ML18152A263
| ML18152A263 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 06/22/1995 |
| From: | Belisle G, Garner L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18152A264 | List: |
| References | |
| 50-280-95-08, 50-280-95-8, 50-281-95-08, 50-281-95-8, NUDOCS 9507120078 | |
| Download: ML18152A263 (17) | |
See also: IR 05000280/1995008
Text
Report Nos.:
UNITED STATES
NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETIA STREET, N.W., SUITE 2900
ATLANTA, GEORGIA 30323-0199
50-280/95-08 and 50-281/95-08
Licensee: Virginia Electric and Power Company
Innsbrook Technical Center
5000 Dominion Boulevard
Glen Allen, VA
23060
Docket Nos.:
50-280 and 50-281.
License Nos.:
Facility Name:
Surry 1 and 2
Inspection Conducted:
April 30 through May 27, 1995
Lead Inspector: £ '--" A--__, (?..__
M. W. Branch, Senior Resident Inspector
Other Inspectors:
Approved by:
D. M. Kern, Resident Inspector
L. W._Gar,,2:7r, Project.Engineer
~D~D, (~
G . 6K.lfe l i s l et/ffe'ct ion Chi e f
Reactor Projects Section 2A
Division of Reactor Projects
SUMMARY
Scope:
t; ..-u.-rr
Date Signed
This routine resident inspection was conducted on site in the areas of plant
status, operational safety verification, maintenance inspections, surveillance
inspections, on-site engineering review, plant support, and Licensee Event
Report follow-up.
Inspections of backshift and weekend activities were
conducted on May 11, 12, 13, 15, 16, 82, 23, 24, and 27, 1995.
Results:
Operations
Unit 2 rod control system failures caused the four control group B2 rods to
drop to the bottom of the core on May 11 and the four control group A2 rods to
drop to the bottom of the core on May 21. Operators responded appropriately
to each event and manually tripped the reactor (paragraph 3.1).
9507120078 950623
ADOCK 05000280
G
2
Operators performed Unit 2 reactor startups in a professional manner.
Control
room communications and use of procedures were good.
Equipment failures
including a control power failure within the N-41 power range nuclear
instrument drawer and loss of main generator hydrogen seal oil pressure
complicated the startups.
In each case operations personnel maintained the
reactor in a safe condition while the failed components were repaired
{paragraph 3.2).
Maintenance
Maintenance technicians and system engineers communicated well during a
corrective maintenance individual cell charge on the IA station battery
{paragraph 4.1).
The rod control failure Root Cause Evaluation {RCE) team considered a broad
range of potential causal factors.
The team, maintenance technicians, and
vendor personnel coordinated their efforts closely during evaluation and
inspection of installed Unit 2 rod control voltage regulator cards {paragraph
4.2).
Interim RCE recommendations were clearly presented during the unit
restart assessment {paragraph 6.2).
RCE recommendations for more comprehensive receipt inspection of rod control
cards were effectively implemented for replacement cards installed prior to
the May 25 restart. The RCE continued toward development of long term
corrective action recommendations for both Units I & 2 at the close of the
report period {paragraph 4.2).
The inspectors observed that rod control failures continued to challenge
operators and maintenance personnel at the close of the report period
following the Unit 2 startup on May 25. Additionally, repairs to date have
not corrected the Unit 2 control rod M-10 position indication (paragraphs 3.1
and 3.2).
Engineering
Post trip reviews properly evaluated equipment responses to two reactor trips
during this period.
The Unit 2 startup assessment conducted prior to the May
25 startup was comprehensive.
Management demonstrated appropriate sensitivity
in soliciting and resolving rod control concerns from the RCE team, the
vendor, and various departments during the startup assessment. Management's
decision to replace all stationary voltage regulator cards prior to restart
demonstrated a sound safety perspective (paragraph 6.2).
The adverse operating environment (temperature and dust) in the vicinity of
the rod control cabinets was previously identified as a problem, but was not
effectively addressed following earlier rod control problems. A temporary
ventilation modification was installed to reduce the temperature within rod
control cabinets following the rod control failures experienced on May 11 and
21.
This modification provided moderate improvement to the rod control *
cabinet environment.
The inspectors noted that licensee efforts to restore
the operating environment to that intended by the vendor continued as part of
the ongoing RCE (paragraph 6.1).
3
A non-cited violation was identified for the low-low pressurizer pressure
protection calibration procedures allowing the safety injection initiation
setpoint to be outside the safety analysis from November 1994 to March 1995.
The actual setpoint was never outside the safety analysis.
Inconsistencies
regarding updating station setpoint documents to reflect changes made during
the procedure upgrade program were identified as a weakness {paragraph 5.1).
Plant Support
An emergency preparedness practice drill was conducted on May 25.
The drill
provided useful emergency plan implementation training to station personnel.
Station security personnel responded appropriately to a reported bomb threat
which was later determined to be noncredible {paragraphs 7.2 and 7.3) .
REPORT DETAILS
I.
Persons Contacted
Licensee Employees
2.
- J. Ashley, Supervisor, Records Management
- W. Benthall, Supervisor, Licensing
H. Blake, Jr., Superintendent of Nuclear Site Services
- R. Blount, Superintendent of Maintenance
- D. Christian, Station Manager
J. Costello, Station Coordinator, Emergency Preparedness
- D. Erickson, Superintendent of Radiation Protection
B. Hayes, Supervisor, Quality Assurance
D. Hayes, Supervisor of Administrative Services
- W. Henry, Maintenance Advisor, Operations
- C. Luffman, Superintendent, Security
- J. McCarthy, Assistant Station Manager
- A. Price, Assistant Station Manager
S. Sarver, Superintendent of Operations
- R. Saunders, Vice President, Nuclear Operations
- K. Sloane, Superintendent of Outage and Planning
E. Smith, Site Quality Assurance Manager
- T. Sowers, Superintendent of Engineering
- B. Stanley, Supervisor, Station Procedures
J. Swientoniewski, Supervisor, Station Nuclear Safety
G. Woodzell, Nuclear Training
Other licensee employees contacted included plant managers and
supervisors, operators, engineers, technicians, mechanics, security
force members, and office personnel.
NRC Personnel
- M. Branch, Senior Resident Inspector
- D. Kern, Resident Inspector
- Attended Exit Interview
Acronyms used throughout this report are listed in the last paragraph.
Plant Status
Unit I began the period at 98.5% power.
Power was limited due to a
steam flow imbalance between SGs which had existed since unit startup on
April 16.
On May 6 reactor power was restored to 100%.
System
engineers continued to trend and evaluate the steam flow imbalance.
The
unit remained at 100% power through the end of the report period.
3.
2
Unit 2 began the period at 100% power.
On May 11 a rod control system
failure resulted in four control rods becoming unlatched and dropping
into the core. Operators manually tripped the unit in response to the
abnormal control rod alignment {paragraph 3.1}. The rod control system
was repaired, the reactor was restarted on May 12, and 100% power was
achieved on May 14.
On May 21 the reactor was manually tripped in response to another rod
control failure in which the four control group A2 rods dropped into the
core.
The unit was restarted on May 25 following detailed inspections
of the rod control system and replacement of numerous circuit cards.
The unit was at 100% power at the end of the report period.
Operational Safety Verification {71707, 93702)
The inspectors conducted frequent tours of the control room to verify
proper staffing, operator attentiveness and adherence to approved
procedures.
The inspectors attended plant status meetings and reviewed
operator logs on a daily basis to verify operational safety and
compliance with TSs and to maintain overall facility operational
awareness.
Instrumentation and ECCS lineups were periodically reviewed
from control room indications to assess operability. Frequent plant
tours were conducted to observe equipment status, fire protection
programs, radiological work practices, plant security programs and
housekeeping.
Deviation reports were reviewed to assure that potential
safety concerns were properly addressed and reported.
3.1
Operator Response to Unit 2 Rod Control Malfunctions
At 10:31 pm on May 11 operators manually tripped the Unit 2
reactor after four rods in the B control bank dropped into the
core.
The manual trip was a required action directed by abnormal
procedure 2-AP-1.00, Rod Control System Malfunction, revision 3.
Based on the inspectors' review of computer information and
interviews with operation personnel, the manual trip was completed
within approximately six seconds after receiving control room
indication that multiple control rods had dropped into the core.
All safety equipment responded as expected after the trip and the
plant was stabilized in a hot shutdown condition.
IRPI for
control rod M-10 was slow in responding to the actual fully
inserted rod position and the rod bottom bistable did not actuate
until approximately 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and 13 minutes after the trip. This
slow response for rod M-10 IRPI has been a recurring problem.
Although the IRPI coil was replaced during the recent RFO, the
repairs to date have not effectively corrected the problem.
The
licensee continues to work toward resolving this indication
problem that complicates responses to plant transients.
At 12:22 pm on May 21, the B-6 control rod in control group A2
dropped into the core. Approximately thirty seconds later, the
remaining three control group A2 rods dropped into the core.
Operators immediately tripped the reactor due to the rod control
4.
3
failure as required by 2-AP-1.00. Safety systems responded as
designed and operators stabilized the plant in a hot shutdown
condition.
The inspectors interviewed operations and maintenance personnel
and *reviewed operator logs, procedures, and records. Procedure
2-AP-1.00 was properly written to respond to the rod control
failures experienced on May 11 and 21.
The licensee provided
accurate information and reported each event to the NRC within the
time period specified in 10 CFR 50.72.
The inspectors concluded
that operators responded appropriately to each event.
3.2
Unit 2 Startup from May 11 and May 21 Reactor Trips
The inspectors monitored portions of Unit 2 reactor startups on
May 13 and 25.
Control room communications and use of procedures
were good.
The May 13 startup was complicated by a control power
failure within the N-41 power range nuclear instrument drawer.
The licensee performed troubleshooting, replaced the control power
fuses and returned the drawer to service.
The May 25 startup was complicated by a degraded H2 seal oil
system.
When raising the turbine to rated speed, H2 seal oil
pressure dropped and operators tripped the turbine to preclude
loss of generator H2 cooling and a H2 release. Engineering's
review of the event, which included vendor consultation,
determined that oil pressure was not properly balanced due to an
abnormal system maintenance alignment. After plant personnel
implemented.vendor recommendations, the H2 seal oil system
functioned properly. The turbine was placed on-line and the unit
achieved 100% power at 11:36 am on May 26.
The inspectors
concluded that during both startups, operators maintained the
reactor in a safe condition while the failed components were
repaired.
Additional rod control alarms were received on May 26 (Unit 1) and
May 29 (Unit 2}. Operators placed control rods in manual control
while technicians and the vendor evaluated rod control card
performance. Corrective maintenance was performed and the control
rods were restored to automatic control. The inspectors discussed
the maintenance activities with technicians. The inspectors
determined that maintenance and operations personnel responded
appropriately to the rod control alarms.
-Within the areas inspected, no violations or deviations were identified.
Maintenance Inspections (38702, 62703)
During the reporting period, the inspectors reviewed the following
maintenance activities to assure compliance with the appropriate
procedures.
4
4.1
Station Battery Individual Cell Charge
Station battery IA was identified to be in the alert range due to
cell 28 voltage being less than 2.13 volts during the monthly
surveillance performed in May.
The inspectors observed the
individual cell charge performed to correct the degraded voltage
condition. Cell 28 was charged using procedure O-ECM-0104-01,
Stationary Battery and Individual Cell Equalizing Charge,
revision 0.
Prior to connecting the portable battery charger to
the cell, technicians observed a voltage differential between the
charger leads and the battery terminals greater than normally
found.
The procedure recognized this as a condition that could
potentially induce an undesirable transient on the station
battery. The technicians stopp_ed work and contacted the system
engineer for resolution as required by procedure. Maintenance
technicians and system engineers communicated well and safely
resolved the voltage differential. The cell was charged, but
remained at 2.12 volts following the charge.
An additional cell
charge was initiated. The cell remained in alert and more
frequent monitoring was being performed.
The inspectors
determined that technicians properly implemented the cell charge
procedure and communicated effectively with the system engineer to
evaluate the voltage differential prior to connecting the charger
to the cell.
4.2
Rod Control System Failure Analysis and Corrective Maintenance
On May 11 operators received a rod control system urgent failure
alarm.
Maintenance technicians determined that a rod control
stationary voltage regulator circuit card had failed and replaced
the card.
When control group 82 control rods were transferred off
of the DC hold bus, all four rods dropped into the core.
Technicians subsequently determined that the replacement card had
a failed resistor that was not identified prior to installation.
On May 21 a control group A2 stationary voltage regulator card
failed, resulting in four control rods dropping into the core.
An
RCE team was formed to fully identify the cause of the card
failures.
The Maintenance department manager was assigned to
manage the issue and coordinate RCE team and maintenance support
activities. The inspectors interviewed personnel, reviewed
maintenance records, and observed troubleshooting activities to
assess licensee efforts to resolve the rod control failure
concern.
Maintenance technicians performed a close visual inspection of the
three failed stationary voltage regulator cards. A vendor
technician with specialized test equipment was requested to assist
in the detailed evaluation of the cards.
The intermittent nature
of one card's failure complicated the inspection.
With the aid of
the vendor, technicians specifically identified the failed
components on each of the three cards.
One card had a loose
solder joint to resistor R52.
The second card had a cracked
resistor RIB.
The third card had a shorted diode and loose
5
transistor solder joint. Card discoloration due to heat exposure
was evident at several locations on the cards.
The failed
components were diverse, but technicians identified potentially
common causal factors including excessive exposure to heat and the
questionable workmanship quality of the original solder joints.
The inspectors observed the card inspection activities and noted
that technicians maintained a high degree of professionalism.
Technicians effectively communicated their observations and
findings to the RCE team.
Management directed that all Unit 2 control rod voltage regulator
circuit cards (twelve stationary voltage regulator cards, four
lift voltage regulator cards, four movable voltage regulator
cards) be inspected and tested. Eleven stationary voltage
regulator cards functioned correctly, while one tested slightly
outside of the vendor's recommended performance criteria. Two
movable voltage regulator cards failed due to broken/weak solder
connections. Technicians replaced the stationary voltage
regulator card and repaired the two movable voltage regulator
cards. A visual inspection of the Unit 2 rod control cabinets was
conducted with no significant problems identified. The inspectors
observed that RCE team, maintenance technicians, and vendor
personnel coordinated their efforts closely during evaluation and
inspection of installed Unit 2 rod control voltage regulator
cards.
Maintenance personnel performed a material history review for
Unit 2 rod control voltage regulator cards. The inspectors
independently reviewed material history including detailed vendor
inspections performed on Unit I in 1988 and Unit 2 in 1989.
Common repairs during these PMs included solder joint repair,
tightening loose fuses, and cleaning off a significant film of
dirt. Seven voltage regulator cards were replaced over the last
seven years. All Unit I and Unit 2 rod control firing circuit
cards were replaced in the last two years. The history review
indicated that the majority of the card failures occurred at
position Cl within the rod control cabinets. Technicians noted
that this location may receive more significant heat exposure than
other card slots due to arrangement of adjacent circuit cards.
Management expedited delivery of fifteen new stationary voltage
regulator cards on May 24.
Maintenance personnel informed
management that visual inspection alone was insufficient to verify
that the cards would perform properly.
In the past a visual
inspection by warehouse receipt personnel was performed without
the aid of l&C technicians or the vendor's specialized test
equipment. Maintenance technicians and the vendor technical
representative coordinated to establish an indepth receipt
inspection plan. Additional inspections performed included a
magnified visual inspection, a reference circuit test, an
auctioneered differential amplifier test, and a ripple detector
circuit test. The inspectors observed the receipt inspection and
6
discussed the receipt inspection criteria with maintenance
personnel and the vendor.
Certificate of Conformance
documentation was properly verified by warehouse material receipt
personnel. Technicians identified several questionable solder
connections which the vendor representative then repaired prior to
acceptance.
The inspectors concluded that the receipt inspection
of rod control cards was effectively implemented for replacement
rod control voltage regulator cards installed to support the
May 25 restart.
Within the areas inspected, no violations or deviations were identified.
5.
Surveillance Inspections {61726)
During the reporting period, the inspectors reviewed surveillance
activities to assure compliance with the appropriate procedure and TS
requirements.
5.1
Low-Low PZR Pressure Channel Calibration Procedure
During this inspection period, additional inspection activities
were conducted associated with PZR protection pressure
instrumentation calibration. Inspection Report Nos. 50-280/95-06
and 50-281/95-06 addressed PZR pressure transmitters 2-RC-PT-2455,
2456 and 2457 being improperly calibrated under sub-atmospheric
conditions with a non-temperature compensated test gage.
In this
period, the inspectors determined that monthly calibration
procedures in effect from November 1994 to February 1995 allowed
the Unit 2 low-low PZR pressure channel setpoint for SI initiation
to be set outside the value used in the safety analysis. A record
review revealed that during this period the Unit 2 setpoints were
not set or left outside the safety analysis value.
In November 1994 upgraded procedure 2-IPT-CC-RC-P-455, Pressurizer
Pressure Protection Loop P-2-455 Channel Calibration, revision 0,
replaced 2-PT-2.4(P-2-455) for calibration of the low-low PZR
protection pressure channel associated with 2-RC-PT-2455.
The old
procedure specified the channel comparator to be set at a voltage
equivalent to 1715 psig with a tolerance of+ 4 psig and - 0 psig.
When potential instrumentation loop errors {e.g., CSA value of
15.4 psig) were taken into consideration, the channel could trip
slightly below the.1700.3 psig safety analysis value.
However,
the old procedure's precaution 4.5 stated, "Reactor Protection and
Safeguard Comparators are set 15 mv in the conservative direction
to minimize the effect of electronic drift which could result in
an unsafe condition." This 15 mv conservative bias {equivalent to
3 psig) provided an administrative control that effectively
changed the setpoint to 1718 psig. Thus, the actual setting when
corrected by the CSA remained above the safety analysis value .
When the upgraded procedure was developed, the administrative
control was deleted and the setpoint was specified as 1715 psig
with a plus or minus 4 psig tolerance. Thus, the channel could
7
have been adjusted (or left) at a value such that it could trip as
low as 1695.6 psig {1715(setpoint)-15.4(CSA)-4(tolerance, i.e., approximately 4.7 psig below the value used in the safety analysis. The upgraded calibration procedures for the other Unit 2 low-low PZR protection pressure channels contained the same error. In 1993 the licensee initiated a project to increase the operating margin associated with this setpoint. During February 1995, a design change was implemented that revised the applicable calibration procedures to specify a 1775 psig setpoint. A review of Unit 1 procedures revealed that a similar procedural problem had also existed during approximately the same time period. A record review demonstrated that the actual setpoint was always above the value used in the safety analysis. The procedure upgrade project manager and the supervisor for the I&C procedure upgrade group indicated that the small amount of margin in the setpoint was well known as exemplified by its discussion in Inspection Report Nos. 50-280/93-01 and 50-281/93-01. The failure to ensure that procedures maintain this setpoint within the safety analysis value was attributed to cognitive errors by the procedure writer and reviewers. The procedure upgrade project manager indicated that this issue would be reviewed with all upgrade procedure writers. The low-low PZR protection pressure calibration procedures were inadequately provided, in that, the allowed SI initiation setpoint was outside that used in the safety analysis. This was a violation of TS 6.4.A.2. The licensee informed the inspectors that a member of their staff, who was not available during the inspection period, had earlier noted this setpoint deficiency but had not completed his review or issued a DR at the time of the inspection. This violation will not be subject to enforcement action because the licensee's efforts in identifying and correcting the violation meet the criteria specified in Section VII.B of the Enforcement Policy. This item is identified as NCV 50-280, 281/95-08-01, Failure To Provide Adequate Calibration Procedures For Pressurizer Protection Channels 455, 456 and 457. During the PZR instrument setpoint review the inspectors noted that conflicts existed between reference documents that were utilized by the procedure upgrade project. Specifically, DRPs were used as reference material when l&C procedures were upgraded. Procedure 2-DRP-OOS, Instrument Setpoints, revisions 17 (issued September 28, 1994) and 18 (issued November 30, 1994), in effect at the time 2-IPT-CC-RC-P-455, 456 and 457 were developed, specified the tolerance band for the low-low PZR protection pressure trip setpoint (1715 psig) as 1715-1719 psig. However, Technical Report EE-0068, Instrument Tolerances For W/Hagan 7100 Process Protection and Control Systems, issued by corporate
6.
8 engineering indicated that a+/- 4 psig tolerance band around this setpoint was desired. This latter document reflected the current desired method for specifying tolerances for setpoints. The+/- 4 psig tolerance for the 1715 psig setpoint was never incorporated into 2-DRP-005. The latest change to this DRP, revision 19, was issued March 16, 1995, and incorporated the new 1775 psig setpoint with a+/- 4 psig tolerance. To determine whether the failure to promptly revised 2-DRP-005 when the procedure upgrade project revised the tolerance band was only an isolated oversight, the inspectors reviewed another protection channel whose setpoint in 2-DRP-005, revision 19, was listed with a minus O tolerance value. The reactor coolant loop low flow trip setpoint (FC-RC414) was specified as 92% indicated flow with a tolerance band of 92% to 92.4%. However, the latest upgraded calibration procedure for this channel, 2-IPT-CC-RC-F- 414, Reactor Coolant Flow Loop F-2-414 Channel Calibration, revision 0, issued December 20, 1993, specified a+/- 0.02v (+/- 0.4%} tolerance around the setpoint. This was verified to be the case for the other channels on Unit 2 and the three similar channels on Unit 1. Not maintaining l/2-DRP-005 current when the upgrade program revised setpoint tolerances in calibration procedures was considered a weakness . Within the areas inspected, one non-cited violation was identified. On-Site Engineering Review (37551) 6.1 Rod Control Cabinet Cooling Temporary Modification Unit 2 rod control circuit card failures necessitated two manual reactor trips during this report period (paragraph 3.1). The RCE team determined that one of the causal factors was thermal degradation due to high ambient temperatures in the rod control cabinets. The vendor recommends ambient temperature be maintained at or below 77 degrees F. The temperature in the vicinity of the rod control cabinets frequently reaches 85-90 degrees F for extended periods of time. Engineers developed TM Sl-95-05 to provide improved cooling to both units' rod control cabinets. The inspectors reviewed the TM and the supporting SE to determine whether the TM was properly evaluated and installed. TM Sl-95-05 was installed in the Unit 1 & 2 normal switchgear rooms on May 25-26, 1995. Prior to installation, room temperature was 87 degrees F and the Unit 2 normal switchgear room air conditioner was degraded to approximately 50% capacity. Two 18 ton capacity spot coolers were positioned in the vicinity of the rod control cabinets on each unit. Flexible hoses directed cool (65 degrees F) air to the floor level vent on each of the rod control power cabinets. The cool air passes through the cabinet internals and exits at the top of the cabinet. A relatively low air flow rate was established to provide about 2 volumetric air
6.2 6.3
9 changes per hour to the cabinet. The inspectors physically verified that the TM was properly installed. The turbine building operator tour routine was modified to include monitoring rod control cabinet temperature and emptying the spot cooler condensing tank. Contact thermometers were attached to the outside of the rod control cabinet doors to provide indications by which operators could monitor the cooling effect of the TM. The inspectors noted that this placement did not provide accurate indication of the cabinet internals. The external thermometers continued to indicate about 85 degrees F, while the interior of the cabinets was significantly cooler. Engineers informed the inspectors that alternate methods of monitoring cabinet temperature in the sensitive components {rod control circuit cards) would be evaluated. The inspectors concluded that operator duties had been properly modified to monitor operation and effectiveness of the TM. The inspectors concluded that the TM moderately improved the rod control cabinet environment. Factors such as equipment EQ, moisture condensation, and temperature were appropriately addressed. The TM is authorized to remain installed through September which will provide temperature relief during the warmest Summer months. The inspectors noted that this was only a temporary compensatory action. Permanent actions to restore rod control cabinet operating environment to that recommended by the vendor remain under licensee review pending completion of the rod control failure RCE. Unit 2 Post Trip Review SNS engineers conducted a post trip review and presented their findings to SNSOC following the Unit 2 May 21 trip in accordance with VPAP-1404, Reactor Control, revision 0-PSOl. The inspectors attended the SNSOC review. Plant response to the trip was discussed in detail. Safety related systems responded to the trip as designed. Required actions to address the rod control failure and minor non-safety related equipment problems were clearly identified. The inspectors also reviewed the post trip review conducted for the Unit 2 May 11 trip. The inspectors concluded that reactor plant response to the trips and problems to be resolved prior to startup were appropriately evaluated. Unit 2 Startup Assessment The inspectors attended the Unit 2 startup assessment on May 24 following initial evaluation and repair of the rod control system. The RCE team, a vendor technical representative, maintenance, and engineering personnel presented their observations, findings, and recommendations to the MRB. The Maintenance department manager summarized the maintenance that had been done on the Unit 2 rod control cabinets since May 11 as well as a maintenance history
10 review conducted on both units' rod control cabinets (paragraph 4.2). The vendor stated that typical factors effecting card failure which he has observed at other facilities include excessive surrounding temperatures, dust or dirt buildup on the circuit cards, and card age. The RCE team informed management that the current condjtion of the Unit 2 rod control system was acceptable to support startup. Several additional observations and recommendations were also presented. All Unit 1 and Unit 2 rod control firing circuit cards were replaced over the last two years due to emergence of aging and heat related failures. Corrective actions implemented at that time included periodic PMs to vacuum cabinet interiors, visually inspect all circuit cards, and replace fuses at each RFO. However recommendations to upgrade rod control cabinet cooling were not implemented. The temperature in the vicinity of the cabinets continued to be above the manufacturer recommended 77 degrees F for extended periods of time. The voltage regulator cards are. installed adjacent to firing cards, which generate significant heat. The vendor estimated the service life of the voltage regulator cards to be approximately 11.4 years. Several of the voltage regulator cards were in service more than 11.4 years. The elevated cabinet temperature may have prematurely aged the cards . The RCE team recommended that a TM to lower rod control cabinet temperature be implemented promptly (paragraph 6.1) pending permanent resolution. Manufacturing quality of the cards was also questioned. Two versions of the voltage regulator card are used at Surry. Most cards installed are the original model (No 6050D16G01) while some of the newer model (No. 1048F56G03) cards have been installed. Technicians observed the manufacturing quality of the newer model card to be superior to the old card. The licensee identified manufacturing defects on over twenty percent of the replacement rod control circuit cards drawn from warehouse inventory. Engineers observed that current receipt inspection methods are not sufficient to identify a significant portion of the defects. The RCE team recommended upgrading the receipt inspection criteria for rod control circuit cards and upgrading the installed voltage regulator cards to the new model when available. The RCE team also noted that the last visual inspection performed on the Unit 2 stationary voltage cards prior to reinstallation may not have been thorough and should be reperformed. Station management asked detailed questions regarding causal analysis and current reliability of rod control on both units. Issues discussed included human performance, manufacturing quality, receipt inspection and PM capabilities, training, rod control cabinet environment, operating history, and applicability to other types of rod control cards. The inspector observed that the assessment meeting was conducted in an open forum which clearly fostered a questioning attitude on the part of station
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11 management and technical personnel ranging to the craft level. Management decided that new voltage regulator rod control voltage regulator circuit cards would be procured for Unit 2 and installed prior to unit restart. Interim recommendations of the RCE team were properly acted upon and the RCE team continued its evaluation to determine long term recommended actions. The inspectors concluded that the Unit 2 startup assessment was comprehensive. Management demonstrated appropriate sensitivity in soliciting and resolving rod control concerns from the RCE team, the vendor, and various departments during the startup assessment. Management's decision to replace all stationary voltage regulator cards prior to restart demonstrated a sound safety perspective. Within the areas inspected, no violations or deviations were identified. 7. Plant Support {71750) 7 .1 7.2 7.3 Plant Tour Observations The inspectors observed radiological control practices and radiological conditions throughout the plant. Radiological posting and control of contaminated areas was good. Workers complied with radiation work permits and appropriately used required personnel monitoring devices. The protected area security perimeter was well maintained with no equipment or debris obstructing the isolation zones. EP Exercise The inspectors observed an EP practice drill on May 25. The licensee ran the drill from the control room simulator and activated the TSC, OSC, and LEOF emergency plan facilities. Operators properly classified the initiating event at the Alert level. The TSC and OSC were properly staffed and activated in a timely manner. Communications within the TSC were good and the Site Emergency Director maintained a clear understanding of plant conditions throughout the event. The event was appropriately reclassified at the TSC as simulated conditions escalated to a General Emergency level. The OSC responded to four requests for assistance during the first two and a half hours of the exercise. Sufficient resources were available at the OSC to respond to a larger number of requests which might be expected during certain accident scenarios. The inspectors concluded that the drill provided useful EP implementation training to station personnel. Bomb Threat On May 12 station security personnel were informed by the local police department that a bomb threat had been received regarding the Surry Power Station. Initial assessment concluded that the
,, 12 threat was most likely a prank call. The licensee reported the bomb threat to the NRC in accordance with 10 CFR 73.71. With the assistance of the local police, the licensee further investigated the origin of the call and pertinent facts. The source of the call was identified and the call was determined to be noncredible. As a precaution, security and operations personnel conducted a physical search of selected areas within the protected area. No evidence of a bomb or suspicious materials was found. The inspectors concluded that licensee response to this event was appropriate. Within the areas inspected, no violations or deviations were identified. 8. Licensee Event Report Follow-up (92700) The inspectors reviewed LERs submitted to the NRC to verify accuracy, description of cause, previous similar occurrences, and effectiveness of corrective actions. The inspectors considered the need for further information, possible generic implications, and whether the events warranted further on-site follow-up. The LERs were also reviewed with respect to the requirements of 10 CFR 50.73 and the guidance provided in NUREG 1022, Licensee Event Report System, and its associated supplements. 8.1 (Closed) LER 50-281/93-01, Momentary Loss of Component Cooling Flow to Heat Exchanger Renders RHR loop inoperable, dated April 30, 1993. This LER described the April 20, 1993 degradation of RHR cooling to the core with the plant in cold shutdown. While performing planned maintenance, electricians inadvertently determinated the power supply for the wrong MOV. Valve 2-CC-TV- 209A closed, interrupting CC flow through the RHR heat exchanger. Operators took prompt action and reestablished CC flow within one minute. No change in RCS temperature was observed during the brief degradation of RHR cooling. The safety consequence of the brief CC interruption was minor. The inspectors' review of the event and proposed corrective actions were previously documented in NRC IR 50-280 & 281/93-11. The LER was accurate and appropriately addressed the reporting requirements of 10 CFR 50.73. The inspectors confirmed that the proposed corrective actions listed in the LER and human performance RCE had been implemented. However, the inspectors noted that one of the contributing causal factors identified in the LER had not been specifically addressed by the corrective actions listed. in the LER or RCE. This factor was the failure of operators to use controlled electrical drawings when preparing the equipment tagout. The inspectors*discussed tagout procedures and implementation with operations management. Management stated that expectations were for both the operator who prepares the tagout and the SRO reviewing the tagout to use controlled station drawings for isolation boundary verification. Interviews with a small sample of operations personnel confirmed that this
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13 expectation was understood by operators. The inspectors noted that no significant tagout discrepancies have been identified in the past six months. Operations management informed the inspectors that OPAP-0010, Tagouts, revision 4-PS3 would be reviewed to ensure this expectation was clearly documented. The inspectors concluded that corrective actions for this event were complete. 8.2 (Closed) LER 50-280/93-12, Safety Injection Accumulator Boron Concentration Level Less Than TS Limits For Greater Than Four Hours. This event and immediate corrective actions were described in Inspection Report Nos. 50-280/93-24 and 50-281/93-24. During this inspection period, the inspectors reviewed the corrective actions identified in the LER to prevent recurrence. A note was added before step 5.2.1 in operating procedure l-OP-SI-002, Safety Injection Accumulators, revision 4, to warn personnel that inleakage into an accumulator may decrease boron concentration and may require sampling for compliance with TS. Technical Staff Continuing Training Lesson Plan TSCT-94.1-LP-4, Current Events,* and Licensed Operator Requalification Program Training Synopsis, SI Accumulator Boron Below Tech Spec Limit, adequately addressed the event. In addition, valves l-Sl-128 and l-Sl-130 were repaired per WO 00272385-01 and WO 00274647-0l during the last refueling outage. These items satisfactorily met the commitments stated in the LER. Within the areas inspected, no violations or deviations were identified. 9. Exit Interview The inspection scope and findings were summarized on June 1, 1995, with those persons indicated in paragraph 1. The inspectors described the areas inspected and discussed in detail the inspection results addressed in the Summary section and those listed below. Item Number NCV 50-280, 281/95-08-01 LER 50-281/93-01 LER 50-280/93-12 Status Closed Closed Closed Description/{Paragraph No.} Failure to Provide Adequate Calibration Procedures for PZR Protection Channels (5.1) Momentary Loss of Component Coolant Flow to Heat Exchangers Renders RHR Loop Inoperable (8.1} SI Accumulation Boron Concentration Less Than TS Limits (8.2} Proprietary information is not contained in this report. Dissenting comments were not received from the licensee.
14 IO. Index of Acronyms CC COMPONENT COOLING WATER CFR CODE OF FEDERAL REGULATIONS CSA CHANNEL STATISTICAL ALLOWANCE DC DIRECT CURRENT DR DEVIATION REPORT DRP DESIGN REFERENCE PROCEDURE ECCS EMERGENCY CORE COOLING SYSTEM EP EMERGENCY PREPAREDNESS EQ ENVIRONMENTAL QUALIFICATION F FAHRENHEIT H2 HYDROGEN I&C INSTRUMENTATION AND CALIBRATION IR INSPECTION REPORT IRPI INDIVIDUAL ROD POSITION INDICATION LER LICENSEE EVENT REPORT LEOF LOCAL EMERGENCY OPERATIONS FACILITY MOV MOTOR OPERATED VALVE MRB MANAGEMENT REVIEW BOARD MV MILLIVOLT NCV NON-CITED VIOLATION NRC NUCLEAR REGULATORY COMMISSION OSC OPERATIONS SUPPORT CENTER PM PREVENTIVE MAINTENANCE PSIG POUNDS PER SQUARE INCH GAUGE PZR PRESSURIZER PT PERIODIC TEST RFO REFUELING OUTAGE RCE ROOT CAUSE EVALUATION RCS REACTOR COOLANT SYSTEM RHR RESIDUAL HEAT REMOVAL SE SAFETY EVALUATION SG STEAM GENERATOR SI SAFETY INJECTION SNS STATION NUCLEAR SAFETY SNSOC STATION NUCLEAR SAFETY AND OPERATION COMMITTEE SRO SENIOR REACTOR OPERATOR TM TEMPORARY MODIFICATION TS TECHNICAL SPECIFICATION TSC TECHNICAL SUPPORT CENTER V VOLT VPAP VIRGINIA POWER ADMINISTRATIVE PROCEDURE WO WORK ORDER
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