ML21197A003
| ML21197A003 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 08/06/2021 |
| From: | Southern Nuclear Operating Co |
| To: | John Lamb NRC/NRR/DORL/LPL2-1 |
| Lamb J NRR/DORL/LPL2 | |
| References | |
| Download: ML21197A003 (25) | |
Text
Vogtle Pre-Submittal Meeting to Revise Technical Specification 3.3.1 & 3.3.2 Allowable Values August 13, 2021
2 Meeting Purpose and Agenda
- The purpose for this meeting is to discuss the proposed amendment request to revise Technical Specification Tables 3.3.1-1 and 3.3.2-1 Allowable Values
- This meeting will cover the following topics:
- Background on the updated instrument uncertainty calculations for the Vogtle Units 1 & 2 Reactor Trip System (RTS) and Engineered Safety Features Actuation System (ESFAS) trip functions
- Proposed License Amendment Request
- Milestones
Background on updated instrument uncertainty calculations for the Vogtle Units 1 & 2 Reactor Trip System (RTS) and Engineered Safety Features Actuation System (ESFAS) trip functions
4 Background
- Instrument uncertainty calculations for the Vogtle Units 1 & 2 Reactor Trip System (RTS) and Engineered Safety Features Actuation System (ESFAS) trip functions have been updated.
- Calculation inputs have been updated to account for component/equipment replacement, operating experience (OE), and vendor communications.
- No change to the nominal trip setpoints (NTS).
- Updated uncertainty calculations for the RTS and ESFAS result in changes to the Allowable Values (AVs) contained in Technical Specifications (TS) Tables 3.3.1-1 and 3.3.2-1.
5 Applicable Safety Analysis Discussion
- In addition to the RTS and ESFAS uncertainties, the uncertainties used in the Revised Thermal Design Procedure (RTDP) analyses were also re-calculated based on the updated inputs used in the RTS and ESFAS trip function uncertainty calculations.
- Parameters are pressurizer pressure, primary coolant temperature (Tavg), reactor power, and Reactor Coolant System (RCS) flow.
- Analysis of Record (AOR) are either consistent with or more conservative than the revised RTDP analyses uncertainty values.
- Updated RTDP uncertainty values will be implemented under 10 CFR 50.59 as a change to the UFSAR.
6 Setpoint Analysis
- NTS in conjunction with the use of as-found and as-left tolerances, together with the requirements of the AV ensure that SLs are not violated during Anticipated Operational Occurrences (AOOs) and that the consequences of Design Basis Accidents (DBAs) will be acceptable.
- NTS are determined from the Analytical Limits in UFSAR Chapters 6 and 15.
- NTS separation from the Analytical Limit is based on a combination of all errors.
- Reactor Protection and ESF actuation function AV provided in TS are limiting values that allow for deviation of the "as found" setting from the NTS during calibration.
- Updated AVs have been calculated using previously NRC approved setpoint methodology for Vogtle 1&2.
- AVs serves as the as-found TS OPERABILITY limit for the purpose of the Channel Operational Test (COT).
- The NTS and AV relationship is shown graphically on the next slide.
7 Setpoint Analysis Setpoint relationships of nuclear safety related setpoints from Regulatory Guide 1.105, revision 3 and ISA 67.04 - 1994
Proposed License Amendment Request
9 Proposed License Amendment Request
- SNC proposes to change the Technical Specifications to revise specified Allowable Values (AVs) contained in Tables 3.3.1-1 and 3.3.2-1.
- The revised AV were determined from the Nominal Trip Setpoint using the method in the following example:
Pressurizer Pressure P-11 Permissive AV Nominal Trip Setpoint = 2000 psig Rack Calibration Accuracy = 0.5% span Pressurizer Pressure Span = 800 psi Allowable Value < NTS + RCA (Span)
Allowable Value < 2000 psig + 0.5% span (800 psi) < 2004 psig
- The revised AVs would move closer to the NTS values.
- TS Bases 3.3.1 Reference 6 and Bases 3.3.2 Reference 7 (WCAP-11269, Westinghouse Setpoint Methodology for Protection Systems Vogtle Station) would be replaced by WCAP-16969, Westinghouse Setpoint Methodology for Protection Systems Vogtle Electric Generating Plant - Units 1&2.
10 TS Table 3.3.1-1 Summary of AV Changes Table 3.3.1-1 RTS Functions Current AV Revised AV NTS Value 2.a. Power Range Neutron Flux High 111.3% RTP 109.3% RTP 109% RTP 2.b. Power Range Neutron Flux Low 27.3% RTP 25.3% RTP 25% RTP
- 3. Power Range Neutron Flux High Positive Rate 6.3% RTP with time constant > 2 sec 5.4% RTP with time constant > 2 sec 5% RTP with time constant > 2 sec
- 5. Source Range Neutron Flux 1.7 E5 cps 1.04 E5 cps 1.0 E5 cps 8.a. Pressurizer Pressure Low 1950 psig 1958 psig 1960 psig 8.b. Pressurizer Pressure High 2395 psig 2389 psig 2385 psig
- 9. Pressurizer Water Level - High 93.9%
92.5%
92%
10.a. Reactor Coolant Flow - Low (Single Loop) 89.4%
89.6%
90%
10.b. Reactor Coolant Flow - Low (Two Loops) 89.4%
89.6%
90%
- 13. Steam Generator (SG) Water Level - Low-Low 35.9%
37.3%
37.8%
14.a. Turbine Trip: Low Fluid Oil Pressure 500 psig 570 psig 580 psig 16.a. RTS Interlock: Intermediate Range Neutron Flux, P-6 1.2 E-5% RTP 1.91 E-5% RTP 2.0 E-5% RTP 16.c. RTS Interlock: Power Range Neutron Flux, P-8 50.3% RTP 48.3% RTP 48% RTP 16.d. RTS Interlock: Power Range Neutron Flux, P-9 40.6% RTP 40.3% RTP 40% RTP 16.e. RTS Interlock: Power Range Neutron Flux (footnote l), P-10 input to P-7 12.3% RTP 10.3% RTP 10% RTP 16.e. RTS Interlock: Power Range Neutron Flux (footnote m), P-10 7.7% RTP 9.7% RTP 10% RTP 16.f. RTS Interlock: Turbine Impulse Pressure, P-13 12.3%
10.5%
10%
11 Table 3.3.1-1 RTS Functions
12 Table 3.3.1-1 RTS Functions
13 Table 3.3.1-1 RTS Functions
14 Table 3.3.1-1 RTS Functions
15 Table 3.3.1-1 RTS Functions
16 TS Table 3.3.2-1 Summary of AV Changes Table 3.3.2-1 ESFAS Functions Current AV Revised AV NTS Value 1.c. Safety Injection: Containment Pressure - High 1 4.4 psig 4.2 psig 3.8 psig 1.d. Safety Injection: Pressurizer Pressure - Low 1856 psig 1866 psig 1870 psig 1.e. Safety Injection: Steam Line Pressure - Low 570 psig 581.8 psig 585 psig 2.c. Containment Spray: Containment Pressure High - 3 22.4 psig 21.9 psig 21.5 psig 4.c. Steam Line Isolation: Containment Pressure High - 2 15.4 psig 14.9 psig 14.5 psig 4.d.(1) Steam Line Isolation: Steam Line Pressure - Low 570 psig 581.8 psig 585 psig 4.d.(2) Steam Line Isolation: Steam Line Pressure Negative Rate - High 125 psi/sec 103.3 psi/sec 100 psi/sec 5.b. Turbine Trip and Feedwater Isolation: Low Reactor Coolant System (RCS) Tavg 561.5°F 563.8°F 564°F 6.b. Auxiliary Feedwater: Steam Generator (SG) Water Level - Low-Low 35.9%
37.3%
37.8%
7.b. Semi-Automatic Switchover to Containment Sump:
Refueling Water Storage Tank (RWST) Level - Low-Low 216.6 in and 210.4 in 216.5 in and 210.4 in 213.5 in 8.b. ESFAS Interlocks: Pressurizer Pressure, P-11 2010 psig 2004 psig 2000 psig
17 Table 3.3.2-1 ESFAS Functions
18 Table 3.3.2-1 ESFAS Functions
19 Table 3.3.2-1 ESFAS Functions
20 Table 3.3.2-1 ESFAS Functions
21 Table 3.3.2-1 ESFAS Functions
22 Table 3.3.2-1 ESFAS Functions
Milestones
24 Milestones
- Submit LAR by end of 3Q2021
- Request NRC approval within twelve months
- Implement within 90 days of NRC approval
Questions?