ML20139A216
| ML20139A216 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 05/18/2020 |
| From: | Dunn R South Texas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NOC-AE-20003733, STI: 35015341 | |
| Download: ML20139A216 (4) | |
Text
May 18, 2020 NOC-AE-20003733 10 CFR 50.55a(z)
STI: 35015341 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 South Texas Project Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 Request for Additional Information for Proposed Alternatives to ASME OM Code 2012 Edition for the Fourth Inservice Test Interval (Relief Request PRR-01)
References:
- 1. Letter; from R. Dunn to U.S. NRC Document Control Desk; South Texas Project Units 1 & 2 Proposed Alternatives to ASME OM Code 2012 Edition for the Fourth Inservice Test Interval (Relief Request PRR-01); January 22, 2020; (NOC-AE-20003700) (ML20022A318).
- 2. E-mail; from D. Galvin to A.M. Richards; South Texas Project - Request for Additional Information - Proposed Alternative to ASME OM Code 2012 Edition - Relief Request PRR-01 (EPID: L 2020-LLR-0007); April 17, 2020; (AE-NOC-20003250) (ML20111A005).
By Reference 1, STP Nuclear Operating Company (STPNOC) submitted a proposed alternative to the requirements of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) 2012 Edition for use during the fourth ten-year Inservice Test (IST) interval at South Texas Project. By Reference 2, the NRC staff identified additional information that would be needed to complete its review. The STPNOC RAI response providing this additional information is contained in the Attachment to this letter.
There are no new commitments in this letter.
If there are any questions regarding this request, please contact N. Boehmisch at 361-972-8172 or me at 361-972-7743.
Roland Dunn General Manager, Engineering
Attachment:
Response to Request for Additional Information cc:
Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 1600 East Lamar Boulevard Arlington, TX 76011-4511
Attachment NOC-AE-20003733 Page 1 of 3 Attachment Response to Request for Additional Information Proposed Alternative Request PRR-01 For Fourth 10-year Interval Inservice Testing Program STP Nuclear Operating Company South Texas Project Units 1 and 2 Docket Nos. 50-498 and 50-499 By letter dated January 22, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession Number ML20022A318), STP Nuclear Operating Company (the licensee) requested Nuclear Regulatory Commission (NRC) approval of a proposed alternative to American Society Of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM CODE) 2012 Edition for the Fourth Inservice Test Interval (Relief Request PRR-01) in accordance with 10 CFR 50.55a(z)(1).
Paragraph (f), Preservice and inservice testing requirements, of Section 55a, Codes and standards, in Part 50, Domestic Licensing of Production and Utilization Facilities, to Title 10, Energy, of the Code of Federal Regulations (10 CFR 50.55a(f)), states, in part, that throughout the service life of a boiling or pressurized water-cooled nuclear power facility, pumps and valves that are within the scope of the ASME OM Code must meet the inservice test requirements (except design and access provisions) set forth in the ASME OM Code and addenda that become effective subsequent to editions and addenda specified in 10 CFR 50.55a(f)(2) and (3) and that are incorporated by reference in 10 CFR 50.55a(a)(1)(iv), to the extent practical within the limitations of design, geometry, and materials of construction of the components.
To complete its review, the NRC staff requests the following additional information.
RAI PRR-01-1 Request PRR-01 proposes to use ASME OM Code Case OMN-18, Alternate Testing Requirements for Pumps Tested Quarterly Within +/- 20% of Design Flow. This Code Case states that a Group A test may be performed quarterly within +/- 20 percent of pump design flow rate, with instrumentation meeting the requirements for the comprehensive and preservice tests, and no comprehensive test is required. The 2012 Edition of the ASME OM Code, which is the Code of Record for the fourth 10-year interval inservice testing program, does not use the term design flow. The term used is comprehensive pump test flow rate.
ASME OM Code, Subsection ISTB, paragraph ISTB-3300(e)(1) states that reference values shall be established at the comprehensive pump test flow rate for the comprehensive test.
Paragraph ISTB-3300(e)(2) states that reference values shall be established at the comprehensive pump test flow rate for the Group A and Group B tests, if practicable. If not practicable, the reference point flow rate shall be established at the highest practical flow rate.
Please state for each pump listed in Request PRR-01 if the flow rate for the modified quarterly test will be the comprehensive pump test flow rate or the highest practical flow rate.
Response to RAI PRR-01-1 The 2012 Edition of the ASME OM Code includes the term comprehensive pump test flow rate, a term not defined in the 2004 Edition, which STP implemented for its current third
Attachment NOC-AE-20003733 Page 2 of 3 Inservice Testing interval. The 2012 Edition, ISTB-2000 defines this term as the flow rate established by the Owner that is effective for detecting mechanical and hydraulic degradation during subsequent testing. The best efficiency point, system flow rates, and any other plant-specific flow rates shall be considered.
For the PRR-01 pumps listed in Table 1, the Reference Value to be used is the comprehensive pump test flow rate. Provided is this flow rate for each pump group listed in PRR-01.
Pump Group Comprehensive Pump Flow Rate (GPM)
Auxiliary Feedwater Pumps 545 Component Cooling Water Pumps 12500 Essential Chilled Water Pumps 885 Spent Fuel Pool Cooling Pumps 2550 These flow values encompass the system full flow testing flow band performed by the inservice test, 1) are sufficient to supply system loads in all modes of operations and 2) are sufficiently high to be effective at detecting mechanical and hydraulic degradation. Additional flow considerations apply to these pump groups:
Essential Chilled Water Pumps: Inservice testing employs ISTB-5221(b), which includes the requirement, Alternatively, the flow rate shall be varied until the differential pressure is as close as practical to the reference point with the variance not to exceed +1% or 2% of the reference point and the flow rate determined and compared with the reference flow rate. As a result, the reference flows for each pump will vary slightly from the Comprehensive Pump Flow Rate.
Essential Cooling Water Pump: These Category A pumps are classified as vertical line shaft pumps with testing requirements delineated in Table ISTB-5221-1. The 2004 Code edition specifies a Required Action high differential pressure of >1.03% for the Comprehensive Pump Test. The 2012 Code edition revised the Required Action high differential pressure to >1.06%.
With this change, the acceptance criteria for a Comprehensive Pump Test are the same as those required to implement OMN-18, including differential pressure instrument accuracy of
+/-0.5%. The 2012 Code edition, ISTB-5000(b) allows for a comprehensive or preservice test to be substituted for a Group A test.
Thus, comprehensive testing requirements will be met during performance of the quarterly inservice test eliminating the necessity to include Essential Cooling Water Pumps in the Relief Request PRR-01. Accordingly, STP withdraws its request to use the OM Code Case OMN-18 alternative testing requirements for the Essential Cooling Water Pumps.
Spent Fuel Pool Cooling Pump: The reference flows for the 1A and 2A pumps vary slightly from the Comprehensive Pump Flow Rate, based on measured flow obtained during the Reference Values test. These variances do not to exceed +2% or -1% of the reference point as specified in ISTB-5121(b).
Attachment NOC-AE-20003733 Page 3 of 3 Table 1: ASME Code Components Affected Pump Identification, TPNS Pump Description 3S141(2)MPA01 Auxiliary Feedwater Pump (Class 3) 3S141(2)MPA02 Auxiliary Feedwater Pump (Class 3) 3S141(2)MPA03 Auxiliary Feedwater Pump (Class 3) 3S141(2)MPA04 Auxiliary Feedwater Pump (Class 3) 3R201(2)NPA1(2)01A Component Cooling Water Pump (Class 3) 3R201(2)NPA1(2)01B Component Cooling Water Pump (Class 3) 3R201(2)NPA1(2)01C Component Cooling Water Pump (Class 3) 3V111(2)VPA004 Essential Chilled Water Pump (Class 3) 3V111(2)VPA005 Essential Chilled Water Pump (Class 3) 3V111(2)VPA006 Essential Chilled Water Pump (Class 3) 3R211(2)NPA1(2)01A Spent Fuel Pool Cooling Pump (Class 3) 3R211(2)NPA1(2)01B Spent Fuel Pool Cooling Pump (Class 3)