LR-N07-0274, Plans Related to Steam Dryer Evaluation

Plans Related to Steam Dryer Evaluation

ML073040393
Person / Time
Site:	Hope Creek
Issue date:	10/23/2007
From:	Barnes G Public Service Enterprise Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LR-N07-0274
Download: ML073040393 (4)

Text

PSEG Nuclear LLC P.O. Box 236, Hancocks Bridge, New Jersey 08038-0236 0 PSEG Nuclear LLC LR-N07-0274 October 23, 2007 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Hope Creek Generating Station Facility Operating License No. NPF-57 NRC Docket No. 50-354

Subject:

Plans Related to Steam Dryer Evaluation

References:

1) Letter from George P. Barnes (PSEG Nuclear LLC) to USNRC, September 18, 2006 2) Letter from USNRC to William Levis (PSEG Nuclear LLC), June 7, 2007 3) Letter from George P. Barnes (PSEG Nuclear LLC) to USNRC, August 3, 2007 In Reference 1, PSEG Nuclear LLC (PSEG) requested an amendment to Facility Operating License NPF-57 and the Technical Specifications (TS) for the Hope Creek Generating Station (HCGS) to increase the maximum authorized power level to 3840 megawatts thermal (MWt)..In Reference 2, the NRC requested additional information concerning PSEG's request.PSEG provided the response to the request for additional information in Reference 3.PSEG met with the NRC on October 11, 2007, to discuss technical evaluations provided in Reference 3 related to qualification of the Hope Creek steam dryer for extended power uprate (EPU) operation.

The.attachment to this letter documents PSEG's understanding of the key issues discussed at the October 11, 2007 meeting and PSEG's plans for additional steam dryer analysis and testing. Upon completion of the testing and analysis, PSEG will submit information in sufficient detail to permit the NRC staff to complete their review.95-2168 REV. 7/99 LR-N07-0274 October 23, 2007 Page 2 PSEG expects to submit the results, with the exception of Unit 2 steam dryer testing, to the NRC by November 30, 2007. To account for bias and uncertainty in frequency response function amplitudes predicted by the finite element model for the HCGS dryer, PSEG is also developing a plan to test the Unit 2 steam dryer. PSEG will be prepared to discuss the schedule for this testing with the NRC staff by November 2, 2007.There are no regulatory commitments contained within this letter. Should you have any questions regarding this submittal, please contact Mr. Paul Duke at 856-339-1466.

Sincerely, George P. Barnes Site Vice President Hope Creek Generating Station Attachment

1. Plans Related to Steam Dryer Evaluation cc: S. Collins, Regional Administrator

-NRC Region I J. Lamb, Project Manager -USNRC NRC Senior Resident Inspector

-Hope Creek P. Mulligan, Manager IV, NJBNE ATTACHMENT 1 Hope Creek Generating Station Facility Operating License No. NPF-57 NRC Docket No. 50-354 Extended Power Uprate Plans Related to Steam Dryer Evaluation PSEG Nuclear LLC (PSEG) metwith the NRC on October 11, 2007, to discuss technical evaluations related to qualification of the Hope Creek steam dryer for extended power uprate (EPU) operation.

The following table summarizes PSEG's understanding of the key issues discussed at the October 11, 2007 meeting and provides PSEG's plans for additional steam dryer analysis and testing.Issue PSEG Plan to Resolve Uncertainty and Bias in Finite Element Model (FEM) Frequency Response Function (FRF) Amplitudes Assess margins to stress limits after Frequency shifting the steam dryer loading accounts for reduction in 80 Hz load component bias and uncertainty in the FEM resonance frequencies (see below).but does not account for errors in the mean and peak frequency response amplitudes due to uncertainty or Assess feasibility of testing on the Unit bias in plate dimensions, boundary conditions (joints 2 dryer to account for bias and between plates and other members), pre-stresses uncertainty in FRF amplitudes within members, and friction between internal vanes predicted by the FEM.and other components.

Model a portion of the dryer including the hood, reinforcing struts, and some FEM Dimensions and Mesh Spacing welds at the current mesh size. Simple Additional information is needed for the NRC to assess loading will be applied. The mesh size whether the FEM dimensions and mesh spacing are will then be reduced, nominally by adequate to establish convergence of strain and stress 50%, and the same load will be fields. applied. Successful mesh convergence is demonstrated if the results differ by less than 10%.

LR-N07-0274 Attachment I Page 2 Issue PSEG Plan to Resolve Stress Analysis Approach Additional information is needed to validate the application of the harmonic finite element stress analysis method in comparison to the time-domain method used previously.

1. Perform a time-domain stress analysis of the steam dryer with 1% Rayleigh damping. Loads are to be based on actual plant loads, nominally from 100 to 150 Hz.2. Perform harmonic stress analysis with damping at each natural frequency the same as the estimated damping at each natural frequency from the time-domain analysis in (1) above.3. Perform harmonic stress analysis with damping at 1% over the frequency range.4. Compare results for maximum stresses and displacements and for alternating stress ratios for each method.Acoustic Circuit Model (ACM) Validation In the absence of additional plant data to validate ACM Revision 4, the reported margins to stress limits for Hope Creek are insufficient to account for uncertainty in predicted loading.Obtain additional main steam line strain gage data upon completion of the current refueling outage. Provide technical basis for reducing the 80 Hz input to the ACM. Calculate margin to stress limits with the revised ACM inrput.