ML110590491
| ML110590491 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 02/28/2011 |
| From: | Jason Paige Plant Licensing Branch II |
| To: | Abbatiello T Florida Power & Light Co |
| Paige, Jason C, NRR/DORL,301-415-5888 | |
| References | |
| Download: ML110590491 (2) | |
Text
From: Paige, Jason Sent: Monday, February 28, 2011 9:57 AM To: tom.abbatiello@fpl.com Cc: jack.hoffman@fpl.com; Tomonto, Bob; Tiemann, Philip; Abbott, Liz
Subject:
Turkey Point EPU - Piping and NDE (CPNB) Request for Additional Information
- Round 1
- Tom, Below are requests for additional information (RAIs) regarding the Turkey Point Extended Power Uprate license amendment request. On February 25, 2011, the Nuclear Regulatory Commission (NRC) staff and Florida Power & Light Company (FPL) discussed draft RAIs to gain a common understanding of the questions. During the call, it was concluded that questions CPNB-1.3 and CPNB-1.5 needed clarification. The below RAIs reflect the questions discussed during the February 25, 2011, call. FPL agreed upon providing its responses within 30 days of the date of this email. If you have any questions, feel free to contact me.
CPNB-1.1 By letter dated October 21, 2010, in the section titled Current Licensing Basis you state that GDC-31 is analogous to the 1967 Atomic Energy Commission Proposed GDC-35 on Reactor Coolant Pressure Boundary Brittle Fracture Prevention which was subsequently deleted in favor of GDC-34. PTN has no commitment to GDC-35. Clarify the above statement and describe how you meet the criteria of GDC-31, insofar as it requires that the reactor coolant pressure boundary (RCPB) be designed with margin sufficient to assure that, under specified conditions, it will behave in a non-brittle manner and the probability of a rapidly propagating fracture is minimized.
CPNB-1.2 Code Case N-729-1 requires: an initial bare metal visual examination to be performed before or during the third refueling outage after installations of the replacement head, or within 5 calendar years or replacement, whichever occurs first; and repeat bare metal visual examinations shall be performed at least every third refueling outage or every 5 calendar years, whichever occurs first. The licensee performed bare metal visual inspections of the Unit 3 replacement reactor vessel closure head (RVCH) during the spring 2009 outage and performed bare metal visual inspections on the Unit 4 RVCH during the fall 2009 outage. What were the results of the bare metal visual examinations of the reactor vessel closure heads for both Units 3 and 4.
CPNB-1.3 Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55(a)(g)(6)(ii)(D)(3) states that, Instead of the specified 'examination method' requirements for volumetric and surface examinations in Note 6 of Table 1 of Code Case N-729-1, the licensee shall perform volumetric and/or surface examination of essentially 100 percent of the required volume or equivalent surfaces of the nozzle tube, as identified by Figure 2 of ASME Code Case N-729-
- 1. A demonstrated volumetric or surface leak path assessment through all J-groove welds shall be performed. If a surface examination is being substituted for a volumetric examination on a portion of a penetration nozzle that is below the toe of the J-groove weld [Point E on Figure 2 of ASME Code Case N-729-1], the surface examination shall be of the inside and outside wetted surface of the
penetration nozzle not examined volumetrically. Turkey Points inspection plan does not appear to be consistent with 10 CFR 50.55(a)(g)(6)(ii)(D)(3). Provide explanation of your inspection plan and any deviations from the regulation. If there are any deviations, provide justification for deviating from the regulation.
CPNB-1.4 The licensee stated that they have recently adopted a comprehensive Alloy 600 management program that identifies Alloy 600.82.182 locations, evaluates and prioritizes the locations based on primary water stress corrosion cracking (PWSCC) susceptibility and develops mitigation and repair options. Summarize the results of volumetric examinations performed during the past inservice inspection of all Alloy 82/182 welds in the reactor coolant system (RCS).
CPNB-1.5 The licensee stated that at Turkey Point a small increase in the hot leg temperature was assessed due to the EPU and that the effect of this change in the service temperature on the thermal aging is considered. The Topical Report WCAP-14575-A, License Renewal Evaluation: Aging Management Evaluation for Class 1 Piping and Associated Pressure Boundary Components, indicates that thermal aging causes reduction in fracture toughness of the cast austenitic stainless steels (CASS) component material and hence reduction in the critical flaw size that could lead to component failure. The impacted RCPB CASS components include RCS piping elbows, valve bodies, reactor coolant pump (RCP) casing and closure flanges. The evaluation documented in WCAP-15354, Technical Justification for Eliminating Large Primary Loop Pipe rupture as the Structural Design Basis for the Turkey Point Units 3 and 4 Nuclear Power Plants for the 60 Year Plant Life, demonstrated that a significant margin exists between detected flaw size and flaw instability. The increase in the hot leg is within the evaluation of WCAP-15354 and accordingly an aging management program to manage the effect for the RCS piping components is not required beyond the examinations required by ASME Section XI.
Westinghouse performed an evaluation of the Code Case N-481 integrity analysis to identify if it is acceptable for the extended operating period. The results of the evaluation concluded that the previous integrity analysis conclusions documented in WCAP-13045, Compliance to ASME Code Case N-481 of the Primary Loop Pump Casings of Westinghouse Type Nuclear Steam Supply Systems, and WCAP-15355, A Demonstration of Applicability of ASME Code Case N-481 to the Primary Loop Pump Casings of the Turkey Point Units 3 and 4, for the Turkey Point Units 3 and 4 RCP casings remain valid for the 60-year licensed operating period. The increase in the hot leg is within the evaluations of WCAP-13045 and WCAP-15355 and an aging management program beyond the examinations required in Section XI is not required to manage the thermal embrittlement effect for the RCP casings.
Topical Report, WCAP-14575-A proposed programs to manage the effects of thermal aging of CASS components during the period of extended operation.
The NRC assessed these programs and the safety evaluation (Section 3.3.3) states that Valve bodies are adequately covered by existing inspection requirements in Section XI of the ASME Code and that screening for susceptibility to thermal aging is not required during the period of extended operation because the potential reduction in fracture toughness of these components should not have a significant impact on critical flaw size. The
licensee believes that thermal aging as a result of the EPU is not expected to significantly affect cast components, including pumps, pimping and valves at Turkey Point. Justify using WCAP reports, WCAP-15354, WCAP-13045, and WCAP-15355 as the basis for considering thermal aging due to the increase of the hot leg temperature.
CPNB-1.6 The licensee states that environmentally assisted fatigue cumulative usage factor (CUF) for RCS components that were evaluated during License Renewal were shown to be less than 1.0 for EPU conditions, with the exception of the RCS hot leg pressurizer surge line nozzle which assumed the presence of conservative stratification loads. The licensee states that this result is consistent with the CUF evaluation performed for License Renewal for which the licensee has committed to inspect all Turkey Point welds in the surge lines of Units 3 and
- 4. All welds have been inspected except one, which will be completed during the 2010 fall outage. Results of all inspections for the surge line welds show no effects of the stratification loads. What was the result of the above mentioned remaining inspection during the 2010 fall outage?
Jason Paige, Turkey Point Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation US Nuclear Regulatory Commission Phone: (301) 415-5888