ML20126C084
| ML20126C084 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 12/16/1992 |
| From: | Gainty C, Jeffrey Jacobson, Replogle G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20126C076 | List: |
| References | |
| 50-373-92-23, 50-374-92-23, NUDOCS 9212220346 | |
| Download: ML20126C084 (17) | |
See also: IR 05000373/1992023
Text
_ _ . _ _ _ _ _ . . _ . . . _ . . _ .
- _ _ _ _ _ . _ . _ _ _ _ _ _ __ .-. _ _ _ _ _ _ . _ _ . _ . _ . _ _ -_ . _ _ .
.
b
!
U. S. ITUCLEAR REGULATORY COMMISSIO!! '
REGIOli III
Reports 110. 50-373/9202 3 (DRS) ; 110. 50-374/92023(DRS)
Docket 14os. 50-373; 50-374 Licenses lio. IIPF-11; ll o . ll P F - 1 8
Licensee: Commonwealth Edicon Company
Opus West III
1400 Opus Place
Downers Grove, IL 60515
Facility llame: LaSalle County lluclear Station
Units 1 and 2
Inspection At: LaSalle Site, Marreilles, Illinois
Inspection Conducte : llovember 2 Decemoer 14, 1992
'
Inspect d ~
4A /2.- ( 6 - 5 L
g
_
C. .. Waint;" Date
'
h/hb&us~
G. D. Rep o 7 le #
n- a -s u
Date
Approved Ofi~~~ / L - /6-1%
1
J. d/ [dobs a n, ChiefMh- Date
Ma cria s Processes Section
J.nnpection Summary
Inspection enI1 ducted 11ovember 2 through December 14, 1992-
(Reports 110. 50-373/92023(DRS); 110. ' 50-374 /92 02 3 (DRS) ) ..
Areas Inqpectedi Announced safety inspection of the licensee's
response to Generic Letter (GL) 89-10, " Safety-Related Motor-
7 Operated Valve (MOV) Testing and Surveillance" (2515/109).
'
Besult;ri The licensee has developed a program which is generally
-consistent with the guidance of GL 89-10. The inspection
disclosed two violations, (Paragraph 2.b.(3)):and three
i
unresolved items (Paragraphs 2.b.(3), 2.b.(4) and 2.b.(5). _
i
l
9212220346 921216 r
! 'PDR ADOCK0500g3
G ,
-. . , - - . -. - .. .- - - . - . . - _ - . . - - - - . . - - . . . .
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Inspection Summary 2
The licensee demonstrated strengths in the following areas.
- The licensee conducted testing of DC motors and proved that
the torque output of the motors was predictable below the
70% voltage rating that was recommended by the vendor.
Although the testing was conducted at significant expense,
the licensee freely shared the information with the rest of
the industry.
The licensee demonstrated weaknesses in the following areas:
Engineering did not demonstrate a thorough understanding of
the equations used to evaluate MOVs and inappropriately used
Limitorque's " stall torque" equation to evaluate MOV
capability, which resulted in a violation of NRC
requirements.
The methods used to evaluate dt.ta from design basis testing
did not ensure that MOVs could perform their safety
functions under design basis conditions. Additionally, when
instruments indicated that actual locked rotor current
values were greater than assumed, appropriate steps to
evaluate the data were not taken.
%
- Additional steps to address negative thrust windows, as
specified in the program document and White Paper 107, were
not taken until concerns were raised by the NRC inspectors.
a Due to the lack of a procedure or adequate training for
, ~
mechanice on valve stem lubrication, the stem lubrication
was not consistently performed.
Torque switches were set in the opening direction, without
proper evaluation, at the same value as that calculated for
the closing direction. This issue had been identified
during previous NRC inspections of CECO facilities.
_ _ _ _ _ _ _ . . .
- - - - ---._--.-- - .. . - . - .- -
_ _ . . .
TABLE OF CQNTDITS
1
Page l
,
1
1. Persons Contacted.................................... 1 l
j 2. Inspection of the Program Developed in Response to !
Generic Letter 89-10............................... 1 1
a. Supplement 3 to GL 89-10........................ 1
b. Generic Letter 89-10 Program Review............. 1
(1) Scope of the Generic Letter Program........ 2 .
(2) Design Basis Reviews....................... 2 !
'
(3) MOV Switch Settings........................ 3 i
-
(4) Design Basis Differential Pressure and
Flow Testing............................. 6 !
(5) Periodic Verification of MOV Capability.... 8
(6) MOV Tailures, Corrective Actions and
i
l
Trending................................. 9
4
(7) Schedule................................... 10
(8) Liberty Technologies 10 CFR Part 21
Review................................... 10
c. Associated Programmatic Reviews................. 10
(1) Design Control for Thermal overload __ 3
-
-
10
'
Protection...............................
,
(2) MOV Setpoint Control....................... 11 .
(3) Maintenance................................ 11 LI
-
(4) Training................................... 12 ;
(5) Operating Experience and Vendor
flotification............................. 13 -
(6) Diagnostics................................ 13
(7) Walkdown................................... 14
'
3 .- Licensee Self-Assessment............................. 14
4. Unresolved Items..................................... 14
5. Exit Meeting......................................... 14
-i
, .~ - - . . , .,,,-------..-,_,_-,---~,-,.-.~,+_-_...,---c,-...-a.-,rn,..--,.- . , , - , . . . . - . - , . ..n ,
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
T& TAILS
1. EcIsons C.ontacted
Colno_rtwgalth Edison Comrany_ICEco)
G. Diederich, Station Manager
- #1. Adams, ENC-Regulatory Assurance
- W. Huntington, Technical Superintendent
- L. Melander, LaSalle Technical Staff
- B. Rybak, ENC-Mechanical and Structural Design
Superintendent
/J. Schmeltz, Production Superintendent ~
- B. Smith, MOV Coordinator
- R. Ungeran, MOV Program Administrator
- R. Williams, Regulatory Assurance, NRC Coordinator
U. S. Nuclear Regula_ tory Commlssion (NRC)
- D. Ilills, Senior Resident Inspector
- C. Phillips, Resident Inspector
- Denotes those attending the exit meeting on November 20,
1992.
- Denotes those participating in the telephone exit
December 1, 1992.
2. Infipect.l_oD of the Prograp_ Developed in Response Mo Generic
Letter 89-1Q
a. Eupplement 3 to Generic Letter 89-10 _
In a letter to the NRC dated September 5, 1991, the
licensee stated that 4 MOVs within the scope of
Supplement 3 to GL 89-10 were deficient and that
moditications were planned to resolve the deficiencies.
The NRC inspectors reviewed the progress of the
modifications and found that the necessary work was
being completed on schedule.
b. Generic Letter 89-10 Proaram Review
The NRC reviewed Commonwealth Edison's commitments to
Generic Letter 89-10, submitted to the NPC by letter
dated September 28, 1990. Additional commitments
regarding the program were submitted to the NRC by
letter dated May 11, 1992. The CECO corporate level GL 89-10 program and Nuclear Operations Directive NOD-
MA.1, " Guidelines for Motor Operated Valve (MOV)
1
l
_ - - _ _ - - _ -__-__-_--- ___ ___
. _ - _ _ _ - - . _ _ . . _ _ - .
Testing, Maintenance and Evaluation," Revision 2 were
implemented at LaSalle by procedure LAP-300-31, " Motor
Operated Valve Program." The licensee had developed a
program that was generally consistent with the GL and
this is discussed in more detail below.
(1) Scope _pf the Generic Letter Procram
The inspectors reviewed system drawings for
reactor water cleanup, residual heat removal, high
pressure core spray, and low pressure core spray
as a sample check for the completeness of the
scope of the program. There were 301 MOVs
included in the program at LaSalle Station. At
the time of the inspection, the licensee was in -
the process of removing six MOVs from the program
with appropriate justification. The inspectors
determined that the scope of the licensee's
program was consistent with the guidance of GL 89-
10.
(2) Qenjan Basis Reviews
(a) Differential Pressure (do) Requirementn
The NRC inspectors reviewed design basis dp
requirements for a sample of MOVs. No
problems were noted.
(b) Reduced Voltace Capability
Some of the design basis documents
incorrectly specified the use of the diesel
generator voltage instead of the worst case _
grid voltage (as specified in the GL) as a
starting point in the calculations. However,
further investigation revealed that the
proper worst case grid voltage was actually
used in the calculations. Changes to the
design basis documents to correct the
inaccurate information may be appropriate.
During design basis testing, the actual motor
current measured, for some MOVs, exceeded the
nameplate locked rotor current and appeared
to indicate that the locked rotor current was
higher than originally assumed. However, the
licensee had not taken steps to evaluate new
information with respect to the degraded
voltage calculations. The inspectors
2
. . - -
considered the failure to evaluate pertinent
data from testing in the MOV evaluations to
be a weakness.
The program did not consider the effects of
high ambient temperatures on the performance
of MOV motors. However, Limitorque was
performing testing and analysis to address
this issue. The licensee planned to
incorporate the information from the testing
into the program when it becomes available.
The licensee conducted testing of DC motors
and demonstrated that the torque output of
the motors was predictable below the 70%
voltage rating that was recommended by the
vendor. Although the testing was conducted
at significant expense, the licensee freely
shared the information with the rest of the
industry. The licensee's efforts in the area
of DC motor testing was considered to be a
strength.
(3) MOV Switch Settinas
MOVs that appeared to be undersized using the
standard industry equation for sizing were
reevaluated using Limitorque's " stall torque"
equation to determine operability. The inspectors
considered the use of the stall torque equation,
for this applicatien, to be inappropriate.
Limitorque's intended use of the equation was to
evaluate the potential for damage to valves and/or
actuators using conservative factors that bounded
the capability of the actuator. The equation
included conservatism to account for the inertial
energy imparted to the unit when the valve disc
was mechanically stopped by slamming it into the
seat and does not represent potential MOV
capability. The licensee did not have appropriate
technical justification for deviating from the
standard industry equation. The inappropriate use
of the stall torque equation is an example of a 10
CFR 50, Appendix B, Criterion III violation (50-
373/92023-01(DRS); 50-374/920'3-01(DRS)).
On November 18, 1992, the NRC inspectors met with
representatives from the licensee's staff to
discuss the violation. At the meeting, the
licensee presented a telephone conversation record
(dated February 6, 1991) which was drafted on
Bechtel letterhead and was signed by a Bechtel
3
- _ - _ _ _ _ _ _ _ - _ - _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ - _ _ - - - _ - _ -_
~- --- --- -.- ._- - - . - - -..--- .-
l
i
I
representative and a Limitorque representative.
The record outlit.ed the factors that could be used
to determine MOV capability for " blowdown valves"
(addressed in Supplement 3 to GL 84-10) and was
presented as justification for deviating frvm the
standard industry equation for sizing. The
approach closely approximated Limitorque's stall
torque equation, but made no mention of the
application factor (normally assumed to be 9 in .
the standard sizing equation and 1.0 in the stall
torque equation). The licensee's use of an
application factor of 1.0 yielded an even less ,
conservative result than would have been obtained I
by following the guidance specified in the Dechtel ;
document. The inspectors were concerned with the 4
- specifics of the document because they appeared to
conflict with documented guidance which-Limitorque
published in Maintenance Updates 89-1 (issued in ;
1989) and 92-1 (issued February,-1992).
Furthermore, the Electrical Power Research
Institute's " Application Guide for Motor-Operated
Valves in Nuclear Power Plants," (dated _ March
'
1990) specifically recommended against using stall
efficiency to evaluate MOV capability.
-t
On November 19,-1992, the NRC inspectors contacted
a Limitorque representative in an attempt to
resolve-the above noted discrepancy. The
Limitorque representative informed the inspectors-
that the individual that signed the Bechtel
document was once a sales representative for ,
Limitorque but was not authorized to sign
technical concurrence documents.- Furthermore, the
information contained in the document did not ;
represent Limitorque's technical position, nor did
it reflect Limitorque's position at the' time the ;
document was issued. The_ representative also
indicated that he had previous discussions with
CECO on this issue and advised the utility that
Limitorque recommended against that the use of the-
stall torque' equation for determining operability..
The inspectors considered the Bechtel document to_ ,
be inappropriate' justification for the-licensee's i
position. Furthermore, the information given to
the NRC was not accurate because it was' presented
jn a manner-which implied-that it was-Limitorque's
technical position. The presentation of
inaccurate information-to.the NRC inspectors was
- considered to be-a violation of 10 CFR 50.9-(50-
373/92023-02(DRS); 50-374/92023-02(DRS)).
- t
s
'r
e w wn--,r,w *e--e, b vm.-, de- re,- -v-- ewr. .e -
.-m v,- -w ,ww.e., rm -w < wt-t-+.- se a* --=,-v E-, - e m* 9 --v y- -t
- - - . - - . - - - - - . _ - - - .. . - . - .- . - . . -
,
6
i
!
The results from the dp testing at LaSalle
appeared to indicate higher stem friction factors, !
higher valve factors and greeter effects from load J
sensitive behavior for some MOVs than was
4
originally assumed. The licensee had compiled .!
,
test data from all six Ceco sites and estimated
that an average valve factor was between 0.4 and
0.5. It is the intent of GL 89-10 that test data
be evaluated for applicability to the overall Mov
program. ;
The " Generic Letter 89-10 Program Document,"
(Revision 1, dated October 15, 1991) and " White
Paper 107" (Revision 0, dated January 24, 1991)
indicated that add.itional. steps would be taken to
address MOVs which had negative thrust windows
(the maximum thrust capability or structural limit
was below the minimum required thrust for
operation). However, several MOVs had negative
windows (at the end of the maintenance cycle, a
degraded condition) but additional steps to '
address the deficiencies had not:-been taken. As a
result of the concerns expressed by tho'HRC _ ,
inspectors, the licensee increased the lubrication
frequencies on the subject MOVs.- At the new
maintenance frequency the windows were no longer
negative. The. failure to-address the negative
thrust windows as specified in the above noted
documents was considered to be a weakness.
Close torque switches were set to values
I consistent with design basis thrust requirements
, for closing. Open torque switches were set to
match-the close torque. switch settings, although,
in some instances tue required opening thrust was '
much greater than the required closing thrust. 'As
such, the open torque switch setting may be
inadequate because of the potential to set the :
switches too low.. In responne'to the NRC concern,
the licensee reviewed all the existing open torque
switch settings at LaSalle to ensure.that.
operability concerns did not exist.. This issue
was previously raised at other Ceco facilities. '
Because this inspection at LaSalle showedfthat the ,
licensce's practice had not-changed, the -
inspectors considered the failure to-previously:
evaluate this issue to be a weakness.
.
!
Upon completing its evaluation of the backlog of
MOV test data, CECO will-be expected to
, incorporate the results of the. assessment of the
test data into:its MOV. sizing and switch setting.
l
5
i
'
Mm d , - m , < , -. y . vre n-% w #w .we .-v..., r. h . .. . . , - - . , , . . . +r.. -m,-+ .- . x w r . M. ,m # w-<n. v w ,. , , , ,-m r- m
. . _ . . _ . - _._. _ _ _ . _ _ _ . _ _ _ _ _ . _ - - . _ _ _ . _ _ _ _ _
'i
+
,
r
methodology in accordance with GL 89-10 guidance. ,
For example, the thrust windows for the tested i
MOVs will need to be corrected where the thrust
requirements were found to be greater than >
predicted. For those MOVs that will not be tested -
under dynamic conditions, test results from valves
similar in type and service, must be considered in ;
the evaluation of valve-capability. !
The licensco stated that, in determining the-
acceptability of certain MOVs, it had relied on
the results from a study by Kalsi Engineering of
the capability of Limitorque actuators to i
withstand thrust greater than their published
ratings. The Kalsi study has been endorsed by ;
Limitorque for thrust levels above the published- ,
ratings for its.SMB actuators for those licenscos !
that have the report and have addressed its
caveats.. CECO however, did'not have a documented
evaluation addressing the. provisoes of the Kalsi
report. The lack of a documented evaluation of,
the provisons constitute an unresolved-item . ,
pending NRC review of the licensee's evaluation
(50-373/92023-03(DRS); 50-374/92023-03(DRS)). l
(4) Desian Basic Dif ferential Pressure and Flow - I+
Testina
Approximately 14 dp tests had boen-performed at *
the timeLof the inspection.- In general, the test
results indicate that several original assumptions
~
utilized for MOV operability evaluations wercinot i
conservative.- It is, however, recognized that :
bounding all factors considered in the evaluation
of MOV performance may not be practicable or.
appropriate and-may lead to an unrealistic
compounding of conservatisms._ However, it is the
intent of GL 89-10 that values of individual
factors be evaluated such that when combined, they ,
provide reasonably conservative bounds on actuator
performance. Results from the testing are
summarized below.
'
(a) ' Stem friction factors varied between 0.08 and--
0.16-during design basis-testing (seven dp
tests) and-did not_ appear to1be. bounded by-
the 0.15-stem = friction factor 1that was
.
- assumed for most-safety-related'MOVs'in a:
l -non-degraded condition. Furthermore, testing
L conducted at other-facilities, and at the '
'
Electrical = power Reserrch;1nstitute, i
_
indicated that same MOVs may;experier.ce' stem- -i
L 1
6
.
r
1
_
-
, , . - - - - , . . , --. - . . _ . , . - , , .- . - - . - . ~ . , _ ~, - -
. . _ . . . .- - _ -- - . --- . . ._. - - - - . ~ . _ _. . - . - . - - - - - _ -
4
friction factors significantly greater than
the 0.15 value that was originally assumed.
(b) Flex-wedge gate valve factors varied between
0.22 and 0.9 during design _ basis testing. Of
the nine valves tested, only one. valve (which
was tested at a very low dp) exhibited a
valve factor which was bounded by the 0.3
valve factor that was assumed for most gate
valves.
1
(c) Globe valves exhibited valve factors that j
varied between 0.02 and 2.08 during design I
basis testing. Of the five globe valves 1
tested, only one had a valve factor greater i
than 1.0. Since it is not theoretically
possible to have a globe valve with a valve
factor less than 1.0, the data may indicate
inaccuracles in the measurement of dp or some
other parameter. Generic difficulties in
measuring test parameters may affect the data ,
'
generated for all design basis tests.
Further investigation into this issue is
appropriate.<
(d)- The_ licensee had not accounted for-load
sensitive. behavior (rate-of-loading) in the ,
methods for setting torque switches. ,
However, load sensitive behavior was observed
during most of the design basis tests and-
varied between 2%'and 23%.
The inspectors reviewed the results and the
licensee's evaluation of the 14 design basis tests '
that had been completed at LaSalle.1 LTS-600-26 -r
requires that the acceptance criteria for-
differential pressure _ tests be satisfied before-
tested MOVs-are returned to service. The
acceptance criteriaoof LTS-600-26 evaluate the
capability of the tested.MOV to provide the
required thrust extrapolated to design-basis -
conditions for both opening and closing the; valve.
The inspectors identified several weaknesses in
the acceptance criteria. Specifically, the
acceptance criteria did not include consideration _7
of diagnostic equipment inaccuracy'orl torque-
switch repeatability-in: evaluating the capabil-ity
- of-the MOV-(for example, motor actuator
capability). .The~ acceptance. criteria-also did not ;
consider torque requirements: or load sensitive :
behavior to ensure motor autuator capability under '
'
degraded voltage conditions. Finally, the ,
7
. - - . .~ :.- = . - . - - - . . - - . . _ , - . - . -
, . - - . - - - ,2. ~ ,- . : - - ,.
acceptance criteria did not justify the omission
of extrapolation of the opening thrust requirement
from test conditions to design-basis conditions
(an example was the acceptance criteria evaluation
for 2WR040). The inspectors did not identify any
operability concerns for the tested MOVs resulting
from these specific weaknesses in the acceptance
criteria at this time. The licensee was currently
in the process of revising its acceptance criteria
in response to a violation of 10 CFR 50 Appendix B
Criterion V identified at Dresden. This is an
area that will be reviewed during the part 2
inspections.
LaSalle had performed some testing at less than -
80% of the design basis differential pressure for
the MOV, which does yield valuable information.
However, the inspectors found that LTS-600-26 did
not require the evaluation of test data if the
test was conducted at less than 80% of full dp.
The inspectors reminded the licensee that testing
MOVs at less than 80% of their design basis
differential pressure can indicate MOV operability
problems. For example, the test may reveal that
little margin exists between MOV capability and
thrust requirements at the test pressure such that
the operability of the MOV under design basis
conditions is questionable. The results of tests
at less than 80% of design basis differential
pressure can also be important in supporting the
basjs for any planned grouping of MOVs in
demonstrating their design basis capability. As
with any data that may reveal problems with _
cafety-related equipment, the licensee is required _
to assess the applicability of the test data and
to determine whether any operability concerns
exist based on that data. The licensee agreed
'
that such an evaluation should be conducted and
stated that the results of testo conducted below
80% of design basis differential pressure would be
evaluated before returning the MOV to service.
This is considered an unresolved item pending
review of the licensee's acceptance criteria for
tests that are performed at less than 80% of full
dp (50-373/92023-04(DRS); 50-374/92023-04(DRS)).
(5) Eeriodic_ Verification of MOV Cayability-
The licensee's plan for ensuring that adequate MOV
switch settings were established and maintained
throughout the life of the plant included static
diagnostic testing of MOVs of valves classified as
8
_____ .____ _ _ _ _ _ _ _
- _ - . . __ _ _ _ _ _ _
priority 1 on an interval that will be determined
once the initial stages of the GL 89-10 program
are completed. The period recommended by GL 89-10
was every third refueling outage. The inspectors
informed the licensee that static testing was not
currently a technically justified method of
periodic verification because of uncertainties in
the relative performance of MOVs under static and
design basis conditions. For valves classified as
priority 2, NOD-MA.1 specified that periodic
testing would not be required provided preventive
maintenance was performed. This is inconsistent
with the GL and the licensee's commitment, which
indicated plans to meet the intent of the GL.
This is an unresolved item pending review of the
licensee's justification for not periodically
testing priority 2 valves (50-373/92023-05(DRS);
50-374/92023-05(DRS)).
(6) ROV Failures, Corrective /Letions and Trellcling
The inspectors reviewed licensee actions for a
number of LER's, deviation reports, and other MOV
failures. In the cases reviewed, the root cause
determination and corrective actions were complete
and well documented. There were no specific
failures that appeared to indicate any program
weaknesses.
The trending program was recently improved to
include a number of parameters, including thrust
at torque switch trip, maximum thrust, and other
parameters that should become useful as more data
is collected. The trending for indication of when _
a refurbishment would be required was based mostly
on the results of grease inspections and no
periodic refurbishments were planned. This could
limit the effectiveness of the station personnel
to detect degradation prior to failure. Some
forms of wear may not be detectable until the
actuators are virtually inoperable. In such a
case, periodic visual inspections may provide a
measure of added assurance. A recent example
where a problem could have been identified prior
to failure by a periodic inspection was 1WR180
where the staking of the stem nut apparently
caused a crack in the drive sleeve and resulted in
failure of the valve to cycle.
9
. .
_.
(7) Schedule
The licensee committed to implementation of all GL 89-10 actions by tho end of the fifth refueling
outages, beginning with the 1991 outages. The
schedule was beyond the time frame recommended by
the GL and there were no plans to dynamically test
MOVs where at least 80% of design basis-dp and
flow could not be achieved. This position and the
implementation schedule for GL 89-10 will be
reviewed by NRR to determine acceptability. The
inspectors did note, however, that LaSalle had
developed an aggressive, but reasonable schedule
to dynamically test those valves considered
practicable to test by the end of the third -
refueling outage, which is more consistent with
the GL schedule than the corporate position.
(8) Liberty Technolonies 10 CFR Part 21 Review
During a meeting with the NRC staff in April 1992,
CECO committed to evaluate the data from tests of
motor-operated valves (MOVs) performed at its
facilities in response to GL 89-10.. In accordance
with 10 CFR Part 21, Liberty Technologies notified
the NRC staff and nuclear power plant licensees in
October 1992 of a generic.jssue regarding the .
accuracy of its VOTES diagnostic equipment used.in
measuring the thrust delivered by motor actuators
in opening and closing their valves. At the time
of the inspection at LaSalle, CECO had completed a
preliminary evaluation of the MOV test data
including an initial effort at addressing the
effect of the increased inaccuracy of the VOTES _ _
-
equipment. -In-an internal memorandum on October-
29, 1992, CECO stated that its consideration of
the increased inaccuracy of the~ VOTES cquipment
would be completed _within.six months of receipt
and validation of new VOTES software, expected in
December 1992.
c. Associated Proctammatic Reviews
The NRC inspectors reviewed other licensee programs
associated with MOVs. 1
(1) Desian Control for-Thermal Overload' Protection
.The NRC inspectors reviewed the licensee's methods
fornthe design control.of. thermal overloads. The
licensee's methods appeared to be acceptable.
10
i
- . . . . . . . . ,
- _ _ _ _ _ _ _ - - _ - _ _ _ _ _ _ _ . _ _ . _ _ _.
(2) MOV Setpoint Control
The NRC inspectors reviewed licensee documents and
discussed MOV setpoint control with personnel.
The licensee's MOV setpoint control program for
torque switches was based on thrust windows for
those valves that had been diagnostically tested.
For those valves that had not been diagnostically
tested, the torque switch setpoints were set
according to original manufacturer
recommendationu. The control of switch settings
appeared to be acceptable.
(3) dalatenanca
The licensee's nominal preventive maintenance (PM) -
frequency was 36 months, which exceeded the
manufacturer's (Limitorque) recommended frequency
for stem lubrication of 18 months. The exact
effects of the extended maintenance frequency are
not known, however, some additional degradation
and increased stem factors would be expected. The
licensee planned to perform some static as-found
diagnostic testing to justify their position and
had completed a few tests. Such justification
would be better supported by as-found design basis
testing since static diagnostic testing may not be
as valuable due to uncertainties in the
relationship between the performance of MOVs under
static and design basis conditions.
The NRC inspectors were concerned that data from
some as-found testing may not adequately reflect
the worst caso degradation that could be ~
experienced by MOVs in the plant. The inspectors
witnessed one as-found test on a reactor core
isolation cooling valve, which was located in the
drywell. Although the stem was last lubricated
approximately 18 months prior to the test, the
lubrication on the stem appeared to be in a
'
pristine condition, possibly due to the atmosphere
in the drywell. Data from this particular test
may not yield useful information related to the
effects of degraded stem lubrication on MOV
performance. Performing as-found testing on MOVs
known to be in the most degraded conditions,
possibly based on direct inspections, would
strengthen the program.
The lubrication of the valve stems was considered
to be a weakness. There was no formal procedure
to specify the details for lubrication of the
~
11
l
l
valve stem, which is a significant task in that
the friction at the stem to stem nut interface has
a direct effect on thrust output of the actuator.
In addition, training for the mechanics was
inconsistent in this area and resulted in
inconsistent results in the past. For examplo,
some mechanics would clean and lubricate only the
exposed portion of the stem and would not cycle
the valve. If the valve happened to be in the
open position at the time, the stem threads could
receive little maintenance. The 2.WR029 valve,
which was last lubricated in February 1992, had
caked-on lubricant on the valve stem, indicating
incomplete cleaning at the last lubrication.
Although there were no specific concerns with the
operability of 2WR029 due to the actual location -
of the cated-on lubricant, this was an example of
where procedures or additional training would
ensure consistency. Since the valves are already
lubricated on a 36 month frequency instead of the
recommended frequency of 18 months, the importance
of complete lubrication should be reinforced.
The NRC inspectors reviewed the licencoe's
position in the area of valve stem packing
adjustments. The practice was to perform a motor
current signature test after packing adjustments.
However, changes in power requirements associated
with packing loading may not be accurately
reflected in ac motor current analysis due to the
changing power factor. Large changes in thrust
requirements due to packing adjustments may result
in only small changes in motor current. The
licensee committed to evaluate data from testing ~
efforts and provide the status of the post
maintenance testing program for MOVs to the NRC at
the end of 1992.
(4) Tritining
The inspectors reviewed the training provided to
personnel performing work associated with the
implementation of the LaSalle MOV program. The
MOV training program at LaSalle was considered
acceptable. However, training for contractors
performing lubrication and refurbishment was
limited to what was covered by the procedures, and
in the case of stem lubrication as discussed
above, could be strengthened.
12
___ - __ _ _
.-__- __-- _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _
(5) pneirat_jagJ;perience and Vendor l{ptif 3 cation
The NRC inspectors found some weaknesses in the
area of processing and control of vendor
information from various sources. The licensee
had taken steps to ensure that certain
information, such as Part 21 information and NRC
Information Notices, was properly screened,
evaluated and maintained by appropriate
organizations and that appropriate actions were
planned. However, in the case of Limitorque
maintenance and technical updates, no formal
review that would ensure proper tracking and
screening, especially for possible procedure or
training updates was established.
The " stall efficiency" was used to evaluate MOV
capability (as part cf the stall thrust equation).
The NRC inspectors were especially concerned about
the use of the stall efficiency because at least
three industry documents (Limitorque Maintenance
Updates 89-1 and 92-1, and the Electrical Power
Research Institute's " Application Guida for Motor-
Operated Valves in Nuclear Power Plants," dated
March 1990) specifically recommended against using
stall efficiency to evaluate MOV capability. The
NRC inspectors assessed the licensee's program for
reviewing information from vendors and found that
all three documents had been reviewed by
appropriate members of the licensee's staff.
Deviations from vendor recommendations are
expected to be evaluated for technical
justification.
The LaSalle program for the processing and control
of operating experience and vendor notifications
was found to be in need of improvement, especially
for thorough review and use of Limitorque
maintenance and technical updates.
(6) Diagnostics
The licensee uses the Valve Operational Test
Equipment System (VOTES) to test MOVs under both
static and dynamic conditions. However, testing
plans did not always include the use of the VOTES
torque cartridge (VTC) to allow the measurement of
spring pack displacement. Deceuse of this, stem
friction factors may not be quantifiable at
different points of interest, such as flow cut-
off. The expanded use of the VTC would strengthen
the program.
13
- -_ -_ _ _ - - _ _ _ _ _ _ -___ _ _ - __ _ - _ -- _ _ -
.
(7) WAD:doWD
The inspectors performed a general inspection of
the plant as well as a detailed inspection of
several MOVs. In general, housekeeping appeared
to be satisfactory in most areas. The valve stems
that were accessible were well lubricated and most
valves appeared to be in good condition. However,
valve 2E51-F022 had the motor located at tne
bottom of the actuator, which may increase the
potential for damage due to grease leaking into
the motor. Additionally, grease (oil) was
observed Icaking past one of the housing gaskets.
3. LitoDsee fielf Assessment _
The licensee had performed self-assessments of the MOV
program au compared to the commitments of the CECO Response
to Generic Letter 89-10, dated Septencer 28, 1990, and to
the GL in general. In addition, the station had prepared an
action plan to addrece certain aspects of the MOV program.
Most of the items in the action plan were either completed
or were scheduled for January 1993. In general, the
licenseo showed a good effort in this area.
'
4. Unremo3 _eJLItems
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
paragraphs 2.b.(3), 2.b.(4), and 2.b.(5) of this report.
5. Egjt Meetinus _
The inspectors met with licensee representatives (denoted in
Paragraph 1) at the conclusion of the inspection on
November 20, 1992. Supplementhl exits were held by
telephone conference on December 1 and 14, 1992. The
inspectors summarized the purpose and scope of the
inspection and the findings. The inspectors informed the
licensee of the two violations and two unresolved items
identified during this inspection. The inspectors also
discursed the likely informational content of the inspection
report with regard to documents or processes reviewed by the
inspectors during the inspection.
14
__ __- ___-_-_-- - _-__ _ -____- _ _-__ _ __- - - -- __ _