NRC-21-0014, Submittal of 2020 Safety Relief Valve Challenge Report, Main Steam Bypass Lines Report, and ECCS Cooling Performance Evaluation Model Changes or Errors Report

Submittal of 2020 Safety Relief Valve Challenge Report, Main Steam Bypass Lines Report, and ECCS Cooling Performance Evaluation Model Changes or Errors Report

ML21116A032
Person / Time
Site:	Fermi
Issue date:	04/23/2021
From:	Offerle M DTE Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC-21-0014
Download: ML21116A032 (9)

Text

DTE Electric Company 6400 N. Dixie Highway Newport, MI 48166 April 23, 2021 TS 5.6.6 NRC-21-0014 10 CFR 50.46 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 Fermi 2 Power Plant NRC Docket No. 50-341 NRC License No. NPF-43

Subject:

Submittal of 2020 Safety Relief Valve Challenge Report, Main Steam Bypass Lines Report, and ECCS Cooling Performance Evaluation Model Changes or Errors Report The Fermi 2 Technical Specifications (TS) contain a requirement for submitting an annual report for safety relief valve challenges (TS 5.6.6). Enclosure 1 provides the Safety Relief Valve Challenge Report for 2020. provides the Service Life of the Main Steam Bypass Lines Report for 2020. This satisfies the commitment stated in Detroit Edison's letter to the NRC dated November 7, 1986 (VP-86-0154). provides the annual Emergency Core Cooling System (ECCS) Cooling Performance Evaluation Model Changes or Errors Report. This report is provided in accordance with 10 CFR 50.46(a)(3)(ii).

No new commitments are being made in this submittal.

Should you have any questions or require additional information, please contact me at (734) 586-5076.

Sincerely, Margaret M. Offerle Manager - Nuclear Licensing

USNRC NRC-21-0014 Page 2

Enclosure:

1. Safety Relief Valve Challenge Report 2020

2. Service Life of Main Steam Bypass Lines Report 2020

3. ECCS Cooling Performance Evaluation Model Changes or Errors Report cc: NRC Project Manager NRC Resident Office Regional Administrator, Region III

Enclosure 1 to NRC-21-0014 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 Safety Relief Valve Challenge Report 2020 to NRC-21-0014 Page 1 Safety Relief Valve Challenges (January 1, 2020 to December 31, 2020)

There were no instances in 2020 where reactor pressure was high enough to require Safety Relief Valve (SRV) actuation. There were also no instances in 2020 where an SRV actuation was demanded by an automatic logic system.

Enclosure 2 to NRC-21-0014 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 Service Life of Main Steam Bypass Lines Report 2020 to NRC-21-0014 Page 1 Service Life of Main Steam Bypass Lines (through December 31, 2020)

In accordance with Detroit Edisons letter to the NRC dated November 7, 1986 (VP-86-0154),

the cumulative time the main steam bypass lines are operated with the bypass valves between 30 and 45 percent open will be reported annually. A cumulative value of 100 days is not to be exceeded without prior NRC notification.

As discussed in Detroit Edisons letter number VP-86-0154, the bypass lines are acceptable for safe operation when operated within the 100-day constraint.

As of December 31, 2020, the main steam bypass lines cumulative usage was 49.01 days.

Enclosure 3 to NRC-21-0014 Fermi 2 NRC Docket No. 50-341 Operating License No. NPF-43 ECCS Cooling Performance Evaluation Model Changes or Errors Report to NRC-21-0014 Page 1 Emergency Core Cooling System (ECCS) Cooling Performance Evaluation Model -

Analysis of Record On April 8, 2020, DTE Energy submitted a re-analysis of the Loss of Coolant Accident (LOCA) using TRACG-LOCA (Reference 1). This re-analysis established a new licensing basis Peak Clad Temperature (PCT) of 1980°F for GE14 fuel and 2150°F for GNF3 fuel which are both associated with the limiting small break LOCA.

ECCS Cooling Performance Evaluation Model Changes or Errors Since the time of the submittal of the analysis of record identified above, General Electric -

Hitachi (GEH) and Global Nuclear Fuel (GNF) have issued the following notifications which indicated that changes had been made in the ECCS-LOCA analyses inputs that affect Fermi 2.

2020-01 April 14, 2020 Reference 2 2021-01 February 18, 2021 Reference 3 2021-02 February 18, 2021 Reference 4 A tabulated summary of the impacts of all errors is provided below.

Current LOCA Model Assessment Description GE14 PCT GNF3 PCT 10CFR 50.46 Baseline Licensing Basis PCT PCT=1980°F PCT=2150°F (Reference 1) 10 CFR 50.46 Notification Letter 2020-01 dated April Not applicable to Not applicable to 14, 2020, PRIME Coding Errors for Zircaloy Fermi 2 LOCA Fermi 2 LOCA Irradiation Growth and Zr Barrier Thermal Analysis-of- Analysis-of-Conductivity as Input to ECCS LOCA Analyses Record Record (Reference 2) (PCT = 0°F) (PCT = 0°F)

Not applicable to Not applicable to 10 CFR 50.46 Notification Letter 2021-01 dated Fermi 2 LOCA Fermi 2 LOCA February 18, 2021, Error in Fuel Pellet to Plenum Analysis-of- Analysis-of-Spring Conductance (Reference 3) Record Record (PCT = 0°F) (PCT = 0°F) 10 CFR 50.46 Notification Letter 2021-02 dated Not applicable to February 18, 2021, Discrepancy in Inner Cladding PCT = 0°F GNF3 fuel Surface Roughness (Reference 4) (PCT = 0°F)

Net PCT PCT=1980°F PCT=2150°F to NRC-21-0014 Page 2

References:

1. DTE Letter to USNRC, Submittal of Plant Specific Emergency Core Cooling System (ECCS) Evaluation Model Reanalysis, NRC-20-0010, dated April 8, 2020 (ML20100B567)

2. General Electric-Hitachi, 10 CFR 50.46 Notification Letter 2020-01, dated April 14, 2020.

3. General Electric-Hitachi, 10 CFR 50.46 Notification Letter 2021-01, dated February 18, 2021.

4. General Electric-Hitachi, 10 CFR 50.46 Notification Letter 2021-02, dated February 18, 2021.