ML17262A960
| ML17262A960 | |
| Person / Time | |
|---|---|
| Site: | Ginna |
| Issue date: | 08/14/1992 |
| From: | Lazarus W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17262A959 | List: |
| References | |
| 50-244-92-09, 50-244-92-9, NUDOCS 9208250074 | |
| Download: ML17262A960 (28) | |
See also: IR 05000244/1992009
Text
U. S. NUCLEAR REGULATORY COMVHSSION
REGION I
Inspection Report 50-244/92-09
License: DPR-18
Facility:
R. E. Ginna Nuclear Power Plant
Rochester Gas and Electric Corporation (RG&E)
Inspection:
Inspectors:
May 27 through July 20, 1992
T. A. Moslak, Senior Resident Inspector, Ginna
E. C. Knutson, Resident Inspector, Ginna
H. Kaplan, Senior Reactor Engineer, Region I
A. Loh ', Senior Reactor Engineer, Region I
Approved by:
W.
s, Chief, Reactor Projects Section 3B
INSPECTION SCOPE
Date
Plant operations, radiological controls, maintenance/surveillance,
security, emergency
preparedness,
engineering/technical
support, and safety assessment/quality
verification.
INSPECTION OVERVIEW
Oy
y
'Mly&
Ip
dMlyllMU*pl
hot shutdown condition following the rupture of a preseparator drain tank.
RG&E
management's
verification that auxiliary operator logkeeping records were accurately
maintained was limited in scope and depth.
dchldl
1: Rd 'vp
i 'yi pl
H
d
personnel exposure was minimized during the transfer of spent resin.
Mainten nce/ urveillance:
Corrective maintenance
was expeditiously performed on a service
water leak in a containment air cooler.
~ecurit:
Site security is provided appropriate coverage to support on-going upgrades to
perimeter security systems.
Emer enc
Pr
redn:
A simulator-driven mini-drillwas carried out in preparation for
the annual exercise.
En ineerin /Techni
1
u
rt; Limitations were identified in the engineering process that
controlled the temporary repairs made to a ruptured preseparator
drain tank.
Safet
A sessment/
lit V rifi ti n:
Senior corporate management
was provided a
detailed briefing by the Quality Performance Department on the status of findings identified
by internal/external organizations.
9208250074
920814
ADOCK 05000244
8
TABLEOF CONTENTS
OVERVIEW
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
1
TABLE OF CONTENTS.................................
~.....
~ ii
1.0
PLANT OPERATIONS (71707) ...................
1.1
Operational Experiences....................
1.2
Control of Operations .....................
1.3
Inspection of Plant Operator Activities (RI TI 92-01) ..
1
1
1
1
2.0
RADIOLOGICALCONTROLS (71707)
2.1
Routine Observations
2.2
Primary Deionizing Resin Disposal..............
2
2
2
3.0
MAINTENANCE/SURVEILLANCE(62703, 61726)
3.1
Corrective Maintenance.........................
3.1.1
"A" Steam Generator Wide Range Level Detector Sensing
Leak
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
0
3.1.2
"C" Containment Recirculation Fan Cooling Water Leak
3.2
Surveillance Observations........................
Line
2
2
2
3
4
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
0
4e0
Security (71707)
o
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
4
4.1
Routine Observations .... ~............ ~..............
4
5.0
EMERGENCY PREPAREDNESS (71707) ............... ~.......
4
5.1
Simulator-Driven Mini-Drill...... ~.....................
4
6.0
ENGINEERING/TECHNICALSUPPORT (71707, 92701)...........
6.1
"A" Preseparator
Drain Tank Rupture ...................
6.1.1
Event Description ...........................
6.1.2
Equipment Description ........................
6.1.3
Licensee Response
6.1.4
Inspector Findings........
~ .
~ .. ~.............
Feedwater Flow Oscillations .........................
Licensee Action on Previous Inspection Findings
6.3.1
(Closed) Unresolved Item (50-244/90-10-02) Licensee to verify
separation of AMSAC Cable Run in Cable Tray No. 372 from
Cable Tray No. 23.
6.4
Erosion/Corrosion (E/C) Integrated Management Team Meeting
~
~
5
~
~
~
5
~
~
~
5
~
~
~
5
6
7
~
~
~
9
9
~
~
~
9
10
11
Table of Contents
7.0
SAFETY ASSESSMENT/QUALITY VERIFICATION(71707, 90712, 90713,
92701, 40500) .............,, ......................
7..1
Periodic Reports
7.2.
Licensee Event Reports (LERs) and Special Report
7.3
Quality Assurance/Quality Control (QA/QC) Subcommittee Meeting...
10
10
11
11
8.0
ADMINISTRATIVE(71707, 30702, 94600)
8.1
Backshift and Deep Backshift Inspection...............
8.~2
Exit Meetings
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
~
\\
~
~
~
~
~
~
~
~
~
~
~
~
~
11
11
11
DETAILS
1.0
PLANT OPERATIONS (71707)
1.1
Operational Experiences
The plant operated at approximately 97% power for most of the inspection period.
On June
9, 1992, the plant was taken off-line and the reactor placed in hot shutdown to support
repairs to a ruptured preseparator
drain tank.
The "A" preseparator
drain tank had failed as a
result of steam impingement on the tank wall. With repairs completed,
the plant was
restarted on June 11, 1992.
Power operations continued through July 2, 1992 at which time
power was reduced to about 74% to support repairs to an off-site transmission substation.
1.2
Control of Operations
Overall, the inspectors found the R. E. Ginna Nuclear Power plant to be operated safely.
The control room was staffed as required,
Operators exercised appropriate control over
access to the control room.
Shift supervisors consistently maintained authority over activities
and provided detailed turnover briefings to relief crews.
Power reduction and escalation were
well controlled.
Operators adhered to approved procedures
and understood the reasons for
lighted annunciators.
The inspectors reviewed control room log books for activities and
trends, observed recorder traces for abnormalities,
assessed
compliance with Technical
Specifications, and verified that equipment availability was consistent with the requirements
for existing plant conditions.
During normal work hours and on backshifts, accessible
areas
of the plant were toured.
No inadequacies
were identified.
1.3
Inspection of Plant Operator Activities (RI TI 92-01)
In response to NRC Information Notice 92-30, "Falsification of Plant Records," licensee site
operations management
conducted a selective review of plant records.
The review was
limited to examining security computer vital area entry/exit data compiled during a one week
period in February 1992.
This review was to verify that unlicensed auxiliary operators were
present in various vital areas, indicating that the operators were performing their assigned
duties.
Site management
found no evidence that operators were not making the appointed
rounds for the period examined.
Through examination of the review process and discussions with site management,
the
inspector concluded that the review was too limited in scope and depth to accurately assess if
all auxiliary operators were conscientiously performing their assigned duties, since individuals
not on site during the review period were not subject to this verification. Additionally, due
to the narrow scope of the review, site management
could not determine whether plant logs
and records were accurately maintained by the individuals entering vital areas during that
period.
Site management
acknowledged the inspector's concerns regarding the inadequacy of this
review.
Management stated that additional attention willbe given this matter, including
integrating other departments into the verification process.
To date, no firm action plan with
implementation dates for a comprehensive self-monitoring program has been established.
As an independent check of auxiliary operator performance,
the inspector accompanied
an
unlicensed operator during the conduct of a set of rounds.
Prior to conducting this tour, the
inspector reviewed applicable operating procedures/technical
specifications and interviewed
plant operations management
on their staff expectations.
Through this spot checking, the
inspector did not identify inconsistencies in the completeness or accuracy of recorded data.
Additional inspection of auxiliary operator on-watch practices by the resident staff will
continue.
2.0
RADIOLOGICALCONTROLS (71707)
2.1
Routine Observations
The inspectors periodically confirmed that radiation work permits were effectively
implemented, dosimetry was correctly worn in controlled areas and dosimeter readings were
accurately recorded,
access to high radiation areas was adequately controlled, and postings
and labeling were in compliance with procedures
and regulations.
Through observations of
ongoing activities and discussions with plant personnel,
the inspectors concluded that
radiological controls were conscientiously implemented.
No inadequacies
were identified.
2.2
Primary Deionizing Resin Disposal
On June 3, 1992, the inspector observed the transfer of spent charging and volume control
system deionizing resin to a shipping cask in preparation for transport for disposal.
The resin
transfer was performed in accordance with the licensee's radioactive discharge (RD)
procedure, RD-10.14, "Handling, Loading and Unloading of Chem-Nuclear 8-120A or B(U)
Transport Cask."
The inspector noted no procedural or operational deficiencies during the
conduct of the discharge.
The inspector also reviewed the ALARApackage (ALARA
number 920105) and associated
special work permits and noted no deficiencies.
Contact and
area radiation levels were appropriately monitored, as was local airborne radioactivity.
There
were no unexpected radiation levels or uncontrolled releases of radioactive materials
associated with the transfer.
3.0
MAINTENANCE/SURVEILLANCE(62703, 61726}
3.1
Corrective Maintenance
3.1
~ 1
"A" Steam Generator Wide Range Level Detector Sensing Line Leak
While observing the containment video monitor on June 23, 1992, the Shift Technical
Advisor noted steam/water leakage from a small diameter pipe in the vicinityof the "A"
reactor coolant pump.
Based on plant arrangement drawings and operator knowledge, the
leaking line was tentatively identified as either the "A" steam generator (SG) wide range level
detector variable leg sensing line, or the "A" SG bottom blowdown sample line. Normal
containment process and radiation monitor levels further supported that the leak was from a
secondary plant system rather than reactor coolant system leakage.
Operators entered
containment later that day to positively identify the source of the leak.
Although successful
in confirming that it was secondary
system leakage, operators were not able to identify the
exact source; the label on the valve closest to the leak (from a compression fitting) was not
legible, and the high area radiation field (approximately 40 rem per hour) precluded
conducting a detailed walkdown.
The operator tightened the fitting and temporarily stopped
the leak.
However, the fitting resumed leaking within several hours.
o
The following day, the licensee developed a plan to positively identify the location of the leak
within the "A" SG system and to attempt further repair.
From position information gained in
the previous day's attempt, operators considered that the leak was most likely from the wide
range level detector.
To verify this, the wide range level detector would first be equalized
and isolated, thus cutting offpressure to one side of the leak; the leak would then stop once
the adjacent isolation valve was closed.
The operator who had tightened the fitting had used
only sufficient torque to stop the leak, and thought that additional tightening was possible.
Therefore, the first attempt at repair would be to further tighten the fitting. Ifthis was
effective in stopping the leak, as demonstrated by zero leakage for approximately one day
with the adjacent isolation valve open, the repair would be considered successful and the level
detector would be placed back in service.
The leak was found to be from the "A" SG wide range level detector sensing line, and
tightening the fitting stopped the leak.
The inspector concluded that the licensee's actions to
identify and correct the problem were conservative and well planned.
The inspector had no
further concerns on this matter.
3.1.2
"C" Containment Recirculation Fan Cooling Water Leak
On the afternoon of July 2, 1992, operators observed a 55% increase in automatic pumpdown
frequency of the "A" containment sump.
This translated to an increased inflow to the sump
of approximately 0.25 gallons per minute.
Based on the fact that routine monthly service
water system testing had been completed several hours earlier, operators immediately
suspected
the source to be a service water leak from one of the four containment fan coolers.
Operators entered containment that evening and identified the source of leakage to be a
service water heat exchanger leak on the "C" containment recirculation fan cooler unit.
Technical specification action statement 3.3.2.2.a allows one recirculation fan cooler unit to
be inoperable for a period of no more than seven days.
This action statement was entered at
8:10 PM, July 2, 1992, when service water to the unit was isolated to stop the leak.
An attempt was made to repair the pinhole leak in the fan cooler unit heat exchanger by
When this was unsuccessful,
the tube was cut and plugged.
Although this stopped
the original leak, a second leak had developed from an adjacent tube, apparently due to its
close proximity to the repair area.
Following the successful braze repair of the second leak,
the access panel was reinstalled with a gasket seal.
The "C" recirculation fan cooler unit was
declared operable on July 7, 1992.
The inspector assessed
that the actions to repair the "C" recirculation fan cooler unit were
proper.
NRC notification of the service water leak in containment was made within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />
as required by IE Bulletin No. 80-24, "Prevention of Damage Due to Water Leakage Inside
Containment."
Management attention and use of overtime through the holiday weekend were
appropriate.
Engineering support was readily available and provided timely development of
repair techniques.
The inspector had no further concerns on this matter.
3.2
Surveillance Observations
Inspectors observed portions of surveillances to verify proper calibration of test
instrumentation,
use of approved procedures,
performance of work by qualified personnel,
conformance to Limiting Conditions for Operation (LCOs), and correct system restoration
following testing.
The following surveillances were observed:
Performance Test (PT)-32-A, Reactor Trip Breaker Testing - "A" Train, revision 12,
dated April2, 1992, observed June 23, 1992
0
PT-12.1, Emergency Diesel Generator 1A, revision 68, dated April 9, 1992, observed
July 10, 1992
No unacceptable
conditions were identified.
4.0
Security (71707)
4.1
Routine Observations
During this inspection period, the resident inspectors verified that x-ray machines and metal
and explosive detectors were operable, protected area and vital area barriers were well
maintained, personnel were properly badged for unescorted or escorted access,
and
compensatory
measures
were implemented when necessary.
Adequate compensatory
measures
were provided to support ongoing site security upgrade modifications.
No
unacceptable conditions were identified.
5.0
(71707)
5.1
Simulator-Driven Mini-Drill
On June 17, 1992, a simulator-driven mini-drillwas conducted to internally assess
emergency
preparedness
capabilities of plant operators and the site technical staff.
The inspector verified
that the on-going drill did not adversely impact control room operations or associated
equipment.
~
~
6.0
ENGINEERING/TECHNICALSUPPORT (71707, 92701)
6.1
"A"Preseparator Drain Tank Rupture
6.1.1
Event Description
On the morning of June 9, 1992, a shift supervisor (SS) noticed a small puddle of water
under the "A" preseparator drain tank (PDT) while conducting a routine plant tour.
Through
comparison by touch, the SS found the "A" PDT lagging to be significantly hotter than that
of the "B" PDT.
He then returned directly to the control room.
As he entered the control
room, he heard a loud roaring noise in the turbine building and saw steam fillingthe
building. Auxiliary operators were dispatched to investigate.
Upon reporting that steam was
emanating from the area where the PDTs and feedwater heaters are located, control room
operators commenced
a 1%/minute load reduction at 4:49 A.M. As a result of the turbine
building steam environment, an erroneous fire alarm on Z-32 (turbine building basement
north) and intermittent 480 volt non-vital bus ground fault alarms were received (and rapidly
cleared) in the control room.
In response to these indications of degrading conditions, the
load reduction rate was increased to 2%/minute.
The main generator output breakers were
opened at 6:12 A.M. and the turbine manually tripped one minute later.
Shutting the turbine
stop and intercept valves isolated the leak.
Subsequent
inspection of the "A" PDT revealed a
wall failure in the form of a fish mouth rupture on the north side of the PDT.
The fish
mouth was approximately 8 inches long with a maximum opening width of about 1/2 inch.
Using the clock location system, the failure area was located at the 3 o'lock position when
viewed from the east end of the "A" PDT.
There were no personnel injuries and no obvious
damage to surrounding plant equipment.
Examination of the ground fault indicating lights by
the auxiliary operators on all safety and non-safety related 480 volt buses indicated no off-
normal conditions.
6.1.2
Equipment Description
The "A" PDT is of carbon steel (A-53-B) construction measuring 36 inches in diameter by
approximately
11 feet long.
The nominal wall thickness of the shell material is indicated to
be 3/8 inch.
The tank serves as an in-line moisture collection header for extraction steam
being routed to the 4A feedwater heater.
Steam exhausted from the eleventh stage of the
high pressure turbine is extracted at two points and directed through separate 31-inch piping
runs to the in-line 1B and 2B preseparators
prior to entering the 1B and 2B moisture separator
reheaters (MSR), respectively.
The saturated steam/water mixture captured in the
preseparators
is channeled initiallythrough two 14-inch lines, then through 16-inch lines to
the PDTs.
Steam/water enters the "A"PDT through two inlet nozzles at the east end.
Elbows installed on the inlet nozzles inside the vessel direct the flow axially along the length
of the vessel.
Through impingement, flow direction changes,
and volumetric expansion,
water is removed from the flow stream.
At full power, the PDTs collect saturated water at
150 psig and 350'F.
Steam with improved quality is directed from the vessels to the 4A and
Water is discharged to the heater drain tank or, on high PDT level,
dumped to the main condenser.
The PDTs were originally installed in 1983 as part of the Engineering Work Request (EWR)
3100 MSR Upgrade Project.
The vessel was designed by the Brown Boveri Corporation and
manufactured by Conring Fabricators.
The internal nozzles and baffles were modified in
1984 to correct level control problems.
At that time, due to space limitations in the "A"
PDT, one of the internal elbows was orientated at an angle with respect to the vessel axis,
directing the flow toward the north vessel wall.
The rupture occurred in this area of the "A" PDT vessel wall, which had been extensively
thinned by an erosion/corrosion (E/C) mechanism.
6.1.3
Licensee Response
Following the rupture at 4:49 A.M., operations personnel initially reduced electrical
generation at 1%/minute.
Upon receiving intermittent alarms for ground faults on the plants
480 volt buses, indicating that the turbine building steam environment could be potentially
degrading balance-of-plant electrical supplies, the rate of power reduction was increased to
2%/minute.
Plant equipment functioned as required.
The main generator output breakers
were opened at 6:12 AM and the turbine was manually tripped one minute later.
Shutting the stop and intercept valves effectively isolated the leaking "A" PDT, permitting
inspection of the wall failure and assessment of repair strategies.
The reactor was maintained
at about 1% power until 9:28 A.M., at which time site management directed that it be placed
in hot shutdown conditions pending completion of PDT repairs.
Earlier, site management
convened a series of planning meetings to identify specific tasks to be completed to affect the
repairs, and additional tasks that could be facilitated during the outage.
A team of corporate
mechanical engineers was assigned to provide continuous on-site coverage to support repair
activities.
Initially, the licensee's Materials Engineering and Inspection Services Group completed a
100% volumetric examination, using ultrasonic techniques, of both PDTs, in order to
determine ifadditional areas of these vessels were at or near the minimum wall thickness.
This inspection revealed that other areas were below the minimum wall thickness
requirements.
Accordingly, repairs were extended to include those areas.
The repair
technique to be used was to provide reinforcing material to the thinned areas through either
the use of 3/8-inch A-36 carbon steel plate overlay, or the use of weld buildup.
The
actual
technique used would depend on the size/location of the area requiring repair.
Following
these UT examinations,
a section of the "A" PDT wall (approximately 3-inches wide by 8-
inches long) containing the rupture was cut out and taken to the RG&E Materials Engineering
Laboratory for examination, verification of material specifications, and determination of the
failure cause.
Final repairs to the "A" PDT consisted of welding three two-foot wide, 3/8-inch thick, rolled
A-36 carbon steel plates to the outside of the tank.
Full penetration welds were provided
between plates.
These plates, extend 180 degrees around the tank, encompassing
the rupture
as well as areas identified to be less than minimum acceptable thickness.
Additionally, two
smaller 3/8-inch thick plate overlays were welded to the tank exterior opposite the rupture to
complete reinforcement of thinned portions of the tank.
Thinned wall areas in the "B" PDT were reinforced through weld buildup in two internal
locations and by installing a 19-inch wide by 26-inch long, 3/8-inch thick, rolled A-36 carbon
steel plate at one external location.
Following weld inspections, integrity of the "A" PDT was tested under operational conditions
in accordance with Power Piping Code B-31.1.
Specifically, with the insulation off, after the
first delivery of steam, a visual leak check was performed for 10 minutes in the vicinity of
the rupture.
Additionally, with the insulation on, a visual leak check was performed over a 4
hour period after full power and maximum pressure were achieved.
No leakage was
detected.
The justification that these repairs provided an adequate margin of safety was documented by
RG&E corporate engineering in the following design analysis reports:
Preseparator
Tanks A & B, Evaluation of required minimum wall thickness, EWR
3100, DA-ME-92-001-01, June 10, 1992
Preseparator
Headers A & B Basis for Repair Methodology, EWR 3100, DA-ME-92-
002-02, June II, 1992.
These design analyses give predicted values for minimum wall thickness,
based on the actual
erosion rates, that can be used in periodic inspections.
The PDTs are scheduled for a
complete reinspection against these predicted values during the 1993 refueling outage.
Until
then, the licensee plans to conduct routine UT examinations over limited areas of the PDTs.
As part of their review of the failure of the "A" PDT, the corporate engineering team
identified several components in balance-of-plant systems that could be susceptible to similar
E/C failures which were not included in the E/C inspection program because they were not
considered piping.
These components,
which included the heater drain tank, house heating
steam condensate
return tank, steam generator blowdown tank, and 2nd and 4th pass MSR
drain tank, willbe examined for wall thinning during the 1993 outage.
6.1.4
Inspector Findings
The NRC resident and regional staff reviewed the licensee's engineering response in
evaluating the failure mode of the PDT and its associated
repair.
The inspectors agreed with
the conclusion of the licensee's metallurgical report that covered the analysis of the ruptured
tank wall. This analysis verified that the failure occurred in an area of the tank that had been
significantly thinned by erosion/corrosion
as a result of water and steam impingement.
The
failure was of a ductile nature and originated in an area of the tank in which the wall
thickness was reduced from a nominal 0.375 inch to 0.014 inch.
The material properties
were found to correspond to the chemical and metallurgical properties of the specified ASTM
A53 carbon steel.
No metallurgical anomalies were observed in the material specifications of
the failed tank.
Based on a review of the licensee's technical justification for the repair strategy, the
inspectors identified several limitations concerning the long-term integrity of the repair.
These limitations included:
The licensee maintained that, although the MSRs were designed to ASME Boiler and
Pressure
Vessel Code Section VIIIrules, no such designation was given to the PDTs.
They were not considered to formally come under the rules of Section VIIIor the
Power Piping Code (B31.1). RGB'tated that, for the original vessel built by
Brown-Boveri, the fabrication principles were to Section VIII,but that no Code Stamp
was necessary.
The inspector was aware of no precedence
set in either Section VIII
or B31.1 to permit lap weld joints acting as welds for Class A horizontal or
circumferential joints (Reference Section VIII,Table U% 12).
The absence of a Code
stamp on the vessel (pipe) would indicate the possibility that the complete set of rules
for vessel or pipe design were not followed. ASME approval of the design would
provide assurance
that the successful experience of Code vessels would provide a
measure of confidence in the design, materials, and fabrication used.
2.
In reviewing the detailed calculations, the inspector found that some elements of the
analysis were'not clearly shown.
In particular, DA-ME-92-001-01 showed a weld
efficiency factor of 0.7, which, for a single lap welded joint, appears to be high and
provides non-conservative
estimates of erosion progress.
3.
Conceptually, the analysis was not clear as to the participation of the remaining
portion of the burst plate with the patch plate in containment of the pressure load.
The plates, when welded together, both act in pressure load restraint. Ifsuch is the
case, there is concern for long-term progression of the burst mouth.
4.
The licensee explained that, since the patch plate neutral axis is not coplaner with that
of the shell wall, a small bending moment would result.
Discussion with the licensee
indicated that a bending stress of approximately 5000 foot-pounds was present.
The
inspector concluded that this stress level should have been given consideration in
formulating the repair strategy.
5.
The repair was necessitated
because of flow impingement upon a shell wall such that,
over a period of time, the wall had eroded to failure thickness.
This indicated a
design deficiency.
Good design practice would provide for material added to the wall
thickness or a sacrificial plate installed to absorb the erosive effect of the impinging
fluid.
In response to these concerns,
the licensee stated that the repairs are only temporary and that
final corrective action would be implemented during the 1993 outage.
Additionally, the
licensee has contracted an independent consultant to review the appropriateness of the
temporary repair in light of ASME rules.
A more detailed evaluation of this area is planned
in an upcoming inspection of the licensee's erosion/corrosion program.
6.2
Feedwater Flow Oscillations
As described in Inspection Report 50-244/92-08 and Licensee Event Report (LER)92-006,
feedwater flow oscillations contributed to a high "A" steam generator water level and a
subsequent
feedwater isolation on May 18, 1992.
During this inspection period, the licensee
continued investigating possible causes for this incident and took corrective action to mitigate
variations in feedwater flow. Through consultation with Westinghouse, RG&E site
engineering determined that by adjusting the gain on the Advanced Digital Feedwater Control
System (ADFCS), the cycling of the main feedwater control valves could be brought into
phase, thereby lessening flow imbalances.
Following review and approval by the Plant
Operations Review Committee (PORC) of the station modification procedure, SM-4773.33,
and supporting procedures to change the ADFCS setpoints, the gain was adjusted on June 16,
1992.
By observing this evolution, the inspector determined that the activity was well controlled by
plant operations management
and the site engineering staff in accordance with licensee
administrative procedure A-52.15, "Significant Infrequently Performed Evolutions." Prior to
making the setpoint change, control room operators were briefed by the Superintendent-Plant
Operations and the cognizant engineer.
Briefings included a summary of individual
responsibilities, confirmation of lines of communications to various plant areas,
expected
ADFCS response,
and anticipated operator actions should ADFCS response be off-normal.
The procedure controlling the station modification, SM-4773.33, was found to be sufficiently
detailed, requiring verbatim compliance with individual step signoffs.
The changes were
completed without challenging plant stability and effectively corrected the cycling phase for
the main feedwater regulating valves.
The licensee is continuing in its root cause analysis of
feedwater flow oscillations to identify measures
to optimize secondary plant performance.
6.3
Licensee Action on Previous Inspection Findings
6.3.1
(Closed) Unresolved Item (50-244/90-10-02) Licensee to verify separation of
AMSAC Cable Run in Cable Tray No. 372 from Cable Tray No. 23.
In RG&E correspondence
to the NRC dated May 27, 1992, the licensee provided the actions
taken to verify the separation of the ATWS Mitigating System Actuation Circuitry (AMSAC)
cable in cable tray No. 372, a non-safety related tray containing AMSAC cable, and cable
tray No. 23, a safety related cable tray.
The ATWS (Anticipated Transient Without Scram)
Rule, 10 CFR 50.62, and RG&E AMSAC modification Design Criteria (EWR 4230) require
~ o'
10
that a means be provided that is both diverse and independent from the existing reactor
protection system for tripping the main turbine and initiating auxiliary feedwater flow
following an ATWS event.
During the 1992 refueling outage, RG&E performed a field
verification to obtain additional data regarding AMSAC cable separation to address
separation
concerns identified in Inspection Report 50-244/90-10.
Subsequent
to the field verification,
licensee review of field data and electrical engineering circuit schedules for AMSAC cable
trays confirmed that the required separation exists.
Based on a review of licensee actions, the
inspector had no further concerns on this matter.
Accordingly, this item is closed.
6.4
Erosion/Corrosion (E/C) Integrated Management Team Meeting
On June 4, 1992, the inspector attended the quarterly meeting of the RG&E E/C Project
Team.
Management representatives
from the licensee's corporate engineering,
maintenance,
quality assurance,
chemistry, and construction departments
attended.
Agenda topics included
a review of nondestructive examination (NDE) results of components inspected during the
1992 outage, feedback on susceptible small bore piping E/C inspection activities, findings
addressing cost/technical requirements for possible replacement of degraded carbon steel
piping with stainless
steel or chrome-moly materials, and the recent acquisition by the RG&E
Materials Engineering Laboratory of a digitization imaging system that enhances video/film
x-ray resolution.
The inspector determined that the meeting was well coordinated, with
active participation by all members.
In-depth discussions
addressed
areas where the E/C
program could be expanded or enhanced
and optimizing repair/replacement
strategies.
The inspector concluded that the licensee is appropriately and systematically addressing E/C
concerns,
7.0
SAFETY ASSESSMENT/QUALITYVERIFICATION(71707, 90712, 90713,
92701, 40500)
7.1,Periodic Reports
Periodic reports submitted by the licensee pursuant to Technical Specification 6.9.1 were
reviewed.
Inspectors verified that the reports contained information required by the NRC,
that test results and/or supporting information were consistent with design predictions and
performance specifications, and that reported information was accurate.
The following
reports were reviewed:
Monthly Operating Report for May, 1992
Monthly Operating Report for June,
1992
No unacceptable conditions were identified.
S'
11
7.2
Licensee Event Reports (LERs) and Special Report
An LER and special report submitted to the NRC were reviewed to determine whether details
were clearly reported,
causes were properly identified, and corrective actions were
appropriate.
The inspectors also assessed
whether potential safety consequences
were
properly evaluated, generic implications were indicated, events warranted onsite follow-up,
and applicable requirements of 10 CFR 50.72 were met.
The following LER and special report were reviewed (Note: date indicated is event date):
LER 92-006, Feedwater Control Perturbations,
Due to a Secondary Side Transient,
Causes
Steam Generator High Level Feedwater Isolation (May 18, 1992)
Special Report addressing
a Service Water Leak in the "C" Containment Recirculation
Fan Cooler (July 2, 1992).
The report was submitted in accordance with IE Bulletin
No. 80-24, "Prevention of Damage Due to Water Leakage Inside Containment."
The inspector concluded that the LER and special report were accurate and met regulatory
requirements.
No unacceptable
conditions were identified.
7.3
Quality Assurance/Quality Control (QA/QC) Subcommittee Meeting
~
~
On June 3, 1992, the inspector attended a quarterly meeting of the RG&E QA/QC
Subcommittee.
The inspector observed that senior corporate management
was briefed on the
status of audit findings, performance indicator trends, quality performance program status and
plans, and the progress of internal self-assessments.
Areas requiring increased attention were
identified by the participants and action items assigned.
The inspector concluded that licensee
management
was properly informed of the effectiveness of programs designed to enhance site
performance.
The inspector had no concerns on these matters.
8.0
ADMINISTRATIVE(71707, 30702, 94600)
8.1
Backshift and Deep Backshift Inspection
During this inspection period, deep backshift inspections were conducted on the following
dates:
June 13, 29, July 3, and 6.
8.2
Exit Meetings
At periodic intervals meetings were held with station management
to discuss inspection scope
and findings.
The exit meeting for this inspection was held on July 24, 1992.
V
f