ML090540458

PINGP Lr - FW: Some More RAI for Prairie Island

ML090540458
Person / Time
Site:	Prairie Island
Issue date:	02/10/2009
From:	Office of Nuclear Reactor Regulation
To:
References
Download: ML090540458 (4)

Text

PrairieIslandNPEm Resource From: Richard Plasse Sent: Tuesday, February 10, 2009 1:21 PM To: Eckholt, Gene F.; Vincent, Robert

Subject:

FW: Some more RAI for Prairie Island Attachments: PINGP RAI response follow-up and new items (Yang on Metal fatig).doc revised draft for telecon 1

Hearing Identifier: Prairie_Island_NonPublic Email Number: 739 Mail Envelope Properties (Richard.Plasse@nrc.gov20090210132000)

Subject:

FW: Some more RAI for Prairie Island Sent Date: 2/10/2009 1:20:58 PM Received Date: 2/10/2009 1:20:00 PM From: Richard Plasse Created By: Richard.Plasse@nrc.gov Recipients:

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

Tracking Status: None "Vincent, Robert" <Robert.Vincent@xenuclear.com>

Tracking Status: None Post Office:

Files Size Date & Time MESSAGE 27 2/10/2009 1:20:00 PM PINGP RAI response follow-up and new items (Yang on Metal fatig).doc 61434 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

Part I - Seeking clarification on some of the PINGP responses to previous RAIs in metal fatigue area Near the end of NSPM response to RAI 4.3.1.4-1, second last paragraph, it appears as follows:

The calculation of the primary nozzle CUFs performed in 1969 for Unit 2 is Formatted: Font: Italic based on photoelastic and thermal transient analyses considering the worst case normal and upset loading conditions. The maximum peak stress intensity considering worst case normal and upset conditions was conservatively applied for the total number of design cyclic applications (i.e.,

24,000 cyclic applications for all transients the unit must undergo, which bounds the applicable design transients in Table 4.3-1 of the PINGP LRA). This resulted in a very conservative cumulative usage factor of 0.88 for the inside surface of the primary inlet nozzle base metal.

(a) Please explain exactly what worst case normal and upset loading conditions means and identify it from the transients listed in LRA Table 4.3-1. If the worst loading condition is not one of the transients listed in LRA Table 4.3-1, explain why. In either case, provide basis to show it is the worst loading condition.

(b) Please explain how you came up with 24000 cycles. The staff tried different ways of adding cycles for the transients listed in Table 4.3-1 of the PING LRA without a match.

Side question:

(1) OBE is not included in LRA Table 4.3-1. Why not? Did you include OBE in fatigue calculations?

(2) Is PINGP Westinghouse design plant?

(3) In LRA Section 4.7.3, on Page 4.7-4, at the beginning of 2nd paragraph: it says that In an effort to revise the RCP flywheel inspection frequency and scope, NMC submitted a License Amendment Request in 2004 based on WCAP-15666, Revision to Reactor Coolant Pump Flywheel Inspection Program (Reference 22)....

With what is the quoted phrase Revision to Reactor Coolant Pump Flywheel Inspection Program associated? Neither does it match the title of WCAP-15666, nor does it match the title embedded in Reference 22, which appears as:

22. NMC letter to NRC dated October 15, 2004, Application for Technical Specification Improvement to Extend the Inspection Interval for Reactor Coolant Pump Flywheels Using the Consolidated Line Item Improvement Process Applicant: notice the obvious discrepancy between Section 4.7.3 and A4.7 on this matter!

(a) Clarify. (b) Is there a document number for the letter? What is the inspection interval requested in the letter? Was it approved? Please fax the letter.

Part II - additional RAI RAI 4.3.1-1 The PINGP metal fatigue of reactor coolant pressure boundary management program relies on transient cycle monitoring to evaluate the fatigue usage described in the license renewal application. This approach tracks the number of occurrences of significant thermal and pressure transients (significant events) and compares the cumulative cycles, projected to cover the renewal period, against the number of design cycles specified in the design specifications. The projected cycles are then used to evaluate the total cumulative usage factor (CUF) which covers the period of extended operation. For this approach to work, none of the significant events tracked should produce stresses greater than those that would be produced by the design transients. That is, the P-T (Temperature and Pressure) characteristics, including their values, ranges, and rates, all must be bounded within those defined in the design specifications. Please provide (a) Additional informationPlease describe the procedures that PINGP has been using for tracking thermal activities so the staff can confirm that the the PINGP aging management program will ensure that P-T characteristics, including their values, ranges, and rates remain bounded within the range defined in the design specifications during the renewed license term.

(b) Please provide Hhistogram (cycle accumulating charts) of heatup transient tracking history, and the histogram for the cooldown transient as well.

RAI 4.3.3-1 The last row of LRA Table 4.3-8 shows that the Fen for RHR Class 1 Piping Tee is 2.55 for stainless steels. Text of the LRA, the 1st line on Page 4.3-24, indicates that this is the bounding Fen. Please explain why this value is bounding when the true bounding Fen for stainless steels is 15.35. The value Fen=2.55 will arrive under two conditions, as indicated on Page 4.3-23 of LRA (a) T<200 oC, any , any DO (b) T 200°C, 0.4%/sec, any DO If you used condition (a) for your Fen calculation, specify the T value used. If you used condition (b),

specify the values with basis. Clarify these questions and revise the LRA appropriately. If you used the true bounding value15.35 for the Class 1 Piping Tee, reflect it on the last row of LRA Table 4.3-8 and make any necessary adjustments.