ML17333A725
| ML17333A725 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 12/27/1996 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML17333A722 | List: |
| References | |
| 50-315-96-12, 50-316-96-12, NUDOCS 9701030236 | |
| Download: ML17333A725 (26) | |
See also: IR 05000315/1996012
Text
U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Docket Nos:
License Nos:
4
50-315; 50-316
Report Nos:
50-31 5/9601 2(DRS):
50-31 6/9601 2(DRS)
Licensee:
Indiana Michigan Power Company
Facility:
Donald C. Cook Nuclear Generating Plant
Location:
7700 Red Arrow Highway
Stevensville, Ml 49127
Dates:
October 21-25, 1996, and December 5, 1996
Inspectors:
A. Dunlop, Reactor Inspector
J. Guzman, Reactor Inspector
R. Cain, Engineering Specialist, INEL
Approved By:
W. Kropp, Chief
Engineering Specialist Branch
1
970i030236 96i227
ADOCK 050003i5
8
f )
EXECUTIVE SUMMARY
~En ineerin
~
This close-out inspection of NRC's review of Generic Letter (GL) 89-10,
"Safety-Related Motor-Operated Valve (MOV) Testing and Surveillance," determined
that the MOV program and implementation at D. C. Cook was not sufficiently
complete to close-out the NRC's program review. Although a number of areas have
been sufficiently addressed,
the inspectors could not conclude that the licensee had
completed verifying all GL 89-10 program MOVs would perform the intended safety
functions under design-basis
conditions.
Specific issues that remain to be resolved
are described
in sections E1.1.b.10; E1.1.b.1.5; E1.1.b.1.9(a); E1.1.b.1.9(b);
E1.1.b.1.9(c); E1.1.b.5; E1.1.b.1.6;
and E1.1.b.1.9(d) of this report.
~
A condition report was not initiated and a prompt operability assessment
was not
made when a potentially adverse condition was identified for the PORV block
valves. (Section E1.1.b.1.3)
4
The licensee made significant progress
on the GL 89-10 program with respect to
previous NRC MOV inspections.
(Section E1.1.b.1)
~
The number of GL 89-10 valves dynamically tested and diagnostically testing
additional plant MOV's was considered
a positive management
position.
(Section
E1.1.b.2)
~
The licensee's
GL 89-10 Closure Summary Reports were well detailed and
contained useful information in determining the MOV's design-basis
capability.
(Section E1.1.b.1)
Safe
Assessmen
Qualit
Verification
~
The recent self-assessment
in the MOV area, although limited in scope, provided
some good technical findings to prepare the MOV program for closure.
The use of
an outside technical MOV expert was also viewed as a positive aspect to provide
additional insights into this highly technical program.
(Section E7.1)
Re ort Details
Summar
of Plan
S atus
Unit 1 was operating at 90 percent power and Unit 2 was operating at 100 percent power
during this inspection period.
III. En ineerin
E1
Conduct of Engineering
E1.1
Generic Le
er 89-10 Pro ram Im lemen a ion
Ins ection Sco
e Tl 2515 109
This inspection evaluated the process for qualifying the design-basis
capability of
MOVs and closure of NRC's review of GL 89-10.
The inspection concentrated
on
MOVs that were tested under static or low differential pressure
(dp) conditions.
A
valve sample that included several program closure m'ethods used by the licensee
was selected to verify design-basis
capability. The inspectors reviewed design-
basis documents, thrust calculations, test packages,
and engineering evaluations for
the following MOVs:
1-FMO-202
Steam Generator (SG) OME-3-2 Feedwater Shutoff (S/0) Valve
1-QMO-226
East Component Cooling Pump IViini-flowto Reactor Coolant Pump
Seal Water Heat Exchanger S/0 Valve
2-IMO-256
Boron Injection Tank Train Inlet S/0 Valve
2-IMO-91 0
Refueling Water Storage Tank to Chemical and Volume Control
System (CVCS) Pump Suction Header Train "A" S/0 Valve
2-FMO-21 1
Turbine-Driven Auxiliary Feedwater
(AFW) Pump PP-4 Discharge to
SG Control Valve
2-NMO-252
Pressurizer
Power-Operated
Relief Valve (PORV) Block Valve
2-IMO-270
Safety Injection (Sl) Pumps Discharge Crosstie Train S/0 Valve
2-IMO-326
West Residual Hear Removal (RHR) and South Sl to Reactor Coolant
System (RCS) Loops 2 5. 3 Cold Legs S/0 Valve
The inspectors also reviewed other licensee documentation
used to justify program
assumptions,
such as stem friction coefficients and load sensitive behavior.
Further, the inspectors reviewed documentation
related to program issues, such as
periodic verification, post-maintenance
testing, and program audits.
b.
Observations
and Findin s
MOV Desi n-Basis Ca abilit
Verification
The inspectors noted that the licensee's
GL 89-10 Closure Summary Reports were
well detailed and contained useful information in determining the MOV's design-
basis capability.
The licensee had made significant progress
on the GL 89-10
program with respect to previous NRC MOV inspections.
In general, the licensee's
design-basis
calculations to verify valve capability were considered adequate.
However, the justifications for several assumptions
used for certain valves or valve
group calculations were not adequately supported.
Based on these concerns, the
inspectors were not able to conclude that the licensee had completed verifying all
GL 89-10 MOVs were capable to meet the design-basis
requirements.
As a result,
the NRC's review of the licensee's
GL 89-10 MOV program will remain open
pending additional support information.
b.1.1
MOV Sizin
and Switch Settin
s
The licensee's thrust calculations utilized the industry's standard thrust equation to
determine thrust requirements for rising stem gate and globe valves.
The applied
stem friction coefficient (SFC) was either the measured
value recorded during a
static test, or 0.174 when the stem factor was not measured.
If the static test
value was less than 0.15, it was generally increased to 0.15.
These values were
used to convert thrust into torque when torque was not measured.
Applied valve
factors were based on licensee testing or best available industry data, such as data
from other utilities and the Electric Power Research Institute's (EPRI) Performance
Prediction Methodology (PPM). A factor of 15% was added to the closed target
thrust to account for the effects of load sensitive behavior and 5% to account for
degradation of stem factors.
Equipment er.ors, such as torque switch repeatability
and diagnostic system accuracies,
were combined in a square root sum of the
squares methodology and used to adjust the upper and lower required thrust, where
appropriate.
Overall, the design basis capabilities of the GL 89-10 valves were
acceptable,
except as noted in the following paragraphs.
b.1.2
Valve Fac ors
The licensee Valve Factor (VF) Technical Paper divided MOVs into 24 groups.
The
grouping was based
on valve type, size, manufacturer,
and pressure
class.
The
licensee used in plant-testing, industry data, the EPRI PPM, or a combination of all
of these to justify the VF applied to the valves in a particular group.
Industry data
was further screened
for flow, temperature,
and pressure to ensure the data would
be applicable to the licensee's
MOVs.
Generaily, if the valves in a group could not be practicably tested, the licensee
would use the thrust obtained from application of the EPRI PPM to back calculate a
VF. Further, the licensee reviewed several industry data points to confirm the EPRI
PPM results.
Once this review was complete, the licensee used the more
conservative of the two methods.
Overall, for the majority of valve groups, the
assumed
VF was adequately justified. There were several valve groups, however,
that had minimal justification for the applied VF. These are discussed
below and in
paragraph E1.1.b.1.3 of this report.
(a)
Valve group "BAAC"was 8" Aloyco 300¹ ball-socket gate valves,
which used a VF of 0.71 based on a single industry test data point.
The inspectors stated that a single data point was insufficient to
justify the VF for the entire group.
The lowest thrust margin for the
valve group in the open safety direction, however, was 178 percent.
The inspectors considered the large calculated margin to be adequate
for program closure.
(b)
Valve groups GL10 and GL11 were 4" Rockwell and Conval 1500¹ Y-Globe
valves, which used a VF of 1.1 based on EPRI testing that indicated VFs
between 0.9 and 1.1 for globe valves.
The inspectors stated that other
globe valves tested in the industry had indicated valve factors higher than
1.1.
Valve group GL11 had 47 percent available margin in the closed
direction and could support an available VF of 1.65, which was considered
adequate
for program closure.
However, in valve group GL10, the most
limiting MOV had a 6 percent available margin in the closed direction and
could only support an available VF of 1.17.
The inspectors con"!dered the
margin for these MOVs to be low. However, based on use of a guide-based
area term that was used to calculate required thrust, the settings for the
group were considered adequate
for program closure.
The licensee indicated they would attempt to find additional data to support the use
of the applied VFs for these valve groups.
b.1.3
0 erabilit
of he Power-0
crated Relief Valve
PORV Block Valves
The inspectors were concerned with the operability of four pressurizer
PORV block
valves based on the use of a 0.4 VF while two PORV block valves were using a
0.51 VF. The licensee has 6 PORV block valves, three for each unit, which were
3" Velan 1500¹ flex-wedge gate valves.
The licensee had applied the EPRI PPM in
October 1996 and back calculated
a required VF of 0.51.
The 0.51 VF was
considered
by the licensee to be conservative
because
EPRI Velan Valve ¹13,
tested under similar conditions (blowdown, hign temperature), showed
a VF of 0.34
in the closed direction. Two MOVs on Unit 2 (2-NMO-152 and -153), which were
modified during the last refuel outage, could support the 0.51 VF. The modification
was not performed on the third Unit 2 valve due to lack of parts during the outage.
However, MOVs 1-NM0-151, -152, -153, and 2-NMO-151 used a VF of 0.40 that
the licensee considered adequate
based on the EPRI test results.
The inspectors had the following concerns with this justification. Ir.formation from
the NRC Safety Evaluation (SE), dated March 15, 1996, of the EPRI Topical Report
TR-103237, "EPRI Motor-Operated Valve Performance Prediction Program,"
Sections II.B.2.a (page 9) and II.B.2.c (page 17), discussed that EPRI did not
precondition the valves tested in-situ and that guide rails in two valves
manufactured
by Velan experienced plastic bending under the high flow conditions.
Based on the SE information and the lack of specific in-plant dynamic test data, the
EPRI PPM information should have been considered the best applicable data once
the licensee had performed the EPRI PPM runs.
As a result of the inspectors'oncerns,
the licensee recalculated the required
thrusts for four unmodified MOVs based on current torque settings and a 0.51 VF.
The revised calculations determined MOV 2-NMO-151 was capable of supporting
the 0.51 VF. MOVs 1-NMO-151 and -153 could only support the 0.51 VF when
rate of loading (ROL) and stem tube degradation were reduced or removed from the
calculation.
This condition was documented
on a condition report (CR) with an
associated
The inspectors reviewed the operability
determination and considered it acceptable until the valves could be modified at the
soonest available opportunity.
MOV 1-NMO-152, however, could not support a VF
of 0.51 with the current torque switch setting.
Based on the results of these
calculations and discussions with the inspectors, the licensee declared MOV
1-NMO-152 inoperable and initiated a CR. The licensee performed the required
Technical Specifications (TS) actions when the MOV was declared inoperable.
Based on the inspectors'eview
of this issue, the licensee should have addressed
the 0.51 VF from the EPRI PPM for the PORV block valves with respect to valve
operability.
Plant Managers Instruction (PMI) 7030, "Corrective Action,"
Revision 22, was the licensee's primary mechanism by which degraded
and
potentially nonconforming conditions were evaluated.
PMI-7030 required the
originator to initiate a CR for known or susPected
adverse conditions or events
(step 6.9.a).
PMI-7030 also defined an adverse condition/event as "A non-
conformance, deficiency, deviation, discrepancy,
or adverse trend of items, services
and/or administrative systems that, if left uncorrected,
could adversely impact
safety, quality, or operability" (step 5.1). The failure to initiate a CR and perform a
prompt operability assessment
following the identification of a potentially adverse
condition from the EPRI PPM information is considered
a violation (50-315/96012-
01(DRS);
50-316/96012-01(DRS))
of TS 6.8.1.
The licensee stated that the three'PORV block valves for Unit
1 were scheduled for
modifications in the upcoming February 1997 outage to verify the valves'esign-
basis capabilities.
The Unit 2 MOV was scheduled for the same modification during
the Fall 1997 refueling outage.
The licensee also stated the'modifications would be
added to the forced outage list if an outage of sufficient duration occurred prior to
the refuel outages.
The licensee stated these modifications would allow the valves
to support the use of a 0.51 VF with sufficient margin.
This will be considered
an
inspection followup item (IFI) (50-315/96012-02(DRS))
pending completion of the
Unit
1 modifications and inspector review of the obtained margins.
b.1.4
Load Sensitive Behavior
The inspectors reviewed the licensee's Technical Report 0012-00204-R02,
"Rate
Of Loading," Revision 0, which was used to perform a statistical analysis of load
sensitive behavior (LSB). The statistical evaluation was performed for three data
sets; gate and globe valves combined, gate valves only, and globe valves only. The
LSB mean plus 2 standard deviations results were 20.1%, 20.8%, and 18.7%,
respectively.
The licensee used
a 15% bias margin for LSB and added
a 5% bias margin for stern
factor degradation.
These were added directly to increase the minimum required
thrust.
Equipment accuracies
and torque switch repeatability were combined in a
square root sum of the squares methodology and then used to increase the
minimum required thrust.
The licensee compared this methodology to the
methodology of adding the statistical LSB bias and the 5% bias for stem factor
degradation with the random LSB combined in a square root sum of the squares
methodology with torque switch repeatability and diagnostic accuracies.
The
licensee's methodology bounded all cases except when the value of torque switch
repeatability was 5% and diagnostic accuracies were less than 7%.
In this case,
the licensee used a 16% direct bias for LSB to hound these values.
Based on the
licensee's test data, the LSB values used in the design-basis
calculations were
considered acceptable.
b.1.5
Stem Friction Coefficien
The inspectors reviewed Technical Report 0012-00204-R01,
"As-Left Stem/Stem
Nut Coefficient Of Friction," Revision 0, which was a statistical study of the
stem/stem nut coefficient of friction (SFC) for static test data.
The licensee
performed two studies, one which included all the test data and one which
excluded those values less than 0.04 (which were considered suspect compared to
industry experience).
The study, which included all the data, resulted in a mean
value of 0.097 and a mean value with 2 standard deviations of 0.178.
The study,
which excluded the values below 0.04, had a mean value of 0.102 and a mean
value with 2 standard deviation of 0.174.
The licensee used the measured static
SFC, generally rounded up to 0.15, if the measured
value was less than 0.15.
For
those MOVs where torque was not measured,
a value of 0.174 was used for the
SFC.
The inspectors had two concerns with the licensee's methodology.
Industry and
NRC sponsored test data has shown that dynamic SFC values (measured at flow
isolation) were generally higher than the values measured
during static testing.
The
licensee performed a second statistical evaluation using the dynamic torque and
thrust values from torque switch trip. The SFC values for this study indicated a
mean of 0.104 and a mean value with 2 standard deviations of 0.174.
The
inspectors discussed with the licensee that the values of SFC may still be higher at
flow isolation verses torque switch trip values.
The inspectors noted that changes
in SFC from static values to dynamic values should be accounted for in the closing
direction by the licensee's
LSB margin.
The inspectors'econd
concern was related to the potential change in SFC in the
open direction due to dynamic conditions.
In this direction, there was no added
LSB margin to account for the change in SFC.
The licensee performed an
evaluation for the inspectors which compared the motor operator open capability to
the minimum required thrust using the measured
SFC and a 15% direct bias for
LSB. No operability concerns were identified at this time, since the MOVs appeared
to have sufficient margin using this methodology.
Based on several issues concerning open motor capability values with respect to
SFC, further licensee review and subsequent
evaluation by the NRC will be required
for program closure.
The licensee needs to: provide the methodology and
justification to address
open motor capability when the appropriate SFC is taken
into account; for all valves with an open safety function, provide the valves
capability margin using the proposed methodology; and provide assurance
that this
issue will continue to be addressed
during the periodic verification program (i.e.,
program or procedure revision).
b.1.6
0 en Un ea in
Forces
During an April 1996 MOV inspection, inspectors identified that the open unseating
force was not accounted for and compared to the operator's capability or structural
limits. Subsequent
to this inspection, the licensee had compared the static
unseating forces to operator thrust and valve structural limits and to the dynamic
test data for MOV open capability (at degraded voltage and high ambient
temperature,
as appropriate).
No concerns were noted with these evaluations.
The
inspectors noted, however, that the licensee had not completed the review of the
static unseating forces compared to the operator's torque capability.
Based on this
finding, the licensee compared the static open unseating force to the operator's
thrust capability and identified MOVs 2-QIVIO-451 and -452 (volume control tank to
CVCS pumps isolation valves) had a potential overtorque condition.
These valves
have high speed actuators and with an unseating torque which would slightly
exceed the motor capabilities torque if the valves were opened at degraded voltage.
Since these MOVs do not have an open safety function, there was not an
operability concern.
The resolution of the potential overtorque condition was being
addressed
by CR-1780.
Although the licensee had modified the dynamic test procedure acceptance
criteria,
the static test procedure acceptance
criteria was not modified to address open
unseating forces.
A revision to the static test acceptance
criteria to address the
MOVs unseating force versus the operator and valve structural limits, and operator
capability needs to be completed prior to program review closure.
b.1.7
Linear Extra ola ion
The inspectors reviewed Technical Report 0012-00192-R02,
"Justification For
Linear Extrapolation Of Gate and Globe Valve Dynamic Test Data," Revision 0. The
licensee used the EPRI study and data to justify the position of linear extrapolation
from 30 percent dp to 100 percent design-basis
dp, with the exception of
blowdown conditions.
The inspectors noted that the lowest percent dp
extrapolated was 61 percent of design-basis
dp.
Further, the licensee noted that dp
loads less than 3000 Ib-force may yield VFs that were inaccurate and misleading.
The Technical Report, however, did not mention a minimum allowed value of dp (an
absolute value, not a percentage) to ensure that all linear extrapolations would be
meaningful.
This was a minor procedure issue that the licensee stated would be
corrected.
The inspectors considered the licensee's
linear extrapolation
methodology to be acceptable.
b.1.8
Tor ue Switch Re eatabili
The licensee's application of margin for torque switch repeatability was acceptable
for program review closure.
Torque switch repeatability values of 5%, 10% and
20% based on torque switch setting and actuator torque were appropriately applied
following Limitorque guidance.
b.1.9
Butterfl
Valve Tes in
Approximately two-thirds of all program butterfly valves (43 out of 66) had been
dynamically tested.
Based on this test information, the licensee's verification of
design basis capability of butterfly valves was near completion, pending completion
of analyses adjusting butterfly valve structural limits. While the majority of the
licensee's butterfly valves exhibited substantial capability margin, several
assumptions
used in the capability verification equations could not be verified by
the inspectors and close-out of GL 89-10 program review was pending submittal of
additional information and NRC review of the following issues:
(a)
To allow a means of comparing valves and determining a dynamic effect
load to apply to static test results, the licensee used a seating/unseating
factor which was based on the bearing equation described in EPRI's
Application Guide for Motor-Operated Butterfly Valves.
Essentially, the
seating/unseating
factors were determined by solving for the bearing y
described
in the Application Guide.
These seating/unseating
factors were
used the same way as valve factors are used for gates and globe valves.
For non-dp tested valves, the seat/unseat
factors were based on the
seat/unseat
factors obtained from dp tested valves in the same group.
However, as discussed
in the section II.B.4.b of the NRC's SE of the EPRI
MOV PPM Topical Report, EPRI testing revealed several areas whero the
Application Guide needed improvement or correction.
EPRI was revising the
Application Guide and plans to include new information on various issues,
including the treatment of bearing torque.
During the ir.spection, the NRC
inspectors were informed that based on discussions with engineers involved
with the Application Guide revision, the planned changes to the Application
Guide did not affect the methodology.
In view of the uncompleted revision
to the Application Guide, the NRC requested
a formal response
on the
impact of the changes
on the bearing equation and whether any proposed
changes impacted the methodology.
(b)
For symmetrical butterfly valves, the licensee assumed
closing hydrodynamic
loads were negligible, and therefore, were not included when comparing
actuator capability verse required seating torque.
The basis for this
assumption was based on the January 1993 EPRI Application Guide, page
3-47.
However, the NRC could not confirm whether information generated
during development of the EPRI butterfly valve model consistently supported
this assumption and requested
a formal response
on this issue.
(c)
The NRC also requested,
upon completion of the ongoing analyses,
a
summary tabulation detailing the structural and weak link margins for all
program butterfly valves.
0
I
4
(d)
The licensee's method for extrapolating tested torque to design basis
conditions used a linear method based on differential pressure if the peak
dynamic torque occurred at less then 15 degree open disc angle.
If the peak
dynamic torque occurs at greater than a 15 degree open disc angle,
extrapolation was performed based on flow rate squared.
The review of the
white paper justifying this position will be completed with review of the
submittals discussed
above.
The inspectors requested that the licensee submit information on items (a)-(c)
above, for NRC review.
The inspectors informed the licensee that the NRC's GL 89-10 program review closure will be contingent upon receipt and NRC review of
these p!ans.
b.1.10
Mar inal Valves
The inspectors noted that a number of valves in the GL 89-10 program were
considered
marginal based on design-basis
calculations.
In view of evolving
industry issues, such as the use of run versus pullout efficiencies, the inspectors
were concerned with the adequacy of several of the licensee's MOVs with less than
10 percent margin.
Although 16 valves were scheduled for margin improving
modifications, there were no established
plans for the other marginal valves.
The
inspectors requested that prior to program closure, the licensee submit any plans to
address the licensee's marginal valves.
b.2
Pro ram Sco
Chan
e
A total of 34 valves were removed from the program since the Part 2 inspection.
Thirty-two were removed based on Supplement
7 to GL-89-10, mispositioning.
The
remaining two were balance-of-plant
(BOP) valves that were not required to be in
the program scope.
Although removed from the program, these valves had been
diagnostically tested, and in some cases were scheduled for a design change to
increase the valves'apability.
With the removal of these valves, the program scope for both units consisted of
220 MOVs: 104 gates, 50 globes, and 66 quarter-turn (butterfly) valves.
Included
in the scope were 12 BOP valves, which was considered
a positive aspect of the
MOV program.
From this scope, the licensee was able to dynamically test 120
MOVs, which was considered
a program strength.
An additional positive aspect
was the position to perform diagnostic testing of MOVs not included in the
GL 89-10 program.
b.3
Periodic Verifica ion
PV of Desi n-Basis Ca abili
The licensee planned to statically test all program MOVs on an initial 3 fuel cycle
period with increased frequencies for valves in high ambient temperatures
or in
harsh environments.
Dynamic testing of program valves that are testable and
meaningful was planned taking into consideration margin and risk. However, as of
the date of the inspection, the licensee did not have a schedule or actual numbers
of valves to be dynamically tested.
10
The NRC staff will review the PV program in greater detail following the licensee's
submittals in response to GL 96-05, "Periodic Verification of Design-Basis
Capability of Safety-Related Motor-Operated Valves." As stated in the Generic
Letter, consideration of the benefits (such as identification of decreased
thrust
output and increased thrust requirements)
and potential adverse effects (such as
accelerated
aging or valve damage) when determining appropriate PV testing for
each program valve needs to be considered.
b.4
Post-Maintenance
Verifica ion
es in
Post-maintenance
verification/testing requirements documented
in Section 6 of the
Motor-Operated Valve Program Description, Revision 5, were reviewed and found
acceptable for program closure by the inspectors.
One program revision was
required to resolve the IFI discussed
in Section E8.1 of this report concerning
testing requirements after valve packing adjustments.
The licensee adequately
established static and dynamic test requirements following MOV maintenance
and
modifications.
b.5
MOV Trendin
and Correc ive Ac ions
The inspectors determined that the licensee's trending program appeared
capable of
tracking and evaluating data to maintain MOV design-basis
capability.
The
licensee's
MOV coordinator maintained
a database that contained baseline
diagnostic test results that would be used to evaluate valve performance during the
PV program.
The licensee's condition report process and the maintenance
rule will
assist the tracking and trending of repetitive problems or to initiate reviews of other
MOVs for similar problems.
Overall, the reviewed MOV-related CRs generated
over the last two years indicated
that MOV failures were appropriately reviewed and dispositioned.
However, the
inspectors were concerned that actions had not been completed on the resolution
of potential MOV overloading due to handwheel operation.
Recent industry MOV
failures, as well as a CR for MOV 2-ICM-311, reemphasized
that certain MOVs,
such as those with SMB-00 operators with a 4.38:1 handwheel ratio, can develop
manual loads that readily approach valve or operator limits. Although guidance to
evaluate MOV handwheel loads was given in Limitorque SEL-11 and EPRI
Application Guide NP-6660-D, the licensee had not fully addressed
this issue.
CR 96-0687 was generated
in April 1996 as a result of licensee identification that
Operations had manually "hand wheeled" MOV 2-ICM-311 into the seat with
enough force to exceed the torque switch settings.
The inspectors reviewed the
CR and determined that, besides identification of susceptible
MOVs, little progress
had been made in resolution of the CR.
Further, the existing procedural
requirements, which require that excessive force not be used during manual
operation, were insufficient. Of concern to the inspectors were the many valves in
the preliminary revie~ that indicated maximum handwheel rim pull forces as low as
10 pounds.
Additionally, the CR investigation due date had been extended twice
and was overdue by three months as of the week of the inspection.
The inspectors requested that the licensee submit plans on resolution of this issue
for NRC review.
The inspectors informed the licensee that the NRC's GL 89-10
program review closure will be contingent upon receipt and NRC review of these
plans.
b.6
NRC Informa ion Notice
"Poten ial for Loss of Remote Shu down
Ca abili
Durin
a Control Room Fire"
IN 92-18 identified the potential for loss of remote shutdown capability during a
control room fire. Due to potential hot shorts caused
by a control room fire, various
MOVs controlled from the remote shutdown panel could go to a stall condition,
since the control signal would not be available to stop power to the motor.
This
could cause valve and/or operator degradation that could result in the loss of safe
shutdown capability.
'he
MOV control circuits use a double break scheme around the open/close valve
contact.
In most cases this was provided by both limit/torque switch contacts and
remote/alternate
transfer switch contacts.
For the above, two hot shorts of the
correct polarity and conductors must occur to operate
a valve.
The licensee's
response to IN 92-18 was recently reviewed by regional engineering inspectors and
is discussed
in Inspection Report No. 50-315/96010;
50-316/ 96010.
The
inspectors had reviewed the electrical design of the Appendix R valves for both
units and concluded that the licensee met the intent of the IN.
Conclusions
The failure to perform an operability determination on the PORV block valves when
new information became available was considered
a violation for failure to
document
a potentially adverse condition and perform an operability determination.
This was a significant concern, considering the previous issues identified by the
NRC in this area.
Although a majority of the significant issues related to the MOV program have been
resolved, a number of issues relating to the design-basis
capability of program
valves remain open.
Therefore, the NRC's GL 89-10 program review will remain
open pending completion and submittal of these open issues as discussed
in the
details of this report.
Aspects of the program adequately completed for program
review closure included program scope, requirements for post maintenance testing,
trending, and corrective action program.
E7
Quality Assurance in Engineering Activities
E7.1
Licensee Self-Assessment
Activities
The inspectors reviewed a recent MOV self-assessment.
Although narrow in scope,
the self assessment
identified several good technical issues.
The use of an outside
MOV expert was considered
beneficial to improving the MOV program.
12
I
III'
Miscellaneous Engineering Issues (92902)
E8.1
Closed
Ins ec ion Followu
I em 50-315 93006-04
50-316 93006-04:
Packing
adjustment PMT requirements did not include diagnostic verification to confirm that
assumed
packing thrust design loads were not exceeded.
The licensee's position
had been that if the original packing gland nut torque was not exceeded
during the
packing adjustment, the packing load would not exceed the value which had been
determined to be acceptable
during the previous diagnostic test.
Although various
tests had been conducted in an attempt to validate this position, the relatively small
amount of data did not support use of this position across all program MOVs.
Further, the position was weakened with on-site examples of increased
packing
loads due to improper maintenance that had resulted in cocked packing glands
resulting in higher packing loads (the nuts had been retorqued to the original
torque).
In view of this, the licensee committed to revise the process and, for all
program MOVs, will diagnostically verify, subsequent
to packing adjustments, that
packing loads did not adversely affect thrust requirements.
This item is closed.
E9
Updated Final Safety Analysis Report (UFSAR) Commitments
E9.1
Review of UFSAR Commi ments
The inspectors reviewed the applicable sections of the UFSAR that related to the
inspection areas discussed
in this report.
The inspectors verified that the UFSAR
wording was consistent with the observed plant practices, procedures and/or
parameters.
V. Mana ement Meetin s
X1
Exit Meeting Summary
The inspectors presented the inspection results to members of licensee
management at the conclusion of the inspection on October 25, 1996.
The
inspectors re-exited with members of licensee management
on December 5, 1996.
The licensee acknowledged the findings presented.
The inspectors asked the
licensee whether any materials examined during the inspection should be
considered
proprietary.
No proprietary information was identified.
13
PARTIAL LIST OF PERSONS CONTACTED
Licensee
¹ "A. Blind, Site Vice President
¹"J. Sampson,
Plant Manager
¹
K. Baker, Assistant Plant Manager
"D. Hafer, Nuclear Engineering
¹"F. Pisarsky, Nuclear Engineering
¹ "D. Powell, Nuclear Engineering
¹ S. Steinhart, Nuclear Engineering
"L. Demaizco, Nuclear Engineering
¹ "A. Gort, Nuclear Engineering-MOV Coordinator
¹"K. Toth, Licensing
"L. Smart, Licensing
.¹
R. Ptacek, Nuclear Safety 5. Assessment
Duke En ineerin
& Services
L. Lutz, MOV Engineer
S. Korn, MOV Engineer
NRC
. Kropp, Chief, Engineering Specialists Branch
1
¹ "B. Bartlett, Senior Resident Inspector
"B. Fuller, Resident Inspector
¹ J. Maven, Resident Inspector
INSPECTION PROCEDURE USED
Safety-Related
Motor-Operated Valve (MOV) Testing and Surveillance
ITEMS OPENED and CLOSED
~Oened
50-31 5/9601 2-01 (DRS);
50-31 6/9601 2-01 (DRS)
Failure to initiate a condition report and perform a
prompt operability determination for the PORV block
valves
50-31 5/9601 2-02(DRS);
50-31 6/9601 2-02(DRS)
IFI
Modifications not completed for the PORV block valves
Closed
50-31 5/93006-04;
50-31 6/93006-04
IFI
PMT requirements following packing adjustments
LIST OF ACRONYMS USED
CR
dp
GL
IFI
IN
INEL
LER
LCO
LSB
NRC
P&.ID
PMI
S/0
SFC
Tl
TS
Balance-of-Plant
Coefficient of Friction
Condition Report
Chemical and Volume Control System
Differential Pressure
Electric Power Research Institute
Generic Letter
High Pressure
Coolant Injection
Inspector Followup Item
Information Notice
Idaho National Engineering Laboratory
Licensee Event Report
Limiting Condition for Operation
Load Sensitive Behavior
Motor Operated Valve
Nuclear Regulatory Commission
Office of Nuclear Reactor Regulation
Piping 5. Instrumentation Diagram
Public Document Room
Plant Manager Instruction
Post Maintenance Testing
Power-Operated
Relief Valve
Performance Prediction Methodology
Periodic Verification
Reactor Coolant Pump
Residual Hear Removal
Rate of Loading
Shutoff
Safety Evaluation
Stem Friction Coefficient
Safety Injection
Structure, System, or Component
Temporary Instruction
Technical Specification
Updated Final Safety Analysis Report
Unresolved Item
Valve Factor
Violation
15
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