ML20034F183
| ML20034F183 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 02/22/1993 |
| From: | Branch M, Hunt M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20034F172 | List: |
| References | |
| 50-395-93-04, 50-395-93-4, GL-89-10, NUDOCS 9303020367 | |
| Download: ML20034F183 (12) | |
See also: IR 05000395/1993004
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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REGION 11
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101 MARIETTA STREET, N.W.
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ATLANTA, GEORCI A 30323
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FEB 2 3 1993 -
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Report No.:
50-395/93-04
Licensee:
South Carolina Electric & Gas Company
Columbia, SC 29218
Docket No.:
50-302
License No.: NPF-12
Facility Name:
V.C. Summer
Inspection Conducted: January 25-29, 1993
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Inspector:
/ ITICl4wJ/
Rd73
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M. D. Hunt '
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D6te Sitned
Accompanying Inspector:
M. N. Miller
Approved by:
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M. W. Branch', Chief
Date Signed
Test Programs Section
Engineering Branch
Division of Reactor Safety
SUMMARY
Scope:
This announced inspection was conducted to assess the adequacy of the
licensee's actions taken regarding the concerns identified during the GL 89-10
Phase I Motor Operated Valve Inspection (MOV) conducted January 27-31, 1992,
(NRC Inspection Report No. 50-395/92-02).
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Results:
In the areas inspected, three examples of inadequate acceptance criteria were
identified in the test procedures used for MOV operability testing, this
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finding is identified as violation 50-395/93-04-01, Inadequate Acceptance
Criteria in MOV Procedure. (See paragraph 3.c.)
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In the area of training, the engineering staff had not received MOVATS
training for signature analysis of motor operated valve test data.
In the
area of staffing, there was only one engineer assigned:as MOV Coordinator, and '
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one electrician assigned to the MOV program. The current staffing level may
explain the delays noted in resolving those open program issues identified in.'
the NRC Inspection Report No. 50-395/92-02. Overall, the licensee's MOV
Program needs additional enhancements to meet the intent of the
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9303020367 930223
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ADOCK 050003951
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recommendations in GL 89-10. An Inspector Follow-Up Item was identified to
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address the concerns that still need to be addressed in the licensee's
program.
The Inspector Follow-up Item, 50-395/93-04-02, is identified as GL 89-10
Program Open Items.
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REPORT DETAILS
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1.
Persons Contacted
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Licensee Employees
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- J. Berley, Specialist, Nuclear Licensing
- C. Bowman, Manager, Maintenance
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- M. Browne, Manager, Design Engineering
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- R. Fowlkes, Manager, Nuclear _ Licensing .
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- M. Hazel, Motor Operated Valve Coordinator, Design Engineering
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- G. Meyer, Senior Mechanical Engineer, Design Engineering
- B. Norcutt, Electrician, Maintenance Department
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- J. Pease,. Specialist, Nuclear Licensing
- C. Price, Coordinator, Engineering Services
- M. Quinton, General Manager, Engineering Services
- J. Skolds, Vice President, Nuclear. Operations
- N. Smith,-Test Coordinator, Technical Services
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- B. Williams, Manager, Operations
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NRC Personnel
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R. Haag, Senior Resident Inspector
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- T. Farnholtz, Resident Inspector
- Attended exit interview
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2.
GENERIC LETTER (GL) 89-10 " SAFETY-RELATED MOTOR-0PERATED VALVE (MOV)
TESTING AND SURVEILLANCE" (2515/109)
The Nuclear Regulatory Commission (NRC). Region 11 conducted a Part I M0V
inspection during January 27-31, 1992, of the V.C. Summer Nuclear Plant
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(NRC Inspection Report No. 50-395/92-02). The inspection examined the
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licensee's actions taken in response to Generic Letter'89-10,
Safety-Related Motor-0perated Valve Testing and Surveillance, and
identified thirteen concerns. Additional information was requested for
two concerns and the eleven other concerns required no written response.
The licensee responded to these two concerns by letter dated May 27,
1992.
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The purpose of this inspection was to review the licensee's actions
taken for each of the concerns identified in the GL 89-10 Part I MOV
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Inspection Report 92-02 and the responses submitted in their letter.
Each concern is listed and discussed below.
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The first part of each section lists the concern as written and
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discussed in the GL 89-10 Part-I MOV Inspection Report 92-02. The.
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second part discusses the findings of this-inspection.
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a.
Concerns Identified - Written Response Requested (WRR)
Concern 1 (WRR)
This concern was discussed in Section 3.d of the Part 1 MOV
report. The licensee has identified 35 groups of MOVs based on
similarity in design, functional characteristics, and operating
conditions.
This grouping methodology takes credit for equivalent
group of MOVs based on successful differential pressure testing of
the least capable MOV within a group.
Implementation of this
methodology will not result in performing a differential pressure
(DP) test where practicable, as recommended in the generic letter.
The licensee does not have a verifiable basis for the assumptions
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used for the grouping methodology. The omission of differential
pressure testing on MOVs where practicable is contrary to the
generic letter 89-10 recommendations and the licensee's commitment
to comply with the generic letter.
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The licensee's response to this concern was submitted May 27,
1992.
A summary of the licensee's response follows. The licensee
will increase the scope of MOVs to be differential pressure (DP)
tested.
The information gained from this expanded testing along
with technical feedback from industry programs will be utilized to
verify assumptions in the static setup and testing of valves which
are not tested under DP conditions. A grouping concept based on
design similarities and environmental conditions will then be
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utilized for these valves. As the predictability of valve
performance improves, through advancements in test equipment,
valve performance history, and industry initiatives, the licensee
will evaluate and adjust the scope of their testing accordingly.
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The expansion of the DP testing will impact their current
commitment to complete initial testing of MOVs by the Fall of
1994.
The licensee will assess the impact of their commitment and
revise it accordingly following the refueling outage in the Spring
of 1993.
Until additional testing is performed during the upcoming
outage,and the extent of the licensee's testing plans are
finalized, the quantity of MOVs to be tested can not be
determined.
This concern will be closed but is included as part
of Inspector Follow-up Item (IFI) 50-395/93-04-02, Program Open
Items.
Concern 2 (WRR)
This concern was discussed in Section 3.c of the Part I M0V
report. The licensee has bypassed the torque switch on the PORV
block valves and used the close limit switch for de-energizing the
motor during MOV close operation.
This practice is not
recommended by Limitorque. Additionally, industry experience has
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shown that these MOVs have had difficulty closing under highly
loaded conditions. The licensee needs to justify use of the above
practice.
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The licensee's response to this concern was stated in their
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May 27, 1992, letter to the NRC. A summary of the licensee
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response follows. Westinghouse, as NSSS designer of VCSNS (plant),
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modified certain valves to the limit close feature in order to
assure closure of the valve under design basis' conditions.
In
some cases the design loads are beyond the known operator range of
calibration such that the torque switch cannot be set with the
confidence that the set point is both adequate and within the
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stall limit of the motor.
The principal benefit of the' limit
closed method is to minimize structural loads imposed on valve and
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the operator.
Subsequent to the modification to the limit close
mode of operation, DP testing was performed on' valves similar and
in the same group as the PORV block valves to confirm operation
under design basis conditions.
Limit switch seating of MOVs is
considered to be appropriate to preclude exceeding the valve or
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actuator ratings at VCSNS. Additionally, leak tightness is
assured. This response was accepted by the NRC.
This item is
closed.
b.
Concerns Identified - No Written Response Requested (NWRR)
Concern 1 (NWRR)
This concern was discussed in Section 3 b.of the Part I MOV
report. Inconsistencies were noted in the licensee's draft design
basis review documents (DBD).
Further engineering review of these
documents will be required to ensure that the licensee's MOV
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torque switches are set appropriately.
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The licensee will review any inconsistencies and make appropriate
changes to the DBD prior to issuing it. The inspectors found that
DBD has not been completed and further review is still needed.
In
addition, design engineering is still reviewing the " master" DBD
and MOV calculations performed by their contractor, ABB Impell
Corporation.
The review of licensee's engineering notes indicated
that changes were also needed in the " master" DBD.
This concern
is closed.
However, it will be addressed in IFI 50-395/93-04-02.
(See paragraph 3.d).
Concern 2 (NWRR)
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This concern was discussed in Section 3.b of the Part I MOV
report. The licensee's generic letter 89-10 program does not make
provisions for evaluating the effects of high ambient temperature
on motor developed torque. The licensee informed the inspectors
that they are waiting for Limitorque to issue a report concerning
high temperature effects on motors. The licensee' called
Limitorque January 26, 1993, to find out when the report would be
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issued.
Limitorque informed the licensee that the high
temperature effects on motors would be issued the next. week.
The
licensee is waiting for the Limitorque information befcre
performing any evaluation of data to be included in the MOV
ralculations. This item is closed. However, it will be addressed
in IFI 50-395/93-04-02. (See paragraph 3.d).
Concern 3 (NWRR)
This concern was discussed in Section 3.c of the Part I M0V
report. The licensee's use of a 0.3 valve factor in calculating
thrust requirements for gate valves is non-conservative. The
licer,see needs to validate this value of valve factor v.ia dynamic
tests or develop specific justification for its use. The licensee-
has now expanded their DP testing to include all valves that are
practical to test. All valve factors will be verified during this
DP testing using new stem cells (strain gauges) and torque thrust
cells In cases where DP testing can not be performed,
justification will be provided by using similar or like kind or
types during an engineering evaluation. The inspectors verified
that the DP testing has been expanded and considered this response
appropriate. This concern was closed based on the evaluation that
- ast be performed as discussed in the Concern 4 (NWRR).
Concern 4 (NWRR)
This concern was discussed in Section 3.c of the Part I MOV
report. The generic letter program does not make provisions for
evaluating DP test results in order to determine available thrust
margin.
Test results are not reviewed to validate assumptions
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used in thrust equations.
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The licensee will add margin to the DBD to account for. uncertainty
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in stem friction factors when determining the minimum required
thrust limit.
Review of DP test results will be performed in a
manner necessary to account for stem friction and load sensitive
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MOV behavior.
Engineering Services Procedure E-424, MOV Program
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Implementation , Revision 0 would be revised to specify the
requirements and criteria for implementing the engineering
evaluations concerning margins. This concern is closed. However,
it will be addressed in IFI 50-395/93-04-02.
(See paragraph 3.d).
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Concern 5 (NWRR)
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This concern was discussed in Section 3.h of the Part 1 MOV
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report.
The generic letter program needs to clearly identify the
margin, related to lubricant aging effects, that is applied to
required thrust numbers. Additionally, the licensee needs-to
evaluate MOV test results to identify the " rate of loading"
effects on load sensitive MOVs.
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The inspectors conducted walkdowns to examine stem lubrication on
various MOVs. All valves inspected were adequately lubricated.
The licensee has a regular lubrication program for the_MOVs
specified in Engineering Services Procedure ES-418. Margin, and-
" rate of loading" effects should be included in licensee's
revision of Procedure E-424 discussed in Concern 4 (NWRR)
evaluation. This item is closed.
Concern 6 (NWRRl_
This concern was discussed in Section 3.f of the Part I MOV
report.
Limit switch seating MOVs, that have leakage criteria,
requires a switch setting that ensures adequate leak tightness
without exceeding the valve or actuator. ratings.
The licensee's response to Concern 2 (WRR) in the May 27, 1992,
letter to the NRC addressed this concern.
The inspectors verified
that the leak tightness of the MOVs was adequately addressed in
General Test Procedure GTP-302, Inservice Testing Of Valves. The
licensee uses the torque switch during the setting of the limit
switches, to determine that over thrusting is not occurring during
closure of the valve. Once this is determined, the limit switches
are set and the torque switch is removed from the electrical
circuit. The electrical circuit can be restored as needed for any
additional limit switch adjustments.
This item is closed.
Concern 7 (NWRR)
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This concern was discussed in Section 3.e of the Part I HOV
report.
Inconsistencies were noted in the licensee's draft thrust
calculation documents.
Further review of these documents will be
required to ensure that the licensee's generic letter MOV torque
switches are set appropriately.
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The torque switch setting should be included as part of the DBD.
See the inspectors finding for Concern 1 (NWRR).
This item is
closed.
However, it will be addressed in IFI 50-395/93-04-02.
(See paragraph 3.d).
Concern 8 (NWRR)
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This concern was discussed in Section 3.c of the Part I M0V
report. The licensee needs to review OP test results, to the
extent necessary, to ensure operability of an MOV prior to
returning the system to operation.
The inspectors reviewed the
acceptance criteria for the MOV test procedures (See
concerns /connents in paragraph 3.c), and the licensee's program-
for initiating a non-conformaace report (NCR). While the test
procedures acceptance criteria appeared to be inadequate,.there
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was sufficient evidence that the M0Vs that have been tested to
date, were evaluated for operability where necessary. The test
acceptance was based on the full closure of the valve under ' full
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DP. A NCR was initiated requiring an engineering evaluation to
determine acceptability and operability for the MOVs that did not
successfully close during full DP testing. The inspectors
determined that the existing program for using a NCR was adequate
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to address this concern. This item is closed.
Concern 9 (NWRR)
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This concern was discussed in Section 3.e of the Part I MOV
report. The program did not justify the use of static tests to
periodically verify M0V capability in accordance with the generic
letter recommendations.
The licensee plans to DP test all those MOVs that are practical to
test. At the present time, it is not necessary or required
(in GL 89-10) to perform DP retesting unless the MOV is replaced,
modified, or overhauled to the extent that existing DP test
results are not representative of tne MOV in its modified
condition.
The licensee's initial testing was to only have the
spring pack displacement monitored using the " thrust measuring
device" (TMD) to determine thrust. The licensee will now use both
the torque thrust cell (TTC) and the TMD.
In addition the
licensee contracted to have calibrated stem strain gauges
installed during the Spring 1993, refueling outage, to supplement
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using the TTC. The inspectors determined that the licensee's
planned methods were adequate at this time. This item is closed.
Concern 10 (NWRR))
inis concern was discussed in Section 3.1 of the Part I MOV
report.
Use of thrust measuring device (TMD) to measure thrust
during dynamic tests will affect the licensee's ability to detect
load sensitive MOV behavior.
The licensee now uses a TTC in addition to the TMD. (See response
to concern 9). The inspectors determined that the licensee's
methodology for using additional instrumentation to measure. thrust
and loading is acceptable.
This item is closed.
Concern 11 (NWRR)
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This concern was discussed in Section 3.1 of the Part I MOV
report.
Calculating maximum expected differential pressure using
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design values for up stream pressure could result in overly
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conservative assumptions. Therefore, achievement' of the
identified worst case conditions during DP test may not be
possible.
The licensee currently considers conservatism an asset. -Expected
test values have been determined such'that margin can be defined.
The inspectors reviewed the licensee's program procedures and
determined the procedures need to be enhanced to clearly define
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the testing limits criteria and how these test limits would.be
evaluated.
Engineering Services Procedure ES-424 will be revised
to address test limits and specifically address the test limits
when it will be less than the worst case DP condition. (This
specifically means that if the required DP test limiticould not be
set up and a reduced DP test limit was used; the acceptance-
criteria for the engineering evaluation would be specified in
ES-424). Other changes for ES-424 are also discussed in the
inspectors findings for Concern 4.
This item was closed and
incorporated as part of item 4 of IFI 50-395/93-04-02.
3.
INSPECTION FINDINGS
a.
Documentation
The inspectors reviewed the licensee's GL 89-10 MOV program
documentation to determine if it had been completed since the last
MOV inspection (January 27-31,1992) and was adequate to support
the MOV program. The documents reviewed included (1) ABB Impell
Instruction 0980-077 ."I-001, Maximum Design Basis Differential
Pressure Determination, and associated calculations, (2) the
licensee's draft MOV design basis document, (3) design
Modification Package MCM No. 21745 E dated December 9, 1992, and,
(4) various engineering, test, and electrical maintenance
procedures.
The licensee informed the inspectors that the
" master" document for the MOV program was the ABB Impell
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Instruction and associated calculations contained in six volumes
(six 3-ring binders).
The ABB Impell documents were considered to be the completed
design basis documents (DBD) until the licensee completed their
draft DBD and issued it.
The licensee's draft DBD was supposed to
be a copy of the ABB Impell documents.
However, the licensee's
draft DBD was not signed and no additional work to complete it was
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identified by the inspectors.
In addition, the inspectors found
the licensee was still in the process of updating the ABB Impell
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DBD.
For example, the maximum valve thrust listed in the
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calculations of the ABB Impell DBD for valves XVK1633A-FW,
XVK1633B-FW, and XVK1633C-FW was 9772 pounds.
For the same valves
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listed in Design Modification Package MCM No. 21745E, the maximum
thrust was 14,647 pounds. .The licensee's design modification
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package had changed these values.
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Another area of concern with the ABB Impell DBD was that the data
used for the calculations was crossed out-in red and new values
hand written in.
For example, Calculation No. 0980-077-DB-002,
pages 120 - 126, for valves XVG6516-VU, XVG6517-VU, XVG6518-VU,
and XVG6519-VU-had hand written changes.
Engineering ~ explained
that several changes to the ABB Impell DBD were not finished at
this time, but engineering was aware of what needed to be done to
complete the DBD and work was in progress to complete the DBD.
The inspectors were satisfied that engineering knew what was
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needed to accomolished to complete the GL 89-10 program.
However, the inspectors could not identify how the licensee
planned to complete the program with'the existing personnel
assigned. Overall, the inspectors determined that the licensee's
documentation for the GL 89-10 MOV program was incomplete at this
stage and'had expected more progress based on the fact that M0V.
testing is to be performed during the upcoming March outage.
b.
Training and Staffing
The inspectors noted that currently there were only two persons
who were active in the MOV program, one engineer ( MOV
Coordinator) and the other was an electrician who directed the
testing. .The inspectors also noted that only the electrician had
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received M0 VATS training. The inspectors were informed that one
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other electrician had received this training but that person was
not presently assigned to the MOV program. The electrician,
currently in charge of testing, explained that he had given
training to other electricians.
The MOV Coordinator had not
received M0 VATS Training. During a meeting with the licensee, the.
inspectors were advised by engineering management that.they did
not feel it necessary that the engineers who perform the
diagnostic trace reviews have the training to perform diagnostic
testing.
However the licensee indicated that additional training
would be made available.
The licensee advised the inspectors that when valve testing is
performed during the next outage, there would be sufficient
trained personnel available to accomplish the necessary testing
and evaluations.
During the last outage the licensee had used
M0 VATS technicians and would take the steps to use qualified
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contract personnel again during the next outage. The inspectors
remarked to the licensee that the two personnel presently assigned
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to the MOV program needed additional support to accomplish the
various tasks to meet the licensee's program schedule commitment.
c.
Testing
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The inspectors reviewed the results of the licensee's
justification of 44 valves that were excluded from DP testing.
This group of valves consisted of suction valves for the' RHR and
SI pumps, and reactor building spray discharge valves. Other .
valves contained in the list were the main steam supply valves tc
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the emergency feedwater pump turbines, accumulator isolation
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valves, and containment isolation valves for the CRDMs cooling
water supply. The evaluations listed the justifications and the
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inspector verified the justifications by review of the appropriate
system P&ID drawings. In the judgement of the inspector, the
licensee demonstrated justification for valves that are exempted
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since the testing of these valves could present a safety problem
or damage equipment.
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A summary of the open concerns for IFI 50-395/93-04-02 are:
(1) Concern 1 (WRR) Additional testing is required to
determine the scope of the MOV testing program.
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(2) Concern 1 (NWRR) Further engineering review of the'DBD
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needs to be completed.
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(3) Concern 2 (NWRR) The effects of high ambient
temperature on the actuator motors needs to be
evaluated.
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(4) Concern 4 and 5 (NWRR) The engineering services
procedure ES-424 needs to be up-dated and revised to
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include the requirements and criteria for implementing
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engineering evaluations concerning margins.
(5) Concern 7 (NWRR) Inconsistencies were noted in the
draft DBD thrust calculations. The DBD needs to be
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completed.
4.
EXIT INTERVIEW
The insp'ection scope and findings were summarized on' January 29, 1993,
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with those persons indicated in paragraph 1.
The inspectors described
the areas' inspected and discussed in detail the inspection results.
Proprietary information is not contained in this report.
Dissenting
comments were not received from the licensee.
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The inspectors informed the licensee that one violation, with three
examples, concerning inadequate acceptance criteria in the M0V
procedures was . identified as Violation 50-395/93-04-01, Inadequate
Acceptance Criteria in MOV Procedures.
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The licensee was also informed that the remaining open concerns
discussed in the report would be identified as an Inspector Follow-up
Item 50-395/93-04-02, GL 89-10-Program Open Items.
5.
Acronyms and Initialisms
ASEA BROWN B0VERY
DESIGN BASIS DOCUMENT
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DP
DIFFERENTIAL PRESSURE
ELECTRIC POWER RESEARCH INSTITUTE,
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GENERIC LETTER
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IFI
INSPECTION FOLLOW-UP ITEM
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IR
INSPECTION REPORT
MOTOR-0PERATED \\ALVE
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M0 VATS
MOTOR-0PERATED VALVE ANALYSIS AND TEST SYSTEM
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NRC
NUCLEAR REGULATORY COMMISSION
NWR
NO WRITTEN RESPONSE REQUESTED
- NSSS
NUCLEAR STEAM SYSTEM SUPPLE
NWRR'
NO WRITTEN RESPONSE REQUIRED
POWER OPERATED RELIEF VALVE
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REGION II
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TMD
THRUST MEASURING DEVICE
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TEMPORARY INSTRUCTION
TORQUE THRUST CELL
V.C. SUMMER NUCLEAR SITE
WRITTEN RESPONSE REQUIRED
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