ML17331A293
| ML17331A293 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 04/23/1993 |
| From: | Huber M, Jeffrey Jacobson, Replogle G, James Smith NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML17331A292 | List: |
| References | |
| 50-315-93-06, 50-315-93-6, 50-316-93-06, 50-316-93-6, GL-89-10, NUDOCS 9304300076 | |
| Download: ML17331A293 (12) | |
See also: IR 05000315/1993006
Text
U. S.
NUCLEAR REGULATORY COI1!'IISSION
REGION III
Reports
No. 50-315/93006(ORS);
No.
50-316/93006(ORS)
Docket I<os.:
50-315;
50-316
Licenses
No.
No.
OPR-74
Licensee:
Indiana tiichigan Power. Company
1 Riverside
Plaza
Columbus,
OH
43216
Facility, Name:
Donald
C.
Cook Nuclear
Power Plant - Units
1
and
2
Inspection At:
Bridgman,
HI
Inspection
Conducted:
t1arch
22 through April 1,
1993
Inspectors:
gy..S. gy~ ave
H..
Huber
X.'/Mrr,
G.
O.
Rep
og
e
ete
Date
mit
>2i7
Date
Observer:
O.
E.
Roth
Approved
By:
75@. v/~ ."'a<
. h.
acobson,
ie
t1aterials
& Processes
Section
ate
Ins ection
Summary
Ins ection conducted
Harch
22 throu
h April 1.
1993
Re orts
No.
50-315
93006
No. 50-316
93006
ORS
Areas
Ins ected:
Announced safety inspection of the implementation of the
licensee's
response
"Safety-Related
l1otor-
Operated
Valve
(t10V) Testing
and Surveillance"
(2515/109).
Results:
The licensee
developed
and
implemented
a program which was
progressing
in accordance
with the guidance of GL 89-10.
The inspection
disclosed
two unresolved
items
(Sections
2.2.2
and 2.3)
and
t.wo inspection
followup items
(Sections
2.3
and 2.8. 1).
9304300076
930423'DR
"ADOCK 05000315
Q
TABLE OF
COf<TENTS
Pacae
1.0
2.0
3.0
4.0
5.0
6.0
Persons
Contacted..
Inspection of the Implementation of the Program
Developed
Response
2.1
Selected
HOVs.
2.2
Design Basis
Reviews
2.2. 1
Differential Pressure
and Flow Requirements..
2.2.2
Degraded
Voltage Calculations
2.3
HOV Switch Settings
2.4
Design Basis Capability.
2 .4 . 1
Review of OATIS Diagnostic Traces'.
2.5
Periodic Verification of IIOV Capability.
2.6
HOV Failures,
Corrective Actions and Trending
2.7
Schedule
2.8
Associated
Reviews
2.8.
1
Haintenance
2.8.2
Diagnostics
2.8.3
'ilalkdown..
2..8.4
Pressure
Locking and Thermal
Binding.
Licensee
Self-Assessment
Unresolved
Items.
inspection
Follow-up Items
Exit Heeting,.
1
ln
2
2
2
2
2
'
3
4
5
5
5
6
6
6
7
7
7
DETAILS
Persons
Contacted
American Electric Power Service
Com an
AEP
D
S
J
J
.S
R
W
J
M
L
A
J
R
T
tl
P
R
M
G
C
F. Powell, Assistant
Section
Manager,
Nuclear Engineering
J.
Brewer,
Group Manager,
Nuclear Safety Licensing Coordinator
B. Kingseed,
Manager,
Nuclear Safety
A. Kobyra, Manager,
Nuclear'Design
and Electrical
Systems
P.
Hodge,
Manager,
Mechanical
Systems
L. Simms,
Manager,
Nuclear Assessment
G. Smith, Jr., Chief Nuclear Engineer
R. Anderson, Assistant
Manager,
Power Systems
and
Human Factors
J. Finissi, Electrical
Engineer
DeMarco, Electrical
Engineer
J.
Lewandowski,
Mechanical
Engineer
G. Nogrady,
Mechanical
Engineer
A. Kadlec,
Mechanical
Engineer'.
Georgantis,
Licensing Engineer
A. Vilken, Nuclear Safety
M. McCarty, Site ljuality Assurance
H. Hevener,
equality Assurance
Engineer
T. Buetlemann,
equality Assurance
Engineer
P. Roulett,
Nuclear Safety
J.
Dudiak, Electrical Training
'ndiana
Michi an
Power
Com an
IM
A. A. Blind; Plant Manager
K.
R. Baker, Assistant
Plant Manager.
Production
J.
E.- Ruteov(ski, Assistant
Plant Manager,
Technical
Support
J.
Hiebe,
Safety
8 Assessment
Superintendent
G.
A.
1 cher,
Plant Engineering
Superintendent
A.
Godet,
MOV Coordinator
R. i(est,
Licensing Coordinator,
Safety
and Assessment
P.
Helms,
Engineering Supervisor,
Plant Engineering
Additional plant
and corporate
personnel
were contacted
during
inspection.
S.
fnuclear
Re ul ator
Commission
NRC
tne
A. Isom, Senior Resident
Inspector
The persons listed above attended
the exit meeting
on April I, !993.
2.0
Ins ection of the
Im lementation of the
Pro
ram Develo
ed in
Res
onse
to Generic Letter 89-10'.1
Selected
The licensee
had
252
HOVs in the
GL 89-10 program
and differential pressure
(dp) testing
was planned for 153
HOVs.
The inspectors
selected
the
HOVs
listed in Enclosure
2 For
a detailed
review to verify the adequacy
of the
program established
in response
to GL 89-10.
The
HOYs were selected
on the
basis of safety significance,
previous test'results,
and to examine
a cross-
section of the
MOV population.
The details of the review are discussed
in the
remainder of the report.
2..2
Desi
n Basis
Reviews
2.2.1
Differential Pressure
and
Flow Reouirements
The inspectors
reviewed the licensee's
design basis
maximum expected
differential pressure
(HEDP) calculations
and
no significant anomalies
were
disclosed.
The
FSAR, technical
specifications,
normal,
abnormal
and emergency
operating
procedures,
and other plant documents
were reviewed to determine
the
worst case
design
basis conditions for each
HOV.
The most challenging
conditions
and resulting
system condition calculations
were used in the switch
setting cal'culations.
2.2.2
De raded Volta e Calculations
Degraded
voltage calculations
performed
by the licensee
were not done using
the methodology described
in GL 89-10
and its supplements.
The calculations
did not
assume
the worst, case grid voltage
as the starting point for
evaluating
the available voltage at
HOV motors.
The worst case grid voltage
was considered
by the
NRC to be 0.896 per unit (pu) (just above the
degraded
voltage relay setpoint
minimum value).
Instead,
the license=
used
the minimum expected grid voltage
(0.938 pu)
eased
on
a study of the previous
grid history.
The licensee
considered
this minimum expected
value,
not the
minimum degraded
voltage relay setpoint,
as
the licensing basis.
In response
to the inspectors'oncerns,
the licensee
performed
HOV capability
calculations
for several
marginal
MOVs .using
.896
pu as
the starting point.
No immediate
HOV operability concerns
were noted
as
a result of the reduced
electrical
system capacity.
However, further
NRC review is required to
determine
the applicability of the licensee's
grid history study to
HOV
capability determinations.
Therefore,
this issue
is considered
an unresolved
item pending further review by the
NRC (50-315/93006-01(DRS);
50-316/93006-
01(DRS)).
The degraded
voltage calculations
did not include margins to account for the
high ambient
temperature
effects
on motor performance.
However, Limitorque
was evaluating
the issue
and
was expected
to provide the
industry.y with
information concerning this matter.
The licensee
planned to incorporate
the
information from Limitorque into the
GL 89-10 program
when it becomes
available.
2.3
MOV Switch Settin
s
The inspectors
reviewed
the licensee's
calculations
and the
MOV switch setting
methodology for the selected
HOVs.
Independent
calculations
were performed
by
the inspectors
for each
HOV in the
sample population to confirm the licensee's
results.
Concerns identified are discussed
below.
The licensee did not justify assumptions
for valve factors,
stem friction
factors
and load sensitive
behavior in the calculations for torque switch
settings.
Additionally, the licensee
did not account for MOV degradation
that
may occur over the maintenance
and refurbishment intervals.
- The
stem
lubrication interval
For most
HOVs was three refueling outages
(approximately
54 months),
which was considered
excessively
long.
The Limitorque recommended
lubrication interval
was
18 months.
The inspectors
evaluated
VOTES static
test data for valve 1-ICM-305 and
found the actual
degradation
oF the
MOV to
be significant (the tests
were performed just prior to and just after
maintenance).
The calculated
stem friction coefficient prior to maintenance
was 0.30 while the factor just after maintenance
was 0. 13.
The analysis
demonstrated
that
MOV degradation
can occur
and
can
be significant.
Furthermore,
the limitations in the
OATIS diagnostic
equipment
used during
testing inhibited the ability to quantify the assumptions.
The licensee
purchased
the
VOTES diagnostic
equipment
which will allow assumptions
to be
evaluated
anc quantified.
The licensee
planned
to appropriately evaluate
future test cata
and justify the assumptions
for valve factors,
stem friction
factors,
loac sensitive
behavior
and
MOV degradation
used
in the switch
setting calculations.
This issue is considered
an inspection
follow-up item
pending furt: er review of the licensee's
justification (50-315/93006-02("RS);
50-316/93006-32(ORS)).
Some thrust windows were calculated
to be negative after. the application of
the
OATIS in-."curacies.
That is, the minimum required thrust
exceeded
the
maximum perm ssible thrust.
Torque switches
on
some
HOVs were set at
a point
that
may
be c: eater
than the motor capability under design basis conditio..s.
As
a result,
- he subject
HOV motors could stall while closing, without
tripping the -.orque switches.
The licenseestarted
an evaluation for each
affected
MOV -.o determine
the potential
consequences.
This issue
is
considered
ar. unresolved
item pending further
NRC review oF the licensee's
evaluation
(:0-315/93006-03(DRS);
50-316/93006-03(ORS)).
Valve struct: al limits were not included
in the weak-link. analysis
performed
for all safe
-related
HOVs.
However,
the licensee
identified this
defi".ienc'rior
to the inspection
and planned
to obtain the appropriate
informatio.. fro;.,
the valve marufacturers.
This issue will be reviewed during
a future
inspection.
2.4
- -=si
n Basis
Ca abilit
The inspecto.s
reviewed completed static
and dp testing
packages
to veri=; the
methodology
sed to demonstrate
HOV capability.
Fifty-two dp tests
were
complete
at :he
time of the inspection
and approximately
100 additional ;ests
were scheduled
to be performed prior to June
1994.
The licensee
had completed
more
dp tests
than most other licensees
in Region III.
The inspectors
considered
the progress
of the dp testing
program to be
a strength.
2.4.1
Review of OATIS Dia nostic Traces
Anomalies observed
during diagnostic'testing
were'ot
always comprehe'nsively
evaluated.
For example,
OATIS diagnostic
traces
for HOVs I/2-HCH-221 and
231
(auxiliary feed turbine isolation globe valves with flow under the seat)
indicated that
an unexpected pull-out force
was required
in the opening
direction
and the thrust requirements
for closing were
much less
than
expected.
These irregularities could indicate lower than expected
dp across
the valves in the closing direction,
reverse installation,
or valve
degradation.
The lack'f an evaluation for these particular
HOV test results
"
was not safety significant because
the valves did not have
a safety function
to reposition against
dp.
However,'he
licensee
was not aware of this fact at
the time the traces
were evaluated
and indicated that other diagnostic traces,
involving other
HOVs, were evaluated
in
a similar manner.
The inspectors
were also concerned
with the accuracy of data
taken during dp
tests.
The dp test data
and subsequent
analysis of the data
must
be accurate
and comprehensive
to allow for comparison of data
and to justify assumptions
that
may
be applied to valves that cannot
be dp tested.
The inspectors
cau-
tioned the licensee
to thoroughly evaluate
data
and anomalies
observed
during
testing.
The licensee's
evaluation of the traces
was considered
a weakness.
Dynamic testing results
at less
than design
basis conditions
were evaluated
using
a one point extrapolation
method.
The licensee
did not provide multi-
point testing or other justificati,on for using the one point extrapolation.
'The program specified that the technique
was sufficient for valve closure
when
at least
80% of the
HEDP was achieved for some
HOVs
(HEDP greater
than or
equal
to 500 psid)
and
50% of the
HEDP was achieved for other
HOVs
(HEDP less
than
500 psid).
The
NRC inspectors
considered
the approach
to be acceptable
for the first stage of the two-stage
approach
outlined in
Extrapolating test results
to the design-basis
HEDP may require further
qualification..
This issue will be reviewed during
a future inspection.
2.5
Periodic Verification of HOV Ca abilit
The licensee
planned
to use static di.agnostic testing
to periodically verify
HOV capability,
however static testing
may not
be adequate
to model
HOV
behavior
under dynamic conditions.
The plans
met the
CL 89-!0 guidance with
respect
to frequency,
but the licensee
needs
to justify the method
used
to
provide assurance
that
an
HOV would. work properly when called upon.
This
issue will be reviewed during
a future inspection.
2.6
HOV Failures
Corrective Actions
and Trendin
The inspectors
reviewed
problem reports
associated
with recent
HOV failures.
Evaluation of HOY failures
and corrective actions
appeared
effective.
The
trending
program
was still evolving.
Only failures were trended,
but
a
program
was under development
that would trend performance
parameters,
with
the intent of being more predictive.
2.7
Schedule
The licensee
planned to meet the
recommended
schedule
in
and testing
was being accomplished
as prescribed
by the Program.
However,
the
number of
tests
that remained indicate that it may be difficult to complete
the planned
dp testing within the schedule.
Additionally, since
the licensee
was
transitioning
from the
use of OATIS diagnostic
equipment
to the more
comprehensive
VOTES system,
they may decide that
some
IIOVs should
be retested
in order to obtain more useful data.
The inspectors notified the licensee
that results of the planned testing
needed
to be evaluated
and incorporated
into the program,
as necessary,
prior to program completion.
If a testing
schedule
extension
becomes
necessary,
the
NRC should
be notified as
soon
as
possible.
2.8
Associated
Reviews
2.8.1
I1aintenance
Oiagnostic testing
was not performed after packing adjustments
as
long
as
the
packing gland nut torque
was not adjusted
beyond
a predetermined
value.
However,
the licensee
did not demonstrate
that the torque limitation method
was
used
since plant startup
and sufficient testing
was not performed -to
determine
the actual
packing loads for each
HOV.
An incorrect
assumption
for
packing
loads could cause
other factors
(such
as valve factor) to
be
incorrectly calculated
and excessive
packing loads could challenge
HOV
operability.
The licensee
based its position
on
a study performed
by Chesterton
Packing
Company.
The study
showed that if the original packing gland nut torque
was
not exceeded
the packing
load would not change significantly.
However,
the
test data
was limited in that testing
was only performed
on one
f10V and
neglected
the effects of various foreign materials
(such
as boric acid
crystals
that
may
be present
at the stem/packing
interface)
or packing
damage
(that
may occur
as
a result of
a packing leak).
As
a result of the
Part
I inspection,
the licensee
planned to perform testing
on
a sample of tlOVs
to justify the assumptions
concerning
packing loads.
However,
adequate
measurement
techniques
were unavailable until recently
when the licensee
acquired
VOTES diagnostic
equipment.
This is considered
an inspection
follow-
up item pending
a review of the licensee's justification (50-315/93006-
04(ORS):
50-316/93006-04(DRS)).
Stem lubrication was required to be checked
(not replaced)
every three
refueling outages
for most
IIOVs and every refueling outage for IIOVs in harsh
environments.
The licensee
had not included
a term for degradation
in the
switch setting calculations
and the
3 refueling outage
interval
was excessive
when compared
to the
18 month interval
recommended
by Limitorque.
Furthermore,
since
the procedure
only required
checking
(not replacing)
the
lubrication,
the actual lubrication interval for individual
HOYs could
be
as
long as six or more refueling outages.
The licensee
planned
to implement
changes
to require replacing lubrication every three
outages
and to =-valuate
degradation
as discussed
in Paragraph
2.3.
2.8.2
The accuracy
recommendations
provided
by the
OATIS diagnostic
equipment
manufacturer
(ABB Impell) were based solely on test data
from the
f10V Users
Group
(HUG) validation testing
program.
The data
from the
HUG validation
testing
was very limited and
may not 'be comparable
to the results
that might
be observed
at the O.C.
Cook plant.
Additionally, another diagnostic
equipment manufacturer,
with an almost identical
system,
perFormed
independent
testing
and reported
inaccuracy
values significantly greater
than the'BB
Impell recommendations.
This issue will be addressed
in
a future Supplement
to
The licensee will be expected
to justify the diagnostic
equipment
accuracy
assumptions
in response
to the Generic Letter Supplement.
The review of the OATIS equipment
accuracy
was identified as
an unresolved
item '(50-315/91009-01(DRS);
50-316/91009-01(ORS))
during the Part
1 inspection
and will remain
open.
2.8.3
1!alkdown
The inspectors
performed
a general
inspection of the plant
as well as
a
detailed
inspection of several
HOVs.
In general,
housekeeping
was reasonable
in most areas.
However, four HOVs were leaking oil from the actuators.
The
licensee
agreed
to evaluate
the leaks
and take appropriate corrective actions.
2.8.4
Pressure
Lockina and Thermal
Bindin
The licensee's
actions
in the areas
of pressure
locking and thermal binding
were considered
acceptable.
The early recognition
and response
to pressure
locking was considered
a strength.
".round
1975 (prior the publication of SOER 84-07),
the licensee
recognized
the
pressure
locking/thermal binding problem
and
began modifying applicable
gate
- alves
by means
such
as equalizing lines.
As subsequent
information about
pressure
locking and thermal
binding became available,
additional corrective
actions
were implemented
to resolve
these
problems.
These actions
included
both equipment modification and procedure
revisions.
About 30 gate valves
were modifiec.
The inspectors
reviewed
the normally closed
valves
in the
systems
where
these
proble...s
were observed
in other plants.
The licensee
took steps
to preclude
=-ither pressure
locking or thermal
binding in all valves subject
to those
": obl e.-:s.
"..0
Licensee
Self-Assessment
The licensee
performed surveillances
and audits of the
HOV program.
The efforts in this area
were considered
to be acceptable.
The audit compared
the
t<OV program to the recommendations
of GL 89-10
and to results of other
HOV
inspections.
The surveillances
reviewed
aspects
of the program related
to
plant quality control requirements.'
4
0
Unresolved
Items
Unresolved
items are matters
about which more information is required
in order
to ascertain
whether they are acceptable
items,
items of noncompliance,
or
deviations.
Unresolved
items disclosed
during this inspection
are discussed
in Sections
2.2.2
and 2.3 of this report.
5.0
Ins ection Follow-u
Items
Inspection
follow-up items are matters
which have
been discussed
with the
licensee
which will be reviewed further by the inspectors
and which in:olve
some action
on the part of the
NRC or licensee or both.
Two inspection
Follow-up items were identified during this inspection
and are discuss=d
in
Sections
2.3
and 2;8.1.
6.0
Exit Heetin
The inspectors
met with licensee
representatives
(denoted
in Paragrapn
I) at
the conclusion of the. inspection
on April 1,
1993.
The inspectors
su.-..-..arized
the purpose
and
scope of the inspection
and the findings, including t;,e
unresolved
items
and inspection follow-up items identified during thi=
inspection.
The inspectors
also discussed
the likely informational content of
the inspection report with regard to documents
or processes
reviewed
L" the
inspectors
during the inspection.
ENCLOSURE
2
MOV REVIEW LISTING
1-ICM-251
BORON INJECTION TANK (BIT) TRAIN "B" OUTLET CONTAINMENT
ISOLATION VALVE - SHB-0 - 4" gate
1-IMO-262
Sl
PUMPS
RECIRC
TO
RWST TK-33 TRAIN "A" S/0
VALVE SHB-00-
2" globe
1-IMO-263 - SI
PUMPS
RECIRC
TO
RWST TK-33 TRAIN "B" S/0
VALVE - SHB-00-
2" globe
1-IHO-270
PUMPS
DISCHARGE CROSS-TIE
TRAIN "A" S/0
VALVE SMB-00-
gate
1- IMO-316 -
EAST
8. NORTH SI
TO
LOOPS
-..'1
8 ;4
COLD
LEGS S/0
VALVE
- SMB-! - 8" gate
2-IHO-2o2
Sl
PUMPS
RECIRC
TO Rl(ST TK-33 TRAIN "A" S/0
VALVE - Sf1B-00-
2" globe
2- IHO-Zo3
PUMPS
RECIRC
TO
RWST TK-33 TRAIN "B" S/0
VALVE - SHB-00-
2
gl obe
2-IMO-256
BIT TRAIN "B" INLET S/0
VALVE - SHB-0 - 4" gate
1-IHO-340 -
EAST
RHR HX TO CENTRIFUGAL CHARGING PUMP
(CCP)
SUCTION S/0
VALVE - SMB-I - 8" gate
I-If10-~}0 -
Rl(ST
TO CVCS
CCPS
SUCTIOl( HEADER TRAIN "A" S/0
VALVE -
Sf1B-
00 - 8" gate
2-IMO-"=11 -
TO
CCPS
SUCTIOl( HEADER TRAIN "B" S/0
VALVE - SHB-
00 - 8'ate