ML121220300
| ML121220300 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 04/27/2012 |
| From: | Swift P Constellation Energy Nuclear Group, Nine Mile Point |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RR-PTRR-02 | |
| Download: ML121220300 (6) | |
Text
P.O. Box 63 C EN GS. Lycoming, New York 13093 a joint venture of Constellation *'eDF wEnemrgy'Z NINE MILE POINT NUCLEAR STATION April 27, 2012 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION: Document Control Desk
SUBJECT:
Nine Mile Point Nuclear Station Unit No. 1; Docket No. 50-220 American Society of Mechanical Engineers (ASME) Code,Section XI, Inservice Inspection Program - 10 CFR 50.55a Request Number RR-PTRR-02 Pursuant to 10 CFR 50.55a(a)(3)(i), Nine Mile Point Nuclear Station, LLC (NMPNS) hereby requests NRC approval of the enclosed request for the remainder of the fourth ten-year Inservice Inspection (ISI)
Interval for Nine Mile Point Unit 1 (NMP 1). NMPl is currently in the fourth ten-year ISI interval, which began on August 23, 2009 and is scheduled to end August 22, 2019. This request is for the application of a proposed alternative to use the provisions of IWA-4132 of the 2004 edition of the ASME Section XI code for the replacement of the reactor recirculation pump seal flange assemblies rotated from stock, Attachment (1). The proposed alternative in this request has been incorporated into IWA-4132 of the 2010 edition of the ASME Section XI code.
A similar request for Duane Arnold Energy Center was approved by the NRC by letter, dated October 3, 2008, from L. James (NRC) to R. Anderson (DAEC), Duane Arnold Energy Center - Authorization of Relief Request NDE-R009 Regarding Stock Rotation of the Recirculation Pump Seal Assemblies (TAC NO. MD8192).
This request is being submitted on an emergent basis due to recent degrading performance of a NMP1 reactor recirculation pump seal assembly indicating the need for replacement prior to the next scheduled refueling outage. NMPNS requests approval of this request by June 1, 2012 to support this maintenance activity associated with rotating the recirculation pump seal flange assembly in a non-refueling outage.
Approval of this request will preclude the need to conduct a full Reactor Pressure Vessel Leak Test and the associated risk of vessel over-pressurization while in a water solid condition, as well as the challenges to reactor pressure vessel level control during transition into and out of test conditions.
This letter contains no new regulatory commitments.
Document Control Desk April 27, 2012 Page 2 Should you have any questions regarding the information in this submittal, please contact John J. Dosa, Director Licensing, at (315) 349-5219.
Very truly yours, Paul M. S Manager, Engineering Services PMS/KJK Attachments: 1. Nine Mile Point Nuclear Station Unit 1 Fourth Inservice Inspection Interval, 10 CFR 50.55a Request Number RR-PTRR-02, Rev. 0, Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(i) cc: Regional Administrator, Region I, NRC Project Manager, NRC Resident Inspector, NRC
ATTACHMENT 1 NINE MILE POINT NUCLEAR STATION UNIT 1 FOURTH INSERVICE INSPECTION INTERVAL 10 CFR 50.55a REQUEST NUMBER RR-PTRR-02, REV. 0 PROPOSED ALTERNATIVE IN ACCORDANCE WITH 10 CFR 50.55a(a)(3)(i)
Nine Mile Point Nuclear Station, LLC April 27, 2012
Nine Mile Point Nuclear Station, Unit 1 Fourth Inservice Inspection Interval 10 CFR 50.55a Request Number RR-PTRR-02 Rev. 0 Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(i)
-- Alternative Provides Acceptable Level of Quality and Safety --
ASME Code Components Affected System: Reactor Recirculation System Class: Quality Group A (ASME Code Class 1)
Component
Description:
Reactor Recirculation Pump Mechanical Joint Components Affected: Reactor Recirculation Pumps32-187, 32-188,32-189, 32-190,32-191
2. Applicable Code Edition and Addenda
ASME Section XI 2004 Edition (No Addenda)
- 3. Applicable Code Requirements For ASME Section XI Repair/Replacement activities, 10 CFR 50.55a(b)(2)(xxvi), Pressure Testing Class 1, 2, and 3 Mechanical Joints, requires the use of the provisions in IWA-4540(c) of the 1998 Edition of Section Xl for pressure testing Class 1, 2, and 3 mechanical joints following Repair/Replacement activities when using the 2001 Edition through the latest edition and addenda incorporated by reference in paragraph 10 CFR 50.55a (b)(2). The 1998 Edition of ASME Section XI IWA-4540(c) states "Mechanical joints made in installation of pressure retaining items shall be pressure tested in accordance with IWA-5211 (a)." The 1998 Edition of ASME Section XI IWA-521 1(a) states "a system leakage test conducted during operation at nominal operating pressure, or when pressurized to nominal operating pressure and temperature."
IWA-4000 provides alternative requirements for specific items that are rotated from stock. For Nine Mile Point Nuclear Station, Unit 1 (NMP1) these provisions are contained within sub-article IWA-4132 of the applicable Code.
- 4. Reason for Request The reactor recirculation pump seal cartridge assembly consists of a seal cartridge, seal flange and seal flange cap screws. The entire assembly (seal flange and seal cartridge) is bolted to the pump casing.
During maintenance on the seal cartridge, the complete assembly (seal cartridge and flange) is rotated as a single unit (i.e., the existing unit is removed and a refurbished seal flange assembly is installed). The seal flange and cap screws are identified as pressure retaining parts (mechanical joint).
The normal activity of testing components under the criteria of IWA-4132 involves removal from installed locations by mechanical means (i.e., disassembly and reassembly of mechanical joints). Subarticle IWA-4132 recognizes that, rather than re-install the same component tested, a similar component from stock can be rotated into service in its place. Seals are periodically changed out with replacement seal cartridges rotated from stock following rebuild. Rebuild includes replacement of the non-pressure retaining seal components.
The ASME Section XI Code recognizes that for certain components rotated from stock, it is acceptable to perform alternatives to the IWA-4000 Repair & Replacement requirements provided the components satisfy specific limitations (such as having previously been in service with no signs of degradation prior to removal from service). The alternatives allowed in the 2004 Edition of ASME Section Xl sub-article IWA-4132 are limited to relief valves and snubbers rotated from stock. The 2010 Edition of the ASME Section XI Code has been updated to recognize the acceptability of applying the IWA-4132 alternatives to other Page 1 of 3
Nine Mile Point Nuclear Station, Unit 1 Fourth Inservice Inspection Interval 10 CFR 50.55a Request Number RR-PTRR-02 Rev. 0 items including pressure-retaining items of pump seal packages (such as the NMP1 recirculation pump seal assemblies). The 2010 edition of the ASME Section XI code has not yet been endorsed by the NRC in 10 CFR 50.55a.
- 5. Proposed Alternative and Basis for Use Pursuant to 10 CFR 50.55a(a)(3)(i), Nine Mile Point Nuclear Station, LLC (NMPNS) requests authorization to apply the provisions of IWA-4132 of the 2004 Edition of ASME Section XI Code for the replacement of Reactor Recirculation Pump Seal assemblies rotated from stock during a non-refueling outage condition or when the refueling outage Class 1 system leakage test is not required to be performed (i.e., in the case of seal replacement during a refueling outage, but following system leakage test completion).
IWA-4132 allows for implementation of the following in lieu of all other requirements of IWA-4000, for items rotated from stock, provided the rotation is only for testing or preventive maintenance of the removed items:
(a) Items being removed and installed shall be of the same design and construction.
(b) Items being removed shall have no evidence of failure at the time of removal.
(c) Items being rotated shall be removed and installed only by mechanical means.
(d) Items being installed shall previously have been in service.
(e) Preservice inspections shall be performed as required by IWA-4500.
(0 The Owner shall track the items to ensure traceability of inservice inspection and testing records.
(g) Use of an Inspector and an NIS-2 form are not required.
In order to satisfy the requirements of IWA-4132 for maintenance change out of a reactor recirculation pump seal assembly for the performance of testing, preventive maintenance or due to degraded performance of non pressure retaining seal cartridges; NMPNS proposes to do the following:
- 1. The seal flange assembly being installed will be a like-for-like replacement (same design) and built to the same construction code.
- 2. The seal flange (pressure retaining portion of seal assembly) shall have no evidence of failure at the time of removal.
- 3. The seal flange assembly will be removed and installed only by mechanical means.
- 4. The seal flange assembly shall previously have been in service.
- 5. Required pre-service inspections will be performed as required by IWA-4500. In addition, NMPNS will perform the following:
- a. The reactor recirculation pump seal cartridge assembly will be bench tested prior to installation on the pump. The seal flange and the seal flange cap screws will be exposed to 1050 psig, a pressure corresponding to slightly greater than normal operating pressure, during the bench test. The seal cartridge, including the mechanical joint (seal flange to test assembly), is examined (VT-2) for leakage during this test.
- b. Following seal cartridge installation on the pump, during the normal drywell closeout inspection, an additional visual inspection of the mechanical joint shall be performed at approximately 900 psig system pressure. It is generally accepted that a seal that is going Page 2 of 3
Nine Mile Point Nuclear Station, Unit 1 Fourth Inservice Inspection Interval 10 CFR 50.55a Request Number RR-PTRR-02 Rev. 0 to leak at normal operating pressure will also leak at this reduced pressure allowing for detection.
- 6. As the seal flange assembly is installed, the work will be controlled under the station's work order process. Unique identification for each item replaced will be tracked and controlled.
- 7. NMPNS may choose to control (plan, schedule, and document) this work under the site Repair &
Replacement program. However, the Code obligations will be limited to those contained in this proposed alternative (provisions of IWA-4132 of the Code of Record).
Because the basic activity of reactor recirculation pump seal assembly rotation from stock by disassembly and re-assembly of the mechanical joint is the same between the requested activity of recirculation pump seal assemblies and that currently permitted for relief valves and snubbers, the proposed alternative would provide an acceptable level of quality and safety, as required by 10 CFR 50.55a(a)(3)(i).
- 6. Duration of Proposed Alternative In accordance with 10 CFR 50.55a(a)(3)(i), NMPNS proposes to implement the proposed alternative through the remainder of the current Fourth ten-year Inservice Inspection interval which began August 23, 2009 and is scheduled to end August 22, 2019.
- 7. Precedents A similar alternative was authorized by NRC Safety Evaluation of "Duane Arnold Energy Center -
Authorization of Relief Request NDE-R009 Regarding Stock Rotation of the Recirculation Pump Seal Assemblies", Dated October 3, 2008, (TAC No. MD8192).
- 8. References None
- 9. Attachments None Page 3 of 3