ML15154B541

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Duke Energy, June 11, 2015, Pre-submittal Meeting Presentation, Harris Nuclear Plant License Amendment Request for Pressurizer and Steam Generator Safety Valves Lift Settings
ML15154B541
Person / Time
Site: Harris 
Issue date: 06/11/2015
From:
Duke Energy Progress
To:
Plant Licensing Branch II
Galvin D, DORL/LPL2-2, 301-415-6256
References
Download: ML15154B541 (39)
v • d • e


Text

Harris Nuclear Plant License Amendment Request for Pressurizer and Steam Generator Safety Valves Lift Settings June 11, 2015

Duke Energy Participants

  • Art Zaremba, Fleet Licensing Manager
  • John Caves, Harris Regulatory Affairs
  • Josh Duc, GO Regulatory Affairs
  • Bob Harvey, PWR Methods Manager
  • Mark Grantham, Harris Design Engineering Director
  • Scott Thomas, Safety Analysis Applications Manager
  • Dean Tibbitts, Safety Analysis Applications
  • Jenying Wu, PWR Methods 2

Agenda

  • Description of Change
  • Background
  • Licensing Approach
  • Technical Analysis
  • Conclusion 3

Description of Change Current Conditions

- LCO: A minimum of one pressurizer code safety valve shall be OPERABLE with a lift setting of 2485 psig +/- 1%

- LCO: All pressurizer code safety valves shall be OPERABLE with a lift setting of 2485 psig +/- 1%

  • Surveillance Requirements in accordance with IST program
  • TS 3.7.1.1 Turbine Cycle Safety Valves, Modes 1, 2, and 3

- LCO: All main steam line Code safety valves associated with each steam generator shall be OPERABLE with lift settings as specified in Table 3 7-2 4

Description of Change Current Conditions Table 3.7-2 Steam Line Safety Valves per Loop Valve Number Steam Generator Lift Setting

(+/- 1%)

Orifice Size (in2)

A B

C 1MS-43 1MS-44 1MS-45 1170 psig 16.0 1MS-46 1MS-47 1MS-48 1185 psig 16.0 1MS-49 1MS-50 1MS-51 1200 psig 16.0 1MS-52 1MS-53 1MS-54 1215 psig 16.0 1MS-55 1MS-56 1MS-57 1230 psig 16.0 5

Description of Change Proposed

- LCO: A minimum of one pressurizer code safety valve shall be OPERABLE with a lift setting of 2485 psig +/- 3%

- LCO: All pressurizer code safety valves shall be OPERABLE with a lift setting of 2485 psig +/- 3%

  • TS 3.7.1.1 Turbine Cycle Safety Valves, Modes 1, 2, and 3

- Table 3 7-2 Lift Setting tolerance changed to +/- 3%

6

Description of Change Proposed New FSAR 15.2.3 Turbine Trip Analysis for primary and secondary system overpressure evaluations

  • Uses Duke Energy methodology similar to that licensed for use at Catawba, McGuire, and Oconee not currently described in the Harris FSAR.
  • Therefore, the new analysis is not eligible for implementation under 10 CFR 50.59.

7

=

Background===

  • HNP TS Safety Valve Tolerance More Restrictive than ASME Code Requirements

- 5 valves tested every operating cycle per IST program

- Frequently found one of five slightly outside 1% tolerance, but rarely were any outside 3%

- Currently testing at increased frequency to compensate for drift outside 1% over 4 1/2 year period.

  • Pressurizer Safety Valve History (3 valves total)

- One valve removed every refueling outage and tested at vendor facility

- As-found condition outside of 1% tolerance on several occasions, but rarely were any outside 3%

8

Licensing Approach

  • Determine FSAR analyses potentially affected
  • Document justification for those analyses (remain bounding, remains non-limiting, or analyze)
  • Reanalyze FSAR 15.2.3 turbine trip for primary and secondary overpressure (NRC approval required)
  • Document acceptable results for FSAR 5.2.2 (NRC approval required)
  • Other associated changes will be implemented under 10 CFR 50.59 9

Technical Approach

  • Scope of Reviews

- Each FSAR Chapter 15.0 Event

- Mass and Energy Releases (FSAR Chapter 6.0)

- OPT and OTT Reactor Trip Equations

- Core Safety Limit Lines (TS Figure 2.1-1)

- Offsite Doses

- PSV evaluation (TMI II.D.1) 10

Analytical Methods and Inputs Used in Review

  • AFW flow decreased for events that involved steam pressure at MSSV setting

Results (Except turbine trip)

  • OPT and OTT Equations
  • Core Safety Limit Lines
  • No impact to dose analysis
  • FSAR Non-LOCA events:

- Bounded by Current Analysis

- Bounded by Overpressure from Turbine Trip

- Specified Acceptable Fuel Design Limits not affected 12

LOCA

  • No impact to Large Break LOCA
  • Small Break LOCA reanalyzed

- Higher MSSV setpoint

- AFW flow decrease due to higher SG pressure

- PCT increase of 32°F 13

Level of Detail in LAR 14

FSAR Analyses With Discussion

  • PSV evaluation (TMI II.D.1)
  • Station Blackout
  • Containment Analysis mass and energy release

Summary of Analyses Exclusive of Turbine Trip

  • Methods approved by NRC
  • Changes within 50.59 16

Turbine Trip Reanalysis

  • Harris FSAR Section 15.2.3 turbine trip analysis is reanalyzed to evaluate changes to the primary and secondary system safety valve tolerances
  • Two cases are analyzed for this event:

- one challenging the primary overpressurization criterion

- one challenging secondary system overpressurization criterion

  • Sensitivity case is performed to confirm the requirements of Standard Review Plan, Chapter 5.2.2 - Overpressure Protection, continue to be satisfied
  • An evaluation of the DNB analysis is also performed 17

Turbine Trip Analysis Methods

  • Turbine trip reanalysis is performed using the RETRAN-3D computer code
  • RETRAN-3D modeling based on previously approved Duke Energy methodology DPC-NE-3000-P-A
  • Harris RETRAN-3D plant model is assessed against the existing AREVA turbine trip analysis of record
  • Analysis approach is based on guidance provided by Duke Energy methodology report DPC-NE-3002-A 18

Turbine Trip Benchmark Analysis

  • Benchmark calculations completed for two cases from FSAR §15.2.3

- Primary and secondary overpressurization

  • Match key analysis inputs and modeling assumptions
  • Following slides compare sequence of events and transient response for each case 19

Event Event Time, s AOR RETRAN-3D Turbine Trip 0.0 0.01 Reactor Trip Signal - High Pressure 5.03 4.74 PSV Setpoint Reached 6.5 6.0 Scram Initiation 7.04 6.74 Peak Primary Side Pressure 7.8 7.7 SG 1st bank MSSVs open 8.4 8.7 SG 2nd bank MSSVs open 9.3 10.4 SG 3rd bank MSSVs open 10.8 11.7 SG 4th bank MSSVs open SG 5th bank MSSVs open Turbine Trip Benchmark Analysis Primary Overpressurization Sequence of Events 20

HNP Turbine Trip - Primary Overpressurization Reactor Power 21

Turbine Trip Benchmark Analysis Primary Overpressurization 22

Turbine Trip Benchmark Analysis Primary Overpressurization 23

Turbine Trip Benchmark Analysis Primary Overpressurization 24

Turbine Trip Benchmark Analysis Secondary Overpressurization Sequence of Events Event Event Time, s AOR RETRAN-3D Turbine Trip 0.0 0.01 Pressurizer spray on 1.0 0.9 Pressurizer compensated PORV open 1.2 1.2 Pressurizer uncompensated PORV open 4.3 4.0 SG 1st bank MSSVs open 5.4 5.3 SG 2nd bank MSSVs open 6.5 5.9 SG 3rd bank MSSVs open 7.9 7.0 SG 4th bank MSSVs open 10.1 9.7 OTT trip signal 11.16 12.06 Reactor scram 12.41 13.32 SG 5th bank MSSVs open 13.2 13.8 Peak pressurizer level 16.2 17.7 (98.7%)

Peak secondary side pressure 18.9 19.3 25

Turbine Trip Benchmark Analysis Secondary Overpressurization 26

Turbine Trip Benchmark Analysis Secondary Overpressurization 27

Turbine Trip Benchmark Analysis Secondary Overpressurization 28

Turbine Trip Benchmark Analysis Secondary Overpressurization 29

Turbine Trip Reanalysis

  • The trip setpoints and time delays assumed in the analysis of this event are unchanged from the current FSAR analysis
  • No credit is taken for the operation of the Steam Dump System or steam generator Power Operated Relief Valves (PORVs)
  • Trip signals that are expected

- high pressurizer pressure, over-temperature T, high neutron flux, high pressurizer water level and low-low steam generator water level

30

Primary System Overpressurization 31 0

500 1000 1500 2000 2500 3000 3500 0

10 20 30 40 50 Reactor Power (MWt)

Time (seconds)

PSVs with +3% drift MSSVs with +3% drift

Primary System Overpressurization 32 2000 2200 2400 2600 2800 0

10 20 30 40 50 Pressure (psia)

Time (seconds)

Pressurizer Pressure (psia)

Pressure at Bottom of Reactor Vessel (psia)

Primary Pressurization Acceptance Criterion = 2750 psia PSV s with +3% drift MSSVs with +3% drift

Turbine Trip Event Summary Primary System Overpressurization - No High PZR Pressure Trip Event Time (sec)

Turbine trips 0.0 PSVs open 7.8 Peak primary pressure at bottom of reactor vessel reached 8.81 PSVs close 11.2 PSVs open 12.5 Bank 1 MSSVs open 12.8 Bank 2 MSSVs open 13.7 Bank 3 MSSVs open 15.0 Bank 4 MSSVs open 17.0 High pressurizer level trip signal reached 19.64 Bank 5 MSSVs open 20.3 Reactor trips on high pressurizer level (control rod motion starts) 21.64 PSVs close 23.2 PSVs open 24.5 PSVs close 25.8 Bank 5 MSSVs close 41.0 Bank 4 MSSVs close 42.8 Bank 3 MSSVs close 46.3 SI signal on low pressurizer pressure Auxiliary feedwater on SI signal 49.5 End of simulation 50.0 33

Primary System Overpressurization SRP 5.2.2 Sensitivity Case 34 2000 2200 2400 2600 2800 0

10 20 30 40 50 Pressure (psia)

Time (seconds)

Pressurizer Pressure (psia)

Pressure at Bottom of Reactor Vessel (psia)

Primary Pressurization Acceptance Criterion = 2750 psia PSVs with +3% drift MSSVs with +3% drift

Secondary System Overpressurization 35 0

500 1000 1500 2000 2500 3000 3500 0

10 20 30 40 50 Reactor Power (MWt)

Time (seconds)

MSSVs with +3% drift

Secondary System Overpressurization 36 800 900 1000 1100 1200 1300 1400 0

10 20 30 40 50 Pressure at Bottom of Steam Generator Downcomer (psia)

Time (seconds)

Secondary Pressurization Acceptance Criterion = 1320 psia

DNB Evaluation

  • Sensitivity cases with different MSSV drift setpoints have been performed using the HNP RETRAN-3D model for the DNB analysis.
  • The sensitivity study result shows that the DNBR results are insensitive to the MSSV setpoints
  • The MSSV setpoint tolerance has no negative impact on the MDNBR results
  • The current HNP DNB analysis remains valid for the MSSV setpoint tolerance change 37

Turbine Trip Summary

  • Turbine trip event has been reanalyzed to evaluate changes to the primary and secondary system safety valve tolerances
  • Cases analyzed demonstrate that the acceptance criteria are satisfied assuming a safety valve tolerance of +/- 3%
  • Sensitivity case demonstrates the design and sizing of the pressurizer safety valves meets the overpressure design criterion cited in SRP Chapter 5.2.2 38

Conclusion

  • NRC approval requested for FSAR 15.2.3 Turbine Trip Analysis for primary and secondary overpressure
  • Proposed changes continue to provide adequate protection to public health and safety.
  • Accelerated review and approval of nine months requested to eliminate need for interim increased test frequencies.

39

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