ML022530266
| 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
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%
- Modal Combination per Regulatory Guide 1.92, February 1976
- Piping modal damping shall be in accordance with Regulatory Guide 1.61
- 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
- Approval is necessary to implement the power uprate
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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