ML20204J005
| ML20204J005 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 03/19/1999 |
| From: | Tuckman M DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-96-05, GL-96-5, TAC-M97030, TAC-M97031, TAC-M97065, TAC-M97066, NUDOCS 9903290233 | |
| Download: ML20204J005 (10) | |
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526 South Church Street P.O. Box 1006 Charlotte, NC 28'i,1-1006 M. S. Tuckman Executive ViceIWsident (704)3l2-2200 0FFICE Nuclear Generation (704) 3&?-4360 FAX March 19,1999 I
U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555
Subject:
Catawba Nuclear Station Units 1 & 2 Docket Nos. 50 -413, 414 TAC Nos.
M97030, M97031-McGuire Nuclear Station Units 1 & 2 Docket Nos. 50 -369, 370 TAC Nos.
M97065, M97066
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Response to Requests for Additional Information Concerning Generic Letter 96-05:
Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves On January 27,1999 and January 28,1999, the NRC issued Requests for Additional Information (RAI) for Catawba Nuclear Station Units 1 and 2 and McGuire Nuclear Station Units 1 and 2,
respectively, in order to complete their review of GL 96-05.
These RAIs were to be responded to within the dates
.specified in the respective letters.
Duke's response to the requested information is provided in j
Attachments 1 and 2 for Catawba and McGuire Nuclear Stations, respectively.
l I declare under penalty of perjury that these statements are true and. correct to the best of my knowledge.
If you have questions or need additional information, please contact 7LJ.ir.on Jones-Young at (704) 382-3154.
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U.S. NRC 3 March'19,'1999 l
Page 2 Very truly yours, M_ Am _ %
o-l M.' S. Tuckman Executive Vice President l-Nuclear Generation
' Attachments.
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I' L.A..Reyes Regional Administrator, Region.II l
F.
Rinaldi, ONRR P.S.
Tam,' ONRR l
S.M.
.9haeffer Senior Resident Inspector (MNS)
D.J.
Roberts-Senior Resident Inspector (CNS)
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1 i-ATTACHMENT 1 Catawba Nuclear-Station's Response to the RAI for GL 96-05 l-I i
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i NRC Question #1 In NRC Inspection Report No. 50-413'& 414/97-03, the Staff closed its review of the motor-operated valve (Nov) program
' implemented at Catewba Nuclear Station (Catawba) in response to Generic Letter (GL) 89-10," Safety-Related Motor-Operated Valve Testing and Surveillance."
In the inspection report, NRC staff discussed certain' aspects of the licensee's Mov program to be i
addressed over the long term.
For example, the inspectors noted that (1) the licensee initiated an action to address the Anchor / Darling double-disc gate valve model conditions specified in'the NRC safety evaluation of-the Electric Power Research Institute (EPRI) Performance Prediction Model (PPM); (2) modifications were planned to increase ~the margins for valves 1NC 31 and 2NC 33; (3) additional Borg Warner gate valve testing was scheduled for the Spring 1997 outage to resolve high valve factor
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. concerns; (4) modifications were planned to increase the margins for. valves in Group WL-01 during the Spring 1997 outages (5) the licensee initiated an-action plan to improve the valve factor basis for several gate valve and globe valve groups; and (6) q
. valve factor data scatter would be reviewed to ensure that thrust calculations use appropriate values.
Please provide a summary status of the actions taken to address the specific long-term aspects of the Mov program at Catawba noted in the inspection.
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RESPONSE
Information requested for items.1 through 5 in Question #1 was addressed and satisfactorily closed in NRC Integrated j
Inspection Report 50-413/98-08 and 50-414/98-08 dated September 14, 1998.
Item (6) is addressed below.
(6)
Valve factor " data scatter" is addressed by selecting and using the bounding valve factor from a given group of tested MOVs.
Statistical evaluation of valve factors is not relied upon.
Data scatter is often caused by low valve factors which are not used (or taken credit for) in Catawba's MOV Program.
Within the' context of how. Catawba dynamically tests MOVs, evaluates the test results, and applies those results to other valves, the " bounding valve factor approach" yields appropriate values.
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. - CNS March 19,1999 Page 2 n
NRC Question #2 Please briefly describe your plans'for the use of test data from the motor control conter (NCC) including (1) correlation of new MCC test data to existing direct force measurements; (2) interpretation of changes in MCC test data to changes in MOV thrust and torque performances (3) consideration of system accuracies and sensitivities to MOV degradation for both output and operating performance requirements; and (4) validation of MOV operability using MCC testing.
Responses-Periodic Verification Tests are conducted and evaluated based on direct thrust and/or torque measurement.
Motor control center
-(MCC)-data is often taken in parallel with direct measurements because it' bas proven to be an effective MOV diagnostic tool.
Collecting MCC data is not a requirement of Catawba's Periodic Verification Program.
Catawba does not rely on MCC data for periodic testing at this point. Future testing may permit MCC testing for Periodic Verification.
NRC Question #3 The JOG program focuses on the potential age-related increase in the thrust or torque required to operate valves under their design-basis conditions.
In the NRC safety evaluation dated October 30, 1997, on the JOG program, the staff specified that licensees are responsible for addressing the thrust or torque delivered by the MOV motor actuator and its potential degradation.
Please describe the plan at Catawba for ensuring adequate'ac and de MOV motor actuator output capability, including consideration of recent guidance in Limitorque Technical Update 98-01 and its supplement 1.
Response
Catawba has implemented the guidance in Limitorque Update 98-01 and its Supplement 1.
Potential actuator degradation will be addressed by:
(1)
Preventive maintenance activities - including actuator re-lube, _ gearbox grease inspection, and exercising every refueling outage; (2)
Performing periodic instrumented static tests and detailed evaluation (as committed to in GL 96-05 Responses). "As
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-Attachment 1 - CNS l
LMarch 19,1999 L
Page13 l
i found" and "as left" data will be evaluated; (3)' Performing ~ periodic dynamic tests _as prescribed by the JOG l
Program.
These tests,'along with others, will be evaluated to determine if load sensitive behavior _(ROL) is changing over time;-
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~ Trending MOV performanceLand' failures:and utilizing Duke
. (4).
L Power's Operating Experience' Program;-
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'(5)z Benchstestingfactuators'(AC) as needed to verify output
. capability (using Kalsi Engineering's Operator Test Bench);
~ (6)
Using MCC test data as a trending and diagnostic. tool (when applicable and/or available);
L (7)_
Participating in industry initiatives.such as the JOG
. Programs"(MOViand AOV), Westinghouse Owner's Group, Motor-operated Valve Users Groups EPRI,- etc~.
' Feedback from these groups will be fed back into Catawba's MOV Program.
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ATTACHMENT 1 McGuire Nuclear Station's Response to the RAI for GL 96-05 4
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F-NRC Question #1:
In'NRC Inspection Report No. 50,369 and 370/96-11, the NRC staff closed its review of the motor-operated valve (MOV) program implemented at McGuire Nuclear Station (McGuire) in response to Generic Letter-(GL) 89-10, " Safety-Related Motor-Operated Valve Testing and Surveillance". In the inspection report, the NRC staff discussed certain aspects of Duke Energy Corporation's (Duke's) MOV program to be addressed over the long-term. For example, the inspectors noted that (1) additional industry data would be obtained and modifications were planned to increase the margins.for four Aloyco split-wedge gate valves; (2) Duke intended to izqprove the margin for Borg Warner gate valve 1CF0129 during the next refueling outages (3) margin-improvement plans
' included the replacement of sight Borg Warner gate valves; (4)
Duke initiated an action plan to improve the margins and the valve factor basis for the Pressurizer Power Operated Relief Valve block valves; (5) program documents required revisions to included the latest load sensitive behavior and stan friction coefficient assumptions; (6) eleven MOV with available valve factors of:less than 0.50 were scheduled for margin improvements during~the next refueling outage; and (7) several dynamic butterfly valve tests were planned to improve the basis for current torque requirements. Duke should provide a summary status of the actions taken to address the specific long-term aspects of the MOV program at McGuire noted in the NRC inspection rsport.
Response
Information requested for all items in Question #1 (except item
- 3) were directly addressed and satisfactorily closed in NRC Integrated Inspection Report 50-369/98-08 and 50-370/98-08, dated September 21, 1998.
Item (3) is addressed below.
(3)
Four valves in Unit 1 have been replaced with Atwood and l
Morrill parallel slide gate valves.
This modification was performed under NSM 12475.
A similar modification will be performed in Unit 2 during 2EOC12 (upcoming refueling outage).
-This work,will be performed under NSM 22475.
The functional margin of all 8 replacement valves will be greater than 50%.
U.S. NRC
. - MNS March 19, 1999 Page 2 I-NRC Question #2 Duke should briefly describe its plans for the use of test data from the motor control center (MCC) including (1) correlation of how MCC test data to existing direct force measurements; (2) interpretation of changes in MCC test data to changes In MOV thrust and torque performance;.(3) consideration of system accuracies and sensitivities to MOV degradation for both output and operating performance requirements; and (4) validation of MOV operability using MCC testing.
Responses All GL 89-10 motor operated valves (MOVs) at McGuire Nuclear Station-(MNS) acquire data from the motor control center (MCC) during periodic verification.
For the vast majority of these valves, data from the MCC is collected as a supplement to other diagnostic methods (i.e., VOTES for gates and globes and strain gauge for butterfly).
Less than 10% of the total safety related MNS MOV population use MCC data for periodic verification.
For these MOVs, no correlation of MCC data to existing direct force measurement is done.
Due to the high margin of these MOVs and the fact that static loads'are representative of dynamic-loads (for these valves), no quantification of force is needed to determine operability. Previous MCC data is compared to current MCC data. -Mininal performance changes are not considered a
-concern where as large data shifts would be followed with a direct force measurement method.
Currently, only selected butterfly MOVs have baseline operability established by MCC data correlation to force (torque), with inclusion of system inaccuracies and factors for degradation and aging.
NRC Question #3 The Joint Owners Group (JOG) program focuses on the potential age-related increase in the thrust or torque required to operate valves under their design-basis-condition.
In the NRC's safety evaluation dated October 30, 1997, on the JOG program, the NRC staff specified:that licensees are responsible for addressing the thrust or torque delivered by the MOV motor actuator and its potential degradation. Duke should describe the plan at McGuire l
L
e U.S. NRC
. - MNS March 19, 1999 Page 3,
for ensuring adequate ac and dc MOV motor actuator output capability, including consideration of recent guidance in Limitorque Technical Update 98-01 and.its supplement 1.
Responses McGuire has implemented the guidance in Limitorque Update 98-01 and its Supplement 1.. McGuire plans to address potential 3
actuator degradation by the following methods.
As-found and as-left data regarding actuator. performance is evaluated for trends and program adjustments initiated as appropriate.
Prior to 4
installation, all actuators are torque tested for suitability to the intended application.
All actuators have comprehensive i
preventative maintenance performed.
MOV (valve as well as actuator) corrective maintenance is reviewed yearly for trends in 3
decreasing performance.
Periodic dynamic tests will be performed on selected MOVs.
McGuire is participating in the JOG effort where four (4) MOVs will be dynamically tested over 5 years.
Also, Duke Power's participation with the Westinghouse owner's Group, Motor Operated Valve Users Group, EPRI, and the JOG will provide feedback into the MNS MOV program via Duke's Operating
(
Experience Program.
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