ML16343A311
| ML16343A311 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon |
| Issue date: | 06/21/1995 |
| From: | Chamberlain D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML16342C955 | List: |
| References | |
| 50-275-95-08, 50-275-95-8, 50-323-95-08, 50-323-95-8, NUDOCS 9506280588 | |
| Download: ML16343A311 (44) | |
See also: IR 05000275/1995008
Text
ENCLOSURE
2
U.S.
NUCLEAR REGULATORY COMMISSION
REGION IV
Inspection Report:
50-275/95-08
50-323/95-08
Licenses:
DPR-82
Licensee:
Pacific
Gas
and Electric Company
77 Beale Street,
Room
1451
P.O.
Box 770000
San Francisco,
Facility Name:
Diablo Canyon Nuclear
Power Plant
(DCPP),
Units
1 and
2
Inspection At:
Diablo Canyon Site,
San Luis Obispo County, California
Inspection
Conducted:
April 2 through
May 13,
1995
Inspectors:
M. Tschiltz,
G. Johnston,
Senior Resident
Inspector
nio
Project Inspector
t
Approved:
D.
.
C
am er
Ins ection
Summar
ann, Acting
>e
,
roJect
rane
ate
Areas
Ins ected
Units
1
and
2
Routine
announced
inspection of operational
safety verification, plant maintenance,
surveillance
observations,
onsite
engineering,
plant support activities,
and in-office review of licensee
event
reports
(LERs).
Results
Units
1
and
2
~0erations:
~
Required testing of the Unit
2 containment
emergency airlock door seals
was not performed following verification of emergency airlock door
interlocks.
Reviews of the completed
procedure
by both the Shift
Technical
Advisor and the Shift Foreman failed to identify this
discrepancy.
This was identified as
a noncited violation (Section 4.3).
Maintenance:
~
A violation was identified because
preplanning,
procedures,
and work
instructions for repair of pyrocrete failed to adequately
consider the
effect
on emergency
diesel
generator
(EDG) radiator exhaust air flow.
Corrective actions
implemented
as
a result of the partial
blockage of
9506280588
95062l
ADOCK 05000275
8
e
radiator exhaust air flow on Unit
1 failed to prevent
a similar problem
when pyrocrete repairs
were performed
on Unit 2 (Section
3. 1).
En ineerin
~
An operability evaluation of Safety Injection (SI)
Pump 2-2 did not
consider
a
known
pump failure mechanism.
The degradation
of pump
performance
was subsequently
attributed to the loosening of the impeller
locknuts.
This problem had previously occurred
at Diablo Canyon
and
had
resulted
in an SI
pump seizing during operation
(Section
5. 1. 1).
Inservice valve stroke time testing
was not performed in a manner which
measured
the as-found condition of the valve.
Several
instances
were
noted where valve cycling occurred prior to stroke timing tests
(Section 5.2).
Plant
Chemical
and
volume control
system
(CVCS) valve seat
leakage
was
previously identified as effecting emergency
core cooling system
(ECCS)
flow balance.
A formal evaluation of the valve leakage
was not
performed until over
6 months later when the leakage
affected
the
performance of routine surveillance testing
(Section 5.4).
~
The questioning
by an Independent
Safety Engineering
Group
(ISEG)
engineer of the blockage of
EOG radiator exhaust air flow caused
by
and associated
tenting installed .in
EOG radiator
exhaust
rooms is considered
strong performance.
As
a result,
the
amount of
and tenting
was limited in order to ensure
adequate
airflow
(Section 3,1.1).
~
Contrary to management
expectations,
the results of a surface
contamination
area
(SCA) survey performed to allow maintenance
without
the use of protective clothing was not documented
(Section
6. 1).
Summar
of Ins ection Findin s:
~
Violation 275/9508-01
was identified (Section
3. 1.5).
~
A noncited violation was identified (Section 4.3.3).
LERs 275/95-02,
Revision 0,
and 323/94-013,
Revision 0, were closed
(Section 7).
Attachments:
I
Attachment
1 - Persons
Contacted
and Exit Heeting
Attachment
2
DETAILS
1
PLANT STATUS
(71707)
1.1
Unit
1
Unit
1 began
the report period at
100 percent
power.
On April 21,
1995,
power
was reduced to 50 percent to perform scraping of marine growth from the
circulating water system conduits.
The unit returned to
100 percent
power on
April 24,
1995, following completion of the tunnel
scraping
and operated
at
100 percent for the remainder of the report period.
1.2
Unit
2
Unit
2 began
the report period at
100 percent
power.
On Hay 8,
1995,
power
was reduced for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to approximately
60 percent at the request of the
system dispatcher.
During the period that power was reduced,
corrective
maintenance
was performed
on Inverter P2000,
which supplies
power to the main
turbine digital electrohydraulic control
system.
Unit 2 operated
at
100 percent for the remainder of the report period.
1.3
Re uest for Notice of Enforcement Discretion
Due to
Ex iration of
Reactor
Coolant
S stem Heatu
and
Cooldown Limits
~Back round
The licensee's
heatup
and
cooldown limitations
were developed
based
on
a projected
fluence equivalent to 8 effective full
power years
(EFPYs).
On April 11,
1995,
the licensee
discovered
a
calculational error in the
EFPY calculation which revealed that Unit
1
exceeded
8
EFPYs of operation
on April 8,
1995,
11 days before the previously
predicted date.
Technical Specification
(TS) 3/4.4.9. 1, "Reactor Coolant
System - Pressure/Temperature
Limits," Figures 3.4-2,
System
Heatup Limitations
Applicable
Up to 8 EFPY,"
and 3-4.3,
System
Cooldown Limitations
Applicable
Up to 8 EFPY," were
no longer
applicable
when Unit
1 exceeded
8
~
The licensee
had previously submitted
License
Amendment
Request
(LAR) 94-09 to
revise
TS 3/4.4.9.
1 applicability beyond
8 EFPYs,
but the
LAR submittal
had
not been
approved
by the
NRC.
On April 12,
1995,
the licensee
performed
an
operability evaluation
which determined that the existing heatup
and cooldown
limits specified in TS 3/4.4.9.
1 were applicable
up to
12
The licensee
then requested
enforcement discretion until
1200
PDT on April 21,
1995,
not to
en'force compliance with TS 3/4.4.9.
1 and to allow continued
use of the current
TS figures until revised figures were approved
as
a part of LAR 94-09.
1.3. 1
EFPY Calculation Error
Plant Engineering
Procedure
R-5, Revision 0,
"Burnup Tracking," is used to
calculate effective full power days
(EFPDs)
and is normally performed
on
a
monthly basis.
Using the data
from this procedure
Reactor
Engineering
had
~
~
~, ~
projected that
8
EFPYs would be exceeded
on April 19,
1995.
The cumulative
calculation
had,
in error,
not included
12 days of coastdown
at the
end of
Unit 1's Cycle 5, which added
another
10
EFPDs to the total.
When the
10
EFPDs were included in the
EFPY calculation
on April 11,
1995, it was noted
that Unit
1 had exceeded
8 EFPYs of operation
on April 8,
1995.
1.3.2
NRC Review
The
NRC evaluated
the licensee's
safety justification assertions
as
a part of
the review of LAR 94-09
and concluded that the
use of the existing heatup
and
cooldown figures
was acceptable
until termination of the Notice of Enforcement
Discretion
(NOED).
The
NRC granted
the enforcement discretion verbally on
April 12,
1995,
at 2:58 p.m.
EST.
On April 13,
1995, at 4:35 a.m.
EST,
LAR 94-09 was issued
approving the licensee's
submittal.
The licensee
formally exited the
NOED on April 14,
1995,
at 9:08 a.m.
PDT after receiving
a
copy of the approval.
1.3.3
Safety Significance
Due to fast neutron irradiation of the reactor vessel
beltline, the nil-
ductility-transition temperature
changes
over the life of the reactor vessel.
Due to implementation of very low leakage
core loading patterns,
the reactor
vessel
peak flux had
been
reduced.
Reactor
vessel
neutron irradiation
measurements,
which utilized two surveillance
capsules,
confirmed irradiation
levels to be less
than projected.
As
a result,
the nil-ductility-transition
temperature
projections for 12
EFPYs were lower than those previously
submitted for 8 EFPYs.
The licensee
performed
an analysis
which established
that the heatup
and cooldown limitations applicable
up to 8
EFPYs were
applicable
and conservative
through
12
This
NOED involved no
violations of regulatory requirements.
1.3.4
Conclusion
The
NRC concluded that the exercise of enforcement discretion
was warranted
since this action involved no effect on safe plant operation
and,
as
a result,
had
no adverse
impact
on public health
and safety.
2
OPERATIONAL SAFETY VERIFICATION
(71707)
2. 1
Auxiliar
Safet
S stem Walkdown
During
a routine walkdown of portions of the
AFW system,
the inspector
noted
that
a pipe cap installed
on
a vent installed
on the steam supply to the steam
driven
AFW pump was different from the type of pipe cap typically used
on
steam lines.
The connection
appeared
to have
a swagelock
type test connection
fitting installed
on the cap.
e
0
2. F 1
AFW System Configuration Requirements
After the inspector identified this configuration to the licensee, it was
determined that the reference
piping Drawing 063930,
"Vents, Drains,
and Test
Connections,
Two Inches
and Smaller," Revision 7, contained
the applicable
requirements
and did not allow for the installed configuration.
The licensee
initiated
an action request
(AR) to document the problem.
The inspector
had
noted several
similar deficiencies with other systems
during the previous
inspection period.
The licensee
had acknowledged
the inspector's
observations,
but had not fully implemented
actions to identify additional
areas
that
may have this problem.
2. 1.2
Safety Significance
The licensee
concluded that this configuration resulted
in no operability
concerns
since the cap
was installed
downstream of the code break boundary.
The licensee's
evaluation
appeared
to have considered
the appropriate factors.
2. 1.3
Conclusion
The installed pipe cap
was not in accordance
with the applicable
drawing
requirements.
The licensee
has initiated actions to resolve this
and other
discrepancies
of this nature.
The licensee's
evaluation
indicated that,
although this installation
was not specifically authorized
by drawing, it was
acceptable.
The licensee
is revising the drawing to allow this type of cap to
be used
and plans to further investigate
the cause of this configuration
control problem.
The licensee's
actions to investigate
and resolve this issue
appear to be adequate.
3
PLANT MAINTENANCE
(62703)
During the inspection period,
the inspector
observed
and reviewed selected
documentation
associated
with the maintenance
and problem investigation
activities listed below to verify compliance with regulatory requirements,
compliance with administrative
and maintenance
procedures,
required quality
assurance/quality
control department
involvement,
proper
use of safety tags,
proper equipment
alignment
and
use of jumpers,
personnel
qualifications,
and
proper retesting.
Specifically, the inspector
reviewed the work documentation
or witnessed
portions of the following maintenance
activities:
Unit
1
AFW Pump 1-1; Repair
FW-1-115 leak
Battery Charger
1-2 Capacitor
Change-out
Replace
Hub on Spent
Fuel
Pool
Pump
1-1
EDG 1-1 Starting Air Compressor
Maintenance
Repair of Pyrocrete
in
EDG Radiator
Exhaust
Area
0
Unit 2
~
Repair of Pyrocrete
in
EDG Radiator
Exhaust
Area
3. 1
P rocrete
Re airs in
EDG Radiator
Exhaust
Rooms
~Back round
Pyrocrete fire barrier material installed in the
common exhaust
plenum of the
EDG radiator
fan exhaust
area,
for both Units
1
and 2,
was noted
to have
been
damaged
following a recent
storm.
The damage
was evaluated
by
the licensee
to potentially effect the design function of the pyrocrete
and,
therefore,
required repair.
A roving firewatch was in effect for the areas
with the damaged
pyrocrete at the time the water
damage
was discovered.
The
licensee
concluded that
no additional
compensatory
actions
were required for
the degraded fire barriers.
Prior to commencing
the repairs,
the pyrocrete
was
sampled
and determined
to contain asbestos.
The installation of
and tenting
was required for the removal of pyrocrete containing
asbestos.
t
3. 1. 1
Evaluation of Unit
and Tenting Installation
On March 8,
1995, prior to installation of the scaffolding
and tenting,
System
Engineering
was requested
to evaluate its effect
on
EDG air flow.
During
operation,
radiator exhaust air discharges
through separate
fan rooms
on the
107 foot elevation
and into
a
common discharge
room open
down to the
85 foot
elevation.
The
common discharge
room opens to the outside through screened
and louvered vents
in the side of the turbine building.
System Engineering
initially provided verbal
assurance,
followed later by
a written response
that
the installation of the scaffolding would not significantly reduce the
radiator exhaust air flow.
After a portion of the work was completed,
the
tenting was
removed
and the scaffolding
was left installed for the remaining
repair work.
The basis for System Engineering's
evaluation
was questioned
by an
ISEG
engineer.
As
a result of the
ISEG engineer's
questions,
System Engineering
and Nuclear Engineering
Services
performed further reviews of the installed
and determined that there
was
a potential for a significant
reduction of
EDG radiator exhaust air flow.
As
a result;
the
amount of
scaffold planking was limited to,three
planks.
This required
removal of
five planks since,
at the time, there
were eight planks installed
on the
The basis for the decision to reduce
the
amount of planking was
engineering
judgement.
At that time,
a detailed analysis
had not been
performed.
Subsequently,
the licensee
conducted
a meeting to discuss
the
EDG air flow
concerns.
During the meeting,
the licensee identified that there
was margin
for radiator cooling based
on ambient temperature,
but there
was
no margin in
the
EDG radiator air flow.
At this point, the licensee
removed the remaining
planks
from the scaffolding until
a detailed analysis
could
be performed to
evaluate
the effect of the scaffolding
and tenting
on
EDG radiator exhaust air
0
flow.
Analysis results
revealed that, with the existing ambient temperature
and wind conditions during the period,
the scaffolding
and tenting were
installed
such that the
EDGs would not have overheated.
In the calculations
for determining operability, the outside
ambient temperature
was required to
be less
than 69'F for the
EDGs to have
been considered
3. 1.2
Unit 2 Pyrocrete
Repairs
Following the repairs to the Unit I pyrocrete,
similar repair work was
commenced
in Unit 2.
In order to ensure that Unit 2
EDGs remained
during the repairs,
a calculation
was performed prior to commencing
the work
to determine limitations for the scaffolding
and tenting.
The scaffold
planking was limited to three planks
(49 square feet).
The tented
area
used
in the analysis
was
25 square feet.
The tented
area of 25 square
feet
was not
included
as
a limitation in the work package.
Initially, during preparation
for the pyrocrete repairs,
the scaffolding
and
tenting were installed within the limits determined
by the engineering
calculation.
Later, additional tenting
was installed which blocked
approximately
85 percent of the entire area for EDG 2-2 air flow to the lower
vents.
This configuration
was observed
by the
EDG system engineer
who
questioned
the blockage of EDG radiator exhaust air flow.
During
a review of
the installed scaffolding
and tenting, it was noted that the tented
area
exceeded
the
25 square
feet included in the calculation.
At that point, the
licensee
removed the additional tenting.
3. 1.3
Procedural
Controls for Scaffolding Installation
The procedure
which describes
the methods for requesting
and controlling the
staging,
erection,
dismantling,
and modification of elevated
work structures
is Procedure
AD7. ID5, Revision 0, "Elevated
Work Structures."
The procedure
was designed
to minimize the potential for damage to safety-related
equipment
caused
by falling structures
and interference with the operation of such
equipment
caused
by the structure during normal conditions
and seismic events.
The precautions
and the instructions require review of the scaffolding
installation for seismic interactions
which could possibly render safety-
related
equipment
and a,check for interferences
which could prevent
access
for operation of components.
The inspector
reviewed the elevated
work structure
requests
which were
used to
authorize
the installation of the scaffolding
and the work orders for the
pyrocrete repairs.
The inspector
noted that these
documents
did not contain
instructions to limit the amount of tenting or scaffold planking.
The
specific size of the scaffolding structure
was listed;
however,
the option to
modify the structure without additional
Engineering
concurrence
was allowed.
3. 1.4
Safety Significance
The licensee
performed calculations
to determine
the operability of EDGs
during the periods that
EDG radiator exhaust
flow was obstructed.
The results
0
indicated that the
EDGs were never inoperable
due to the scaffolding
and
tenting restricting air flow through the radiators..
Due to the lack of proper
planning
and adequate
work instructions,
the potential
existed
under certain
elevated
outside
temperatures
and adverse
wind conditions for the
EDGs to have
been
3. 1.5
Conclusion
The failure to adequately
evaluate
the impact of the pyrocrete repairs
on
operability when preplanning
the work and the failure to provide written
procedures
and documented
instructions
which limited the obstruction of
radiator exhaust air flow is
a weakness.
TS 6.8. 1, states,
in part, that
written procedures
shall
be established,
implemented,
and maintained
covering
applicable
procedures
recommended
in Appendix
A of Regulatory
Guide 1.33,
Revision
2, dated
February
1978.
Appendix
A of Regulatory
Guide 1.33,
Revision
2,
recommends
that procedures
for performing maintenance
which can
affect the performance of safety-related
equipment
should
be properly
preplanned
and performed
in accordance
with written procedures,
documented
instructions,
or drawings appropriate
to the circumstance.
Contrary to these
requirements,
during the period of March
3 through April 5,
1995, for Unit 1,
and April 26 though
May 2,
1995, for Unit 2, pyrocrete repairs
were performed
which affected
the performance of the
EDGs without adequate
preplanning
and
without procedures
and documented
work instructions which were appropriate
to
the circumstance.
This was identified as
a violation of TS 6.8. 1 (275/9508-
01).
4
SURVEILLANCE OBSERVATIONS
(61726)
Selected
surveillance tests
required to be performed
by the
TS were reviewed
on
a sampling basis
to verify that:
(1) the surveillance tests
were correctly
included
on the facility schedule;
(?)
a technically adequate
procedure
existed for performance of the surveillance tests;
(3) the surveillance tests
had
been
performed at
a frequency specified in the TS;
and
(4) test results
satisfied
acceptance
criteria or were- properly dispositioned.
Specifically, portions of the following surveillances
were observed
by the
inspector during this inspection period:
Unit
1
Surveillance
Test Procedure
(STP) P-AFW-ll, "Routine Surveillance
Test
of Turbine Driven Auxiliary Feedwater
Pump 1-1"
SP S-312S,
"Security System
Emergency
Power Source
and
Load
Transferring
System Test"
STP I-38-A. 1,
"SSPS Train A Actuation Logic Test in Modes
1,
2, 3, or 4"
Unit
2
STP I-36-S4EPT,
"Protection
Set
IV Eagle
21 Partial Trip Board Actuation
Test"
4. 1
AFW Pum
1-1 Surveillance
~Back round
The surveillance
accomplished
a remote
manual
warm start of
turbine-driven
AFW Pump 1-1.
4. 1.1
Equipment Observations
Steam traps
were verified to be properly aligned
and appeared
to be
functioning properly.
A minor packing leak was noted
on
a valve associated
with one of the
steam traps.
An AR was written to document
the leakage.
The
surveillance verified operation of the
steam
admission trip throttle valve.
The trip lever, trip mechanism,
and associated
linkage were noted to operate
freely.
After remotely starting the turbine,
the as-found
speed
was slightly
greater
than the reference
speed
but within that allowed by the surveillance.
The steam supply valves
(FCV-37 and
FCV-38) were stroked
one at
a time and
verified not to affect the turbine
speed (i.e.,
adequate
steam flow through
one supply line was verified).
AFW control valve operation
was also verified during the surveillance.
4. 1.2
Conclusion
The surveillance test verified the capability to perform
a remote
manual
warm
start of turbine-driven
AFW Pump 1-1.
Operators
closely followed procedural
requirements.
4.2
Securit
S stem
Emer enc
Power Source
and
Load Transferrin
S stem Test
~Back round
On April 28,
1995, the inspector
observed
the monthly test of the
security diesel
generator
in accordance
with STP
SP S-312S,
Revision
7C,
"Security System
Emergency
Power Source
and
Load Transferring
System Test."
The inspector
attended
the pretest briefing and accompanied
operators
to the
diesel
generator
room to observe
the performance of the test.
4.2. 1
Security Inverter Display Panel
Deficiency
While observing
the operators verify the system alignment for STP
SP S-312S,
the inspector
noted that, during Step 11.3.2.g,
the operators
stopped
to
obtain direction from the shift foreman prior to continuing with the
procedure.
The step required that the security inverter panel display
indicate that the maintenance
bypass
switch is normal (i.eis the associated
alarm message
LED is off).
This step could not
be completed
as written since
the display panel
had
been previously noted not to illuminate when the
maintenance
switch was placed
in the bypass position.
This problem had
been
documented
on
an
AR.
After the discussion
with the shift foreman,
the
0
-10-
i
operators verified the position of the maintenance
bypass
switch.
The
operators
then annotated
the procedure to indicate the actions
taken.
These
actions
appeared
to be appropriate
and in keeping with management
expectations.
The inspector
questioned
the operators
as to how Step
11.3.
1 had
been
performed,
which required
v rifying that all display messages
were
functioning.
The maintenance
LED had
been
covered
in March 1995,
when
a
nameplate
was installed which referenced
the
AR written on the display panel
deficiency.
The operators
acknowledged
that the maintenance
bypass
LED could
not
be verified as required
by Step
11.3. 1.
Contrary to management
expectations,
the operators
did not stop to evaluate their inability to
perform this procedure
step
as written.
4.2.2
Safety Significance
The operators
were able to adequately verify that the maintenance
bypass
switch was in the proper position for testing the security diesel
generator
with the display panel deficiency.
The security diesel
started
and operated
within the specified limits of the procedure.
4.2.3
Conclusions
The security inverter panel display deficiency
had existed for over
6 months.
The surveillance
procedure
had not been revised to provide instructions
on
how
to accomplish the test with the deficiency.
Each time the surveillance
was
performed,
operators
were left to determine
the appropriate
actions.
While
performing this surveillance,
the operators
were slow to exhibit
a questioning
attitude
when they could not strictly adhere to the
STP.
The licensee
has
since
issued
a change to the procedure
which provides
more specific
instructions regarding
the verification of display panel
indications.
The
licensee's
ultimate actions,
while not particularly timely, appear to have
resolved
the procedural
work around created
by the status
panel deficiency.
4.3
Emer enc
Airlock Interlock Verification
Backcaround
STP II-BE2, "Emergency Airlock Door Interlock Verification," was
performed for Unit
2 on
May 4,
1995.
Following performance of the interlock
verification, the emergency airlock door seals
are required to be demonstrated
operable within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
On May 10,
1995, during
a review of STP M-8E2 test
results,
the licensee
determined that the testing of the door seals
had not
been
accomplished.
The interlock verification procedure,
STP M-8E2, contained
three specific
steps,
11.2. 16,
11.2. 17,
and 11.2. 18, which referred to the testing of the
airlock seals.
These
steps
had
been
signed
as complete.
No other
documentation
existed that
showed that the test
had
been
completed.
M-
8E2,
Step
11.2. 16, requires that Engineering
be notified to complete testing
of the door seals within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of closing the doors,
or prior to mode 4.
Step 11.2. 17 requires that
a Plant Information Management
System
TS tracking
0
-11-
sheet
be initiated for the Unit 2 emergency airlock door seal test.
Step
11.2. 18 requires verification that the emergency airlock door seals
have
been tested
by STP H-8G.
The licensee
subsequently
discovered that the
individual performing the test
signed off Steps
11.2. 16,
-17 and -18 as being
complete without performing any of the specified actions.
The administrative
reviews of the surveillance
by both the shift technical
advisor
and the shift
foreman did not provide verification that all of the steps
had actually
been
performed.
4.3.
1
Licensee
Actions
Upon Discovery of Hissed Surveillance
After discovering that the testing of the emergency airlock door seals
had not
been
accomplished,
the licensee
performed
STP H-8G, Revision
2,
"Leak Rate
Testing of the
Emergency Airlock Seals."
The test results
were within
specification
and demonstrated
the operability of the seals.
The licensee
investigation
found that the individual,
who had
been
in
containment
during the performance of the test,
signed off the procedure
steps
after he left containment
and signed off more steps
than were performed
due to
his inattention to detail.
The licensee
counseled
the individual according to
their disciplinary program.
4.3.2
Safety Significance
There is no safety significance
associated
with this problem since the testing
performed following the discovery of the problem demonstrated
that the
emergency airlock door seals
were operable
even
though they had not been
tested within the timeframe required
by TS.
4.3.3
Conclusions
The failure to test the emergency air lock door seals,
as required
by STP H-
8E2, Revision
1,
"Emergency Interlock Verification Test," is
a violation of
TS 4.6. 1.3.a which states,
in part, that each
containment air lock shall
be
demonstrated
by verifying the seal
leakage.
Contrary to the
requirements,
operators
failed to perform the required actions of STP H-8E2,
which required testing the emergency air lock door seals following opening of
the air lock doors.
This violation was identified by the licensee.
Following
the discovery of the missed surveillance,
the test
was performed which
verified the operability of the door seals.
A nonconformance
report
was
initiated
on this problem.
Based
upon the licensee's
actions, this violation
is not being cited.
5
ONS ITE ENGINEERING
(37551)
5.1
Pum
2-2 0 erabi1 it
Evaluation
~Back round
Si
Pump 2-2 was replaced
during the last inspection period.
Replacement
of the
pump was performed following a period of degraded
pump
performance.
The decision to replace
the
pump was
made after it failed to
0
-12-
produce
the required total developed
head
(TDH) during periodic surveillance
testing.
Prior to failing the surveillance test,
Engineering
performed
an
analysis of the
pump performance
data
and investigated
potential
mechanisms
for the degradation
of performance
in order to evaluate
pump operability.
5. 1. I
Pump 2-2 Failure
Node Effects Analysis
The failure mode effects analysis
performed
as
a part of SI
Pump 2-2
operability evaluation prior to pump replacement,
determined that there
were
two plausible failure mechanisms
which could cause
the noted
symptoms of
degraded
performance.
The mechanisms
included failure of the 0-ring sea'.s,
which provide
a static seal
between
the
pump stage diffusers
and the
pump
casing,
and the degradation
of wear rings,
which seal
between
each impeller
stage
and it's associated
stationary diffuser.
These failure mechanisms
were
considered
plausible
as the expected
and observed
symptoms of degradation
matched.
Other failure mechanisms
considered
and evaluated
as not being
plausible included:
impeller wear,
boundary valve leakage,
pump motor
degradation,
and inadequate
suction pressure.
The SI
Pump 2-2 operability evaluation
stated that additional
data
was
required to identify a conclusive trend of pump degradation
or
a degradation
rate.
The licensee
stated
they had not performed
more frequent testing of the
pump to determine
the degradation
rate
because
the
ASNE Code Section
XI alert
value of 90 percent of the reference
pump differential pressure
(dP)
had not
been
achieved.
The inspector
noted that the
dP could
and did go below the
TS
required value prior to the licensee establishing
more frequent monitoring.
The inspector
reviewed the previous surveillance test results
and noted that
there
had
been
a degrading
trend toward the
TS value.
The licensee
replaced
the impeller and shaft (rotating assembly)
with a
new
rotating assembly that
had
been
procured
from another utility.
The licensee,
therefore,
had not verified that the impeller locknuts
had
been
coated with
Following the replacement
of SI
Pump 2-2, disassembly
of the
degraded
pump revealed
loosening of the impeller locknuts located at each
end
of the shaft outboard of the impeller.
Loosening of the locknuts allowed for
axial
movement of the impeller which caused
reduced
developed
head.
Industry
experience
indicated that this failure mechanism
had,
in certain instances,
resulted
in the
pump seizing during operation,
The loosening of the impeller
locknuts
had not been considered
as
a potential failure mechanism
in the
licensee's
operability evaluation.
Investigation of component history records
revealed that
an SI
pump
had
previously seized
due to loosening of the impeller locknuts at
DCPP.
Further
investigation of industry experience
revealed that
6 of 24 similar model
pumps
were
known to have failed due to the loosening of the impeller locknuts.
In
response
to the failures,
the
pump vendor revised
the vendor manual
maintenance
procedure
to require the application of Loctite to the impeller
nut threads
during
pump assembly.
Upon disassembly
there
was
no evidence that
the degraded
pump
had Loctite applied to the impeller locknuts.
The licensee
noted that they had previously incorporated
the revision to the vendor manuals
0
-13-
and revised
maintenance
procedures
to ensure
the application of Loctite to the
impeller locknuts
as
a corrective action to the previous
pump failure.
5. 1.2
Operability of the Replacement
Pump 2-2
After determining
Pump 2-2 degraded
pump performance
was
due to the
loosening of the impeller locknuts,
the licensee
attempted
to determine if
Loctite had
been applied
by the vendor
on the locknuts of the replacement
pump
by reviewing procurement
records.
Based
upon available evidence,
the licensee
concluded that Loctite had not been applied
on the locknuts of the replacement
pump.
The licensee
performed
a review of maintenance
records for the
remaining three installed
pumps for Units I and
2 and confirmed that Loctite
had
been applied
on the impeller locknuts of all three remaining
pumps during
pump assembly.
The licensee
performed
an operability evaluation for the replacement
pump due
to the potential
mechanism for loosening of the locknuts.
Due to the
increased
potential for degraded
pump performance,
the licensee instituted
compensatory
actions
associated
with SI
Pump 2-2 operation.
The compensatory
actions
were necessary
to ensure that the conclusions
in the operability
evaluation
remained valid.
The actions required that additional
pump
performance
data
be obtained during surveillance testing
and that the SI
pump
be monitored for reverse
shaft rotation during operation of the opposite train
pump.
The vendor
has identified reverse rotation of the
pump shaft
as the
mechanism for locknut loosening.
These actions
appear
to be prudent
and
necessary
to ensure early detection of SI
Pump 2-2 impeller locknut loosening.
In reference
to the monitoring for reverse
shaft rotation, the inspectors
noted that the only concern
was that
a leak in the'discharge
check valve of an
idle SI
pump could allow backflow and subsequent
reverse rotation of the idle
pump during operation of the opposite train SI pump.
Since
such
an event
had never occurred at Diablo Canyon,
the inspectors
considered
the licensee's
actions to be precautionary.
5.1.3
Safety Significance
Pump 2-2 was replaced
when surveillance testing indicated the
pump
TDH to
be less
than the specified value.
The replacement
pump has subsequently
been identified as being potentially susceptible
to the
same type of
degradation.
The licensee
has
increased
the monitoring of the
pump to ensure
early detection of any significant changes
in pump performance
during routine
surveillance testing.
5. 1.4
Conclusion
i
The licensee's initial operability evaluation of the degraded
pump
performance failed to consider the potential for the loosening of the impeller
locknuts,
a known mechanism for pump failure based
on
and industry
experience.
As
a result,
the potential for the
pump seizing during operation
was not considered
in the evaluation.
14-
The operability evaluation of the replacement
pump,
which addressed
additional
concerns
regarding
the performance of the replacement
pump,
appeared
thorough.
The evaluation
provided the licensee
with a formal method
for assessment
of additional
pump operating
parameters.
5.2
Pum
2-2 Performance
Test Instrumentation
Backcaround
During the performance of the Sl
Pump 2-2 routine surveillance
test, prior to pump replacement,
the inspector questioned
the acceptability of
the range of the digital instruments
installed for the test.
The system
engineer incorrectly responded
that the digital instruments
met the code
requirements.
Subsequent
to the inspector questioning
the range of the
digital instruments,
an
AR was written to document that the digital
instruments
installed to monitor the SI
pump discharge
pressure
and
dP did not
meet the
ASME Code
pump requirements.
According to the licensee,
this
AR was
written independent
of the inspector's
questioning.
The licensee
is in the process
of implementing the
new requirements
of ASME
Operation
and Maintenance
(OM) Standard
OM-1987, with addenda
through
OMa-
1988.
During the transition period,
the licensee
committed to revise
pump
and
valve
STPs to the
new inservice test requirements.
Upon revision of the
surveillance
procedures,
the
new requirements
were to be placed in effect.
STP P-SIP-22,
"Routine Surveillance
Test of SI,Pump 2-2," had
been revised
and, therefore,
was required to comply with the
new inservice testing
requirements.
ASME Section
XI Part
6 Section 4.6. 1.2(b) of OMa-1988 requires that digital
instruments
shall
be selected
such that the reference
value shall not exceed
70 percent of the calibrated
range of the instrument.
For the SI
Pump 2-2
surveillance,
the expected
or reference
value for the discharge
pressure
reading
was approximately
1500 psig, which was greater
than
70 percent of the
calibrated
range of the 0-2000 psig range discharge
pressure digital
instrument.
Similarly the reference
pump
dP exceeded
70 percent of the range
of the
dP digital instruments installed for the test.
5.2. 1
Licensee Corrective Actions
I
The licensee
issued
a change
to
STP P-SIP-22 to install test instrumentation
for measuring
the
pump discharge
pressure
which was in compliance with the
ASME code requirement.
The licensee
has
performed
a review of other
pump
surveillance
procedures
which were required to be in compliance with the
new
OM standard
requirements.
The review identified several
other
pump
surveillance
procedures
where the
same discrepancy
existed.
Revisions to the
effected
procedures
have
been
issued.
The licensee
has written
a quality
evaluation
on this problem.
5.2.2
Safety Significance
Since the implementation of revised
pump surveillance
procedures,
the only
ASME Section
XI required surveillance test performed with incorrect
instrumentation
installed
was the surveillance for SI
Pump 2-2.
The
0
-15-
surveillance test
was reperformed
using the correct
range digital instrument
following the procedure
being changed
to identify the required
instrument
range.
That test confirmed that the replacement
pump met
TS requirements
for TDH.
Prior to the implementation of the
new
ON standard
requirements,
there
was
no specific requirement for limiting the reference
value of digital
instrumentation
to 70 percent of the calibrated
range.
Surveillance testing
performed prior to the implementation of the
new requirements
utilized digital
instrumentation
which exceeded
the
70 percent limitation.
Digital instrument
calibration
was performed for these tests
which verified the accuracy of the
instrumentation prior to and after the test in the range in which the
instrument
was used.
Based
upon the licensees
actions,
the accuracy of
previous test results
is not in question.
5.2.3
Conclusion
During the transition to the
new requirements
of the
ASME OH standard,
the
licensee
did not properly implement the requirements
for the
use of digital
instrumentation
in pump surveillance
procedures.
Initially, licensee
personnel
appeared
not to exhibit
a questioning attitude with respect
to the
inspector's
questioning
on proper test equipment.
The licensee's
subsequent
actions to resolve this issue
appeared
appropriate.
5.3
Inservice Valve Stroke
Time Testin
~Back round
During the inservice stroke time testing of Unit
1 Valves
FCV-37
and
FCV-38, the motor-operated
steam
supply isolation valves for AFW Pump 1-1,
the inspector
noted that the valves
had
been operated just prior to the stroke
time testing during the performance of slave relay testing.
The inspector
questioned
the sequence
of testing since operation of valves prior to their
inservice stroke time testing did not appear to meet the intent of testing in
the as-found condition.
"Guidelines for Inservice Testing at
Nuclear
Power Plants," describes
the condition of the valve to be as-found,
without prestroking or maintenance.
The
ASHE Code does
not specifically require testing to be performed for
components
in the as-found condition,
except for safety
and relief valves.
However, if as-found testing is not performed,
degradation
mechanisms
may not
be identified.
5.3.
1
Licensee
Procedures
for Valve Stroke
Time Testing
The licensee's
general
procedure
governing the exercising of safety-related
valves is
STP V-3, "Exercising Safety Related
Valves General
Procedure."
STP V-3 required that the first stroke of the valve, in the test direction,
be
recorded
as the official test.
A separate
detailed
procedure
is written for
each
valve to be exercised.
The individual procedures
for performance of
valve stroke timing listed
STP V-3 as
a reference
but did not include
requirements
for the operator to refer to
STP V-3 and comply with the
-16-
requirement for timing the first stroke of the valve.
In discussing
stroke
time testing with the Operations Director, the inspector
noted that it was not
management's
expectation for operators
to read
STP V-3 prior to performing
individual valve stroke time tests.
STP M-16N, Revision
11A, "Operation of Trains
A and
B Slave Relays
K632 and
K634," contained
a procedural
note which allowed the operator the option of
performing the stroke timing of Valves
FCV-37 and
FCV-38 after the valves
have
been
operated
during the performance of the slave relay test.
The sequencing
of the slave relay surveillance
and the stroke timing tests
did not meet the
licensee's
procedural
requirement for timing the first stroke of the valve in
the test direction.
In addition,
the stroke time test procedure,
STP V-3R6,
Revision 4, "Exercising
Steam Supply
FCV-37 and
FCV-38 Stroke
Time Test,"
was
written with the assumption that Valve FCV-37 and
FCV-38 were in the
open
position at the start of the test.
As
a result,
when performing the test of
Valve FCV-37 as
sequenced
in accordance
with STP M-16N, the operator
was
required to open the valve without
a specific step in the procedure
in order
to perform the stroke time test
in the closed direction.
Based
upon the inspector's
concerns for inservice valve stroke time testing,
the surveillance test group reviewed this issue
and determined that procedural
changes
were necessary
to avoid the possibility of cycling valves prior to
performing stroke time testing.
5.3.2
Safety Significance
The licensee
conducted
a review to determine
the number of times that valve
cycling occurred prior to inservice stroke time testing in the past.
The
results of the review indicated that stroking of a valve prior to inservice
testing
had previously occurred
on at least
one other occasion.
Based
upon
the results of the review, the cycling of valves prior to valve stroke time
testing
does not appear to be
a programmatic
problem.
5.3.3
Conclusion
The inspector
observed that,
in certain
instances,
the licensee
is not
performing the inservice stroke timing of valves during the first stroke in
the test direction.
The licensee
is revising surveillance test procedures
to
ensure that inservice valve stroke time testing is performed during the first
stroke of a valve wherever practical.
The licensee's
response
to the
inspector's
concern for the preconditioning of valves prior to performing the
periodic inservice stroke time test
appeared
adequate.
5.4
Centrifu al
Char in
Pum
1-2
B
ass
Valve Seat
Leaka
e
~Back round
During the performance
of the Unit l reactor coolant
pump
(RCP)
seal
flow measurement
surveillance,
Pump 1-2 Bypass
Valve CVCS-1-8387C,
was
noted to be leaking past its seat.
A flow measuring
instrument (controlatron)
was attached
to the piping, which confirmed that there
was flow past the shut
valve.
-17-
CVCS-1-8387C seat
leakage
during the
ECCS flow balance testing would effect
the flow balance results.
Since the point in time that
CVCS-1-8387C
seat
leakage
started
is unknown, it is possible that the seat
leakage
occurred
during the most recent
ECCS flow balance test.
During the
ECCS flow balance
testing,
actual
charging flow to the
RCP seals
is secured.
Charging flow to
the
RCP seals
is simulated
by establishing
80
gpm charging
flow as read
on the charging
pump discharge
header flow indication.
CVCS-1-8387C seat
leakage
provides
a parallel flow path during the
ECCS flow balance,
which
bypasses
the charging
pump discharge
header flow element.
As
a result,
CVCS-
1-8387C seat
leakage
would not have
been
included in
ECCS flow balance
measurements.
5.4. 1
Evaluation of CVCS-1-8387C
Impact
on
Flow Balance
Unit
1
ECCS flow balance testing
was most recently completed during the
previous refueling outage
(IR6).
CVCS-1-8387C seat
leakage
had subsequently
been
noted
and documented
in an
AR on October
5,
1994.
At that time,
an
evaluation
was performed
by engineering
to determine
the effect of the valve
seat
leakage
on the
CC pump,
RCP seal injection,
and other surveillances for
acceptability.
The evaluation
documented
that the next performance of STP V-
15,
"ECCS Flow Balance Test,"
may not meet the test
acceptance
criteria with
the existing
CVCS-1-8387C
seat
leakage.
A prompt operability assessment
of
the leakage
on
ECCS flow rates
was not performed at that time,
On April 21,
1995, during the performance of STP M-54,
"Measurement of Reactor
Coolant
Pump Seal
Injection Flow," CVCS-1-8387C
was again noted to be leaking.
A more detailed evaluation of the effect of leakage
on
ECCS flow balance
was
performed.
The evaluation revealed that the valve seat
leakage
had the
potential to cause
the total flow for CC
Pump l-l to exceed
pump runout
limitations.
To address
this concern,
an in-depth analysis of the effects of
the valve seat
leakage
on each portion of the
ECCS flow balance
was performed.
The evaluation required
a detailed engineering
evaluation to assure
operability.
Specific parameters
which were evaluated
included:
total cold
leg injection flow rate, line-to-line flow imbalances,
the
sum of the three
lowest injection flow rates,
and total
CC pump flow.
CC pump flow
requirements
were determined
by the licensee
to be within the
TS limits only
after instrument error uncertainties
were
removed
from the analysis
through
review of the posttest
instrument calibration data.
5.4.2
Safety Significance
The detailed analysis
performed
by the licensee
which considered
the effect of
CVCS-1-8387C seat
leakage
indicated that
ECCS flow rates
were within TS
allowed limits.
5.4.3
Conclusion
The inspector
noted that the initial evaluation of CVCS-1-8387C seat
leakage
failed to adequately
consider the impact of valve leakage
on
ECCS flow rates.
Subsequently,
over
6 months later, after failing to meet
RCP seal
injection
0
-18-
flow requirements
due to the effect of CVCS-1-8783C
seat
leakage
on measured
seal
injection flow,
a detailed evaluation
was required to assure
that
TS
requirements
were met.
6
PLANT SUPPORT ACTIVITIES
(71750)
The inspectors
evaluated
plant support activities
based
on observation of work
activities, review of records,
and facility tours.
The inspectors
noted the
following during these evaluations.
6. 1
S ent Fuel Pit
Pum
1-1
SCA Surve
s
~Back round
On
Nay 12th the inspector
observed
maintenance
being performed
on
Pump 1-1.
The area
in which the maintenance
personnel
were working was
within an area
marked with radiological
tape normally used to denote
an
SCA
boundary.
The inspector
noted that the mechanics
were not wearing
anticontamination
clothing and questioned
the mechanics
as to whether
a survey
had
been
performed to allow working in the area without SCA controls.
The
mechanics
indicated that
a radiation protection
(RP) technician
had performed
a survey of the work area
the previous
day and
had determined that it was not
contaminated.
The workers noted that the tape
had not been
removed
due to the
concern that the paint
on the floor would be marred
when the tape
was removed.
When exiting the
RCA, the inspector
reviewed the latest
survey of the
Pump
1-1 work area.
The survey indicated that only the
pump shaft
had
been
surveyed
and not the foundation
area
under the
pump shaft.
The inspector
questioned
whether the proper radiological
work practices
were being followed
for the work on
Pump l-l. After raising this concern,
RP personnel
performed
a survey of the area
underneath
the
pump shaft which showed that
there
was
no contamination
in the area.
Further investigation
by the licensee
indicated that
an
RP technician
had performed
a survey of the area the
previous
day and
had failed to document the survey results.
6. 1. 1
Survey Documentation
Requirements
The requirements
for recording
survey results
are contained
in procedure
RCP D-500, Revision
11A, "Radiation
and Contamination
Procedures."
Paragraph
7.4. 1 of the procedure
states
that,
"Survey results
should
be
recorded
in red ink on the sketch portion of the appropriate
Radiation
and
Contamination
Form."
Licensee
procedure
AD1. ID2, "Procedural
Use
and
Adherence,"
specifies that
"The word "should" is used to denote
a
recommendation
and is
NPG management's
preference."
6. 1.2
Licensee Corrective Actions
Discussions
with the
RP Director revealed that management
expectations
for
documentation
of surveys
should
be more clearly communicated
to the
technicians.
The practice of not documenting
the performance of certain
radiological
surveys
was not uncommon,
even though the procedure
covering
radiation
and contamination
surveys specified that surveys
should
be
0
-19-
documented.
The
RP staff has
been briefed
on this situation
and the
Director plans to revise the procedure
to more precisely
communicate
management's
expectation
for the documentation
of surveys.
The
RP Director
has
noted that it is appropriate
and expected
to document
a survey which
reflects
a significant change
in radiological conditions.
The actions
appear
to appropriately
address
the inspector's
concerns.
6. 1.3
Conclusion
In this particular circumstance,
the failure to document
the performance of a
survey which reflected the change
in radiological conditions is considered
a
poor radiological
work practice.
7
IN OFFICE REVIEW OF
LERs
(90712)
The inspectors
performed
a review of the following LERs associated
with
operating
events.
Based
on the information provided in the report,
review of
associated
documents,
and interviews with cognizant licensee
personnel,
the
inspectors
concluded that the licensee
had met the reporting requirements,
addressed
root causes,
and taken appropriate corrective actions.
The
following LERs are closed:
275/95-002,
Revision 0, Access/Egress
for the Plant Significantly
Hampered
by the Closure of All Access
Roads
Due to Mud Slides
and
Flooding
~
323/94-013,
Revision 0, Containment
Spray
Pump
4
kV Breaker Closing
Spring Failed to Charge
Following Misalignment of Charging Solenoid
Due
to Personnel
Error
l
1
PERSONS
CONTACTED
1. 1
Licensee
Personnel
ATTACHMENT 1
G.
H. Rueger,
Senior Vice President
and General
Manager,
Nuclear
Power
Generation
Business
Unit
- W. H. Fujimoto, Vice President
and Plant Manager,
Diablo Canyon Operations
L.
F.
Womack, Vice President,
Nuclear Technical
Services
H. J.
Angus,
Manager,
Regulatory
and Design Services
- H. R. Arnold, Senior Engineer,
Predictive Maintenance
Engineering
T.
R. Baldwin, Senior Engineer,
Systems
Engineering
- J.
R. Becker, Director, Operations
- J.
E. Bonner, guality Control Specialist,
Nuclear guality Services
- M.
Burgess,
Senior Engineer,
Secondary
Systems
Engineering
- K. W. Brungs, Director,
Outage
Maintenance
Support
Processes
E.
Chaloupka,
Engineer,
Secondary
Systems
Engineering
H.
G. Coward,
Engineer,
Secondary
Systems
Engineering
- W. G. Crockett,
Manager,
Engineering
Services
- R. N. Curb,
Manager,
Outage Services
- T. F. Fetterman,
Director, Electrical
and Instrumentation
and Control
Systems
Engineering
J.
H. Galle,
Engineer,
Systems
Engineering
- R. D. Glynn, Senior Engineer, guality Assurance
T. L. Grebel,
Supervisor,
NRC Regulatory Support
- C. D. Harbor,
Engineer,
Regulatory Support
- D. B. Hiklush, Manager,
Operations
Services
- J.
E. Molden, Manager,
Maintenance
Services
P. T. Nugent,
Engineer,
Regulatory Support
D.
H. Oatley, Director, Mechanical
Maintenance
L. H. Parker,
Engineer,
Independent
Safety Engineering
H. J. Phillips, Director, Technical
Maintenance
J.
L. Portney,
Senior Engineer,
Balance of Plant
Systems
Engineering
- J. A. Shoulders,
Director, Engineering
Services
D.
W. Spencer,
Engineer,
Secondary
Systems
Engineering
- D. A. Vosburg, Director,
Systems
Engineering
- R. A. Waltos, Director,
Balance of Plant Engineering
- J.
C.
Young, Director, guality Assurance
1.2
NRC Personnel
- H. D. Tschiltz, Senior Resident
Inspector
G.
W. Johnston,
Senior Project Inspector
- Denotes those attending
the exit meeting
on May 18,
1995.
In addition to the personnel
listed above,
the inspectors
contacted
other
personnel
during this inspection period.
2
EXIT MEETING
An exit meeting
was conducted
on May 18,
1995.
Ouring this meeting,
the
resident
inspectors
reviewed the scope
and findings of the report.
The
'licensee
acknowledged
the inspection findings documented
in this report.
The
licensee
did not identify as proprietary
any information provided to, or
reviewed by, the inspectors.
ATTACHHENT 2
ACRONYHS
ASHE
dp
ISEG
kv
LER
NPG
SCA
TS
auxi 1 i ary feedwater
action request
American Society of Hechanical
Engineers
centrifugal charging
chemical
and volume control
system
Diablo Canyon
Power Plant
differential pressure
emergency
core cooling system
emergency
diesel
generator
effective full power day
effective full power year
flow control valve
Independent
Safety Engineering
Group
kilovolt
license
amendment
request
licensee
event report
Nuclear
Power Generation
Notice of Enforcement Discretion
operation
and maintenance
pump
radiation protection
surface
contamination
area
spent fuel pit
safety injection
surveillance test procedure
total developed
head
Technical Specification