ML083181015
| ML083181015 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 11/20/2008 |
| From: | Richard Plasse License Renewal Projects Branch 2 |
| To: | Wadley M Northern States Power Co |
| Plasse, Richard 301-415-1427 DLR/RPB2 | |
| Shared Package | |
| ML083181040 | List: |
| References | |
| Download: ML083181015 (2) | |
Text
REQUEST FOR ADDITIONAL INFORMATION PRAIRIE ISLAND UNITS 1 AND 2 LICENSE RENEWAL APPLICATION Section 4.7.1 RCS [Reactor Coolant System] Piping Leak-Before-Break Analysis RAI 4.7.1-1 Discuss the inspection history and results of the piping that has been approved for leak-before-break (LBB) at Prairie Island Units 1 and 2. Discuss the future inspection plans.
RAI 4.7.1-2 In Section 4.7.1, second paragraph, the applicant stated that primary coolant piping is made of cast austenitic stainless steel (CASS). In the fourth paragraph, the applicant stated that CASS is used in the pipe fittings. (a) Confirm that pipe fittings and straight sections of the primary coolant piping at Units 1 and 2 are all made of CASS. (b) Discuss the material used in fabricating the surge lines at Units 1 and 2.
RAI 4.7.1-3 The applicant submitted LBB analyses for the Unit 1 pressurizer surge line. Confirm that LBB has not been implemented and LBB analyses have not been submitted to the NRC for the Unit 2 pressurizer surge line.
RAI 4.7.1-4 Nickel-based Alloy 600/82/182 material in the pressurized water reactor environment has been shown to be susceptible to primary water stress corrosion cracking (PWSCC). (a) Identify any piping that has been approved for LBB for both units which contain Alloy 82/182 weld metal and Alloy 600 components. (b) If LBB piping contains Alloy 600/82/182 material, discuss any mitigation measures (such as weld overlays or mechanical stress improvement) that have been or will be implemented to reduce the effects of PWSCC on the LBB piping components. (c)
Discuss the inspection history and future inspection frequency of the Alloy 81/182 dissimilar metal butt welds (see Question number 1 above).
RAI 4.7.1-5 The applicant discusses Aging Management Program (AMP) B.2.1.41, Thermal Aging Embrittlement Of Cast Austenitic Stainless Steel (CASS), in Appendix B of the license renewal application. However, Section 4.7.1 does not mention this AMP for managing the LBB piping that is made of CASS. Discuss how CASS material of the LBB piping will be managed because AMP B.2.1.41 does not seem to be used to monitor the CASS components in the LBB piping systems for thermal aging embrittlement.
RAI 4.7.1-6 By letter dated May 19, 2000, the NRC forwarded to the Nuclear Energy Institute an evaluation of thermal aging embrittlement of CASS components (ADAMS Accession ML003717179). In the NRCs evaluation, the staff provided its positions on how to manage CASS components.
Discuss how the CASS components in the LBB piping at both units satisfy the staff positions in its evaluation dated May 19, 2000.
RAI 4.7.1-7 Explain whether the current fatigue crack growth analyses, as discussed in the fatigue crack growth section, are performed for 60 years. If not, discuss whether the current fatigue crack growth analyses, which are analyzed for 40 years, are applicable to 60 years. Provide the technical basis in detail.
RAI 4.7.1-8 Discuss whether the Unit 1 pressurizer surge line has experienced temperature transients in which temperature differences exceeded the design transients used in the LBB analyses. If out-of-limit transients occurred, describe how the LBB analyses for the Unit 1 surge line were re-evaluated to determine their acceptability.
Section 2.5 Scoping and Screening Results: Electrical and Instrumentation and Controls Systems RAI 2.5 In the license renewal application, the applicant described the station blackout recovery paths for license renewal. As the licensee did not specifically exclude the associated control circuits and structures for the switchyard circuit breakers, it is assumed that these components are included in the scope of license renewal. In accordance with Title 10 of the Code of Federal Regulations (10 CFR) Section 54.4(a)(3) and License Renewal Sections 2.1.3.1.3 and 2.5.2.1.1 of the Standard Review Plan, the control circuits and structures associated with the circuit breaker should be in the scope of license renewal. Please confirm that these components are within the scope of license renewal.