ML022530266

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Attachment 2 to Summary of 07/24/2002 Meeting with Entergy Nuclear Operations, Inc., Regarding Pilgrim Nuclear Power Station Proposed Safety-Relief Valve Seismic Analysis Methodology
ML022530266
Person / Time
Site: Pilgrim
Issue date: 09/09/2002
From: Travis Tate
NRC/NRR/DLPM/LPD1
To:
References
Download: ML022530266 (13)


Text

P--- Enutergy Pilgrim Nuclear Power Station July 24, 2002 Ail Attachment 2

Overview

  • 1.5% feedwater flow uncertainty reduction Amendment Request submitted 7/5/02
  • Implementation during April 2003 Refueling Outage
  • Amendment Request developed in conjunction with Grand Gulf and River Bend
  • Amendment Request scope limited to items necessary for uprate

Modifications

  • Design changes to implement uprate SEnhanced Feedwater Flow Measurement

)>New High Pressure Turbine

>New Turbine Control Valves

New Moisture Separator Internals

>Relief Valve Capacity Increase

SRV Capacity Increase

"* Current SRV capacity inadequate with the 2% Main Steam Flow increase necessary for the requested power uprate

"* SRV throat sizes are to be increased by 7%

"* Current analytical margins do not support the increased loads due to the higher SRV flow

  • Operating License changes
  • Application of the Independent Support Motion (ISM) methodology described in UFSAR 12.2.3.5.5 for piping/support analysis for the increased SRV flow

History

"* Current methodology for this piping is the Enveloped Response Spectra (ERS)

Method described in UFSAR 12.2.3.5.4

"* ISM was previously used for the seismic analysis of the Recirculation, RHR and RWCU systems in conjunction with IGSCC piping replacement and is described in UFSAR 12.2.3.5.5

"* NRC SER was focused on IGSCC issues

"* NRC performed inspection including review of the Owners Specification

Benefits

"* ISM provides a more complete and accurate analytical approach

"* Performing the analysis using ISM will reduce the required scope of modifications

"* Current walk down information is insufficient to support the significant modifications required if ISM is not used

"* Substantially reduced worker dose

  • Requires simultaneous application of the three dimensions of seismic motion o Only applied to piping systems between separate floor levels, and/or individual structures
  • The number of support groups are kept to a minimum and spectra within.a support group shall be enveloped and used for all supports within that group
  • Current licensing basis seismic response spectra are peak broadened to +/- 15%
  • High frequency modes are included in the analysis to reasonably obtain the full mass contribution
  • ISM group responses for each direction are combined by the SRSS method
  • Seismic inertial responses are to be combined with the seismic anchor motion and other dynamic event responses by-the Absolute Sum method
  • The stresses and reactions from rapid valve closure or opening are to be combined with seismic inertial stresses and reactions by the SRSS method
  • Design evaluation are in accordance with the requirements of ASME B&PV Code Section III 1977 Edition through Summer 1977 addenda

"* PNPS will be implementing a small power uprate that includes TPO and efficiency improvements

"* Increased SRV capacity is required resulting in increased piping loads

"* Proposed use of the ISM methodology as described in FSAR 12.2.3.5.5 with realistic models of the piping systems

  • The method exhibits both increases and reductions in conservatism
  • Minimizes the modifications in the drywell and a large ALARA benefit

THIS PAGE IS AN OVERSIZED DRAWING OR FIGURE, THAT CAN BE VIEWED AT THE RECORD TITLED:

DRAWING HANDOUT FROM 6-24-2002 MEETING RE PILGRIM PROPOSED SAFETY-RELIEF VALVE SEISMIC ANALYSIS METHODOLOGY WITHIN THIS PACKAGE NOTE: Because of these page's large file size, it may be more convenient to copy the file to a local drive and use the Imaging (Wang) viewer, which can be accessed from the Programs/Accessories menu.

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