ML24198A072
| ML24198A072 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/21/2024 |
| From: | Mahesh Chawla NRC/NRR/DORL/LPL4 |
| To: | Entergy Operations |
| Chawla M, NRR/DORL/LPL4 | |
| References | |
| EPID L-2023-LLA-0052 | |
| Download: ML24198A072 (1) | |
Text
August 21, 2024 ANO Site Vice President Arkansas Nuclear One Entergy Operations, Inc.
N-TSB-58 1448 S.R. 333 Russellville, AR 72802
SUBJECT:
ARKANSAS NUCLEAR ONE, UNIT 2 - CORRECTION TO ISSUANCE OF AMENDMENT NO. 333 RE: REVISION TO TECHNICAL SPECIFICATIONS TO ADOPT TSTF-505, REVISION 2, PROVIDE RISK-INFORMED EXTENDED COMPLETION TIMES - RITSTF INITIATIVE 4b (EPID L-2023-LLA-0052)
Dear Site Vice President:
By letter dated June 25, 2024 (Agencywide Documents Access and Management System Accession (ADAMS) Accession No. ML24101A179), the U.S. Nuclear Regulatory Commission (NRC) issued Amendment No. 333 to Renewed Facility Operating License No. NPF-6 for Arkansas Nuclear One, Unit 2 (ANO-2). The amendment consisted of changes to the technical specifications (TSs) in response to your application dated April 5, 2023 (ML23095A281), as supplemented by letters dated January 11, 2024 (ML24011A293), and April 24, 2024 (ML24115A246). Specifically, the amendment revised the ANO-2 TSs to adopt Technical Specifications Task Force (TSTF) Traveler TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF [Risk-Informed TSTF] Initiative 4b, to permit the use of risk-informed completion times for actions to be taken when limiting conditions for operation are not met.
Following issuance of Amendment No. 333, an error was found in the associated safety evaluation (SE). Entergy Operations, Inc. (the licensee) informed the NRC staff that in section 3.2.2, on page 7 of the SE, the NRC states, in part:
ANO-2 SAR section 8.3.1.1.3, states that AC offsite power connects to the Class 1E onsite power system through 4.16 kV SU 1 with SU 2 being an alternate offsite power source,.
In this sentence, the startup transformer SU 1 is incorrect and should be SU 3 because SU 1 is the startup transformer for Arkansas Nuclear One, Unit 1. This was correctly stated in the preceding paragraph in the SE. As shown below, this sentence should be modified as follows:
ANO-2 SAR section 8.3.1.1.3, states that AC offsite power connects to the Class 1E onsite power system through 4.16 kV SU 3 with SU 2 being an alternate offsite power source.
The NRC staff determined that this error was inadvertently introduced during the preparation of the license amendment and is administrative in nature. This administrative error does not affect the NRC staffs overall conclusions associated with the approval of Amendment No. 333 and does not affect the associated notice to the public.
The enclosure to this letter contains the corrected version of page 7 of the SE. The revised page contains a marginal line indicating the area of change. Please replace the corresponding page issued by Amendment No. 333 for ANO-2.
We regret any inconvenience this may have caused. If you have any questions, please contact me at 301-415-8371 or via email at Mahesh.Chawla@nrc.gov.
Sincerely,
/RA/
Mahesh L. Chawla, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-368
Enclosure:
Correction to SE page 7 of Amendment No. 333 for ANO-2 cc: Listserv
ENCLOSURE CORRECTION TO PAGE 7 OF THE SAFETY EVALUATION TO AMENDMENT NO. 333 ENTERGY OPERATIONS, INC.
ARKANSAS NUCLEAR ONE, UNIT 2 DOCKET NO. 50-313 TS 3.8.2, AC Distribution - Operating TS 3.8.2.3, DC [Direct Current] Sources - Operating; Condition b For the TS LCOs specific to I&C (i.e., TS 3.3, Instrumentation, specifically: TSs 3.3.1 and 3.3.2), the NRC staff reviewed the specific trip logic arrangements, redundancy, backup systems, manual actions, and diverse trips specified for each of the protective safety functions and associated instrumentation, as described in the associated safety analysis report (SAR)
(Reference 20) sections, and as reflected in the LAR, as supplemented. The staff verified that, in accordance with the ANO-2 SAR Amendment 30 and equipment and actions credited in enclosure 1 to the LAR, as supplemented, in all applicable operating modes, the affected protective feature would perform its intended function by ensuring the ability to detect and mitigate the associated event or accident when the CT of a channel is extended. Furthermore, the staff concludes that there is sufficient redundancy, diversity, and defense-in-depth, to protect against CCFs and potential single failure for the ANO-2 instrumentation systems evaluated in LAR enclosure 1, as supplemented, during a RICT. There is at least one diverse means specified by the licensee for initiating mitigating action for each accident event, thus providing defense-in-depth against a failure of instrumentation during the RICT for each TS LCO. The staff confirmed that the defense in depth specified by the licensee does not overly rely on manual actions as the diverse means; therefore, there is not over-reliance of programmatic activities as compensatory measures. Therefore, the staff finds that the intent of the plants design criteria (e.g., safety functions) for the above TS LCOs related to I&C are maintained.
ANO-2 SAR section 8.3.1.1.2, Unit Auxiliary Transformer, Startup Transformers and 6900-Volt Systems, states that AC offsite power connects to the Class 1E onsite power system through 4.16 kilovolt (kV) startup transformer (SU) 3 with SU 2 being an alternate offsite power source, specifically associated with proposed changes to TS LCO 3.8.1, Conditions a, c, and d, and TS LCO 3.8.2.1, concerning offsite power. SAR sections 8.3.1.1.3, 4,160-volt Auxiliary System, and 8.3.1.1.8.6, Redundant Bus Separation, states the Class 1E onsite power system consists of two engineered safety features (ESF), redundant 4,160-volt buses, each backed by its diesel generator (DG) (specifically associated with proposed changes to TS LCO 3.8.1, Condition b and TS LCO 3.8.2.1, concerning DGs).
ANO-2 SAR section 8.3.1.1.3, states that AC offsite power connects to the Class 1E onsite power system through 4.16 kV SU 3 with SU 2 being an alternate offsite power source, which is applicable to the proposed changes to STS 3.8.1, Conditions a, c, and d and STS 3.8.9, Condition a concerning offsite power. The Class 1E onsite power system consists of two fully redundant buses (one bus per train), which are backed by DGs for safe shutdown. This is applicable to proposed changes to STS 3.8.1, Conditions b and d, and STS 3.8.9, Condition a, for the onsite power system and its AC sources. SAR section 8.3.2.1.3, DC Control Centers, also states that the 125 volt (V) DC system consists of two redundant DC buses with only one required for its safe shutdown. This is applicable to the proposed change to STS 3.8.4, Condition a, and STS 3.8.9, Condition c concerning the 125 V DC system. SAR section 8.3.1.1.6, 120-Volt Uninterruptable AC Power System, shows that the 120 VAC (volt alternating current] Vital AC system has four redundant distribution panels (two per train) with each panel supplied by one inverter, but only two inverters associated with one train are required for safe shutdown. This is applicable to the proposed changes to STS 3.8.7, Condition and STS 3.8.9, Condition b.
SAR section 8.3.2, DC Power Systems, states that the Class 1E 125 V DC system consists of two independent, physically and electrically separated 125 V batteries (one battery and two battery chargers (one normally operating and one spare per train)) with only one train required
- concurrence via email NRR-106 OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA*
NRR/DEX/EEEB/BC*
NAME MChawla PBlechman WMorton DATE 7/18/2024 7/17/2024 8/7/2024 OFFICE NRR/DORL/LPL4/BC*
NRR/DORL/LPL4/PM*
NAME JRankin MChawla DATE 8/19/2024 8/21/2024