ML20249A791
| ML20249A791 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 06/15/1998 |
| From: | Ewing E ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-MA0264, TAC-MA264, W3F1-98-0068, W3F1-98-68, NUDOCS 9806180243 | |
| Download: ML20249A791 (17) | |
Text
TT, En
/ perations, Inc.
Kinona. LA 70066 Tel 504 739 6242 Early C. Ewing, til a afety & Rugulatory Affan W3F1-98-0068 A4.05 PR June 15,1998 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555
Subject:
Waterford 3 SES Docket No. 50-382 License No. NPF-38 Request for Additional Information Regarding the Waterford 3 Second 10-Year Interval inservice Testing Program and Associated Requests for Relief (TAC Number MA0264)
Gentlemen:
Entergy Operations, Inc. submitted the Second 10-year Interval inservice Testing (IST) Program and Associated Requests for Relief for Waterford 3 Steam Electric Station by Letter W3F1-97-0265, dated December 1,1997. An NRC Request for Additional Information (RAI) regarding the submittal was subsequently received via j
an NRC letter dated April 15,1998. In accordance with the RAI (except for itern 3),
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the requested information to assist in the review of the Waterford 3 SES IST Program and the Associated Requests for Relief is provided in the attachments.
With respect to RAI Item 3, supplemental information will be provided in a separate letter within 30 days. Additional time is required to determine any appropriate and
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practical alternatives for inservice testing of solenoid valves at Waterford 3. The
/J need for this additional time and its impact was discussed with the Waterford 3 NRC Project Manager on June 11,1998.
9006190243 990615 Fin"
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Request for Additional Information Regarding the Waterford 3 Second 10-Year Interval inservice Testing Program and Associated Requests for Relief (TAC Number MA0264)
W3F1-98-0068 Page 2 June 15,1998 The following attachments are provided:
RAI Responses Waterford 3 SES IST Program Revised Relief Request PRR-01 Waterford 3 SES IST Program Revised Relief Request PRR-02 Waterford 3 SES Pump and Valve Inservice Test Plan, Page 233 Waterford 3 SES Pump and Valve Inservice Test Plan, Page 152 If you have any questions concerning this submittal, please contact me at (504) 739-6242 or Walter Lowe at (504) 739-6212.
Very truly y,ours, h
LP /
E.C. Ewing Director Nuclear Safety & Regulatory Affairs ECE/ PRS /rtk Attachments (w/ Attachments) cc:
E.W. Merschoff, NRC Region IV, C.P. Patel, NRC-NRR, NRC Resident inspector (w/o Attachments) cc:
J. Smith, N.S. Reynolds i
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ATTACHMENT 1 TO W3F1-98-0068 RAI RESPONSES
w Response to the Request for Additional Information Waterford 3 Second 10-Year Interval inservice Testing Program
- 1. Scope / Status of Review The staff is reviewing the second 10-year interval inservice testing program and associated requests for relief for Waterford Steam Electric Station, Unit 3 (Waterford 3), submitted by letter dated December 1,1997.
- 2. Additionalinformation Recluired Based on the above review, the staff requested additionalinformation. The questions and responses are as follows:
ltem 1 RELIEF REQUESTPRR-01:
Since the analog charging pump discharge flow instmment in question meets the +/-
2 percent accuracy requirements but exceeds the maxirnum allowed full-scale range of three times reference value by approximately 13%, address the applicability of NRC guidelines in NUREG-1482, section 5.5.1, " Range and Accuracy of Analog Instmments," and provide justification if PRR-01 deviates from these guidelines. A range of greater than three times the reference value can be acceptable if the instrument is proportionately more accurate than required. As indicated in section
- 5.5.1 of NUREG-1482, an altemative can be approvedif the combination of range and accuracy yields a reading that meets t 6 percent of reference value. If the guidelines in section 5.5.1 are not applicable because the combination of range and accuracy yields a reading that exceeds t 6 percent of reference value, an allemative should be proposed to compensa!o for the additional uncertainty. One possible allemative is to add the additional uncertainty onto measurements above the reference value and subtract the additional uncertainty from measurements below the reference value when comparing to the allowable ranges of flow.
Response to item 1 The charging pump discharge flow indicator has a full scale range of 150 gpm. This is 3.4 times the individual pump discharge flow rate of 44 gpm. The accuracy of the instrument used for measuring charging pump discharge flow is 10.7%. This accuracy is more conservative than the 12% required by OM-6. The combination of range and accuracy for the charging pump discharge flow instrument is 2.39% which is moia conservative than the combined range and accuracy of instruments that t
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meet the minimum code requirements (i.e. up to ! 6%). Relief is requested in accordance with Section 5.5.1 (Range and accuracy of Analog Instruments) of NUREG-1482. Relief request PRR-01 basis has been revised to include this ducussion of combined range and accuracy. See Attachment 2.
j Item 2 j
RELIEF REQUESTPRR-02:
The Code mquires the frequency response range of vibration measurement instruments to extend as low as one-third minimum pump shaft rotational speed. For the positive displacement charging pumps in question, one-third of the minimum pump rotational speed is approximately 65 rpm, which corresponds to 1.1 hertz.
However, the frequency response range ofinstrumentation used for these pumps extends only as low as 5 hertz, using static testing, and as low as 10 hertz, using dynamic testing. In order to support the statement in PRR-02 that the instrumentation willprovide adequate information to evaluate pump condition, please provide documentation, including manufacturers recommendation, that demonstrates that these pumps are not susceptible to rolling element bearings degradation mechanisms that result in increased vibration levels seen at frequencies below the pump rotational speed frequency, such as impacts from rolling element bearing cage defects.
Also, a few standards laboratories may provide a calibration of vibration monitoring instruments that extends to as low as 3 hertz. Address the practicability of calibrating these instruments down to about 3 hertz at one of these standards laboratories.
OM-6 allows either displacement or velocity in measuring vibration. NUREG/CP-0111, " Proceedings of!he Symposium on Inservice Testing of Pumps and Valves,"
contains a paperpresented by J. Howard MaxweII, " Measurements of Vibrational Parameters for Pump Testing," which states that displacement is the better parameterin determining vibration severity of machines which operate below 600 rpm. Please address the applicability of measuring displacement for the charging pumps in this relief request.
Response to item 2 The charging pumps at Waterford 3 were manufactured by Gaulin Corporation and are Model Number NP18-3TPS. The charging pumps do not contain any rolling element bearings and are not susceptible to rolling element bearings degradation mechanisms that would result in increased vibration levels at frequencies below the pump rotational speed frequency. This fact was confirmed in a conversation with Regis Bopp and Blaine Potter of Gaulin Corporation.
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y The adequacy of Waterford 3's current vibration testing equipment calibration (i.e. 5 hertz static and 10 hertz dynamic testing) was also discussed with the manufacturer.
The manufacturer indicated that there are no degradation mechanisms for the charging pumps which could not be detected by Waterford 3's current vibration monitoring equipment as presently calibrated (i.e. 5 hertz static and 10 hertz dynamic testing).
Displacement is the vibration parameter that is monitored during charging pump testing. This is appropriate since the charging pumps have a rotational speed of 195 rpm. This statement about displacement as the parameter monitored during charging pump tests has been added to relief request PRR-02. See Attachment 3.
Item 3 RELIEF REQUESTS VRR-01, VRR-02, VRR-03, AND VRR-05:
It is not evident based on the information presented in VRR-01, VRR-02, VRR-03, and VRR-05 that stroke timing is impractical or would result in hardship without a compensating increase in the level of quality and safety. If the stroke timing requirements cannot be met, please provide a basis in sufficient detail tojustify a proposed attemative, following the applicable guidelines in NUREG-1482, section 4.2.3. " Measurement of Valve Stroke Time,"section 4.2.8, " Solenoid-Operated Valve,"and appendix A, pp A-24 to A-34. The basis should also address the following anomalies:
3.1 The statement in the relief requests that "there is no criticallimit on the stroke time " appears to be inconsistent with the NRC guidelines in GL 89-04, position 5,
" Limiting Values of Full-Stroke Times for Power-Operated Valves," and NUREG-1482, appendix A,
- Position, Questions, Responses, and Current Considerations Regarding GL 89-04,"pp A-24 to A-34.
1 3.2 Some valves in question have a safety function to close; therefore, the basis i
should be expanded, as necessary, to include discussions on stroke timing in the closed direction.
3.3 VC-10, a clarification cf valve testing, referenced on page 111 of the IST program, appears to be missing lmm the program.
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3.4 The basis does not address non-intrusive techniques or assigning a reasonable, objective acceptance criterion to an observable parameter, such as a flow rate or AP, to measure stroke times and assess degradation.
Response to item 3 A complete response to item 3 will be submitted by separate letter within 30 days.
The additional time is needed in order to determine an appropriate alternative for inservice testing of the solenoid valves that is practical for Waterford 3.
The valve testing clarification mentioned in item 3.3 (VC-10) is located on Page 233 of the Pump and Valve Inservice Test Plan submitted on December 1,1997. A copy of Page 233 of the Pump and Valve Inservice Test Plan is enclosed. See.
Item 4 RELIEF REQUESTS VRR-04 AND VRR-06:
With regard to VRR-04 and VRR-06 on the individual closure verification of category A check valves, please address the applicable guidelines in NUREG-1462, section 4.1.1, " Closure Verification for Series Check Valves without Intermediate Test Connections," and providejustification if the requests deviate from these guidelines.
Response to item 4 The check valves listed in VRR-04 for which relief is requested (SI-107 A and B) are not series check valves. They are each located in their respective safety injection suction header on the outlet of the Refueling Water Storage Pool (RWSP).
Therefore the provisions stated in NUREG-1482, Section 4.1.1 do not apply.
The check valves described in relief request VRR-06 are tested in accordance with the guidelines described in NUREG-1482, Section 4.1.1. The LPSI Pump Suction Check Valves listed in VRR-06 are on the LPSI A and B pump suctions from the j
RWSP. Check valves SI-1071 A(B) and SI-108A(B) have a safety function to open to I
allow flow to the LPSI pumps. Only SI-108 A and B are credited with a closed safety function to prevent diversion of shutdown coolina flow. Because there are no test connections between check valve pairs SI-1071 A/SI-108A and SI-1071B/SI-1088, the SI-108A(B) check valves cannot be individually tested for closure. Due to the inability to individually test the SI-108A(B) check valves for closure, they will be tested for closure as a pair with their associated SI-1071 A(B) check valve. In 4
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accordance with the guidelines provided in NUREG-1482, Section 4.1.1, the SI-1071 A(B) check valves have also been assigned an active closed safety function in the IST plan. If a valve pair fails the backflow testing, then both valves shall be deciamd Moperable and appropriate corrective actions taken.
Item 5 The following relief valves appear to be Code Class 2 and to have a safety function to protect safety systems: SI-2034 A/B, A, and B (Drawing G-167, sheet 1 of 4, coordinates F-5, J-5, and D-5); and CVC-115 (drawing G-168, sheet 1 of 3, coordinate E-7). Providejustification for not including these valves in the IST program, in accordance with Section 1.1 of OM-10.
Response to item 5 Relief valves SI-2034 A/B, A, and B (HPSI pump suction relief valves) are included in the IST plan and are located on page 152 of the IST plan. A copy of Page 152 of the Pump and Valve Inservice Test Plan is enclosed. See Attachment 5.
Relief Valve CVC-115 (Letdown Heat Exchanger inlet Relief to Hold Up Tanks) opens to protect intermediate pressure letdown piping and the letdown heat exchanger from overpressure. However, the letdown system does not perform a required function during any postulated accident scenarios at Waterford and is not required to shut down the reactor to the cold shutdown condition or maintain the cold shutdown condition. In addition, during major accidents the letdown system is isolated from the Reactor Coolant System. CVC-115 therefore does not have a safety function and is not included in the IST program.
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i ATTACHMENT 2 TO W3F1-98-0068 WATERFORD 3 STEAM ELECTRIC STATION INSERVICE TESTING PROGRAM REVISED RELIEF REQUEST PRR-01
ENTERGY OPERATIONS, INC.
SecondIST
~ ENTERGY WATERFORD 3 Interval PUMP AND VALVE INSERVICE TEST PLAN 7.2 Requests for Relief from OMa-1988 Part 6 Testing Requirements, Page 1 of 5 PRR-01 " Charging Pumps Discharge Flow Indicator" Component (s) Affected CVC-MPMP-0001A, Charging Pump A CVC-MPMP-0001B, Charg'ng Pump B
- CVC-MPMP-0001 A/B, Charging Pump A/B Test Requirement OMa-1988 Part 6 Article 4.6.1.2(a) requires that the full-scale range of each analog instrument shall be not greater than three times the reference value.
Basis of Relief The Charging Pumps' discharge flow indicator does not comply with this requirement.
Each of the three pumps produces a flow of 44 gpm. The flow gauge has a full-scale range of 150 gpm in order to accommodate three-pump flow, such as during safety injection operations. The full-scale range is 3.4 times the reference value. The accuracy of the instrument used for measuring charging pump discharge flow is 10.7%. This accuracy is more conservative than the 12% required by OM-6. The combination of range and accuracy for the charging pump discharge flow instrument is 2.39% which is more conservative than the combined range and accuracy of instruments that meet the minimum code requirements (i.e. up to 16%). Relief is requested in accordance with section 5.5.1 (Range and accuracy of Analog Instruments) of NUREG-1482.
Alternate Testing The existing, installed flow indicator will be used for quarterly pump operability testing. The accuracy of the installed flow indicator is within OMa-1988 Part 6 Table 1 requirements.
Status Relief granted (Number 2.1.2) for first ten-year interval per NRC SER dated February 7, 1989.
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ATTACHMENT 3 TO W3F1-98-0068 WATERFORD 3 STEAM ELECTRIC STATION INSERVICE TESTING PROGRAM REVISED RELIEF REQUEST PRR-02 l
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ENTERGY OPERATIONS, INC.
SecondIST
~- ENTERGY WATERFORD 3 Interval PUMP AND VALVE INSERVICE TEST PLAN 7.2 Requests for Relief from OMa-1988 Part 6 Testing Requirements, Page 2 of 5 PRR-02 " Charging Pumps Vibration Monitoring" Component (s) Affected CVC-MPMP-0001 A, Charging Pump A CVC-MPMP-0001B, Charging Pump B CVC-MPMP-0001A/B, Charging Pump A/B Test Requirement OMa-1988 Part 6 Article 4.6.1.6 requires that the frequency response range of the vibration measuring transducers and their readout system shall be from one-third minimum pump shaft rotational speed to at least 1000 Hz.
Basis of Relief The Charging Pumps are positive displacement pumps that operate at 195 RPM (3.3 hertz). They were manufactured by Gaulin corporation and have a model number of NP18-3TPS. The Charging Pumps have the following types of bearings:
l Eccentric Shaft Bearings; sleeve bearing, babitted Connecting Rod Bearings; insert sleeve bearing, babitted Crosshead Bearing; ball and socket bearing, babitted Possible causes for vibration on the Charging Pumps include unbalance, misalignment, and mechanical looseness. All of these problems are identifiable at frequencies at or above pump shaft rotational speed. While oil whirl is identified at subsynchronous frequencies, this problem only occurs on equipment provided with pressure lubricated bearings and operating at relatively high speed. Because the Charging Pumps operate at low frequencies, oil whirl is not a problem. Therefore, there are no known failure mechanisms that would be revealed by vibration at frequencies below that of pump shaft rotational speed (3.3 hertz). Furthermore, pump degradation will not be masked by instrumentation unable to collect data below this frequency.
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ENTERGY OPERATIONS, INC.
SecondIST WATERFORD 3 Interval
~ ENTERGY PUMP AND VALVE INSERVICE TEST PLAN 7.2 Requests for Relief from OMa-1988 Part 6 Testing Requirements, Page 3 of 5 l
PRR-02 " Charging Pumps Vibration Monitoring"(cont'd)
Based upon OMa-1988 Part 6 Article 4.6.1.6, the frequency response range of the transducer and readout system used to monitor vibration on the Charging Pumps must be from 1.0 hertz to at least 1000 hertz. However, obtaining a certifiable calibration of vibration monitoring instruments for pumps that operate below 600 RPM (10 hertz) is difficult. To confirm proper operation, the calibration should be accomplished by dynamic testing using a shaker table. Whi!a vibration instruments which can read 1 hertz are available, most calibration laboratories cannot perform dynamic calibrations below 10 hertz. Calibration below this frequency requires more sophisticated and expensive equipment which is only found in a few standards laboratories. Furthermore, calibration of instruments at frequencies less than 3 hertz is not traceable to the National Institute of Standards and Technology.
Waterford 3 can obtain a certifiable calibration of vibration instruments down to 10 hertz using dynamic testing. We can also obtain a calibration of vibration instruments at data points down to 5 hertz by utilizing a static test. However, we cannot calibrate the vibration instruments below 10 hertz by dynamic testing or below 5 hertz by static testing.
Alternate Testing While the vibration monitoring system (transducer and readout system) utilized to monitor vibration on the Charging Pumps is capable of a frequency response range of 1 hertz to 1,000 hertz, this instrumentation will only be calibrated over the frequency response range of 10 hertz to 1,000 hertz using dynamic testing. In addition, static testing will be performed between 5 and 10 hertz. Displacement is the vibration parameter that is monitored during charging pump testing.
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Request for relief is submitted as part of the submittal of the IST Plan for the second ten-year interval.
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ATTACHMENT 4 TO W3F1-98-0068 WATERFORD 3 STEAM ELECTRIC STATION PUMP AND VALVE INSERVICE TEST PLAN, PAGE 233 l
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W ENTERGY ENTERGY OPERATIONS, INC.
Second IST WATERFORD 3 Interval PUMP AND VALVE INSERVICE TEST PLAN Revision 0 7.7 Clarifications of Valve Testing Methods, Page 7 of 14 VC-09 "Feedwater To Steam Generator Check" Component (s) Affected FW-181 A FW-181B Clarification OMa-1988 Part 10 Article 4.3.2.4(a) states that the necessary valve obturator movement shall be demonstrated by exercising the valve and observing that either the obturator travels to the seat on cessation or reversal of flow, or opens to the position required to fulfill its function, as specified in para.1.1, or both.
These 20 inch check valves are open during normal plant operation to provide feedwater flow to the Steam Generators. During cold shutdown when feedwater has been secured, these valves will be tested in the as found position and verified that they are closed.
VC-10 " Hydrogen Analyzer Annulus Sample" Ccmponent(s) Affected HRA-0201A HRA-0201B HRA-0202A HRA-0202B Clarification The above valve pairs are controlled by the same actuating relay from the respective Hydrogen Analyzer Control Panel A (B). These valves are not equiped with position indication. During performance of quarterly stroke testing of these valves, travel to the open and closed position is verified by monitoring system flow. However, the indication of low flow can be obtained by the closure of one valve.
Further assurance of valve closure is obtained during the' performance of leak rate testing each refueling in accordance with Technical Specification 6.8.4(a).
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ATTACHMENT 5 TO W3F1-98-0068 WATERFORD 3 STEAM ELECTRIC STATION PUMP AND VALVE INSERVICE TEST PLAN, PAGE 152 I
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