ML090090170

PINGP Lr - Prairie Island LRA RAI 9-25-08.doc

ML090090170
Person / Time
Site:	Prairie Island
Issue date:	10/01/2008
From:	Office of Nuclear Reactor Regulation
To:
References
Download: ML090090170 (4)

Text

PrairieIslandNPEm Resource From: Richard Plasse Sent: Wednesday, October 01, 2008 4:08 PM To: Eckholt, Gene F.

Subject:

prairie island LRA RAI 9-25-08.doc Attachments: prairie island LRA RAI 9-25-08.doc draft RAIs 1

Hearing Identifier: Prairie_Island_NonPublic Email Number: 281 Mail Envelope Properties (Richard.Plasse@nrc.gov20081001160800)

Subject:

prairie island LRA RAI 9-25-08.doc Sent Date: 10/1/2008 4:08:29 PM Received Date: 10/1/2008 4:08:00 PM From: Richard Plasse Created By: Richard.Plasse@nrc.gov Recipients:

"Eckholt, Gene F." <Gene.Eckholt@nmcco.com>

Tracking Status: None Post Office:

Files Size Date & Time MESSAGE 12 10/1/2008 4:08:00 PM prairie island LRA RAI 9-25-08.doc 25198 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

REQUEST FOR ADDITIONAL INFORMATION PRAIRIE ISLAND UNITS 1 AND 2 LICENSE RENEWAL APPLICATION SECTION 4.7.1 RCS PIPING LEAK BEFROE BREAK ANALYSES BY PIPING AND NDE BRANCH DIVISION OF COMPONENT INTEGRITY Section 4.7.1 RCS [Reactor Coolant System] Piping Leak-Before-Break Analysis

1. Discuss the inspection history and results of the piping that have been approved for leak-before-break (LBB) at Prairie Island Units 1 and 2. Discuss the future inspection plans.

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.

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.

4. Nickel-based Alloy 600/82/182 material in the pressurized water reactor environment has been shown to be susceptible to primary stress corrosion cracking (PWSCC). (a) Identify any piping that have 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).

5. The applicant discusses Aging Management Program 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 aging management program (AMP) to manage the LBB piping that are 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.

6. By letter dated May 19, 2000, the NRC forwarded to 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.

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.

8. Discuss whether the Unit 1 pressurizer surge line has experienced temperature transients in which temperature differences exceeded the design transients used in 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.