ML21252A005
| ML21252A005 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/20/2021 |
| From: | Thomas Wengert NRC/NRR/DORL/LPL4 |
| To: | Keele R Entergy Operations |
| Wengert T | |
| References | |
| L-2021-LLA-0015 | |
| Download: ML21252A005 (9) | |
Text
From:
Wengert, Thomas Sent:
Friday, August 20, 2021 3:17 PM To:
Keele Jr, Riley D Cc:
Clark, Robert; REID, MARK; Dixon-Herrity, Jennifer
Subject:
ANO-1 and 2 Final RAI RE: License Amendment Request to Allow the ECP to Remain Operable On a One-Time Basis for Up to 65 days to Perform Piping Upgrade (L-2021-LLA-0015)
Attachments:
ANO - Final RAI RE Emergency Cooling Pond TS LAR.pdf On August 9, 2021, the U.S. Nuclear Regulatory Commission (NRC) staff sent Entergy Operations, Inc. (the licensee) the draft Request for Additional Information (RAI) identified below. This RAI relates to the one-time license amendment request that would allow the emergency cooling pond (ECP) to remain operable on a one-time basis for up to 65 days to perform proactive upgrades to the ECP supply piping for Arkansas Nuclear One, Units 1 and 2.
On August 18, 2021, the NRC staff held a conference call with the licensee staff to clarify this request. During the call, the licensee requested additional clarification of RAI EMIB-1. Following discussion, the NRC staff agreed to revise this RAI for clarify. Subsequently, the licensee agreed to provide a response to this RAI within 30 days of this correspondence. A publicly available version of this final RAI (attached with Draft removed and RAI EMIB-1 revised) will be placed in the NRCs Agencywide Documents Access and Management System (ADAMS).
From: Wengert, Thomas Sent: Monday, August 09, 2021 11:19 AM To: Keele Jr, Riley D <rkeele@entergy.com>
Cc: Clark, Robert <RCLARK@entergy.com>; REID, MARK <mreid1@entergy.com>; Dixon-Herrity, Jennifer
<Jennifer.Dixon-Herrity@nrc.gov>
Subject:
ANO-1 and 2 Draft RAI RE: One-Time License Amendment Requests to Allow the ECP to Remain Operable On a One-Time Basis for Up to 65 days to Perform Piping Upgrade (L-2021-LLA-0015)
By letter dated February 8, 2021 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21039A756), Entergy Operations, Inc. (Entergy) requested license amendments for Arkansas Nuclear One, Unit 1 and Unit 2 (ANO-1 and ANO-2) concerning Emergency Cooling Pond (ECP) Technical Specifications (TSs) ANO-1 TS 3.7.8 and ANO-2 TS 3.7.4.1. The proposed amendments would allow the ECP to remain operable on a one-time basis for up to 65 days to perform proactive upgrades to the ECP supply piping. In its letter dated February 8, 2021, the licensee stated that this change would allow Entergy the time to perform upgrades on piping from the ECP to the Service Water System intake bays prior to a spring outage for each unit.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the application and, as described in the attached request for additional information (RAI), is required for the staff to complete its review of this application. This RAI is identified as draft at this time to confirm your understanding of the information that the NRC staff needs to complete the evaluation. If the request for information is understood, please respond to this RAI within 30 days of the date of this request.
Please contact me if you would like to set up a conference call with the NRC staff to clarify this request for information.
Tom Wengert Project Manager - Arkansas Nuclear One NRR/DORL/LPL4 (301) 415-4037
Hearing Identifier:
NRR_DRMA Email Number:
1323 Mail Envelope Properties (MN2PR09MB5449A6B2FE2FAB8A15FC5D878FC19)
Subject:
ANO-1 and 2 Final RAI RE: License Amendment Request to Allow the ECP to Remain Operable On a One-Time Basis for Up to 65 days to Perform Piping Upgrade (L-2021-LLA-0015)
Sent Date:
8/20/2021 3:16:36 PM Received Date:
8/20/2021 3:16:00 PM From:
Wengert, Thomas Created By:
Thomas.Wengert@nrc.gov Recipients:
"Clark, Robert" <RCLARK@entergy.com>
Tracking Status: None "REID, MARK" <mreid1@entergy.com>
Tracking Status: None "Dixon-Herrity, Jennifer" <Jennifer.Dixon-Herrity@nrc.gov>
Tracking Status: None "Keele Jr, Riley D" <rkeele@entergy.com>
Tracking Status: None Post Office:
MN2PR09MB5449.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 2895 8/20/2021 3:16:00 PM ANO - Final RAI RE Emergency Cooling Pond TS LAR.pdf 203995 Options Priority:
Normal Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
REQUEST FOR ADDITIONAL INFORMATION CONCERNING PROPOSED ONE-TIME LICENSE AMENDMENTS TO ALLOW THE EMERGENCY COOLING POND (ECP) TO BE OPERABLE FOR UP TO 65 DAYS TO PERFORM PIPING UPGRADES TO ECP SUPPLY PIPING ARKANSAS NUCLEAR ONE, UNITS 1 AND 2 DOCKET NOS. 50-313 AND 50-368 By letter dated February 8, 2021 (Agencywide Documents Access and Management System Accession No. ML21039A756), Entergy Operations, Inc. (Entergy, the licensee) requested license amendments for Arkansas Nuclear One, Unit 1 and Unit 2 (ANO-1 and ANO-2) concerning Emergency Cooling Pond (ECP) Technical Specifications (TSs) ANO-1 TS 3.7.8 and ANO-2 TS 3.7.4.1. The proposed amendments would allow the ECP to remain operable on a one-time basis for up to 65 days to perform proactive upgrades to the ECP supply piping. In its letter dated February 8, 2021, the licensee stated that this change would allow Entergy the time to perform upgrades on piping from the ECP to the Service Water System (SWS) intake bays prior to a spring outage for each unit. The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the application and has determined that additional information is needed to complete its review, as described below.
Regulatory Basis Title 10 of the Code of Federal Regulations (10 CFR) 50.36, Technical Specifications, requires, in part, that the operating license of a nuclear production facility include TSs. The regulations in 10 CFR 50.36(c)(2) require, in part, that the TSs include limiting conditions for operation (LCOs), which are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When an LCO for a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the TSs, until the condition can be met.
ANO-1 and ANO-2 are not licensed to 10 CFR 50, Appendix A, General Design Criteria (GDC) for Nuclear Power Plants. Both plants were originally designed to comply with the Proposed General Design Criteria for Nuclear Power Plant Construction Permits, published in July 1967.
The ANO-1 and ANO-2 Safety Analysis Reports provide comparisons with the Atomic Energy Commission GDC published as Appendix A to 10 CFR 50 in 1971.
The following GDCs are applicable:
GDC-5, Shared Structures, Systems, and Components (SCCs) and GDC-44, Cooling Water.
Entergy provided a detailed discussion of GDC-5 and GDC-44 in Section 4.1, Applicable Regulatory Requirements/Criteria in the LAR.
The NRC staff used the following guidance to evaluate the LAR:
NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition, Chapter 18, Revision 3, Human Factors Engineering, provides
the NRC staffs guidance for the review important actions and human performance for applicants.
NUREG-1764, Guidance for the Review of Changes to Human Actions, Revision 1, issued September 2007 (ADAMS Accession No. ML072640413), is used by the NRC staff to risk-inform the review of changes to manual actions.
Regulatory Guide 1.174, An Approach to Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, Revision 3, issued January 2018 (ADAMS Accession No. ML17317A256), describes an approach that is acceptable to the NRC staff for developing risk-informed applications for a licensing basis change that considers engineering issues and applies risk insights.
Request for Additional Information (RAI)
RAI STSB-1 Page 7 of the enclosure to the license amendment request (LAR) states, in part:
In accordance with the LCO Note, the temporary pumping system may be removed from service for testing or to support any necessary maintenance provided its availability can be restored within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, consistent with the TS allowed time to restore an inoperable [Service Water System] SWS loop.
The NRC staff understands that the statement consistent with the TS allowed time to restore an inoperable SWS loop refers to the 72-hour Completion Time for one SWS loop inoperable per ANO-1 TS 3.7.7 and ANO-2 TS 3/4.7.3. Please confirm that this understanding is correct.
RAI STSB-2 Pages 7 and 8 of the enclosure to the LAR lists several compensatory measures/actions that the licensee will maintain during the 65-day ECP piping upgrade.
Describe how these compensatory measures will be implemented. In addition, identify any safety-related equipment or functions that would be affected by the compensatory measures and how such safety-related equipment would be addressed.
RAI STSB-3 Regarding specific compensatory measures:
- a. The fourth bullet on Page 7 of the LAR enclosure states:
The temporary pump system will be started to ensure its continued availability on a weekly basis.
Describe how this weekly testing will be proceduralized and documented.
- b. The third bullet on Page 8 of the LAR enclosure states:
The SWS pumps, bays, traveling screens, and sluice gates that are important for ensuring cooling water is provided to the supported SSCs will be given protected train status.
Please list/describe the specific steps involved in ensuring protected train status.
- c. The last bullet states:
The ECP level will be maintained (greater than or equal to) 5.5 ft during the 65-day preventative maintenance window.
Briefly describe how the ECP level will be maintained during the preventive maintenance window.
RAI STSB-4 Page 8 of the enclosure to the LAR states, in part (emphasis added):
The first three items above are performed prior to initial entry into the 65-day ECP piping upgrade window. Because unforeseen circumstances could arise that may temporarily prevent meeting one of the other ongoing commitments during the maintenance window, Entergy intends to consider the ECP to remain operable in such an event provided action is taken to restore the commitment without delay.
This is considered reasonable since failure to meet one or more ongoing commitments does not immediately render the temporary ECP pumping system unavailable. The markup of the respective TS Bases included in Attachment 2 of this enclosure provides the Operator guidance necessary to properly apply the proposed LCO Note.
The following are associated with the items shown in bold text above:
- a. Please provide or refer to specific actions in ensuring the operability of the ECP.
- b. Please specify the delay time or explain the term delay?
RAI STSB-5 (Ref. Page 8 of 26 of the enclosure)
A statement in the first paragraph of Plant Operation with Application of the LCO Note states, in part:
The temporary ECP pumping system will be capable of supplying the SWS with the necessary flow to facilitate a normal plant shutdown or a shutdown during accident conditions.
Discuss how the use of a temporary nonsafety-related system will ensure the necessary flow to facilitate a normal plant shutdown or a shutdown during accident conditions.
RAI STSB-6 The proposed TS NOTE is added at the top of ANO-1 TS LCO 3.7.8, page 3.7.8-1, whereas same proposed NOTE is added on ANO-2 TS LCO 3/4 7-16 (pdf page 34) after the TS surveillance (4.7.4.1). Please explain the proposed TS formatting.
RAI STSB-7 The proposed TS NOTE states:
The ECP may be considered OPERABLE on a one-time basis for up to 65 days during upgrade of the ECP supply piping to the SWS intake bays provided:
- a. A loss of Lake Dardanelle event is not in progress, and
The temporary pumping system may be unavailable for testing or necessary maintenance provided its availability is restored within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
In the enclosure to the LAR, the licensee provided an evaluation of the proposed changes.
Section 3.2, Justification, of the enclosure contains a list of compensatory measures the licensee will implement in support of the temporary ECP pumping system. The licensee stated that these are considered regulatory commitments and will be maintained during the 65-day ECP piping upgrade. The regulatory commitments are identified in Attachment 4 of the enclosure to the LAR. The licensee further stated that these commitments will expire at the end of the 65-day preventative maintenance window. It appears that part of the justification for the proposed 65-day operability of the ECP in support of the upgrade of the ECP piping supply to the SWS intake bays relies on the compensatory measures identified in Section 3.2 of the enclosure.
Provide justification for the proposed 65-day operability that does not mention the compensatory measures. Alternatively, consider rewording the proposed TS NOTE language to indicate that the 65-day operability is contingent on implementation of the compensatory measures identified in Section 3.2 of enclosure to the LAR.
RAI DRA-1 In the LAR, the licensee states that Regulatory Guides (RGs) 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to The Licensing Basis, and 1.177, Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications, were used to develop the application.
In RG 1.174, the NRC staff describes five Key Principles of risk-informed decision making. The guidance in Section C.2.2.1 of RG 1.177 indicates that consideration of compensatory measures is part of ensuring that the defense-in-depth philosophy is maintained. This is part of Key Principle 2. The guidance in Section C.2.3.6 of RG 1.177 states that when compensatory measures are part of the analysis of a Technical Specification change, those measures should be included in the application.
On page 8/26 of the enclosure to the LAR, the following ANO-2 compensatory measure is identified:
During the ANO-2 ECP piping upgrade, equipment will be staged near each ECP pipe opening to allow pipe closure, within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, when external flooding is projected to exceed 350 [feet mean sea level] ft MSL.
It is unclear to the NRC staff whether there is or should be a corresponding ANO-1 action.
Therefore, provide the following:
- a. Clarify whether there is a corresponding ANO-1 measure
- b. If there is, provide similar detail for the ANO-1 measure
- c. If there is not a corresponding ANO-1 measure, explain why this measure is indicated for ANO-2, but not for ANO-1.
RAI EMIB-1 In Section 3.2, Justification of the LAR, the licensee stated that a temporary ECP diesel-driven pumping system will be utilized as a compensatory measure in the highly unlikely event the preferred ultimate heat sink source (i.e., Dardanelle Reservoir) is lost or becomes temporarily unavailable during the proactive upgrade of the ECP supply piping. In addition, the licensee stated that proper SWS bay level will be maintained by the pump using a mechanical float control valve to regulate flow from the temporary ECP pump.
The licensee also stated that prior to removing the installed ECP supply piping from service, the temporary pump will be tested, and minimum flow requirements verified.
However, based on the information provided in the LAR, it is not clear to the NRC staff how sufficient minimum flow requirements would be determined. Please describe how the minimum system flow requirements would be determined and why they would be sufficient to support the intended safety function of the ECP temporary pumping system.
RAI EMIB-2 In Section 3.2 of the LAR, the licensee stated that an adequate fuel supply will be maintained to supply the temporary pump for approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of continuous operation. Provide the basis for the fuel storage requirement of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of continuous pump operation. The response should define the expected mission time and, if greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, how the fuel supply would be replenished. In addition, please clarify whether there will be a fuel refilling procedure in place.
RAI IOLB-1 In Section 3.0, Technical Evaluation, of the LAR, Entergy stated the following, in part:
Existing procedures direct Operators to transfer the suction of the SWS pumps from the reservoir to the ECP if bay level drops below 333 ft MSL. This is accomplished by first initiating manual closure of the Dardanelle Reservoir sluice gate and then opening the ECP supply sluice gate once level in the SWS bay starts to drop. This sequence minimizes ECP inventory loss to the lake. The same sequence would be followed when the temporary system is in place but rather than opening the ECP sluice gate, the temporary pump would be started since the pump discharges directly into the respective SWS pump bay.
Based on Entergys statements, the NRC staff understands that the manual operator actions do not change. However, the location (i.e., intake building) where the operator takes these actions and where (i.e., temporary pumping system) does change.
Existing procedures allow for minimal disruptions because the operator is familiar with the actions they must take and there is confidence that the operators can complete these actions within the time available. However, it is not clear to the NRC staff that the temporary system described by Entergy is similar enough to the current system such that the existing ANO procedures would be applicable.
Please confirm that the existing procedures contain the necessary information so that the operator(s) will be able to use the existing procedures on the temporary system instead of relying on temporary procedures.
RAI IOLB-2a In the letter dated February 8, 2021, Section 3.2, Justification, subsection, Intake Building Considerations, Entergy stated the following, in part:
During installation and use of the temporary ECP piping, one or both of the SWS intake building access doors will be removed to allow routing the temporary ECP pipe into the SWS bays. Temporary security measures will be in place to limit access to the building. Temporary closure of the door opening will be provided, when needed, to maintain ambient temperatures inside the Intake Building during extreme cold weather conditions.
Please provide additional information on the training and/or procedures that would be available to the operators to determine when the door opening must be temporarily closed and how.
RAI IOLB-2b With respect to routing the temporary ECP pipe in the SWS bays via the SWS intake building access doors, please discuss, as applicable, any impediments that Entergy has considered and the resolution to those considerations.