did issue a letter to all of its nuclear employees emphasizing the seriousness of the finding, reminding them of DCPP's zero tolerance drug policy, and noting that Employee Assistance Program counselors are available.
3.2.1 Conclusion
!
The inspector considered the licensee's actions were aggressive in the investigation of this matter.
The efforts made to keep the NRC informed of the results of the investigation were considered to have been noteworthy.
The inspector's assessment was that the licensee's response to this occurrence was thorough and appropriate to the circumstances.
PLANT MAINTENANCE (62703)
During the inspection period, the inspector observed and reviewed selected documentation associated with the maintenance and problem investigation activities listed below to verify compliance with regulatory requirements, compliance with administrative and maintenance procedures, required quality
assurance department involvement, proper use of safety tags, proper equipment alignment and use of jumpers, personnel qualifications, and proper retesting.
Specifically, the inspector reviewed the work documentation or witnessed portions of the following maintenance activities:
4. 1 EDG Electronic Governor Assembl Re lacement Unit
Background - The licensee noted that load swings of approximately 200 kilowatts (kW) occurred on EDG 2-1, during loaded operation with the EDG parallelled to the grid.
The inspector observed the condition and witnessed subsequent troubleshooting efforts, repair actions, and testing.
The licensee performed the work in accordance with work order (WO) C0136812,
"DSL Gen 1-2; Troubleshooting and Repair."
Licensee troubleshooting determined that the diesel governor could not be properly adjusted.
The licensee replaced the governor, adjusted the new governor, and then performed a 1-hour loaded run and partial load rejection test.
4. 1. 1 EDG 1-2 Governor Troubleshooting At the completion of the troubleshooting and the associated testing, the inspector reviewed the associated data.
The inspector had the following observations:
Troubleshooting actions which were performed with the EDG in operation were adequately coordinated between the technical maintenance and control room personnel.
During EDG 1-2 initial troubleshooting, with the EDG running and electrically loaded, several rapid load swings in excess of 300 kW occurred.
The inspector noted that control room personnel asked technical personnel present during the test what magnitude of EDG oscillations were acceptable and at what point the EDG should be secured.
The technical personnel did not provide the operators with a limit for the oscillations.
The inspector reviewed other troubleshooting documents, including WO C0136812 and noted none of the documents provided limits for expected kW oscillations during operation of EDG 1-2 for troubleshooting.
Step 2 of WO C0136812 required that the new governor be dedicated in accordance with instructions contained in the WO.
This step was initialed as complete on July 19, 1995.
In addition, maintenance personnel initialled final review of the WO on July 20, 1995.
Also on July 20, 1995, engineering personnel signed the WO indicating review of the adjustment procedure for the new governor.
Subsequently, during the inspector's review of the WO, it was noted that the resistance value for a governor potentiometer recorded in Step 21 of
the dedication procedure was outside the listed acceptance criteria, which had not been identified by previous reviews and had not been evaluated.
4. 1.2 Safety Significance-The inspector reviewed the measured potentiometer resistance with engineering personnel.
These personnel stated that the resistance value recorded was acceptable, but that the WO should not have been initialed complete until a
technical evaluation of the out-of-specification data had been performed.
Based on a satisfactory governor adjustment and a review of the associated circuits, the inspector concluded that the licensee's technical evaluation of the resistance reading was acceptable.
4. 1.3 Conclusion The licensee personnel who signed completion of the WO failed to identify and resolve the out-of-specification readings.
Additionally, the technical and administrative reviews failed to note the out-of-specification resistance.
The inspector also considered as a troubleshooting weakness the failure to establish limits for kW oscillations which were expected to occur during testing of EDG 1-2.
4.2 EDG Jacket Water Ex ansion Tank Relief Valve Re lacement Unit
Background The EDG 1-2 jacket water expansion tank relief valve had been previously noted to be leaking during EDG 1-2 operation.
The EDG jacket water expansion tank lower sight glass valve isolation valve was also noted to have a significant packing leak when the valve was in the open position.
Haintenance activities were initiated by the licensee to correct these deficiencies.
Preplanning for the maintenance was inadequate in that it failed to note that the replacement assembly which had been prefabricated could not be installed due to inadequate clearances between level indication piping, the jacket water expansion tank, and the replacement assembly.
This problem required modifications to the replacement assembly, as well as the installation of a temporary jumper, and resulted in delays in the work.
The inadequate planning of EDG 1-2 corrective maintenance resulted in an increase in the maintenance outage time of EDG 1-2.
4.2.
Licensee Requirements for Verification of Clearances The inspector noted during an observation of maintenance activities that procedures were inconsistent regarding the need for subclearance walkdowns prior to reporting on the clearance.
In preparation for corrective maintenance on EDG 1-2, a master clearance was issued which removed the EDG from service to ensure the protection of maintenance personnel performing the work.
The licensee's interdepartmental administrative procedure, OP2. ID1, Revision 1,
"DCPP Clearance Process,"
required that mechanical maintenance verify the master clearance and hang a
-10-subclearance at one or more of the master clearance points.
Procedure OP2. ID1, Section 4.2.2, required that a thorough walkdown of the subclearance be performed prior to reporting on the subclearance.
The procedure also requires that after the subclearance has been verified the clearance be "reported on," which signifies that the sub-clearance has been walked down and work on the system is starting.
In discussing the job with the mechanic performing the work, the inspector noted that the subclearance for the work had been reported on by the foreman prior to the hanging and verification of the subclearance.
Discussion with the mechanical maintenance foreman responsible for the work indicated that it was a common practice to report on the subclearance prior to accomplishing the walkdown, even though the procedure required that the walkdown be performed first.
The inspector noted that Section 5,3. 11 states that the subclearance should be walked down prior to being reported on and work commencing.
The licensee indicated "should" represents a management expectation and is not considered as a requirement.
The inspector observed that the various procedural guidance contained in Procedure OP2. IDl were conflicting on this point.
The licensee was performing a review of the procedure and was considering revision of the procedure to clarify the requirements.
4.2. 1. 1 Safety Significance The inspector noted that, although the mechanical maintenance foreman had not strictly adhered to the clearance procedure and management expectations, the clearance was verified to provide adequate protection for the worker prior to commencing the work.
Therefore, the failure to follow the specific administrative procedural guidelines did not result in any concern for personnel safety.
4.2. 1.2 Conclusion The failure to walk down the master clearance and hang the subclearance prior to the foreman reporting on the subclearances did not meet management expectations and the licensee procedure does not provide consistent guidance.
4.3 Overhaul of Control Room Ventilation Dam er Motor 0 erator Unit
Background - The inspector observed portions of the maintenance performed on the Limitorque motor operator for Damper VAC-1-MOD-3; Damper VAC-1-MOD-3 is a
control room ventilation damper in the ventilation duct which supplies outside air.
Damper VAC-1-M00-3 is open during normal control room ventilation system operation and is closed during the recirculation or pressurization modes of operation.
The inspector reviewed both the maintenance procedure and WO for the maintenance activity.
Discussions with the mechanic performing the work revealed that, during the disassembly of the operator, the declutch fork was noted to have been improperly installed with the fork arms pointing up vice down, contrary to the current installation instructions.
The individual performing the work contacted his foreman after finding this discrepancy.
The foreman wrote an AR to document the problem.
The cognizant engineers assessed
-11-the improper declutch fork installation as having no adverse effects on the damper operation.
This conclusion was based on previous testing performed on a mock-up with the declutch fork upside down to determine effects on operability.
The testing indicated that the actuator functioned properly with the declutch fork installed upside down.
4.3. 1 Valve Operator Torque Switch Installation While observing the reinstallation of the torque switch assembly, the inspector noted that the technician had installed a new limiter plate.
The inspector questioned the mechanic on this point since neither the maintenance procedure or the WO provided work instructions which authorized replacement of the limiter plate.
The technician stopped reinstallation of the torque switch and reviewed the work package.
After the technician was unable to find the instructions for limiter plate replacement, the foreman was contacted.
Subsequently, it was determined that the licensee had technically evaluated replacement of the limiter plates in certain Limitorque operators as documented in an AR.
4.3.2 Safety Significance The torque switch limiter plate is installed to limit the range of adjustment of the torque switch and provide an upper limit on the range of torque switch settings.
In the event that the torque switch setting adjustment moved from it's initial setting, the torque switch limiter plate would prevent damage to the component by limiting the magnitude of torque settings for the torque switch.
4.3.2 Conclusion Based upon the engineering evaluation of the potential effect of the improper declutch fork installation, the inspector concluded that the improper declutch fork installation deficiency had been properly evaluated.
The installation of the new limiter plate did not effect the operability of Damper VAC-1-MOD-3, but was a weakness in that the work package was deficient in that it did not contain instructions which authorized the installation of a different range limiter plate.
4.4 Other Maintenance Observations Other maintenance activities were observed:
Unit
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"Stage, Install, Inspect RV 296" (Relief valve on EDG 1-3 turbo air drier inlet piping)
"Sample, Change Oil, Clean, Inspect Turbo Air Compressor 3" on EDG 1-3
-12-
"PDP 1-1 Replace, Packing, Inspect Plungers,"
and Mechanical Maintenance Procedure M-8.4, Revision 11, "Reciprocating Charging Pump Maintenance"
Inspect and Lube SI-1-8801A," Limitorque Motor Operator preventive maintenance These activities were performed adequately.
SURVEILLANCE OBSERVATIONS (61726)
Selected surveillance tests required to be performed by the TS were reviewed on a sampling basis to verify that:
(1) the surveillance tests were correctly included on the facility schedule; (2)
a technically adequate procedure existed for performance of the surveillance tests; (3) the surveillance tests had been performed at a frequency specified in the TS; and (4) test results satisfied acceptance criteria or were properly dispositioned.
Specifically, portions of the following surveillances were observed by the inspector during this inspection period:
5. 1 Reactor Tri Breaker B Testin Unit
Background Portions of surveillance test procedure (STP) I-38-B.2, Revision 1,
"SSPS Train B SI Reset Timer and Slave Relay K602 Test in Modes 1,
2, 3, or 4," testing activity for Reactor Trip Breaker B were observed.
The racking in of the associated reactor trip bypass breaker was observed by the inspector.
The racking in of the breaker was performed in accordance with the procedure.
However, the inspector noted that the operator performing the operation initially tried to set the breaker in place manually rather than using the racking device.
The operator quickly noted that the procedure required the use of a racking device and proceeded from that point to utilize the device.
Other than this observed action on the part of the operator, the inspector determined that the operator performed the actions appropriately.
The inspector then observed the initiation of a trip signal to actuate the reactor trip breaker, which operated successfully.
5.1.1 Conclusion The inspector concluded that the surveillance test was valid.
With the exception of the performance of the racking operation, the performance of the surveillance test was as intended.
5.2 Moderator Tem erature Coefficient Determination - Unit
Background The inspector observed the tailboard briefing for the STP R-7B, Revision 13A, "Determination of Moderator Temperature Coefficient at Power,"
which was done the day before the test by the crew and the cognizant engineer.
The discussion included test parameters, an estimate of the time to.conduct the test, the prerequisites, and the TS requirements.
The inspector noted
-13-that the test director emphasized the need to have stabilized conditions prior to the commencement of the test.
The initial conditions were RCS boron concentration less than 300 ppm with T,, 1.5'bove T., at 99 percent reactor power for at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> prior to commencing the test.
This meant that the oncoming crew had to be briefed also on the activity, since the stabilization period would occur overnight.
The test involved varying temperature with boration and then dilution, holding reactor power constant such that the average reactor coolant temperature varied.
The change in boron concentration during the change in temperature would then be determined by boric acid titration.
The change in concentration would then give a reactivity defect representative of the temperature change.
A calculation that factors in the effect of U"'oppler temperature broadening in the fuel was done later that determined the actual moderator temperature coefficient.
The inspector observed that the work was well executed in coordinating the boration and the subsequent dilution.
The coordination was such that no operating limits were approached.
5.2. I Conclusion The inspector concluded that the surveillance was well planned and coordinated, noteworthy in that the surveillance is not routinely performed.
5.3 0 eration of Train A Slave Rela s
K609 Safet In 'ection and K633 Hotor-Driven Auxiliar Feedwater AFW Pum Start Background The inspector observed portions of STP H-16E, Revision 5A,
"Operation of Train A Slave Relays K609 (Safety Injection)
and K633 (Hotor-Driven AFW Pump Start)," which was performed to verify actuation of engineered safeguards equipment upon receiving a slave relay test signal from the solid state protection system (SSPS)
safeguard test cabinet.
The tailboard conducted prior to commencing the test involved all personnel performing the surveillance.
The precautions and limitations were discussed, as well as the coordination for the restoration of the steam generator blowdown valves which were to be closed during the AFW pump start slave relay actuation.
Discussions between personnel involved in the test were constructive and facilitated a
common understanding of the testing coordination.
At the end of the brief, the Shift Supervisor noted that during the test the Unit 1 standby auxiliary saltwater (ASW)
pump would be expected to auto start due to low pressure and that the pump should be placed in manual during the performance of the surveillance to preclude the low pressure auto start of the pump.
The procedure which was referenced to accomplish the change in the ASW pump control switch alignment was OP E-5: IV, Revision 4, "Auxiliary Saltwater System Changing Over Pump and Heat Exchanger Trains."
Precaution 5.3 of Procedure OP E-5: IV states that starting or stopping an ASW pump may result in a low pressure auto start of an ASW pump on the opposite unit.
The licensee has attributed the low pressure auto start to a system pressure wave which is transmitted to the opposite unit via the closed ASW unit cross-tie valv The inspector verified that placing the ASW pump in manual does not block any other auto start signals other than low pressure signal.
The surveillance procedures have not been revised to include precautions or action steps to alert the operators to the potential for the low pressure auto start during surveillance testing.
This situation created an operator work around which compensated for the system anomaly.
The licensee has written an AR to document the need for the change to surveillance procedures.
In discussions with operators, there was not a
common understanding of the conditions which would result in the auto start, nor was there a
common understanding of management expectations of when actions should be taken to prevent the low pressure auto start of the standby ASW pump.
5.3. 1 Conclusion The inspector will review the long term acceptability of the ASW system conditions which resulted in the pressure wave condition.
This issue will be examined further during the next inspection period (Followup Item 275/9512-01).
5.4 Other Surveillance Tests Other surveillances were observed:
Unit
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STP H-21A, Revision 19,
"Hain Turbine/Generator Functional Tests."
Unit 2
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STP I-38-A. 1 Revision 1,
"SSPS Train A Actuation Logic Test in Hodes 1,
2, 3, and 4"
~
Procedure OP A-3: IV, Revision 14XPR, "Control Rod System - Hanual Operation of Reactor Trip and Bypass Breakers,"
(performed in conjunction with STP I-38-A. 1).
These surveillances were performed adequately.
ONS ITE ENGINEERING (37551)
6.1 Failure of EDG 1-2 Due to De raded Volta e Re ulator Performance Background - The inspector reviewed the licensee's Special Report 95-03 submitted to document the valid failure of EDG 1-2 to successfully load due to a malfunction of the voltage regulation equipment.
The valid failure occurred on June 22, 1995, during periodic surveillance testing.
After starting EDG 1-2, approximately 10 minutes after paralleling with Bus G, volts-ampere reactance (VAR) oscillations were noted.
Operators unloaded and separated EDG 1-2 from Bus G, secured the EDG, and declared it inoperable.
The licensee
-15-performed testing of the remaining Unit
EOGs within the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to verify operability as required by TS.
6. 1. 1 Licensee Investigation of EDG 1-2 Failure The troubleshooting identified a loose wire connection and loose fuse holder associated with the motor-operated potentiometer (MOP) in the voltage regulation panel.
No other abnormalities were noted during the inspection.
The licensee evaluated the operating environment for the MOP and concluded that neither the mechanical or electrical vibration levels present with EOG 1-2 in operation were large enough to loosen wire or ferrule connections.
Following tightening the loose connections, testing was performed.
There were no volt-amperes reactance fluctuations noted during the testing.
EOG 1-2 passed the testing and was declared operable.
6. 1.2 Corrective Actions Each refueling outage the licensee performs a check of the MOP wire connections for tightness, this check did not require checking for loose ferrules.
The licensee revised the existing instructions to include a check for loose fuse ferrules.
EDG 1-2 MOP wire connections were last checked for tightness on April 26, 1994.
The inspector questioned the basis for the licensee's decision not to verify that the remaining EDGs did not currently have similar deficiencies that had not been detected.
As a result, the licensee changed the corrective actions to include an inspection of the remaining EDG's voltage regulator MOP during the next scheduled EDG maintenance period.
The licensee has committed to revise the corrective actions to prevent recurrence listed in Special Report 95-,03 in a subsequent report on EDG 1-2 failures, 6. 1.3 Safety Significance EOG 1-2 function is to provide power to safety-related (Class 1E) electrical loads supplied from the 4160 volt Bus G.
Remaining Unit
EDGs 1-1 and 1-3 were available during the period when EOG 1-2 was inoperable.
Testing was performed which verified EDG 1-1 and 1-3 operability during the period EDG 1-2 was inoperable.
Since accident analysis is supported with two vital buses being powered from their respective EDGs, there was no adverse.impact on safe operation during the 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> and 52 minutes that EOG 1-2 was inoperable.
6. 1.4 Conclusions
The licensee's initial corrective actions to prevent recurrence were not comprehensive in that they did not require verification that similar conditions did not exist on the remaining EDGs.
When requested to provide the justification for this decision, the licensee revised the corrective actions to require inspection of the remaining EDGs during the next scheduled maintenance activity.
These actions appeared to adequately address the inspector's concern for the potential for common mode failur PLANT SUPPORT ACTIVITIES (71750)
The inspectors evaluated plant support activities based on observation of work activities, review of records, and facility tours.
The inspectors noted the following during these evaluations.
7. 1 Housekeeping During a routine tour of the Unit 2 EDG rooms, the inspector noted an area with difficult access which contained gum wrappers, candy wrappers, and magazines.
The inspector noted that the area was adjacent to EDG components and was marked as a no eating area.
The licensee cleaned up the area.
The inspector also noted an aerosol can beneath EDG 1-2 when the EDG was operating and informed the system engineer.
During tours of the RCA, the inspector noted an improvement in housekeeping practices and cleanliness,
FOLLOWUP PLANT MAINTENANCE (92902)
8. 1 Closed Violation 275 95-08-01 EDG Airflow Reduction Due to Procedures Ina ro riate to the Circumstances The violation cited the failure of the licensee to perform adequate preplanning and provide adequate work instructions for work which was performed on both Units 1 and 2 in the EDG radiator fan exhaust plenum.
The work required the installation of scaffolding and tenting which significantly blocked EDG radiator airflow.
Subsequent reviews indicated that the reduction of airflow was significant in that, under different environmental conditions, within the design basis, the EDGs would have been inoperable.
The inspector reviewed the licensee's response to the violation and determined that the corrective actions initiated appeared adequate.
Corrective actions included:
revision of work planning procedures to heighten awareness for work which could restrict heating, ventilation, and air conditioning flow to vital equipment and development of a clear definition of the degree of detail necessary when requesting an engineering analysis.
The latter guidance will be incorporated into the Nuclear Technical Services Engineer's Handbook.
These actions appeared to address correction of the root cause of the violation.
Based upon this review, the violation is closed.
IN OFFICE REVIEW OF LERs (90712)
The inspectors performed a review of the following LERs associated with operating events.
Based on the information provided in the report, review of associated documents, and interviews with cognizant licensee personnel, the inspectors concluded that the licensee had met the reporting requirements, addressed root causes, and taken appropriate corrective actions.
The following LER was closed:
-17-LER 275/94-013, Revision 0, Unplanned Diesel Generator Start (Engineered Safety Features Actuation)
When the Startup Feeder 4160 V Bus F
Undervoltage Relay was Actuated Due to an Inadequate Procedure
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PERSONS CONTACTED ATTACHMENT 1 1. 1 Licensee Personnel G.
H. Rueger, Senior Vice President and General Manager, Nuclear Power Generation Business Unit W.
H. Fujimoto, Vice President and Plant Manager, Diablo Canyon Operations L. F.
Womack, Vice President, Nuclear Technical Services M. J.
Angus, Manager, Regulatory and Design Services C.
R. Beck, Foreman, Technical Maintenance J.
R. Becker, Director, Operations S.
Bednarz,, Engineer, System Engineering D.
H. Behnke, Senior Engineer, Regulatory Services
- F. Bosseloo, Assistant to Vice President, Nuclear Power Generation Business Unit
- W. G. Crockett, Manager, Engineering Services
- R. N. Curb, Manager, Outage Services T.
F. Fetterman, Director, Electrical and Instrumentation and Control Systems Engineering T.
LE Grebel, Director, Regulatory Support
- D. L. Gouveia, Engineer, Nuclear guality Services
- C. R. Groff, Director, Secondary Systems Engineering
- C. D. Harbor, Engineer, Regulatory Support
- R. J. LaVelle, Foreman, Mechanical Maintenance R. J.
Hagruder, Shift Supervisor, Operations
- D. B. Hiklush, Manager, Operations Services
- J.
E. Molden, Manager, Maintenance Services
- H. D. Nowlen, Senior Engineer, Technical Maintenance P.
T. Nugent, Senior Engineer, Regulatory Support
- D. H. Oatley, Director, Mechanical Maintenance
- R.
P.
Powers, Manager, guality Services H. J. Phillips, Director, Technical Maintenance R.
G. Todaro, Director, Security R. A. Waltos, Director, Balance of Plant Engineering
- J.
C.
Young, Director, guality Assurance 1.2 NRC Personnel
- H. D. Tschiltz, Senior Resident Inspector
- Denotes those attending the exit meeting on August 15, 1995.
In addition to the personnel listed above, the inspectors contacted other personnel during this inspection period.
EXIT MEETING An exit meeting was conducted on August 15, 1995.
During this meeting, the inspectors reviewed the scope and findings of the report.
The licensee
~,
acknowledged the inspection findings documented in this report.
The licensee did not identify as proprietary any information provided to, or reviewed by, the inspector ATTACHMENT 2 ACRONYMS AFW ASW AR DCPP EDG kv kw LER PDP ppm RCA RCS RTD SI SSPS STP TS WO auxiliary feedwater auxiliary seawater action request Diablo Canyon Power Plant emergency diesel generator kilovolt kilowatt licensee event report Positive Displacement Pump parts per million Radiologically Controlled Area reactor coolant system resistance temperature detector safety injection solid state protection system surveillance test procedure technical specification work order
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