ML022670132
| ML022670132 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 09/20/2002 |
| From: | Barnes G Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML022670132 (8) | |
Text
Exelkns.
Exelon Generation Company, LLC wwwexeloncorpcom Nuclear LaSalle County Station 2601 North 21'Road Marseilles, IL 61341-9757 10 CFR 50.55a(a)(3)
September 20, 2002 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-1 1 and NPF-1 8 NRC Docket Nos. 50-373 and 50-374
Subject:
Response to Request for Additional Information Relief Request RV-14
References:
(1)
Letter from G. P. Barnes (Exelon Generation Company, LLC) to the NRC, "Request to Implement the 1995 Edition and 1996 Addenda of the American Society of Mechanical Engineers Code for Operation and Maintenance of Nuclear Power Plants," dated June 14, 2002 (2)
Letter from W. A. Macon, Jr. (NRC) to J. L. Skolds (Exelon Generation Company, LLC), "LaSalle County Station, Units 1 and 2 - Request for Additional Information (TAG Nos. MB5529 and MB5530)," dated August 15, 2002 Exelon Generation Company (EGC), LLC, in Reference 1 proposed Relief Request RV-14 to implement the American Society of Mechanical Engineers (ASME) /American National Standards Institute (ANSI), Operation and Maintenance of Nuclear Power Plants, OMa-1996, Subsection Inservice Testing Code (ISTG), as it applies to motor operated valves, including the Code Case OMN-1, "Alternative Rules for Preservice and Inservice Testing of Certain Electric-Operated Valve Assemblies in Light-Water Reactor Power Plants." The NRC in Reference 2, requested additional information by September 20, 2002, to complete their review of the EGG submittal.
Attached are the LaSalle County Station responses to the requested additional information.
SAoL[
September 20, 2002 U.S. Nuclear Regulatory Commission Page 2 Should you have any questions concerning this letter, please contact Mr. Glen T. Kaegi, Regulatory Assurance Manager, at (815) 415-2800.
Respectfully, George P. Barnes Site Vice President LaSalle County Station
Attachment:
Request for Additional Information on Relief Request RV-14 for LaSalle County Station, Units 1 and 2 cc:
Regional Administrator - NRC Region III NRC Project Manager, NRR - LaSalle County Station NRC Senior Resident Inspector - LaSalle County Station
REQUEST FOR ADDITIONAL INFORMATION ON RELIEF REQUEST RV-14 FOR LASALLE COUNTY STATION, UNITS 1 AND 2 Under "Proposed Alternative Provisions" in Relief Request RV-14, the licensee proposes to use the motor-operated valve (MOV) testing provisions in ASME OMa-1 996, Subsection ISTC, at LaSalle County Station, Units 1 and 2, in lieu of its present inservice testing (IST) requirements in its Code of record, OMa-1 988, Part 10. Discuss planned changes to inservice testing intended at LaSalle County Station through this relief request, other than the application of the provisions of ASME Code Case OMN-1, "Alternative Rules for Preservice and Inservice Testing of Certain Electric Motor-Operated Valve Assemblies in Light Water Reactor Power Plants."
LaSalle County Station Response:
LaSalle County Station does not intend any changes to inservice testing as a result of this relief request, other than the application of the provisions of OMN-1.
There are very few technical differences between OMa-1 988 and OMa-1 996 with regard to inservice testing of Motor Operated Valves.
Only programmatic references (e.g. Program Plan, Bases Document) to the applicable Code of record will be updated. The update to the 1996 addenda as the ASME Code of record for MOVs is consistent with a previous LaSalle County Station update to the 1996 addenda for all check valves. As discussed in the response to Question 4 below, only those MOVs that are not subject to diagnostic testing will be subjected to ISTC requirements.
- 2.
In paragraph B under "Proposed Alternative Provisions" in Relief Request RV-14, the licensee requests relief from Sections 3.3(b), 3.4, and 6.3 of ASME Code Case OMN-1. In paragraph B, the licensee describes its commitment to conduct sample as-found testing to validate its assumptions for MOV degradation (rather than performing as-found testing in all situations). Discuss the planned activities as alternatives to Sections 3.4 and 6.3 of the code case.
LaSalle County Station Response:
As-found testing will not normally be performed on valves scheduled for corrective maintenance or modification. The purpose of the request for relief from the requirements of Section 3.4 was to address any as-found testing requirements that may be implied in this section.
Deviations between the previous and new inservice test values will be identified and analyzed after MOV maintenance repair or replacement; however, this analysis will be between post-maintenance testing and previously performed pre-service or post-maintenance testing.
LaSalle County Station will not in all cases analyze performance
directly prior to maintenance and directly after maintenance since as found testing will not always be performed.
Section 6.3 states, in part, "Evaluations shall determine the amount of degradation in functional margin that occurred over time". The diagnostic practice at LaSalle County Station does not require as found testing in all cases. When maintenance is scheduled, required diagnostic testing is performed as a post-maintenance activity, but not pre-maintenance in all cases. To "determine the amount of degradation in functional margin that occurred over time", as-found testing would have to be performed and a comparison of previous as left data be performed. Section 6.3 is a discussion of the evaluation of test data, and it is stated that the Owner shall determine the method for evaluating test data. The section further discusses the use of the evaluations in establishing appropriate time intervals for future tests.
LaSalle County Station has determined, and proceduralized, methods for evaluation of test data. In general, the method involves analyzing data from a sample of as-found tests to determine rates of degradation, and applying these degradation factors to remaining valves in order to determine margin, which is used to determine the length to the next test interval. Only in those instances where sample as-found testing is performed will evaluations consider functional margin degradation over time. When as-found testing is not performed, evaluation of changes over time is usually inappropriate, since the maintenance activity results in margin rebaseline. In cases where maintenance is performed without as-found testing, ongoing valve life is determined by applying degradation factors and calculating an appropriate frequency of operation until future maintenance and testing is required. In this later case, the calculated operating frequency may be adjusted as necessary based on other sample as-found testing and evaluation of functional margin.
- 3.
In paragraph C.3 under "Proposed Alternative Provisions" in Relief Request RV-14, the licensee states that LaSalle County Station does not consider stem lubrication to invalidate the as-found condition of an MOV. In Section 3.3(b), ASME Code Case OMN-1 notes that MOV stem lubrication might invalidate the as-found condition for inservice testing. In paragraph B under "Proposed Alternative Provisions," the licensee commits to perform sample MOV as-found testing to validate its degradation assumptions. Discuss plans to continue the commitment to conduct sample MOV as-found testing to support the ongoing assumption that stem lubrication does not adversely impact the as-found condition of the MOV.
LaSalle County Station Response:
LaSalle County Station will continue to perform a sampling of as-found testing per our commitment to Generic Letter (GL) 96-05" Periodic Verification of Design-Basis Capability of Safety-Related Motor Operated Valves". Per the commitment, LaSalle County Station Response to GL 96-05, dated 3/15/97, "Maintenance activities, including stem lubrication, may occur between periodic verification tests; therefore, most of the valves will not be tested in the as-found
condition. ComEd will analyze the data from as-found tests to determine rates of degradation and apply these degradation rates to the remaining MOVs in order to determine the length of the next test interval." The adequacy of MOV stem lubrication degradation will be observed through MOV performance monitoring and trending. If necessary, the stem lubrication and tests intervals will be adjusted as required.
- 4.
In paragraph E under "Proposed Alternative Provisions" in Relief Request RV-'14, the licensee states that it will continue to perform exercise tests and position indication tests in accordance with ISTC requirements for those MOVs identified as having IST requirements, but are not subject to diagnostic testing. The diagnostic test provisions of ASME Code Case OMN-1 are applicable to all MOVs within the scope of the code case. Supplement I to Generic Letter 89-10, "Safety-Related Motor-Operated Valve Testing and Surveillance," indicated that successful industry experience with some valve types (such ball and plug valves) could be used to justify the omission of MOV dynamic tests in validating their design-basis calculations. Discuss plans to satisfy the provisions for diagnostic testing of MOVs within the scope of ASME Code Case OMN-1.
LaSalle County Station Response:
Additional information is provided on the five categories of MOVs in the IST program that are not currently diagnostically tested. Four of these categories do not contain any Generic Letter 96-05 Program valves. The fifth category does include Generic Letter 96-05 Program valves. However, as part of LaSalle County Station's Generic Letter 89-10 closure, the quarter-turn valves were accepted without diagnostic testing based on analytical methods. There are no plans to diagnostically test these five groups of valves.
Category 1 The following valves are classified as "passive", and do not require stroke time testing per OM-10 or ISTC. Currently only Position Indication testing is required.
1(2)B21-FO01 Reactor Head Vent Upstream Valve 1(2)B21-F002 Reactor Head Vent Downstream Valve 1(2)E12-F073A/B Residual Heat Removal Heat Exchanger Shell Side Downstream Vent Valve 1(2)E12-F074A/B Residual Heat Removal Heat Exchanger Shell Side Upstream Vent Valve No diagnostic testing is required or planned for this category of valves.
Position Indication testing will continue as part of ISTC.
Category 2 The following motor operated valves are manually repositioned per the IST program:
ODG009 1(2)DG01 1 1(2)E22-F319 1 (2)E12-F336A/B Diesel Generator Cooling Water Backwash Strainer Valve Diesel Generator Cooling Water Backwash Strainer Valve High Pressure Core Spray Diesel Generator Cooling Water Backwash Strainer Valve Residual Heat Removal Service Water Backwash Strainer Valve These valves have a safety function to be manually operated upon a loss of power (not fed by a safety related bus). These valves will continue to be cycled manually for IST, and since the motor operators provide no electrical safety function, it is reasonable to conclude that diagnostic testing would not pertain. Exelon Procedure direction specifies which valves are included in the Generic Letter 89-10/96-05 program. These valve actuators are classified as non-safety related and therefore are not included in the GL 89-10/96-05 program.
Manual verification of valve operation is performed by existing surveillances and no additional diagnostic testing is required or planned for this category.
Category 3 This group of valves does not have any safety function. However, in an NRC letter dated April 5, 1996, refuel-frequency stroke timing was committed to as part of alternate leakage treatment (ALT) path associated with the removal of the main steam isolation valve (MSIV) leakage control system (LCS). These valves will continue to be stroke time tested and position indication tested per ISTC as augmented scope instead of diagnostic tested per OMN-1.
l(2)B21-F020 l(2)B21-F021 1(2)B21-F070 1 (2)B21-F071 Main Steam Equalizing Header Upstream Stop Valve Inboard Main Steam Line Header Orifice Bypass Valve Main Steamline Drain Upstream Orifice Bypass Valve Main Steamline Drain Upstream Orifice Inlet Valve
1(2)B21-F072 1(2)B21-F073 Main Steamline Drain Downstream Orifice Bypass Valve Main Steamline Drain Downstream Orifice Inlet Valve 1(2)B21-F418A/B Main Steam Auxiliary Supply Steam Stop LaSalle County Station will continue to stroke time test the above valves per ISTC. No additional diagnostic testing is planned.
Category 4 This valve category has a passive closed safety function. These valves are administratively controlled closed with power removed in operating modes 1, 2, and 3. These valves are leak rate tested for IST.
1(2)E12-F011 A/B Residual Heat Removal Heat Exchanger Steam Condensing Suppression Pool Return Isolation These valves will be seat leakage tested per the requirements of ISTC. No diagnostic testing is planned.
Category 5 This category includes quarter-turn motor operated valves that are included in both the IST and GL 96-05 MOV program. The Supplement to GL 89-10 and LaSalle County Station GL 89-10 closure inspection provide the provision for compliance without diagnostic testing for LaSalle County Station butterfly valves as identified below.
1(2)VG001 1(2)VG003 1(2)VQ037 1(2)VQ038 1 (2)VP 1I3A/B I(2)VP 114A/B Standby Gas Treatment Equipment Train Inlet Damper Standby Gas Treatment Equipment Train Outlet Damper Primary Contain Purge Air Filter Unit Upstream Isolation Primary Contain Purge Air Filter Unit Downstream Isolation DW Cooler Inlet Inboard Isolation Valve DW Cooler Outlet Inboard Isolation Valve As part of LaSalle County Station's Generic Letter 89-10 closure, the quarter-turn valves were accepted without diagnostic testing based on
analytical methods. These valves operate under low differential pressures and have significant margin.
These valves will be stroke time tested and position indication tested per ISTC. These valves will also undergo actuator inspections and motor current signature traces from the motor control center to ensure proper operation. No additional diagnostic testing is planned.
Future modifications or Program changes may result in additional valves that are not subject to diagnostic testing but would require some form of IST. In those cases, in lieu of OMN-1 requirements, IST requirements of ISTC will be established on the basis that it provides an acceptable level of quality and safety.