ML22046A274
| ML22046A274 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 02/15/2022 |
| From: | Perry Buckberg NRC/NRR/DORL/LPL2-2 |
| To: | Taylor A Tennessee Valley Authority |
| Buckberg P | |
| References | |
| L-2021-LLA-0145 | |
| Download: ML22046A274 (4) | |
Text
From:
Buckberg, Perry Sent:
Tuesday, February 15, 2022 1:19 PM To:
Taylor, Andrew Charles Cc:
Victor, William Ross
Subject:
SQN TSTF-505 SNSB Audit Question - L-2021-LLA-0145 Attachments:
Sequoyah - TSTF 505 SNSB audit question for TS 3.5.2 Cond A 2-15-2022.pdf
- Andy, The September 15, 2021, Audit Plan (ML21246A053) includes that..the NRC staff will provide the licensee with audit questions and audit-related requests so that the licensee can better prepare for audit discussions with NRC staff. Attached is and additional audit question from the NRC/NRR Nuclear Systems Performance Branch (SNSB).
Please contact me at any if a clarification is needed. Also, please post the response to the question to the Certrec Portal and let me know when that happens.
- Thanks, Perry Buckberg Senior Project Manager / Agency 2.206 Petition Coordinator U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation office: (301)415-1383 perry.buckberg@nrc.gov Mail Stop O-8B1a, Washington, DC, 20555-0001
Hearing Identifier:
NRR_DRMA Email Number:
1524 Mail Envelope Properties (BLAPR09MB7409A2CA0CFB837EE25C81479A349)
Subject:
SQN TSTF-505 SNSB Audit Question - L-2021-LLA-0145 Sent Date:
2/15/2022 1:19:05 PM Received Date:
2/15/2022 1:19:00 PM From:
Buckberg, Perry Created By:
Perry.Buckberg@nrc.gov Recipients:
"Victor, William Ross" <wrvictor@tva.gov>
Tracking Status: None "Taylor, Andrew Charles" <actaylor@tva.gov>
Tracking Status: None Post Office:
BLAPR09MB7409.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 840 2/15/2022 1:19:00 PM Sequoyah - TSTF 505 SNSB audit question for TS 3.5.2 Cond A 2-15-2022.pdf 127775 Options Priority:
Normal Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
AUDIT QUESTIONS LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATIONS TO ADOPT TSTF-505, REVISION 2 TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NUMBERS 50-327 AND 50-328 By application dated August 5, 2021, Tennessee Valley Authority (the licensee) submitted a license amendment request (LAR) for Sequoyah Nuclear Plant, Units 1 and 2 (Sequoyah)
(Agencywide Documents Access and Management System (ADAMS) Accession No. ML21217A174). The amendment would revise technical specification (TS) requirements to permit the use of risk-informed completion times (RICTs) for actions to be taken when limiting conditions for operation (LCOs) are not met. The proposed changes are based on Technical Specifications Task Force (TSTF) Traveler TSTF-505, Revision2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative4b, dated July 2, 2018 (ADAMS Accession No. ML18183A493). The U.S. Nuclear Regulatory Commission (NRC) issued a final model safety evaluation (SE) approving TSTF 505, Revision 2, on November 21, 2018 (ADAMS Accession No. ML18269A041). The NRC staff has determined that the following information is needed to complete its review.
Nuclear Systems Performance Branch (SNSB) Audit Question SNSB AUDIT QUESTION 02 - Technical Specification (TS) 3.5.2 ECCS - Operating The design basis of the safety function for the emergency core cooling system (ECCS) is established by the capacity to cool the reactor core to meet the acceptable criteria in 10 CFR 50.46 during a loss of coolant accident (LOCA). Sequoyah Final Safety Analysis Report (FSAR), Section 15.4.1 discussed the analysis of the LOCA showing that a loss of function (LOF) of the ECCS would not occur.
The 3rd paragraph on Page 15.4-2 of FSAR Section 15.4.1 indicates for the LOCA case with the worst single-failure considered that:
The analysis assumes that one charging pump, one safety injection pump, one RHR pump and two containment spray pumps are operating. At Sequoyah, the major components of each ECCS train consists of one charging pump, one safety injection pump, one RHR pump. Page B 3.5.2-2 of the Sequoyah TS Bases 3.5.2 clarifies that each ECCS train is capable of suppling 100 % of the flow required to mitigate the LOCA consequences.
The licensee proposed to apply the risk-informed competition time (RICT) program to TS 3.5.2 Condition A that allows one or more required ECCS trains inoperable. Since the TS LCO 3.5.2 requires two ECCS to be operable, Condition A would result in no required ECCS operable, which is less than one ECCS assumed in the LOCA analysis. Therefore, a LOCA with no required ECCS operable (allowed by Condition A) would not be bounded by the case in FSAR, Section 15.4.1.
The NRC-approved NEI-06-09 provides guidelines for application of the RICT program.
Specifically, Condition 3 in the NRC safety evaluation approving NEI-06-09 (ML12286A322) imposes a restriction that when a LOF of specific safety function for the affected TS system occurs, the Risk Management TS cannot be applied.
Provide information of an adequate LOCA analysis for conditions discussed above to show that no required ECCS operable would not result in an LOF for mitigating the LOCA, when applying the RICT program to TS 3.5.2 Condition A.