ML091590627

St. Lucie Nuclear Plant, Unit 1 - RR-31 and RR-32 RAI

ML091590627
Person / Time
Site:	Saint Lucie
Issue date:	05/11/2009
From:	Mozafari B L Plant Licensing Branch II
To:	Frehafer K Florida Power & Light Co
Mozafari B L, NRR/ADRO/DORL, 415-2020
References
Download: ML091590627 (4)

Text

From: Brenda Mozafari Sent: Monday, May 11, 2009 4:19 PM To: 'Frehafer, Ken'

Subject:

RR 31 and 32 RAI request Ken, As discussed:

By letter dated February 6, 2009, (Agencywide Documents Access & Management System (ADAMS) ML0904430304) the licensee, Florida Power and Light Company, submitted Requests for Relief RR 31 and 32 from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, for St. Lucie, Unit 1. The requests for relief are for the third 10-year inservice inspection (ISI) interval, in which the licensee adopted the 1989 Edition of ASME Code Section XI, No Addenda, as the code of record.

In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee has submitted RR-31 and RR-32 for limited examinations in multiple ASME Code Examination Categories. The ASME Code requires that 100% of the examination volumes or surface areas described in ASME Code,Section XI, Tables IWB-2500 and IWC-2500 be performed during each interval. The licensee stated that 100% of the ASME Code-required volumes or surface areas are impractical to obtain at St. Lucie, Unit 1.

10 CFR 50.55a(g)(5)(iii) states that when licensees determine that conformance with ASME Code requirements is impractical at their facility, they shall submit information to support this determination. The NRC will evaluate such requests based on impracticality, and may impose alternatives, giving due consideration to public safety and the burden imposed on the licensee.

Pacific Northwest National Laboratory (PNNL) has reviewed the information submitted by the licensee, and based on this review, determined the following information is required to complete the evaluation.

2. REQUEST FOR ADDITIONAL INFORMATION

2.1 Request

for Relief 31, ASME Code,Section XI, Examination Category B-A, Items B 1.11, B1.12, B 1.21 and B1.22, Reactor Pressure Vessel Shell Welds and Bottom Head Welds The licensee's submittal states in section 6.0, Proposed Alternative and Basis for Use , first paragraph:

FPL [Florida Power and Light Company] performed inservice examinations of selected welds in accordance with the requirements of 10 CFR 50.55a, plant technical specifications, and the 1989 Edition, No Addenda, of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI.

In the fourth paragraph of the same section, the licensee's submittal states

FPL performed ultrasonic [(UT)] examinations of all reactor vessel welds in accordance with the requirements of 10 CFR 50.55a, plant technical specifications, and the 1995 Edition, No Addenda, of ASME [Code,] Section XI to the maximum extent possible.

2.1.1 Please

clarify which Edition and Addenda of the ASME Code,Section XI was used to examine the reactor pressure vessel (RPV) welds.

The licensee requested relief from examining 100% of the ASME Code-required volumes for RPV welds: Shell-to-Lower Shell Circumferential Weld (9-203), RPV Circumferential Bottom Head-to-Lower Shell Weld (10-203), RPV Upper Shell Longitudinal Seam Weld at 15 Degrees (1-203B) and RPV Lower Head Peel Segment Welds (204-03-A through F). The licensee has provided technical descriptions and sketches; however, it is unclear from the licensee's submittal how these appurtenances specifically limit the subject examinations. For example, the roll-out sketches do not provide dimensions and there is no description of the ultrasonic scanning apparatus, or any other details of the listed obstruction (e.g., size, shape, proximity to the weld, etc.).

2.1.2 Please

submit further specific information to support the basis for each limited examination in Request for Relief 31, and therefore, demonstrate impracticality. Include descriptions (written and/or sketches, as necessary) of the interferences to applied nondestructive examination (NDE) techniques. As applicable, describe NDE equipment, show accessibility limitations, and discuss whether alternative methods or advanced technologies could be employed to maximize ASME Code coverage.

2.2 Request

for Relief 32, All Examination Categories Specific inspection techniques used to examine the subject welds are unclear. The figures included in the licensee's submittal show that various angle beam transducers were used and note the areas applied. However, the wave mode (shear or refracted longitudinal), and actual beam propagation angle, have not been identified. In addition, materials of construction and thickness of components have not been provided.

2.2.1 Summarize

the inspections techniques (e.g., 0-degree longitudinal, and/or 30-, 45- and 60-degree shear wave; etc.) for each of the welds included in RR-32.

2.2.2 Clarify, if not specifically noted in the licensee's Table 1

[1], whether the examinations listed in the Table were conducted prior to, or after, implementation of ASME Code, Section XI, Appendix VIII requirements.

2.2.3 Prior

to the requirement to implement ASME Code,Section XI, Appendix VIII, state to what ASME Code inspection requirements were used to examine the subject welds in all the ASME Code,Section XI, Examination Categories listed in RR-32.

2.2.4 State

the materials of construction, wall thickness, and schedule (for piping) for each of the components in RR-32. Note any specific features, such as cladding on the inside

[1] Table 1 is not included in this Technical Letter Report (TLR) and can be found in the licensee's submittal dated February 6, 2009.

diameter (ID) of any of the carbon steel components, etc. If not already described, list the system and/or specific component, as applicable, to which each of the subject welds is associated.

The licensee lists examination coverage for certain welds as 100% from one side (e.g., pipe), and lists varied coverage from the opposite side of the weld. However, if these welds were examined after implementation of ASME Code,Section XI, Appendix VIII requirements, it is unclear how the licensee can credit the full volume (100%) from only one side, as qualifications for detecting flaws on the far-side of austenitic welds has not been demonstrated.

2.2.5 Please

clarify the volumetric coverage(s) obtained (and claimed) for all of the subject welds. 2.3 Request for Relief 32, ASME Code,Section XI, Examination Category B-J, Items B9.11 and B9.21, Austenitic Stainless Steel Piping Welds In Attachment 2, Page 1 of 45, under Section 3.0, Applicable Code Requirement, of the licensee's letter dated February 6, 2009, a Table is included containing certain ASME Code references and requirements. However, for certain ASME Code,Section XI, Examination Category B-J welds, the licensee states that a Risk-Informed Inservice Inspection (RI-ISI) program was approved by the NRC on March 25, 2004 (ADAMS ML040850587), for St. Lucie, Unit 1. It is unclear how this affects the current request for relief. A review of the Safety Evaluation for the RI-ISI program notes that the Westinghouse Owners Group Topical Report WCAP-14572, Westinghouse Owners Group Application of Risk-Informed Methods to Piping Inservice Inspection Topical Report, Revision 1-NP-A , February 1999, was used as a basis for the RI-ISI program. This method invokes ASME Code Case N-577, Risk-Informed Requirements for Class 1, 2, and 3 Piping, Method A,Section XI, Division 1, for revised Examination Categories.

2.3.1 State

whether any of the piping welds in RR-32 were examined in accordance with the RI-ISI program, and if so, why these welds have not been designated as Examination Category R-A per ASME Code Case N-577, with specific Item numbers associated with potential degradation mechanisms.

2.3.2 State

whether new examination volumes, based on risk, have been applied to these welds, and whether the current limited examinations apply to these new inspection volumes. 2.3.3 Confirm that only volumetric examination was performed on all subject RI-ISI program welds, i.e., no surface examinations were performed.

E-mail Properties Mail Envelope Properties ()

Subject:

RR 31 and 32 RAI request Sent Date: 5/11/2009 3:59:42 PM Received Date: 5/11/2009 4:19:00 PM From: Brenda Mozafari

Created By: Eliot.Brenner@nrc.gov

Recipients:

Ken.Frehafer@fpl.com ('Frehafer, Ken')

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MESSAGE 26462 5/11/2009

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