ML15224A695
| ML15224A695 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/26/1990 |
| From: | Binoy Desai, Shymlock M, Skinner P, Wert L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML15224A693 | List: |
| References | |
| 50-269-90-17, 50-270-90-17, 50-287-90-17, GL-88-14, NUDOCS 9007170295 | |
| Download: ML15224A695 (15) | |
See also: IR 05000269/1990017
Text
UNITED STATES
0G
NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTA STREET, N.W.
ATLANTA, GEORGIA 30323
Report Nos.:
50-269/90-17, 50-270/90-17, 50-287/90-17
Licensee: Duke Power Company
422 South Church Street
Charlotte, N.C.
28242
Docket Nos.:
50-269, 50-270, 50-287
License Nos.:
Facility Name:
Oconee Nuclear Station
Inspection Conducted:
May 20 - June 16, 1990
Inspectors:
V/
P. H. Skinner, Senior esident Inspector
Date Signed
L. D. Wert, Resident
nspector
B. .
esal, Residen7Inspector
Date Signed
Approved by:
_
_
_
_
___
_
__
_
M. B. Shymlock, Section Chief
Date Signed
Division of Reactor Projects
SUMMARY
Scope:
This routine, announced inspection involved inspection on-site in
the
areas of operations, surveillance testing, maintenance
activities, an unmonitored discharge from the Unit 1 vent, and plant
startup from refueling.
Results:
One apparent violation was identified involving the Penetration Room
Ventilation System. The inspectors identified that the system would
be inoperable under certain accident conditions (paragraph 5).
It
was also noted during this review that the licensee's response to
Generic Letter (GL)
88 -
14, Instrument Air Supply System Problems
Affecting Safety Related Equipment, was inadequate (paragraph 5).
A violation was cited for failure to follow procedures involving
calibration
and testing of the Reactor Protection System
(paragraph 3.b).
Three Non-cited Violations (NCV) were identified:
-
Violation of Technical Specifications regarding radioactive
effluent monitoring (paragraph 6).
2
-
Inoperability of the Safe Shutdown Facility Makeup.System due
to a mispositioned valve (paragraph 8).
-
Violation of Technical Specifications associated with Upper
Surge Tank minimum level requirements (paragraph 2.b).
A weakness was noted in the control of scaffolding over
safety-related equipment (paragraph 4.b).
REPORT DETAILS
1. Persons Contacted
Licensee Employees
B. Barron, Station Manager
D. Couch, Keowee Hydrostation Manager
- T. Curtis, Compliance Manager
J. Davis, Technical Services Superintendent
D. Deatherage, Operations Support Manager
- B. Dolan, Design Engineering Manager, Oconee Site Office
- W. Foster, Maintenance Superintendent
- T. Glenn, Engineering Supervisor
D. Hubbard, Performance Engineer
E. LeGette, Compliance Engineer
- C. Little, Instrument and Electrical Manager
- H. Lowery, Chairman, Oconee Safety Review Group
B. Millsap, Maintenance Engineer
- D. Powell, Station Services Superintendent
- G. Rothenberger, Integrated Scheduling Superintendent
- R. Sweigart, Operations Superintendent
Other licensee employees contacted included technicians, operators,
mechanics, security force members, and staff engineers.
NRC Resident Inspectors:
a
Skinner
- L. Wert
- B. Desai
- Attended exit interview.
2.
Plant Operations (71707)(71710)
a. The inspectors reviewed plant operations throughout the reporting
period to verify conformance with regulatory requirements, Technical
Specifications (TS), and administrative controls. Control room logs,
shift turnover records,
temporary modification log and equipment
removal and restoration records were reviewed routinely.
Discussions
were conducted with plant operations, maintenance, chemistry, health
physics, instrument and electrical (I&E), and performance personnel.
Activities within the control rooms were monitored on an almost daily
basis.
Inspections were conducted on day and on night shifts during
weekdays and on weekends.
Some inspections were made during shift
change in order to evaluate shift turnover performance.
Actions
observed were conducted as required by the licensee's Administrative
Procedures.
The complement of licensed personnel on each shift
inspected met or exceeded the requirements of TS.
Operators were
2
responsive to plant annunciator alarms and were cognizant of plant
conditions.
During this report period, the inspectors reviewed the licensee's
posting of Notices to workers required by 10 CFR 19.11.
Several
minor discrepancies were noted concerning a security violation issued
on December 21, 1989.
The
licensee promptly corrected the
deficiencies.
Plant tours were taken throughout the reporting period on a routine
basis.
The areas toured included the following:
Turbine Building
Auxiliary Building
CCW Intake Structure
Independent Spent Fuel Storage Facility
Units 1, 2, and 3 Electrical Equipment Rooms
Units 1, 2, and 3 Cable Spreading Rooms
Units 1, 2, and 3 Penetration Rooms
Unit 1 Containment
Station Yard Zone within the Protected Area
Standby Shutdown Facility
Units 1, 2, and 3 Spent Fuel Pool Rooms
Keowee Hydro Station
During the plant tours, ongoing activities, housekeeping, security,
equipment status, and radiation control practices were observed.
During this report period, the inspector walked down the Penetration
Room Ventilation (PRV)
System in accordance with the requirements of
Inspection Procedure
71710:
Engineered Safety Feature System
Walkdown.
Paragraph 5 contains further details of the results of
this inspection.
Additionally the inspectors completed detailed
walkdowns
of
safety-related
portions
of
the
following
systems/locations:
Unit 1 Reactor Building Spray System
Unit 1 High Pressure Injection Pump Rooms
Unit 1 Emergency Feedwater System
Unit 1/2 Low Pressure Service Water
Unit 1 East Penetration Room
Minor discrepancies
noted were communicated to the licensee.
Paragraph 7 contains details of the East Penetration Room Walkdown.
-
Unit 1 entered this reporting period in a refueling outage.
On
June 5, the unit was taken critical, and on June 6, the
generator was
closed onto the grid and power escalation
commenced.
3
b. Units 2 and 3 operated at 100 percent power for the duration of
the report period.
b.
Upper Surge Tank Low Level During Hot Shutdown Operations On. Unit 1
On June 4, 1990, at approximately 9:15 a.m.,
the Control
Room
Operator (CRO) observed a rapid increase in Condensate Storage Tank
(CST)
level and an associated decrease in Upper Surge Tank (UST)
level.
The level in the UST was noted to be 5.85 feet which was
below the TS 3.4.4 lower limit of 6 feet.
Secondary makeup was
immediately commenced to increase level to above TS requirements.
The level was returned to greater than 6 feet at approximately
9:50 a.m.
Investigation into this problem by the inspectors and licensee
personnel identified that the condensate and feedwater systems were
in a "condensate cleanup" mode.
This recirculates water from the
hotwell,
through the condensate system, and back to the hotwell.
Unit 1 at this time was also transferring water from the Unit 1 CST
to the Unit 3 CST.
Upon completion of the transfer to Unit 3, the
transfer pump was secured.
At the same time, a reduction in steam
supply to one of the secondary system heaters occurred.
These
actions appear to have caused the rapid level changes.
The level in
the UST reached a low level indication of approximately 4 feet.
The
licensee is continuing the investigation of this problem and will
submit an LER in accordance with 10 CFR 50.73(a)(2)(i)(B).
TS 3.4.4 requires a minimum of 6 feet of water to be available in the
UST.
Following this occurrence, this TS was discussed in detail.
The TS is unclear as to what applicable plant conditions must be in
effect for this requirement.
The licensee is reviewing the adequacy
of this TS and will consider submittal of a revision to clarify the
applicable plant conditions.
The failure to maintain UST levels greater than 6 feet as required by
TS 3.4.4 is being identified as non-cited violation
(NCV),
50-269/90-17-03:
Failure to Maintain Level In UST Above 6 Feet.
This licensee-identified violation is not being cited because
criteria specified in Section V.G.1 of the NRC Enforcement Policy
were satisfied.
One violation was identified.
3.
Surveillance Testing (61726)
a. Surveillance tests were reviewed
by the inspectors to verify
procedural and performance adequacy.
The completed tests reviewed
were
examined for necessary test prerequisites,
instructions,
acceptance criteria, technical content, authorization to begin work,
data collection, independent verification where required, handling of
deficiencies noted,
and review of completed work.
The tests
4
witnessed, in whole or in part, were inspected to determine that
approved procedures were available, test equipment was calibrated,
prerequisites were met, tests were conducted according to procedure,
test results were acceptable, and systems restoration was completed.
The following surveillances were reviewed and witnessed in whole or
in part:
PT/O/A/0610/06
100KV Power Supply From Lee Steam Station
OP/1/A/1106/06
Turbine Driven Emergency Feedwater Pump
Overspeed Testing
PT/1/A/0600/12
Turbine Driven Emergency Feedwater Pump
Performance Test
PT/3/A/0600/12
Turbine Driven Emergency Feedwater Pump
Performance Test
IP/O/A/0330/003A
Control Rod Drive Drop Time Test
PT/1/A/0150/15D
Intersystem LOCA Leak Test
PT/1/A/0261/07
Emergency CCW System Flow Test
PT/1/A/251/19
Main Steam Block Valve Leakage
PT/3/A/0203/06
Low Pressure Injection System Performance
Test
TT/T/A/0711/13
Unit 1 Cycle 13 Zero Power Physics Test
(ZPPT)
PT/O/A/0290/002
Main Steam Stop Valve Closure Time
b. Reactor Protection System Instrumentation Problems Unit 2
On June 4, 1990, Reactor Protection System (RPS) channel C for Unit 2
tripped due to a signal from the flux/flow -
imbalance circuitry. An
investigation by operations personnel indicated that the flux/flow
imbalance was within the TS required criteria and that the signal was
due to a spurious actuation of the instrumentation.
The signal had
returned to normal indications and the channel was reset.
A work
request
(WR)
was written for I&E personnel to troubleshoot the
channel
as necessary..
I&E technicians performed
checks of the
channel later on June 4 but did not identify any faults.
On June 5,
recorders were connected to various inputs to the channel to provide
additional data for further analysis.
On June 6, a WR was generated by I&E Engineering requesting that RPS
channel A loop
'B'
flow transmitter be calibrated since flow
deviations had increased slowly since unit startup. On June 11, I&E
technicians commenced a calibration on RPS channel A flow instrument
in accordance with Instrument Procedure (IP)/2/A/3n5/PI dated
October 2, 1989.
This calibration requires an entry into containment
to connect a test device to the sensing element and to introduce test
signals at the device while recording results at the RPS instrumen
tation cabinet.
This action was performed in accordance with step
5
10.8.7 of IP/2/A/305/1I,
and data was taken as required.
The data
taken was not within the tolerance specified by the procedure. The
supervisor in charge of the test was confused due to the abnormal
readings obtained and felt that the test equipment was in error. He
stopped the procedure in progress, disconnected the test gear, and
after review of the existing parameters and discussion with the unit
supervisor, he concluded the channel was operable and placed it back
in service.
Following this work
on channel A, I&E personnel
commenced a
calibration RPS channel C since the I&E engineer had identified from
the instruments installed on June 5 that the flow channel was
operating on the low side.
Using the same equipment that was used on
channel A, RPS
channel C was calibrated in accordance with
IP/2/A/305/1K dated September 22, 1989. The I&E supervisor then went
back to the procedure used for channel A and re-evaluated the
results, discussed this evaluation with an I&E Engineer and then
declared the channel out of service.
The inspector reviewed the WRs involved in these calibrations.
The
review identified that during the calibration of channel A, I&E
technicians did not follow the required
steps in procedure
IP/2/A/305/1I.
After completion of step 11.8.7, which was performed
and resulted in out of tolerance readings,
the next step is to
perform individual component calibration as appropriate until the
error is found and corrected.
Since this step was not performed, an
RPS channel
was placed in operation although the calibration
indicated the channel was not functioning properly. This resulted in
a violation of TS 3.5.1.1 in that the minimum channels operable
(Table 3.5.1-1) for RPS flow imbalance instruments was not met.
Channel A had been declared operable in error,
and Channel C was
removed for calibration purposes.
Station Directive 3.1.2,
Activities Affecting Station Operation, dated April 27, 1990, section
4.1, identifies that some items are clearly inoperable upon initial
discovery and provides as an example a device failing to meet
quantitative acceptance criteria such as a calibration.
requires the plant to be operated in accordance with approved
procedures.
The failure to follow procedure IP/2/A/305/1I
is
identified as violation 50-270/90-17-02:
Failure to Follow
Procedures Resulting in Violation of TS 3.5.1.1.
One violation was identified.
4. Maintenance Activities (62703)
a. Maintenance activities were observed and/or reviewed during the
reporting period to verify that work was performed by qualified
personnel and that approved procedures in use adequately described
work that was not within the skill of the trade.
Activities,
6
procedures,
and work requests were examined to verify proper
authorization to begin work, provisions for fire, cleanliness, and
exposure control, proper return of equipment to service, and that
limiting conditions for operation were met.
The following maintenance was reviewed and witnessed in whole or in
part:
O/MP/3009/14
RBCU Fusible Patches Preventive Maintenance
Inspection and Functional Test
WR 50868J
1C-391 Repairs
WR 57113D
Preventive Maintenance on Main Steam Emergency
Feedwater Turbine
WR 98722C
Installation of OE-3049, Increase '3C' LPI Pump
Recirculation Loop Flow Orifice
b. Concerns Regarding Use of Scaffolds Above Safety-Related Components
On June 6, 1990, the inspector observed a large multi-level scaffold
erected over the Unit 3 Turbine Driven Emergency Feedwater Pump. A
tag on the scaffold indicated it may have been in place as early as
April 17, 1990.
It was built to enable repairs to be conducted on a
plant heating system valve. The scaffold was not tied off to prevent
falling or movement into safety-related equipment.
The licensee
subsequently identified that the work had been completed and removed
the scaffold.
Since several other examples of scaffolding concerns had been noted
during this inspection period (see paragraph 7),
the inspectors
discussed control
of scaffolding with maintenance engineering
personnel.
From these discussions (along with the examples noted
above), the inspector concluded that the installation of scaffolding
near safety-related equipment is not formally controlled at Oconee.
Apparently,
in most cases,
scaffolding erected over or near
safety-related equipment is inspected by a coordinator in the
maintenance engineering department, but since the program is
informal,
numerous scaffolds are erected without this coordinator's
knowledge.
The bulk of the problems appear to be caused by a failure
to promptly remove scaffolding once the task is completed.
The
inspectors noted that significant improvements
have been made
recently in the quality of scaffolding construction and attention to
details concerning safety on and near scaffolding.
Station and maintenance management acknowledged that the controls on
scaffolding could be more rigid. The inspectors were informed that a
task force has been established to develop some basic guidance and
criteria to
be utilized to ensure scaffolding erected over
safety-related equipment will not hazard the operability of that
equipment.
The inspectors will continue to closely follow the
licensee's actions in this area.
7
No violations or deviations were identified.
5. Penetration Room Ventilation System Inoperable Under Certain Conditions
Due To Inadequate Design (71710)(71707)
On June 12,
1990, while in the process of performing a detailed walkdown
of the Reactor Building Penetration Room Ventilation (PRV)
System, the
inspectors identified an apparent design error which could render the
system inoperable under specific circumstances.
The PRV system is
designed to minimize the levels of radioactive materials released to the
environment due to post-accident Reactor Building
(RB)
leakage.
The
system functions by pulling RB leakage (maintains negative pressure in
penetration rooms after an accident) into the two penetration rooms and
passing it
through a pair of filter trains.
Each train consists of a
particulate prefilter, an absolute (HEPA) filter, and a charcoal filter in
series. A fan downstream of each filter train discharges the filtered air
through a common
discharge line to the unit vent for release to
atmosphere.
The filter trains and fans are redundant; only one fan and
one filter train is required to accomplish the system's safety function.
The fans are actuated on an Engineered Safeguards (ES)
signal (Channels 5
and 6, high RB pressure).
The fan discharge valves PR-15 and PR-19
automatically open when the fans start.
In addition to local gages which display differential pressure across the
different filter assemblies,
there is a remote display (located just
outside the room that contains the PRV system)
of air flow at the
discharge of each filter train. Adjacent to each of these flow gages is a
manual loader to permit control of the system flow control valves,
and 1PR-17 (filter discharge valves).
In the control room (CR), PRV fan
and fan discharge valve status indications are available.
Room pressure and excessive or insufficient vacuum annunciators are also
available in the CR.
TS 3.15.1 requires that two trains of the PRV system shall be operable at
all times when containment integrity is required or the reactor shall be
shutdown within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
(A 7-day limiting condition for operation is
permitted if
only one train is inoperable provided that all active
components of the other train have been demonstrated to be operable.)
The principle discrepancy noted during the walkdown inspection was that
the flow control valves, PR-13 and PR-17, appeared to be designed to fail
shut on a loss of instrument air (IA) pressure to their controllers. IA
is a non-safety non-seismic system at Oconee. Additional related concerns
noted by the inspectors during followup investigation include:
-
There is not a readily available means to override or manually
position the valves open if they were required and air pressure was
not available to their operators.
8
-
The operation of these valves (or the PRV system) is not addressed in
Abnormal Procedure AP/1,2,3/1700/22:
Loss of Instrument Air.
-
Table 6.5-2 of the FSAR; Single Failure Analysis for the PRV system
states that on a loss of IA to the remote loaders, PR-13 and PR-17
fail open.
-
The licensee's response to GL-88-14:
Instrument Air System Problems
Affecting Safety Related Equipment, did not address valves PR-13 and
PR-17.
The inspectors concluded that portions of this response may
not be complete to ensure that all air-operated safety-related
components will perform
as
expected in accordance with all
design-basis events including a loss of the normal instrument air
system.
-
The inspectors noted a report indicating that a study completed by
the licensee's DE group had identified that these valves would fail
shut on a loss of IA resulting in a loss of the PRV system.
Apparently the significance of this data was overlooked.
The inspectors discussed their concerns regarding the failure position of
PR-13 and PR-17 on a loss of air pressure with the PRV system accountable
engineer and the Operations Support group.
After review by DE,
at
5:00 p.m., on June 13, 1990, the license declared the PRV system inoper
able for a LOCA scenario with a loss of IA to the valves.
At 5:45 p.m.,
the licensee reported this issue in accordance with
(b)(1)(ii)(B).
The licensee exited the 12-hour LCO on each unit after a
Temporary Station Modification (TSM)
was installed which blocked PR-13
open (such as it would not fail shut on a loss of air pressure),
and the
system was tested.
The 7 day LCO on the remaining train was subsequently
exited after PR-17 was blocked open on each unit.
Incorporating design
basis requirements into the design and operation of safety systems is
essential to ensuring those systems will be able to perform their intended
function when called upon
and
is required
by Criterion III of
This design inadequacy is an apparent
violation and is identified as violation 50-269,270,287/90-17-01:
Penetration Room Ventilation System Inoperable Under Certain Conditions
Due to Design Deficiencies.
One apparent violation was identified.
6. Unmonitored Discharge From Unit Vent
At about 10:00 p.m.,
on May 18,
1990,
the licensee identified that the
portable sampler being used for Particulate and Iodine activity sampling
had been removed from service for a 12-hour period. The portable sampler
was being used since the regular monitors were being modified.
9
Review of this event identified that the Unit 1 installed Particulate and
Iodine samplers (RIA 43 and 44) were being replaced during the outage in
progress. In preparation for the Nuclear Station Modification (NSM) being
implemented,
a portable sampler was connected to the piping associated
with the installed units as allowed by TS 3.5.5.2(c) since the electrical
portion of the system had been disconnected.
The portable sampler was
connected into the sample piping of the monitor. Since the sample piping
was to be modified, an alternate portable sample system had been staged in
the area of the first portable sampler, except it could not be connected
to take a sample until a new connection to the stack had been installed.
Due to a communication problem,
the alternate portable sampler sample
lines were connected at the pump,
and the pump was started for sampling
purposes.
The sample lines to the vent stack had not been connected.
This was identified by the Technical Engineer responsible for the NSM. He
immediately notified Radiation Protection (RP) personnel.
RP started the
portable sampler which was still connected to the system and obtained the
required sample.
The licensee reviewed all discharges into the vent
system and determined no abnormal activity had been exhausted to the
system in the previous 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. A report will be submitted to the NRC in
accordance with 10 CFR 50.73(a)(2)(B).
TS 3.5.5.2(c) allows the continuation of effluent releases when the normal
monitoring instrumentation is unavailable provided auxiliary sampling
equipment is used for continuous sample collection.
This failure to
provide for continuous sample collection is identified as non-cited
violation
(NCV)
50-269/90-17-04:
Failure to Provide for Continuous
Sampling of the Unit Ventilation Effluent.
This licensee identified violation is not being cited because criteria
specified in Section V.G.1 of the NRC Enforcement Policy were satisfied.
The actions taken by the licensee are considered to be acceptable for this
incident.
Subsequent review during the modifications to Units 2 and 3
will be performed by the inspectors to further assess the adequacy of the
licensee's corrective actions.
7. Plant Startup From Refueling (71711) (Unit 1)
On June 1, 1990,
following a 41-day, EOC-12,
refueling outage, Unit 1
exceeded 200 degrees F. Hot shutdown conditions were reached on June 3,
1990.
The inspectors witnessed portions of PT/0/A/0290/002, Main Steam
Stop Valve Closure Time Test, and IP/0/A/0330/3A, Control Rod Drive Trip
Test.
The test results were within the acceptance criteria of these
procedures. The inspectors witnessed in part TT/1/A/0711/13, Unit 1 Cycle
13 Zero Power Physics Test, which commenced on June 5, 1990.
The measured
10
total worth of rod group 5, 6, and 7 was determined to be 10.6 percent
greater than the predicted worth.
Since the acceptance criteria is
plus/minus 10 percent of predicted, the worth of rod group 4 had to be
measured.
The total worth of rod groups 4, 5, 6, and 7 was within the
acceptance criteria.
In addition, on June 4, 1990,
the inspectors toured the Unit 1 East
Penetration Room.
Unit 1 was in hot shutdown conditions, proceeding with
reactor startup.
Among the significant discrepancies noted were the
following items:
-
Several examples of scaffolding (not being utilized for work in
progress)
over safety-related equipment were identified.
One
scaffold was against the air operator on valve 1FDW-315,
Emergency
Feedwater flow control valve.
-
Several examples of unsealed or unprotected safety-related cabling
terminal box connections including a missing junction box cover were
identified.
-
Several examples of poor -cable connections (metal sheathing not
properly attached)
involving safety-related power operated valves
were identified.
- -
Two High Pressure Injection system vent or drain valve pipe caps were
found not installed, and two minor packing leaks were identified.
The discrepancies were discussed with station management.
Corrective
actions were initiated immediately. The scaffolding which was not being
utilized was removed from the Penetration Room or moved away from
safety-related equipment.
Work Requests were initiated to correct the
cabling and junction box discrepancies, the packing leaks, and several
other discrepancies. By June 6, the licensee informed the inspectors that
all of the cabling discrepancies had been corrected, work was initiated to
build a terminal
box cover,
and Work Requests written on other
discrepancies not yet fully resolved. Followup discussions on scaffolding
issues are described in paragraph 4.b of this report.
When attempts were made to synchronize the generator to the grid on
June 6,
the turbine control
valves did not respond as expected.
Apparently,
a small stator coolant leak was wetting some electrical
contacts in the EHC cabinet.
This caused a stator coolant runback
circuitry relay to stick which prevented the turbine speed from
increasing.
Following repairs, the generator was placed on line at 8:26
p.m.
Power was gradually escalated and was held at 93 percent due to
problems with the 102 heater drain pump motor.
The unit reached power
approximately 98 percent and operated at that level for the remainder of
the report period.
No violations or deviations were identified.
11
8. Valve SSF-1HP-405 Found Open (71707)
On June 6, 1990, at approximately 8:00 p.m., a non-licensed operator (NLO)
making rounds in the Safe Shutdown Facility (SSF)
discovered that valve
SSF-1HP-405 was open.
This valve is utilized for testing and is located
on the discharge side of the SSF Makeup Pump in a recirculation line. The
valve should be normally shut so the the makeup pump discharges into the
Reactor Coolant Pump (RCP) seal injection lines for reactor coolant system
(RCS) inventory makeup.
The SSF is a separate bunkered installation designed to provide an
alternate secure means for attaining and maintaining hot shutdown
conditions on all three Oconee units.
It was intended for incidents of
sabotage, fires, and some flooding scenarios.
The SSF systems are
manually actuated and are to be utilized only if the installed normal and
emergency systems are inoperable.
The primary makeup portion of the SSF
is designed to maintain the RCS filled to sufficient pressurizer level to
assure natural circulation and core cooling.
Following the postulated SSF event, once the decision has been made to
utilize the SSF,
operators will start the SSF diesel generator and shut
SSF controlled RB isolation valves. Next, the breakers for the SSF makeup
pump and makeup system valves are closed, and the makeup pump is started.
The procedure (OP/O/A/1600/11:SSF Emergency Operating Procedure) does not
require closing in of the breaker associated with SSF-1HP-405 since the
valve is supposed to be maintained shut and is only utilized for testing
purposes.
Valve SSF-1HP-417 is a separate recirculation line to permit
reduced RCS makeup flowrate once pressurizer level is recovered and
stable.
The mispositioned SSF-1HP-405 was discovered through a routine Unit 1 SSF
Control Room panel alarm test. The NLO noted that the annunciator for the
"RC Makeup Containment Not Isolated" alarm would not light, replaced the
light bulb, and found the alarm locked in. With the assistance of other
operators and supervisors it was determined that the alarm was caused by
SSF-1HP-405 being left open.
Subsequently, the valve was closed and the
breaker reopened.
Additional information was gained through followup
investigation by the licensee and the inspectors;
-
Apparently there was some problem with the SSF CR annunicator. The
alarm condition had not been noted despite several other NLO rounds
being completed. After SSF-1HP-405 was shut, it was noted the alarm
would again not test.
A Work Request was initiated to repair the
alarm circuit.
-
SSF-1HP-405 had been left open after a test of the Unit 1 SSF RC
makeup pump manual override circuitry had been completed late in the
refueling outage.
This test was completed by
I&E utilizing
is
IP/O/A/0100/001, Troubleshooting and Corrective Maintenance, and an
12
accompanying checklist of instructions.
The procedure was not
adequate to control the work process and ensure the system was
restarted after testing.
Unit 3 had completed the same test during its most recent outage
utilizing IP/3/A/0370/004,
SSF Unit 3 Makeup Pump Manual Override
Circuitry Test,
(a specific procedure to address this test).
However,
the inspectors noted that this procedure incorrectly
required SSF-1HP-405 to be left open at the end of the test.
Additionally the inspectors noted statements in the safety evaluation
for this procedure which were incorrect.
Apparently these incorrect/inadequate procedures have not been a
problem with earlier tests because additional procedures were
performed after this test which shut SSF-1HP-405 prior to unit
startup.
Due to the location of the
SSF makeup flow detector,
the
mispositioned valve would be hard to detect.
Since its breaker is
not required to be shut, no SSF CR indication is available. If the
valve breaker was shut an interlock with the pump would cause the
valve to automatically shut.
SSF-1HP-405 is a containment isolation valve but the actions required
by TS 3.6.3c were already met since there are additional valves in
the system which were deenergized and shut.
The inspectors noted that NUREG/CR-5006, PRA Applications Program for
Inspection at Oconee Unit 3, specifically discusses a failure to shut
SSF-1HP-405 after testing as a condition which could lead to failure
of the SSF HPI system.
The licensee submitted a set of proposed TS addressing the SSF which have
not yet been approved by the staff.
Proposed TS 3.18.3 requires the SSF
RCS Makeup System to be operable for each unit at or above 250 degrees F.
SSF-1HP-405 being open significantly affected the ability of the Unit 1
SSF Makeup Pump to accomplish its intended function.
The SSF makeup system is required to be operable in order for the Oconee
units to achieve and maintain hot shutdown conditions in certain
postulated met. This issue will be addressed as NCV 50-269/90-17-05:
SSF
Makeup Pump Inoperable Due to Mispositioned Valve.
This licensee
identified violation is not being cited because criteria specified in
Section V.G.1 of the NRC Enforcement Policy were satisfied.
13
9. Exit Interview (30703)
The inspection scope and findings were summarized on June 18, 1990, with
those persons indicated in paragraph 1 above.
The inspectors described
the areas inspected and discussed in detail the inspection findings. The
licensee did not identify as proprietary any of the material provided to
or reviewed by the inspectors during this inspection.
Item Number
Description and Reference
VIO 269,270,287/90-17-01
Room
Ventilation
System
Inoperable Under Certain Conditions Due to
Design Deficiencies (paragraph 5)
VIO 270/90-17-02
Failure to Follow Procedures Resulting in
Violation of TS 3.5.1.1 (paragraph 3.b)
NCV 269/90-17-03
Failure to Maintain Level in UST Above 6
Feet (paragraph 2.b)
NCV 269/90-17-04
Failure to Provide for Continuous Sampling
of
the
Unit
Ventilation
Effluent
(paragraph 6)
NCV 269/90-17-05
SSF Makeup Pump
Inoperable Due to
Mispositioned Valve (paragraph 8)
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